HFA-PFC Systems for Tactical Mobile Electric Power Systems

Transcription

1 ATIZFR-95/0010 HFA-PFC Systems fr Tatial Mbile Eletri Pwer Systems Mark BQadky Axim Tehnlgy Internatinal Crpratin 1995 CEM Belvir RD&E Center DISTRIBUTIN STATEMENT A Apprved fr Publi Release Distributin Unlimited,«*,«* 0EB QUALITY INSPECTED 4

2 ATI/FR-95/0010 HFA-PFC Systems fr Tatial Mbile Eletri Pwer Systems Prepared by Mark Hladky Axim Tehnlgy Internatinal Crpratin 1501 Rbert J Cnlan Blvd. Suite Palm Bay, Flrida September 1995 Cntrat DAAB12-95-C-0010 Prepared fr CEM Belvir RD&E Center Night Visin & Eletrni Sensr Diretrate Frt Belvir, VA 22060

3 REPRT DCUMENTATIN PAGE Frm Apprved MB N Pubt ripr^ butf «n lr nl< Uttln et Wmulian U ufaultd t wtra* 1 hm nuinuin^ir«d4unttd(4.indn^«lk<gtndnvl«^taetetanlhmmln. S«ndmn»rtrK»n^»^bi«tMJm»l«f»meth«f»»p^(l^e«)fn(Wmu8^ lndu1i^iuw«it^lwr»du(ngw»buf^twuhlngl» VA W02. >nd t th«hi el Min»g«m«nt ind Budget. PtpwrH BtduMn Pr»t ( M). WuHngtn, DC AGENCY USE NLY (Leave B/anA) 2. REPRT DATE 14SEP95 4. TITLE AND SUBTITLE HFA-PFC Systems fr Tatial Mbile Eletri Pwer Systems. 6. AUTHR(S) Mark Hladky. REPRT TYPE AND DATES VERED Final Reprt 15MAR9S-15SEP95 5. FUNDING NUMBERS - DAAB12-95-C PERFRMING RGANIZATIN NAME(S) AND ADDRESS(ES) Axim Tehnlgy Internatinal Crpratin 1501 Rbert J. Cnlan. Blvd., Suite Palm Bay, FL PERFRMING RGANIZATIN REPRT NUMBER ATI/FR-95/ SPNSRING/MNITRING AGENCY NAME(S) AND ADDRESS(ES) CEM - Belvir RD&E Center Night Visin & Eletrni Sensr Diretrate Frt Belvir, VA SPNSRING/MNITRING AGENCY REPRT NUMBER 11. SUPPLEMENTARY NTES Final Submissin 12a. DISTRIBUTIN/AVAILABILITY STATEMENT 12b. DISTRIBUTIN DE Apprved fr Publi Release; Distributin Unlimited 1. ABSTRACT (Max/mum 200 wrds) Tatial Mbile Eletri Pwer Systems have the ptential fr signifiant weight savings. An average derease f 87.2% may be ahieved thrugh the use f a high frequeny alternatr - pwer frequeny nverter mbinatin, when mpared t the standard 1800 rpm fixed speed 60 Hz generatr. A ptential 48.6% derease is pssible when nsidering the mplete engine generatr set. A gearbx prvides the neessary speed inrease fr high speed/high frequeny peratin. This als prvides an il management system fr ling equipment and ultimately prviding a higher pwer density system. Integratin f additinal funtins, suh as a starter generatr, prvides fr added weight savings. The apprah may be extended t a mdular system nept t redue the number f unique system mpnents, and ammdate grwth requirements. Additinal new features suh as variable speed peratin f the engine may be integrated t redue the average fuel nsumptin, austi emissins and IR emissins when perating-at less then full lad. This will assist in imprving engine life span, and ptentially reduing sheduled maintenane. 14. SUBJECT TERMS Generatr, High Frequeny Alternatr, Pwer Frequeny Cnverter, Inverter 15. NUMBER F PAGES PRICE DE 17. SECURITY CLASSIFICATIN F REPRT Unlassified NSN 7S SECURITY CLASSIFICATIN F THIS PAGE. Unlassified REF9 19. SECURITY CLASSIFICATIN F ABSTRACT Unlassified 20. LIMITATIN F ABSTRACT UL Standard Frm 298 (Rav. 2-49) PlwtMd ky ANSI M. ZU-II att-ti

4 Table f Cntents 1. Summary 2. Intrdutin 2.1. Tatial Pwer Generatin Bakgrund 2.2. Prjet Purpse 2.. Prjet Spe 2.4. Reprt rganizatin.. Methds, Assumptins, andpredures_.1. Apprah :.2. Assumptins... Predures 4. Results and Disussin 4.1. Requirements Definitin 4.2. HFA-PFC System 4.. PFC Tplgy ptimizatin_ 4.4. HFA Apprah ptimizatin 4.5. Engine peratin Review 4.6. Pwer Semindutr Seletin 4.7. Cling and Pakaging 5. Cnlusins. 6. Remmendatins 7. Referenes 8. Distributin List _i _2 _2 4 _4 _5 _5 _7 _ _81 _82 _8 84 APPENDICES Appendix A Standard Family Speifiatins Appendix B HFA-PFC System Arhiteture Blk Diagrams Appendix C PFC Funtinal Blk Diagrams. Appendix D PFC Pwer Swith perating Charateristis Appendix E PSPICE Ciruit Simulatin Results Appendix F Pwer Semindutr Infrmatin. A-l B-l -i D-l JE-1 F-l

5 List f Figures Figure 1. Standard Vltage Cnnetin Requirements Figure 2. Maximum allwable Engine Generatr Set Weights Figure. General HFA-PFC System Blk Diagram. Figure 4. ptimized Rennetin Capability fr Mdular Apprah Figure 5. Pwer Frequeny Cnverter Blk Diagram Figure 6. Fundamental Three Phase Inverter Bridge Figure 7. Permanent Magnet Mahine Funtinal Diagram. _ Figure 8. Cmpnents f a Variable Relutane Mahine. Figure 9. Swithed Relutane Mahine Funtinal Diagram. Figure 10. Cntrl and Exitatin Ciruits fr SRM Tehnlgy Figure 11. SRM Mtr Exitatin Phase Current Simulatin Figure 12. Wund Rtr Brushless DC Mahine Blk Diagram : Figure 1. Generatr Pwer Density Grwth. : Figure 14. Speed Inreaser/Gearbx Prviding Dual Munting fr Mdular HFA-PFC System Figure 15. 1J. Simplified tmjjujuu il %-rn Shemati ukr«»»»*- Figure 16. Triple HFA Mdule Munting Cnfiguratin fr Speed Inreaser/Gearbx _ Figure 17. Right Angle Gearbx ptin. _ Figure 18. Pwer Semindutr Tehnlgy Timeline. Figure 19. PFC Installatin Tray Cnept. 11 J J 5 J 27 _7 _5 56 J7 _60 Jl _68 J59 J _7 78 List f Tables Table 1. Eletrial Perfrmane Charateristis, AC _ Table 2. Eletrial Perfrmane Charateristis, DC ; 10 Table. Generatr Set Derating fr Altitude and Temperature Table 4. Estimated Pwer Densities _ Table 5. ptimum HFA-PFC System Arhitetures and Features fr Varius Pwer Ranges 18 Table 6. HFA-PFC System Weight Preditins Summary J 4 _5 6 Table 7. HFA-PFC System Arhiteture Trade-ff Table Table 8. ptimum PFC Tplgies fr Appliatin Table 9. 0 PFC Tplgy Trade-ffTable Table PFC Tplgy Trade-ffTable Table 11. General PFC Tplgy Trade-ffs Table 12. DC PFC Tplgy Trade-ffs Table 1. Six - Bridge Cnverter utput THD Table 14. N Lad utput %THDfr Varius utput Bridge Cnfiguratins_ Table 15. HFA Tehnlgy Appliatin Table 16. HFA Tehnlgy Trade-ff. Table 17. Mahine Attributes vs. Tehnlgy Table 18. Eletrial Fault Cnditins vs. Mahine Tehnlgy _ Table 19. ptimum Engine Interfae Cnfiguratins Table 20. Engine Interfae Tehnlgy Trade-ff _ Table 21. Pwer Semindutr Appliatin Matrix Table 22. Pwer Semindutr Tehnlgy Cmparisn_ Table 2. ptimum Cling and Pakaging Arrangements J _4 J 5 50 Jl _ _72 79

6 List f Symbls, Abbreviatins, and Arnyms A AC ACU APU BIT BLDC DC DD EMC emf EMI EP HFA IGBT IR khz kw lb(s) MCT MIES MEPS MSL NPS Amperes Alternating Current Alternatr Cntrl Unit Auxiliary Pwer Unit Built-in Test Brushless DC (Mahine) Diret Current Department f Defense Eletrmagneti Cmpatibility Eletrmtive fre. Eletrmagneti Interferene External Pwer High Frequeny Alternatr Insulated Gate Biplar Transistr Infrared Kilhertz Kilwatt Pund(s) Ms-Cntrlled Thyristr Mdem Imagery Explitatin System Mbile Eletri Pwer Sure Mean Sea Level Nninterruptible Pwer Sure pf Pwer Fatr PFC Pwer Frequeny Cnverter PM Permanent Magnet PM BLDC Permanent Magnet Brushless DC PMG Permanent Magnet* Generatr RMS Rt Mean Square rprn Revlutins Per Minute SCR Silin Cntrlled Retifier SA Safe perating Area SRM Swithed Relutane Mahine THD Ttal Harmni Distrtin UPS Uninterruptible Pwer Sure V Vlt VA Vlt-Ampere VRM Variable Relutane Mahine VSCF Variable Speed Cnstant Frequeny VSTL Very Shrt Take-ff and Landing VTL Vertial Take-ff and Landing W Watt XFMR Transfrmer ill

7 1. SUMMARY Appliatin f a High Frequeny Alternatr - Pwer Frequeny Cnverter (HFA-PFC) System an substantially redue Tatial Mbile Eletri Pwer Sure weight and size. An 87.2% average weight redutin is antiipated ver the existing eletri generatrs in the 5 t 1000 kw pwer levels. A 46.6% average weight redutin is pssible fr the engine generatr sets ver the same pwer level range. The engine generatr set may arue an additinal weight savings f apprximately 2% when using an integrated starter generatr apprah. These, estimates are inlusive f all equipment neessary t perate the HFA-PFC System. These results warrant further explratin f the nepts thrugh prttype hardware design, develpment, and demnstratin. The majrity f weight savings is attributed t the use f a high frequeny alternatr. Nminal perating frequenies as high as 2 khz are ahievable by inreasing the generatr base speed with a gearbx. Mahine tehnlgy inluding swithed relutane, wund rtr brushless DC, and permanent magnet allw the design f high pwer density generatrs. An il management system is integrated with the gearbx t prvide lubriatin fr the gearbx and HFA bearings, and ling fr the gearbx, HFA and PFC. perating frequenies abve this range start t exhibit diminishing returns due t inreased mahine lsses. The PFC may intrinsially prvide many funtins with little r n hardware mdifiatins. A time limited uninterruptible pwer supply arhiteture is pssible and essentially inherent when a starter generatr nfiguratin is used. The PFC may be used as a lal pwer nditiner, perating ff a freign utility grid The engine and HFA wuld beme a bakup sure f pwer in the event f the grid failure. The wrk perfrmed during this effrt is appliable t unique designs fr eah pwer level r t a mdular system apprah. A mdular apprah will ammdate different funtinal ptins, and the appliatin f standard equipment designs t a range f pwer levels. The weight analysis is based upn the mdular nept. There is apprximately a 15% penalty in HFA-PFC System weight t implement the mdular apprah. This is assiated with less then a 1.% impat when nsidering the engine generatr set as a whle. Variable speed peratin f the engine and HFA will prvide inreased engine and HFA life expetany, redue fuel nsumptin, and redue austi and IR signatures f the equipment. Ptential inreases in sheduled servie intervals may be experiened whih will ntribute t lwer life yle sts. Future tehnlgies may easily be integrated with an HFA-PFC apprah as they mature. This is due t the mdular arhiteture f the system, and being able t evlve nly affeted prtins f the design. New pwer semindutr tehnlgy suh as silin arbide will imprve PFC effiieny and will inrease thermal design margins n the mpnent appliatin. Smart pwer systems may eventually prvide lad sheduling and missin renfiguratin fr autmated peratin. The wrk perfrmed under this prjet addressed reduing size and weight f mbile tatial engine generatr sets t imprve mbility and deplyability. Mbility will be imprved thrugh a diret weight redutin f the equipment being twed r transprted. Deplyability will be imprved thrugh lwer paylads and smaller size allwing faster and larger deplyment with arg airraft transprt. Pwer levels frm 0.5 t 1000 kw were addressed in this prjet. The wrk mprised all required mpnents frm the engine interfae t the eletrial utput terminals f the engine generatr set. Supprt f the existing equipment infrastruture was integrated int the verall analysis.

8 2. INTRDUCTIN 2.1. TACTICAL PWER GENERATIN BACKGRUND Advaned eletrial pwer generatin tehniques are required t supprt a new Army gal f highly dynami nflits. As the battle theater definitin evlves t inlude "sht and st" senaris, supprt equipment must embrae the new requirements and speifiatins. A high degree f mbility and deplyability is required fr using pwer generatin equipment with new highly mbile tatial weapns systems Additinally, as the battlefield bemes "mre eletri", a grwing demand fr eletrial generatin apaity exists while imprving mbility. Inreased apability f enemy target aquisitin and fire ntrl systems has neessitated mre stringent tehnial requirements n austial emissins and infrared signatures. Traditinally this type f pwer generatin requirement has been satisfied by Tatial Pwer Generatin Sets As defined in MIL-STD-12, Tatial type inludes "generatr sets designed fr high mbility m diret supprt f military fres where utput f generatr sets is nrmally, but nt exlusively used at generated vltage Life harateristis are nsidered sendary t light weight, small size, and a high degree f mbility". Typial existing equipment inludes a 60 Hz generatr perating at 1800 rpm. This apprah restrained the eletrmagneti design f the generatrs with the mprmise f weight. The eletrmagneti design size is inversely prprtinal t its perating frequeny fr a given pwer. In a synhrnus mahine, frequeny an be diretly related t rtr r shaft speed, and the number f ple pairs. A substantial size and weight savings may be realized by perating the generatr at high speeds. In rder t amplish this, a pwer nverter is required t nditin the utput pwer f the system t a useable 60 Hz, regulated vltage. Further redutins in generatr set weight may be arued by integrating mmn funtins f the new pwer generating system and the engine. ne suh pprtunity is t eliminate the starter, and use the generatr ntrlled and pwered by the pwer nverter. ther areas fr imprvements inlude engine and generatr perating life, fuel nsumptin, austial and IR signatures. These may be addressed by a mmn fatr f reduing average engine speed The use f a high frequeny alternatr and a pwer nverter an allw the engine speed t vary dependent upn eletrial utilizatin lad. Existing generatr equipment is perated at a fixed speed independent f lad. At light and varying lads, this an redue effiieny and inrease fuel nsumptin, emit strnger signatures, and redue equipment life. The ptential weight savings will bring substantial benefits t trp mbility and deplyability. This an be signifiant when nsidering air transprt f rapid deplyment fres. Carg airraft and trp transprt are restrited by paylad apability fr basi transprt as well as perating in VTL/VSTL envirnments. Any weight savings n air arg an diretly inrease the amunt f equipment being transprted, and results in imprved mbility. Additinally, the lgistial supprt f the equipment will be redued by inreased fuel effiieny, and an be further enhaned by designing mmn standardized mdules, where spares servie several pwer levels. The high speed generatr alternative an be met with a High Frequeny Alternatr (HFA) upled with a Pwer Frequeny Cnverter (PFC). New and future develpments in high pwer eletrnis make the HFA-PFC apprah a st effetive, tehnially viable alternative fr highly mbile, tatial pwer generatin units. The variable engine speed peratin may be met by using the HFA-PFC in a Variable Speed Cnstant Frequeny (VSCF) nfiguratin. This allws the engine speed, and subsequently the generatr frequeny t vary dependent upn lad, while prduing a high quality - fixed frequeny,

9 regulated vltage utput. The advaned tehnlgies and future tehnlgy trends nw ffer alternatives t the traditinal fixed-lw speed generatrs urrently in use PRJECT PURPSE This prjet was undertaken t explre the ptential fr generatr set size and weight redutin thrugh the use f integrated pwer mpnents with mbile engine generatr sets. The primary fus is n the use f engine driven High Frequeny Alternatrs mbined with Pwer Frequeny Cnverters t prvide military standard utput pwer. 2.. PRJECT SPE The spe f the prjet is t define ptimum HFA-PFC System arhitetures, PFC tplgies, HFA tehnlgies, and identify ptimum pwer semindutr tehnlgies. The definitins are appliable t the pwer generatin range f 0.5 kw t 1000 kw. The harateristis f primary nern during evaluatin f the varius tehnlgies, arhitetures, and tplgies are: size and weight, perfrmane, and st. Perfrmane inludes funtinal apability, pwer quality, effiieny, and reliability. The prjet essentially vers frm the HFA shaft input t the PFC utput nnetins and its interfae with a nventinal internal mbustin engine prime mver. Alternative prime mvers, r ther raw pwer sures suh as a fuel ell r phtvltai array are nt inluded in this wrk. The wrk is targeted at the stand alne mbile engine generatr set - man transprtable r munted n a twable trailer. Muh f the results are diretly appliable t ther types f installatins suh as an integrated pwer unit hused in a mmand enter trailer suh as the Mdern Imagery Explitatin System (MIES), r a pwer generatin system integrated with a vehile drive engine. Limited mputer analysis was determined t have benefiial input t the results, and therefre, was inluded as part f the wrk. Cmputer simulatins were nt a requirement f this prjet. The range f tehnlgies evaluated inludes tehnlgy that is urrently available fr integratin int near term prdutin hardware, t tehnlgies that may be integrated in the future as they mature REPRT RGANIZATIN An verview f the apprah used t ndut the researh, assumptins made during the wrk, and predures fr mpleting eah majr task in the prjet are presented in setin. Setin 4 gives detailed disussins f the results fr eah majr prjet task. The material f eah subsetin in setin 4 is typially arranged in a mmn frmat: beginning with a summary f the task results, fllwed by a tabular mpilatin f alternative mparisns, then nluded with a review f the infrmatin and data lleted with respet t that task Extensive supprting data is lated in referened appendixes where appliable. The subsetin rganizatin f setin 4 fllws the frmat and shedule f the riginal prjet tasks. Setin 5 presents nlusins resulting frm the wrk tasks. Remmendatins fr ntinued wrk and areas t fus future develpment effrts are desribed in Setin 6.

10 . METHDS, ASSUMPTINS, AND PRCEDURES.1. APPRACH The verall apprah t this prjet was t evaluate a variety f advaned tehnlgy alternatives fr eletrial pwer generatin as defined by the spe f this prjet. In general, a review f the funtinal and perfrmane requirements established the baseline requirements t whih equipment must perfrm. Then addressing the requirements frm a system tp level dwn apprah, alternative tehniques were reviewed and evaluated. This apprah was amplished by subdividing the prjet int the fllwing majr tasks: 1. Requirements Definitin 2. HFA-PFC System. PFC Tplgy 4. HFA Tehnlgy 5. Engine Interfae 6. Pwer Semindutr 7. Cling and Pakaging Alternative tehnlgies in eah task were evaluated based upn mparing the fllwing primary riteria: size, weight, funtinal perfrmane, and st. While it is the primary purpse f this prjet t explre ways t redue generatr set size and weight t imprve trp mbility, it is als imprtant that these apprahes be able t supprt the existing infrastruture f utilizatin equipment. This requirement was addressed by satisfying the existing military standards and speifiatins. Fr example, the generatr set utput shuld be field rennetable fr different utput vltage nfiguratins as the immediate appliatin requires. Muh f this effrt was an iterative press. Even thugh the reprt is rganized in a partiular rder, sme infrmatin generated in later setins is fed bak int earlier setins. Ciruit simulatins were perfrmed n several tplgies reviewed under the PFC task. The purpse was t verify peratinal apability f ertain tplgies and t mpare perfrmane harateristis suh as utput harmni ntent, filter urrents, and swithing stresses f ertain tplgies. Mirsim PSPICE, versin 6.1a, based upn the University f Califrnia at Berkeley SPICE2G.6 was used t perfrm the simulatins. This is a urrent versin, released in September 1994, and is apable f mixed analg/digital iruit simulatin with an extensive library f disrete mpnents and analg behaviral mdels. The mputer mdels and simulatins used during this prjet have frmed a fundatin fr ntinued mdeling and integrated mdeling during a detailed design phase. The PSPICE sftware will allw integratin and simulatin f all system mpnents. PSPICE has the ability t mdel systems using analg behaviral mdeling tehniques whih may be mbined with disrete iruit mdeling. This apability allws the integratin f eletrni iruits and eletrmehanial systems fr mputer simulatin. The fundatin fr muh f the wrk based upn aerspae eletri mahine appliatins. These designs typially represent state-f-the-art tehnlgy sine aerspae appliatins are very nerned with weight. This apprah als prvides a gd base t evaluate future trends in tehnlgy appliatin. Spae based pwer generatin systems were nsidered and viewed as future ptential sine these are usually limited t ne f a kind installatins with a very high assiated st.

11 .2. ASSUMPTINS A general assumptin was that reasnable hanges t the engine uld be ammdated These are typially nt signifiant mdifiatins and may inlude remval f the existing DC starter, r that engines may be perated at a variable speed, et. N majr redesigns f the engines wuld be neessary t use the HFA-PFC apprah. A general guideline was used t evaluate the weight f existing generatrs sine there is suh a wide expanse f pssible engines and 60 Hz generatrs fr a given pwer level. Present mbile engine generatr sets have a weight distributin f apprximately 1/ t eah majr mpnent - the generatr, the engine and the trailer. Exluding the trailer, the engine/generatr weight distributin is apprximately equal ( 50% / 50% ) fr a set n rails. This assumptin was validated with data n several engine generatr sets where the divisin was atually 47.6% and 52.4% fr the engines and generatrs respetively. The sample dispersin was very tight having a standard deviatin f Fr the purpses f this reprt, the term Mbile Eletri Pwer Sures (MEPS) is defined t mean a engine generatr set munted n a trailer. The phrase "engine generatr set" r "generatr set" implies a prime mver r engine, and a 60 Hz generatr r a HFA-PFC System t prvide fixed 60 Hz utput. The "engine generatr set" r "generatr set" is munted n supprt rails. The differene m terminlgy is mst imprtant when evaluating weights, and is indifferent mst ther times. The definitin f pwer density fr this reprt is defined as weight per unit pwer. In mst instanes it is in punds/kilwatt (lbs/kw). This nventin was used sine muh existing data f pwer density is in this frmat... PRCEDURES The fllwing predures desribe sme f the detailed steps used in perfrming eah majr task in the prjet. The Requirements Definitin Task was used t define perfrmane and peratinal requirements fr the tatial pwer generatin equipment vering the identified pwer ranges in this study. This task nsisted f reviewing existing speifiatins inluding: MIL-STD-6E Military Standard Mbile Eletri Pwer Engine Generatr Standard Family General Charateristis MIL-STD-12B Definitins f Tatial, Prime, Preise, and Utility Terminlgies fr Classifiatin f the DD Mbile Eletri Pwer Engine Generatr Set Family The review determined suh parameters as ambient perating envirnment, utput pwer quality requirements, and utput pwer harateristis and nfiguratin. A Phase I kik-ff meeting was held with the Army at CEM Frt Belvir, Virginia in rder t present the wrk plan utline, and asertain that the wrk plan was prperly targeted with emphasis plaed n apprpriate evaluatin riteria. Additinally, sme infrmatin gathered under this task was derived frm telephne ntats with the CEM, Frt Belvir Researh Develpment and Engineering Center.

12 Past studies were referened t assess the evlutin f requirements and establish additinal fundatins. Sme f these reprts inlude: PWER NDITINING EQUIPMENT A VAILABIUTY SURVEY Reprt 295, Deember 198, DTIC W. David Lee US Army Belvir Researh & Develpment Center The primary purpse f HFA-PFC System task was t develp and mpare several tp level HFA-PFC system arhitetures. The majr elements f this task inluded interpreting the requirements established in the previus task, develping alternative arhitetures and reating a matrix f appliatins, and reviewing the arhitetures fr the varius pwer ranges. Blk diagrams f the varius system arhitetures were generated t supprt the evaluatins. A variety f texts, tehnial jurnals and papers, and experiene were nsulted t perfrm this task. The PFC Tplgy ptimizatin task reviewed numerus tehniques f slid state pwer nversin as alternatives fr the PFC tplgy. A matrix f appliatins was generated t selet andidate tplgies. A mparisn table was mpiled t prvide a tabulatin f general infrmatin regarding eah tplgy. General desriptins f the alternative tplgies was prvided with the assiated blk diagrams. The PFC apprahes were mpared against the seletin f the HFA-PFC System arhitetures t assure the tplgy is suited fr appliatin in the respetive arhiteture. Trade-ffs inluded funtinality, flexibility, mplexity, mpnent stress, size, and weight. The HFA Apprah ptimizatin task was rganized in the same fashin as the PFC Tplgy ptimizatin task. An appliatin table and a matrix f tehnlgy mparisns were reated. A review f eletri mahine tehnlgy was perfrmed. The majr harateristis nsidered inluded size, weight, funtinality, reliability, perfrmane, and st. The Engine peratin Review task reviewed typial engine perating harateristis and evaluated ptential features that uld be integrated with the HFA-PFC System t enhane verall perfrmane. Engine interfae requirements suh as a gearbx are addressed under this task. Funtins that uld be integrated fr enmies f sale were nsidered highly imprtant as they have the ptential t assist in ahieving the verall prjet gal. A review f Pwer Semindutr tehnlgy was dne. This inluded evaluating the ptential appliatins fr presently available devies, and prjeting future pwer semindutr develpments and evaluating their ptential appliatins. An integral part f the HFA-PFC System is the Cling and Pakaging apprah. The results f this task reviewed varius apprahes t further enhane tehnial advanes. This is a summary f ptins, with speifis n the PFC and HFA inluded in their respetive subsetins.

13 4. RESULTS AND DISCUSSIN The results and disussin subsetins presented in this setin rrespnd t the majr wrk tasks identified in the wrk breakdwn struture fr this prjet REQUIREMENTS DEFINITIN The requirements definitin task has established the baseline peratinal and perfrmane requirements fr the equipment. During this task, evaluatin riteria were als established and ranked in imprtane t assist in seleting the ptimum nfiguratins and tehnlgies as the prjet prgressed. A review f existing speifiatins and evlving US Army field requirements has develped a general set f requirements fr a standard family f advaned lightweight tatial pwer generatin units. These inlude: Addressing pwer generatin frm 0.5 kw t 1000 kw Prviding multiple pwer utput nfiguratins and vltages perating typially ver the ambient temperature range f -25 F t 125 F perating in the typial altitudes f Mean Sea Level t 8000 feet Varius tehnlgies were evaluated t satisfy the abve general requirements with respet t size, weight, perfrmane (inluding pwer quality, effiieny, reliability, and handling requirements), st, eletrmagneti mpatibility, and austi nise signatures. This subsetin establishes the minimum aeptable standards and perfrmane requirements fr evaluating the varius tehnlgies EXISTING SPECIFICATIN REVIEW Numerus military standards and speifiatins are appliable t the tatial generatr sets. A review f the relevant speifiatins prvides a fundatin fr muh f the design requirements and the mparisns with existing tehnlgy. A summary f the relevant material is prvided here as referene. MIL-STD-12B Definitins f Tatial, Prime, Preise, and Utility Terminlgies MEL-STD-12B defines lassifiatins f equipment based upn use and apability. These lassifiatins must be fulfilled by equipment designed t perate in the pwer levels f this study. Classifiatins are subdivided int three main ategries. The type, desribing the equipment appliatin and intended use. The lass defining eletrial perfrmane harateristis. The mde defining the utput pwer type.

14 1. TYPE a) Tatial - Designed fr high mbility in diret supprt f military fres. N eletrial transfrmatin r extensive distributin system is used. Ranking f harateristi imprtane: (1) Light weight (2) Small size () High degree f mbility (4) Reliability (5) Life b) Prime - lng term use in semi-fixed latins fr extended perids f time. High vltage utput fr distributin, requires transfrmatin. 2. CLASS Ranking f harateristi imprtane: (1) Lng life (2) Reliability () Size (4) Weight (5) Mbility a) Class 1 - Preise - Clse ntrl f vltage and frequeny perfrmane fr ritial appliatins. b) Class 2 - Utility - pwer fr general purpse appliatins. Three grades whih are mpatible with mmerial pwer. (2A, 2B, 2C). MDE a) Mde I - 50/60 Hz apability b) Mde n Hz ) Mde ffl - 60 Hz nly d) Mde IV - DC utput nly

15 The standard details the eletrial perfrmane harateristis f the generatr sets as shwn in Tables 1 and 2. The harateristis fr the Preise Class f equipment are shwn fr simpliity sine these are the tighter regulatin tleranes and faster transient respnses that will be required. Table 1. Eletrial Perfrmane Charateristis; AC AC Charateristi Preise (Class 1) Test Methd (MIL-STD-705) Vltage Charateristis Regulatin (%) se stability (% BW) Transient Perfrmane Lad appliatin Dip (%) Revery (se) Lad Remval versht (%) Revery (se) Mtr Lad (2 PU urrent) 5kW<x<500kWgenset Dip (%) Revery t 95% (se) Wavefrm (<i>, add 1% fr 1$) Max. Deviatin (%) Max. Ind. Harmni (%) Vltage Unbalane (%), unbalaned lad Phase Balane Vltage (%) Vltage adjustment (% min) -5, Frequeny Charateristis Regulatin (%) se stability (% BW) Transient Perfrmane Lad Appliatin Undersht (%) Revery (se) Lad Remval versht (%) Revery (se) Frequeny Adjustment (% min) +/

16 DC Charateristi Table 2. Eletrial Perfrmane Charateristis, DC Utility (MdelV) Test Methd (MIL-STD-705) Vltage Charateristis Regulatin (%) Steady state stability (% BW) Transient Perfrmane Lad appliatin Dip (%) Revery (se) Lad Remval versht (%) Revery (se) Ripple Vltage (%) Vltage Adjusting Range 2 t nrm amb +/- extreme temp Pwer generatin apaity is derated with respet t speifi equipment pwer ranges and perating altitude. Table shws the appliable temperature ranges fr varius pwer levels and types f engines. Table. Generatr Set Derating fr Altitude and Temperature DD Standard Capaity at Varius Envirnmental Cnditins kw Rating MSL,-2S"Ft +125 F USL,-6S Ft *12S F 1500 ft, 90 "F 5000 ft, 107 F 8000 ft, 95 F 0.5,1.5 kw reiprating engine driven thru 200 kw reiprating engine driven & gas turbine engine driven (GTED) Abve 200, thru 750 kw reiprating engine driven Rated kw N/A Rated kw Rated kw 90% Rated kw Rated kw Rated kw Rated kw Rated kw 90% Rated kw Rated kw N/A Rated kw 80% Rated kw 75% Rated kw Abve 200, thru 750 kw GTED RatedkW-25 Ft +60 F; 70% rated kwt+125 F N/A 90% Rated kw 75% Rated kw 70% Rated kw The extreme lwer temperature limit f-65 F fr peratin f equipment in the kw thru 200 kw range is imprtant when evaluating pwer semindutr and mpnent appliatins in PFC designs. MIL-STD-12 als details the vltage nnetins and pssible utput nfiguratins as defined in Figure 1. 10

17 STANDARD VLTAGE NNECTINS wi^smn..^vsaqa 1 fffl-ft:-:*:*?:-:*^ i r?m T T11 j 1* * mm 1* 12V-2«*» 240V-2wire Uav-ivm 120/240 V wire 120/240 v -a»** 120/208 V 4wire 240/416 V 4 wire *1 «jmwv*«wtwt :». >.. t.'.'.'.'. l. l. L. L '. 1.'.'.'. 1...'.-, 2MSWV 4vA«^^^^8 2400/4160 V 4 wire 2400 V- wire SWP* *«HW Figure 1. Standard Vltage Cnnetin Requirements Figure 1 illustrates the flexibility required in the HFA-PFC utput in rder t ammdate varius utput nfiguratins and vltage levels. In eah f the standard family pwer levels that rss mre then ne nfiguratin, the utput must be apable f supprting the different nfiguratins r different utput vltages. The rennetins, e.g. frm l(j> t <(>, r frm 120 V - 2 wire t 240 V - 2 wire, must be prvided fr in the field. Based n the assumptins f weight distributin defined earlier under the Assumptins setin, and the speifiatin weights arding t MBL-STD-12, estimated pwer densities are shwn in Table 4. 11

18 Table 4. Estimated Pwer Densities Maximum Dry Pwer Density (Ib/kVA) kw Rating Weight GEN SET GEN* ENG* 0.5 ' * Pwer density assumes a 52.4% /47.6% weight divisin between the generatr and the engine respetively. Atual data nfirmed the apprximatins. The weights given are the maximum allwable fr an engine generatr set n rails based upn MIL-STD-12. The atual existing generatr set weights as given in MIL-STD-6 traked the maximum allwable weights f the speifiatin fairly lse. The maximum weights per MIL-STD-12 are pltted in Figure 2 fr referene. 12

19 Pwer vs. Gen Set Weight -W«ght Pwer Rating (kw Figure 2. Maximum allwable Engine Generatr Set Weights MIL-STD-6E Mbile Eletri Pwer Engine Generatr Standard Family Charateristis This standard prvides details n the physial and eletrial harateristis fr eah member f the existing DD apprved family f mbile eletri pwer engine driven generatr sets. The data lleted frm this standard is presented in tabular frm in Appendix A. Several appliable bservatins were made frm the standard family harateristis: Rpe start, r manual start, is available n engines up t the 10 kw pwer range. Eletri start is available n gas engines starting at 5 kw. Eletri start is standard n all diesel engines dwn t the minimum 5 kw pwer level. Liquid led engines are fairly standard at 15 kw and abve. Sine these harateristis represent typial engine appliatins, the tehnlgies being addressed in this prjet must be apable f integrating with the apprpriate engine qualities suh as eletri start funtins, ht battery bakups, and shared funtins like ling and ntrl. 1

20 PHASE I LAUNCH MEETING A rdinatin meeting was used t nfirm ertain aspets f the prjet. These inluded the spe f pwer ranges t be vered, and the evaluatin riteria The spe f the appliable pwer range was expanded t ver 0.5 kw t 1000 kw frm the riginal 5 kw t 1000 kw. Tw fatrs ntributed t the expansin. CEM identified that tatial generatr sets frequently ver pwer levels as lw as 1.5 kw, and MIL-STD-12 vers the pwer ranges frm 0.5 kw t 750 kw. These ranges mbined with the mdular nepts being explred set the lw pwer level dwn t 0.5 kw. Mbile tatial equipment typially enmpasses 1.5 kw t 60 kw pwer levels. Man-prtable hardware is defined t inlude 0.5 kw t kw, and typially less then 120 lbs. With the grwth f the eletrni battlefield, transprtability and deplyability must be nsidered fr pwer levels up t 1000 kw, as seen with Grund Based Radar (GBR) systems. Part f the requirements definitin inludes the evaluatin riteria used t assess the varius tehnlgies and system arhitetures. That is the ability, r the requirement, f the tehnlgy t satisfy ertain riteria. This riteria has been identified as fllws: 1. Weight 2. Size. Perfrmane a) Pwer Quality b) Effiieny ) Reliability d) Funtinality e) Lgistial Supprt 4. Eletrmagneti Cmpatibility 5. Austi Nise Signatures 6. Infrared Signatures 7. Cst Criteria 1 & 2 are usually lsely linked and demnstrate a psitive interdependene. The evaluatin riteria ranking shuld be used as a guide. Speifi pwer ranges may experiene varying degrees f imprtane fr the riteria ADDITINAL REQUIREMENTS ASSESSMENT A reprt entitled "PWER NDITINING EQUIPMENT A VA1LABILITY SURVEY" detailed the results f a study t identify a family f eletri pwer nditiners that wuld mplement the DD standard family f Mbile Eletri Pwer Sures (MEPS) with eight units ranging frm 1.5 kw t 200 kw. The riginal intent appears t be using the pwer nditiner in series with the existing MEPS. The reprt prvided sme fundatin as t alternative uses f the PFC equipment evaluated during this prjet. This reprt utlined a ptential requirement fr develping hardware that has an integrated pwer nditining funtin. Additinal nsideratins were given t enhaning the funtinality f the HFA-PFC system. Reviewing funtins that may be integrated within the HFA-PFC baseline design by virtue f the intrinsi design will assist in diluting aquisitin sts f the hardware, and further imprving the pwer generatin and funtinal apability t weight rati. 14

21 4.2. HFA-PFC SYSTEM Establishing baselines fr the High Frequeny Alternatr - Pwer Frequeny Cnverter (HFA-PFC) System was neessary t define the requirements fr the individual HFA and PFC evaluatin riteria This press is essentially a tp dwn apprah in rder t define the ptimum system nfiguratin and features that shuld be inrprated int the design in rder t redue weight and size, and in sme areas prvide additinal funtins. As wrk was perfrmed n the individual PFC and HFA tehnlgies, the resultant infrmatin was fed bak t ptimize the system. A tp level blk diagram fr an HFA-PFC System vering the 20 t 60 kw pwer range is shwn in Figure. This is representative f the general HFA-PFC System Arhiteture. Slight variatins fr the different pwer ranges may be enuntered, suh as the number f parallel mdules mprising a system. The suggested mdular apprah is the basis fr the subdivisins f pwer ranges. Eah pwer range has a base mdule fr bth the HFA and PFC. /^^ ~~^\ 120/240 VAC > 60 Hz ' utput I ENGINE J <j= > UJ< UlUJ z 'L _ M uia :-< «. "',1 Starter/Gensratr 'L- /l ST" -v HFA Starter/Generatr HFA Slaner/Generatr K < - - > Is- LL a. * A A PFC PFC PFC / 1 _ J ENGINE/GENERATR SET *NTE: The existing DC starter is remv ed ( Battery I r.. L! ptinal Pwer Mdule <- ptinal (e.g. 50 Hz, 220V) Dtted line blks represent mdular units r ptinal units Figure. General HFA-PFC System Blk Diagram A summary f the HFA-PFC System arhitetures with suggested features is presented in Table 5. The mdular apprah allws fr a building blk nept. The HFA and PFC mdules are apable f perating in a paralleled nfiguratin respetively t prvide inreased utput apability, and the subsequent verage f higher pwer utput requirements. The main fundatin fr this apprah is t develp a standard set f hardware that will assist in reduing lgistial supprt f missins. Fr instane a spare 20 kw PFC r HFA base unit will prvide spare replaement f the 20, 40, r 60 kw MEPS. The mdular apprah als prvides pprtunities t ustm nfigure utputs if bth AC and DC pwer are required It als allws integratin f add-n features suh as pwer nditining interfae units, allwing the MEPS t perate as a freign pwer utility grid - pwer nditiner. The mdular apprah is mre fault tlerant and an ntinue peratin at derated utput during ertain mdes f PFC r HFA faults. A Variable Speed Cnstant Frequeny (VSCF) peratin, where the generatr and engine are ntrlled t perate ver a speed range dependent upn lad is ptimum fr all ategries. Certain hallenges may 15

22 be enuntered in the higher pwer ategries where the engine respnse time slws signifiantly due t its effetive mment f inertia and aeleratin apability. Many system dynamis are enuntered when perating in this mde inluding transient respnse apability f the engine, the HFA, and the PFC. This is ne f the reasns behind inluding pwer management in the kw range. Pwer management will help t assess lad demand as a leading funtin in the engine speed ntrl algrithms. The Nninterruptible Pwer Supply (NPS) apability is intrinsi t the mdular design sine paralleling lgi and apability is required t supprt the mdular peratin f PFCs nneted in parallel. NPS refers t the ability f MEPS t perate in parallel, nneted t a mmn lad bus. The Uninterruptible Pwer Supply (UPS) is als intrinsi ne a battery is inluded with the MEPS t prvide starter pwer, whether r nt using a starter/generatr nfiguratin. The UPS prvides a ht bak pwer sure eliminating any brwnuts r mmentary lss f pwer due t primary engine shutdwn. This is a time-limited pwer sure based upn battery apaity and state f harge. Sme f the HFA-PFC System integral funtins will assist in reduing the net weight f the MEPS. The starter/generatr funtin eliminates the existing DC starter used n the primary engine fr engine start. The eletri mtr apability is an intrinsi apability f the HFAs nsidered The PFC by nature an supply the required exitatin t ntrl the mtr as a starter with additinal ntrl algrithms when used with a swithed relutane eletri mahine. The additinal funtins will als redue the lgistis f deplyment. Fr instane, prviding an integrated pwer nditining funtin will allw the use f the lal pwer grid in the theater f peratin while redue the perating time f the engine t prdue 60 Hz, regulated eletrial pwer. Even thugh the added funtin has a slight additinal weight assiated with it, it redues the verall weight f equipment that wuld nrmally have t be transprted t perfrm the same funtins. Additinally,, these funtins an be supplied while still prviding a signifiant weight redutin t the tatial MEPS. 16

23 Estimated System Weights A summaiy f the HFA-PFC System Weight Preditins is presented in Table 6. All weights are given in punds (lbs). This tabulatin and mparisn addresses all mpnents required t implement the baseline mdular HFA-PFC System and integrate it with a MEPS engine. The "Ttal HFA-PFC System Weight" represents the mprehensive weight required t implement eah pwer level. It shuld be nted the gearbx weight is idential arss the pwer levels rrespnding t ne ategry. The reasn is t use nly ne gearbx, and standardize the gearbx arss the ategry. Mre disussins n the gearbx may be fund under the Engine Interfae Setin f this reprt. The mparisn f weights is made based n generatr set weights identified in MIL-STD-6. The estimated generatr weights are based upn the general rule fr generatr/engine/trailer weight distributin desribed is the assumptins setin f this reprt. The weights derived frm MIL-STD-6 are atual hardware weights withut a mbile trailer. These trak fairly lse t the speifiatin, MIL- STD-12, maximum weights fr eah pwer level. The "Prjeted Weight Savings ver 60 Hz Generatr" and "(%) SAVINGS" represent the predited weight savings f eletrial pwer prdutin equipment nly. That is, the HFA-PFC savings ver the 60 Hz generatr. The "(%) TTAL GEN SET SAVINGS" refers t the ptential weight savings assiated with a Generatr Set n rails. It shuld be nted that weight savings attributed t the remval f the DC starter was nt inluded in these estimatins. It may be estimated at apprximately 2% f the engine generatr set weight. This wuld inrease the "(%) TTAL GEN SET SAVINGS" by 2%. 17

24 8 >. Ü m IT fd.2 1 If 1 J u <n t I Z 0- l E> B ) a. M s I- 8 >» ü «1 18 A H 1 5 Z Q. I a B- i<8 te i i JC I m i _fd let 2. g es > u s es s es 2 S 1 0. t 8 Je!5 < S _ i_ CQ Q I I I «! i t CQ «J S 0. j- in t I i i u ST t s S I " - Q) " 2 S.2 j '»- s > J8 J2 5 Z Q. Ü 1 6 Z Q. I S-2 g te "i I Q. I.2 g is S" i CL m <D * m i T 'S. ÜÜ «2 g E^.2 fd 'S. Ü 2- s G i S 1 V5 eu I Je Je Si.2 00 J 5.2 _ m s ta IAQ.I 2 ^ IN r-^ I II U5 C8 ^ Q fe f XJ s :> b - CB ST fd s «a 1 i Cj fd Ü g I IS * i e (0 S UJ p: a. 1 8 (0 ii S öl m 81 l 0 - ÜJ a ^ a: ± < J: a «i >- ^ a: 2 ^ 0* t UQ S iu I* s p I

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26 REQUIREMENTS INTERPRETATIN An interpretatin f the speifiatins and requirements is neessary t assure the HFA-PFC System and its submpnent HFA and PFC, alng with any supprt mpnents, will perfrm satisfatrily. The majrity f the requirements were identified and utlined in the "Requirements Definitin" setin f this reprt. An imprtant riteria is the ability t supprt the existing infrastruture f equipment in the field. ne f the urrent requirements previusly utlined is shwn in Figure 4. This diagram shws the existing speifiatin requirements, and the expanded range f apability by using a Mdular HFA-PFC System Arhiteture. Field rennetin f utput wiring nfiguratin allws the generating system t be mpatible with a wider variety f utilizatin lads. The mdular apprah expands the range f renfiguratin sine the base mdule design must ammdate the renfigurability. This is nw available arss all appliable pwer levels assiated with that partiular base mdule. STANDARD VLTAGE NNECTINS Mathed t Prpsed Standard Family Grups Expanded regin f apability UTN.R Figure 4. ptimized Rennetin Capability fr Mdular Apprah It is imprtant t nte that when nsidering PFC peratin in bth a 1< > and a <(» nfiguratin, the internal filtering must be sized ardingly. The 1< > nfiguratin presents the high lad ripple t the PFC, and thus must be nsidered when sizing the PFC internal DC link filter. 20

27 ARCHITECTURE MPARISNS Numerus arhitetures are available fr implementing the HFA-PFC System. The mre appliable nes inlude: 1. HFA-PFC - Single Funtin 2. HFA-PFC / Starter-Generatr. Mdular System Arhiteture 4. Pwer Management 5. Uninterruptible Pwer Sure 6. Nninterruptible Pwer Sure 7. Pwer Cnditining 8. HFA-PFC Independent Regulatin 9. HFA-PFC Crdinated Regulatin 10. Remte Pwer Generatin /LalizedPwer Cnversin General mparisns f these apprahes and tabulatins f advantages and disadvantages f eah are mpiled in Table 7. Detailed desriptins alng with funtinal blk diagrams f eah'are in the next setin ne tehnlgy that is appliable arss the varius arhitetures is peratin in the variable speed nstant frequeny mde. This alternative is disussed in detail under setin 4.5. fr Engine Interfae Cnsideratins. The ntrl f engine utput pwer must be lsely linked with the PFC utput apability; A leading ntrl tehnique must be used t antiipate HFA-PFC System lad. The engine must be able t supply suffiient pwer in a shrt respnse time therwise the PFC will try t mpensate by inreasing urrent. This mmentarily raises stress n the pwer semindutrs while the engine utput pwer inreases. As the engine mes up t speed, the semindutr urrent will drp respetive f the HFA utput vltage. This area is a balane amng lad transient respnse, HFA exitatin apability, and PFC utput regulatin apability. 21

28 a 10 a> a "> >. m tö w 'S I rn m k. % r Q. F x: a) a m TJ E F (') W? IB = C > (0 «1 ku I I <B >. Q.. a a Ü (0 r> <B 5 a 'S 4-i >< a. a. a. (0 a Ü Ü a *J >> Q. a. a e Ü,r rn. s H a es H S u C J s t a. (0 Ü >. Q. _ C tf) (A <n a TJ (1) *i rr f (0 _l 7 'S 8 8? a Ö >._ g x: ' ) 'S *ä ü " * 8 Q. I.2" W i (0 P t N (0 2 C» S ) 5 g (B T t " I ml t: >- (0 ) " IS» HZ Q. I I 1-2 "5 S t if I 'I 8 < fi ü i i s 01 4-» I» >%» U t PL, H t D m a. a. a. (0 S <u Q. t- ) W I Q.I- UJ =.2 -, 4j ^ = HJ 8.1 S'S W 0- Q. i = "2 & "^ k_.f TJ 5> '5 6,g> -"= t tt fe I I a '5> ^'5? j S <0 - s Ü & E.2 (0 s < >.s g_:s I E uj 8 tt i i E m <e ' 5 ra - ) "> 1* g. ü E 0 g <#1 E 1 E =.2".«m r- 5T H w I I n.i'v x S t 8 (Ö <.Eg (0 " * " ^0 >> B> fs ( <S i.i m "8 Ü g s Sue =** ^ «n a. CQ ra l ^ K a IS JZ s <0 zi a. <B (0 a. 5 it is l:.2 ' Ü u. CL < u. I t: a ß. LL 0. I < < E \ 5 a 5 a a a. i_ i_ g C 0 0. J "S. tn

29 <fl TJ E m <U n -J t ra ±2 (0 in, u TJ <n 0) r IC C >. n u a) t. r <0 m Ü 1 1 Q n «s it < '~U 'S " S &! «,& Q. p a> - > -g.!» Q-E I D (D <D n «a I a> 10 a. < a> % D. i* ra ra > Ü =E a. W > E S H t I 0 a. (0 <i) r a> a) w n 0 E F 0 a> < W u. T Li. 0 a. a < a> Li. E 1 <N E 8 'S a. s J2 T ö E = "2 < > P Q. ) CL D a ID <l> s u. <D m «I C 5 ID s ±i a. a i l C ) (B "t a> t Q. I X g S.S 5 i -Z 't < a = «<q <D S i "K t <5 a. E <z> I r fi g. Q. "StS lie P in < > U "=!..2>8 tdij ' Ü 0. s a) <D a: 0 a. a> 7 Ü < u. I.0 "J XJ "S Ü u. 0. T <D N 0) r h_ a. 0 ü R 1 E 0 a: I a. 0)

30 4.2.. BLCK DIAGRAMS Blk diagrams f varius system arhitetures were reated t assist in evaluating their appliability. A mprehensive set f blk diagrams is presented in Appendix B. These rrespnd t the fllwing brief desriptins f eah system arhiteture. The blk diagrams were reated generially s they are independent f the pwer ranges fr initial nsideratins. Fr this reasn, inputs, utputs, and internal pwer busses are represented by ne-line tehniques. The arhiteture system number rrespnds t the numbers used in the evaluatin matries. The nventins is "SYS - # ". The HFA r the PFC tehnlgy represented in eah f the desriptins may be based upn the alternatives presented in the fllwing HFA and PFC setins f this reprt. The blk diagrams represent the pwer flw, lgi and ntrl signals are mitted fr simpliity unless therwise nted. Sine there are many perturbatins pssible f sme features, nly basi arhitetures are presented and disussed. Many features may be mbined t prdue multifuntin apability. Funtins that prvide enmies f sale are independently disussed. Funtins that may be appended t varius base arhitetures are desribed with respet t nly ne arhiteture, but they may be applied t ther arhitetures. Fr example, the pwer management funtin is shwn applied t the HFA-PFC Single Funtin (SYS-1) arhiteture, but it may als apply t a Mdular System Arhiteture (SYS-). SYS-1 HFA-PFC Single Funtin This arhiteture is the mst fundamental fr HFA-PFC appliatins. Its single funtin apability uses an HFA driven diretly frm an engine t generate eletrial pwer. This pwer is supplied as an input t the PFC, where it is nditined and regulated fr utput t utilizatin equipment. SYS-2 HFA-PFC/Starter-Generatr This arhiteture builds n the previus SYS-1 arhiteture by adding the engine starter funtin t the HFA-PFC system. The purpse f this alternative is t eliminate the existing engine starter mtrs n the engine generatr sets, thus reduing net weight. The impat t the HFA and PFC depends upn the speifi tehnlgy used fr eah. Fr instane, using a swithed relutane mahine as a generatr prvides intrinsi peratin as a mtr due t the methd f mahine exitatin. Hwever, using a synhrnus wund rtr r a permanent magnet mahine requires ntatrs t ntrl pwer flw either int, r ut f the rtating mahine. This nfiguratin is represented in SYS-2a. A battery input t the PFC is required, similar t the battery input t a traditinal DC starter. ne this input is available, the UPS funtin bemes intrinsi t the arhiteture, and nly requires a ntrl algrithm hange. SYS- Mdular System Arhiteture A mdular nept was develped t supprt field nfigurability, redue lgistial supprt, and redue sts. The general nept is t develp a base unit design fr bth the HFA and PFC that frms the fundatin fr a grup f pwer levels in the standard family f pwer ranges. The base unit utput will be parallelable t prvide step inreases in utput pwer apability. A standard gearbx fr eah pwer gruping will allw the peratin f paralleled HFAs dependent upn the engine size seleted. Unused munting pads n the gearbx will be apped ff. PFCs are parallelable by a standard plug in rak fr eah pwer gruping The plug in rak will maintain the flexible utput nnetins fr rennetin apability in the field. The parallel ntrl f the PFCs will be integral t their peratin as an extensin f the utput frequeny ntrl. All neessary internnets will be made thrugh the plug in rak 24

31 Arhiteture SYS-a represents a variatin f the base SYS-, where independent utputs are available frm a three unit parallel nfiguratin. Eah utput may be independently regulated and ntrlled, eah having a different utput pwer type. Depending upn the HFA-PFC internal arhiteture, eah HFA utput may be independently ntrlled and distributed t a respetive PFC. If PM based HFA mahines are used, a mmn internal bus wuld be reated, with eah PFC prviding utput regulatin. SYS-4 Pwer Management The pwer management funtin takes a basi HFA-PFC System arhiteture and appends an utput pwer ntrl stage. This feature an be used t prvide lad shedding in the event f system degradatin. Anther feature wuld be used t ntrl lad sheduling in a smart pwer management apprah. Utilizatin lads uld be manually sheduled fr autmati energizatin and de-energizatin in rder t limit maximum lading. ptinally, an intelligent ntrller may be used t prvide autmated lad sheduling based upn data lleted during nrmal peratin. Lad sheduling may be used t level utilizatin lads thrughut an interval f time s that smaller pwer sures may be used. Nn-ritial lads may be perated during ff-peak lad perids. Additinally, this feature an prvide sure bus integrity by remving faulted utilizatin lads. A system arhiteture that supprts ht mdule replaement may benefit by autmatially shedding lads t perate within the system rating while underging repairs. Missin ritial utilizatin lads an remain n-line. SYS-5 Uninterruptible Pwer Sure This arhiteture represents the lassi uninterruptible pwer supply. A ht battery bak-up is available as a time limited pwer sure input t the PFC. The duratin is determined mainly by battery size, utilizatin lad, and PFC effiieny. A typial senari may inlude a 40 A-hr battery perating at 5 kw lad. The UPS wuld prvide apprximately 12 minutes f bakup pwer frm a fully harged battery. This time wuld be suffiient t prperly shut dwn intelligent systems having vlatile data and thus prtet infrmatin, ptentially remedy the primary pwer sure utage, r swith t an alternate pwer sure. The UPS apprah uld be upled with a pwer management apprah t shed nnritial lads during a primary pwer sure lss in rder t extend the perating time. The depited UPS arhiteture shws a mmn urrent eletri DC starter using a battery. The battery pwer is als made available as an input t the PFC. In ther wrds, with an eletri start based engine generatr set, the battery is already available and integrated with the intrinsi pwer nversin ability f the PFC. Naturally, the UPS feature is diretly appliable t starter generatr arhitetures. Arhiteture SYS-2 shws the UPS apprah fr a starter generatr appliatin. There is effetively n arhiteture hange required t implement this apprah. SYS-6 Nninterruptible Pwer Sure The nninterruptible pwer sure apprah has the ability t parallel pwer generatin sures (HFA- PFC utputs) tgether. This tehnique prvides an n-line, nninterruptible, nn-time limited pwer generatin sure. The utputs f eah MEPS may be internneted thrugh an arrangement f ntatrs as shwn in the blk diagram. This apprah limits the maximum number f paralleled MEPS by the pwer rating f the ntatrs. Internnet harnesses are required t synhrnize the paralleled sures and identify a master MEPS, with the remaining paralleled units ating as slaves. Alternately, eah MEPS may have an utput ntatr fr nnetin t a mmn bus. This apprah uld use a first n-line designatin as master. The remaining MEPS wuld synhrnize as they ame nline. In the event f a master failure, the slave wuld regnize the fault nditin thrugh harmnis n the line and return t internal ntrl. The faulted unit will de-exite sensing an ut f limit perating nditin. 25

32 SYS-7 External Pwer Cnditining This alternative arhiteture prvides a pwer nditining funtin fr an external pwer sure. The pwer nditining funtin is intrinsi t the PFC design sine the utput pwer nditining iruits and mpnents are already present. In effet, the PFC is an external pwer nditiner. The feature an be used t nditin pwer t a high quality 120 V - 60 Hz utput frm sures suh as the 50 Hz Eurpean eletrial grid. Primary pwer sure may be the external pwer, with the engine and HFA as a bakup pwer sure. A battery bakup fr UPS peratin wuld prvide a ht uninterruptible pwer sure while the engine is started and the HFA is brught up t perating speed. The battery bakup is nt depited in the blk diagram fr SYS-7, please refer t SYS-5. In rder t effet this ptin, an independently regulated PFC that an ammdate a variety f input vltages typially enuntered thrughut the wrld is required. ptinally, a prenditining unit may be used. Inrpratin f this funtin within the PFC, r as an ptinal mdule, an make the PFC a stand alne pwer nditiner. When integrated with a battery, it may als prvide a UPS funtin..alternately, an independent frnt end nverter may be nfigured t prenditin the external pwer t the required input t the PFC. This independent frnt end may als beme an ptin n the MEPS t prvide the pwer nditining funtin when the hardware is installed. Nrmal peratin fr this pwer nditining nfiguratin wuld be withut the engine perating. The engine may beme a bakup pwer sure in the event f a primary pwer sure, that is a freign utility grid utage. The battery bakup wuld energize the UPS funtin t prvide uninterruptible pwer while the engine is brught up t perating speed. SYS-8 HFA-PFC Independent Regulatin The system arhiteture is shwn t represent varius system ntrl tehniques. The independent regulatin sheme has separate regulatrs fr the HFA and the PFC. Als shwn is an integrated engine speed ntrl whih may be used t regulate engine pwer utput and speed. SYS-9 HFA-PFC Crdinated Regulatin The rdinated regulatin arhiteture uses ne regulatin lp t ntrl utput vltage levels. Als shwn is the engine speed bias signal t ptimize engine perating pint based upn utilizatin lads. If a PMG mahine is used with rdinated regulatin shemes, the speed bias signal wuld be the avenue f utput vltage regulatin. SYS-10 Remte Pwer Generatin / Lalized Pwer Cnversin The last prminent HFA-PFC arhiteture presented is a remte pwer generatin and lal pwer nversin system. This arhiteture an generate eletrial pwer fr distributin t ne r mre remtely lated pwer nversin units. 26

33 4.. PFC TPLGY PTIMIZATIN Pwer Frequeny Cnverter (PFC) tehnlgy has experiened signifiant strides in perating pwer levels and pwer densities as a result f majr advanes in pwer semindutr tehnlgy ver the last 10 years. The st effetiveness has als been imprved due t demand by high vlume nsumers suh as the autmtive industry. These fatrs translate int st effetive pprtunities t redue weight and size f tatial mbile eletri pwer generating sets. A blk diagram shwn in Figure 5, depits the internal pwer nversin funtins required t prvide an integrated peratin with the HFA and supprt additinal system features. The input bridge prvides the internal pwer bus. The battery input is fr use with the eletri start funtin and uses a flybak nverter t interfae with the DC link This als prvides the path fr uninterruptible pwer supply peratin in the event f lss f engine r generatr peratin. The f 1+ inverter prvides the 60 Hz AC utput An ptinal prenditining mdule is shwn that an be used t prvide the pwer nditining funtin when abnrmal external pwer is available (e.g. 50 Hz). This mdule is based n a nndistrting input pwer fatr design, presenting a unity pwer fatr lad t the external pwer sure. PWER FREQUENCY NVERTER lw, WMI A - * -4 HFA Input Input Cnverter/ Exitatin Cnv ((>/1(t> utput Battery Input Bidiretinal Flybak Cnverter Cntrl & Prtetin External Pwer Input (ptinal) Prenditining Cnverter PTINAL PWER NDITINING MDULE Figure 5. Pwer Frequeny Cnverter Blk Diagram Table 8 summarizes the speifi PFC tplgies fr rrespnding pwer ategries in the standard set f tatial mbile pwer sets as defined in the mdular nfiguratin. The tplgies are apable f perating in parallel t supprt the mdular system nept identified in the HFA-PFC System setin. Supprting infrmatin n the seletin f the tplgies an be fund in the sueeding subsetins. The features are PFC funtins in additin t the basi nverter funtin, f prduing a high quality 60 Hz utput pwer. Sme f these features are iterative frm the HFA-PFC System evaluatin. They are inluded here sine they will affet the PFC tplgy. UPS refers t an uninterruptible pwer sure, mre mmnly knwn as a battery bakup t the input pwer. The NPS refers t nninterruptible pwer sure 27

34 that effets paralleling apability f multiple MEPSs. Eletri start is used in njuntin with the HFA t replae the existing DC starter assiated with the main engine. The basi fundatin t many f these features is intrinsi t the design f the PFC, and it is nly a ntrl funtin t inlude the extra apability The renfigurable utput apability assures rennetin f the utput t satisfy the multiple utput nfiguratins defined in ML-STD-12. Pwer management features are remmended fr peratin in the high pwer ategry ( kw) due t the utput vltage levels enuntered. Tins prvides autmated lad nnetin ntrl when the PFC has pwer ready, and it an mitigate the risk f shk by wrking lse t high vltages. The weight estimates are fr the base unit rating in eah f the pwer ategries. These ategries are shwn at the tp f the table. The weights rrespnd t the respetive ling tehnique whih has a signifiant impat n weight and size. Weight estimatins at this pint indiate an il led PFC design is apprximately 50% f an air led PFC design weight fr a given arhiteture. It shuld be nted that the tw signifiant ntributins t inreased PFC weight and size are air led systems and transfrmer upled designs. It is als imprtant t nte that the utput transfrmers perate at a higher fundamental frequeny then t 60 Hz utput due t the summing tehniques as desribed later in the apprpriate subsetin n the Summing Cnverter. This allws a weight advantage ver a 60 Hz design. The weight fr the 5 kw base unit inludes an allwane t perate in a l<t> nfiguratin, sine this requires mre DC link filtering apaity. Cling is based upn the HFA-PFC System apprah. ptimum peratin f the HFAs is based upn il led hardware. ne this il management system has been established, it is simple t integrate the PFC int the il lp. This apprah will yield the lightest weight and smallest system. 28

35 * *s ' Je 1! P ).a n SK «B - (5 E W m <0 I 8 0. S m ZCLhC E t Ü «(0t) 1 *" Q. 0- ffl <S S D Z 111 m 1- CC CM Ö s Q. a e a> > n a Si )- HI a w-sg 8 S a. D % <s> Z HI 0C s a H a) Je > U P- 1 -S g 8 s _ Q. 0. t <B fl *-* 00 Ä H DZiumK CM 5 ü Q <D Je 'S* s L_ a> < 5 r- t CC 1 Q CJ* l_ Je "* < 0) Di 1 p h«e 1» tt "9 I 5 i g«g8j is S S is * ea.

36 4..1. IDENTIFICATIN F ALTERNATIVE TPLGIES The grwth f the pwer nversin industry has presented numerus alternative tplgies fr use in a PFC. This prjet identified likely andidates and.reviewed the benefits and appliability f eah. The PFC tplgies reviewed inlude: 1. <(» Resnant DC Link 2. <j> Stepped Wavefrm/Summing Transfrmer. <p Pulse Width Mdulated Inverter 4. < > High Frequeny AC Link 5. Phase Cntrlled Cnverter 6. HalfBridge 7. Full Bridge 8. Push-Pull Inverter 9. Flybak The tplgies inluded bth AC and DC utputs sine sme DC utput apability is required. Additinally, 1< > and < > iruits were reviewed t supprt renfiguratin f system utput. In rder t mpare the ptins, matries f advantages and disadvantages were mpiled This represents the lletive desriptins f eah apprah. A set f funtinal blk diagrams f eah tplgy was generated as a referene fr mpiling harateristis and understanding the perating priniples f eah. The desriptins, where appliable are fund a subsetin after the matries, and the respetive diagrams are lated in the appendix. Many general nsideratins and alternate tehnlgies apply t the tplgies desribed abve, in a similar fashin. Sme f the relevant nes inlude: Grunding Renfigurable utput Cnnetins Battery Charge Funtin Mdular Arhiteture Paralleling Capability Cntrl & Prtetin Future Trends Renfigurable utput nnetins fr 1«)) r «(> peratin is typially addressed by hanging the utput nnetins in the Mdular System Tray in muh the same way utput rennetins f urrent generatrs are made. This step will als signal t the PFC the required utput phase shift between the individual utput phases. A 1< > requires n phase shift, a < > nfiguratin requires 120 phase shift amng phases. Speial nsideratin must be given during the detailed design t assure lad sharing amng utputs when perating in 1< > mde. Cnverters that perate an perate in the tw utput nfiguratins must have their internal DC link sized fr ripple assiated with the wrst ase 1< > peratin. Different utput vltages an be perfrmed in the same manner, thus requiring a physial peratin, reduing the pssibility f misnneting utput vltages t inapprpriate lad ratings. The «)) Summing Transfrmer Inverter arhiteture requires physially renneting utput wiring nfiguratin. The diret upled inverter utputs, vltages hanges may be perfrmed by a seletin swith. The < > Summing Transfrmer arhiteture is nt renfigurable t a 1< > peratin, sine extensive wiring mdifiatins wuld be required t vetrily sum the phases. Speial attentin must be given t the seletin f utput filter mpnent seletin in rder t satisfy seletability f 120 r 240 VAC. The utput filters must be apable f perating with the mplementary V*I harateristis f the utput rating. 0

37 A battery harge funtin may be supplied in several fashins. The mst simplisti is t flat the battery n a retified step dwn utput vltage f the HFA-PFC System utput. Similar t many appliatins tday. Alternately, the input nverter used during eletri start may be nfigured as a bidiretinal nverter t harge the battery under nrmal system peratin. This apprah is extremely attrative when using the battery t supply the UPS mde f peratin in the HFA-PFC System. A fully harged battery will be assured fr maximum bakup time. The mdular nfiguratin autmatially defines the nverters must be apable f perating in a parallel utput arrangement. This is an advantage that allws the parallel peratin f MEPS sine the ntrl algrithms are established, and the paralleling apability is inherent in the design. r the inverse uld be true, if parallel peratin is a requirement (exists in urrent MEPS), then the funtin is inherently present t supprt the mdular nept. The PFC frequeny ntrl is established by an internal referene. This may be varied t prvide n break pwer transfers, where a send MEPS may paralleled and brught n-line withut interruptin f bus pwer. The frequeny ntrl an be used t slave t ther units fr mdular peratin, r parallel MEPS peratin. A detailed design press must address the ntrl and prtetin requirements f the PFC and HFA-PFC System. These inlude lgial peratin, fault detetin and respnse, and Built-in Test (BIT). Interfae with the equipment peratrs must be addressed at the detailed design stage. ptinal rhestat type ntrl must be nsidered t allw the user t set the utput vltages required depending upn distributin wire lengths. This may be prvided as an ptinal remte pint f regulatin. The PFC uses a disrete sensing wire t regulate utput based upn remte sensing. This senari an default t utput vltage regulatin, if the wiring is nt nneted. Future trends in pwer nversin will push perating envelpes f the resnant DC link arhitetures t higher pwers as pwer handling apability f mpnents ntinues t grw. This will result in their appliatin in the higher pwer ranges with these develpments. In nert, pwer densities will ntinue t imprve. This will als be supprted by further miniaturizatin f ntrl iruits and inreases in mputatinal ability fr ntrlling mplex resnant arhitetures and mtr ntrl funtins. Appliatins f fuzzy lgi and neural netwrk ntrl algrithms may evlve that allw a system t "fine tune" utput under varying lad nditins MATRIX F TPLGY MPARISNS The matries presented in the fllwing pages summarize the infrmatin n eah tplgy. Table 9 shw advantages and disadvantages f varius < > tplgies. The tplgies are further defined in subsetin 4.. Tplgy Desriptins, and have rrespnding blk diagrams fr referene in the appendix. Table 10 applies t 1$ nfiguratins. General tplgy nsideratins are given in Table 11. Apprahes t DC utput tplgies are presented in Table 12. Tables mparing key vltage and urrent perating harateristis fr the inverter tplgies and the pwer semindutrs is lated in Appendix D. It shuld be nted that there are may pssible variatins n eah f these tplgies that may be used t refine the atual detailed design and ptimize seletin f a speifi pwer semindutr hip. These tables result frm an analysis perfrmed using an EXCEL spreadsheet. Three tplgies are mpared arss all pwer ranges nsidered in this prjet. The first table in Appendix D, n page D-2 mpiles the atual perating utput pwer levels in watts. The send table lists the system utput vltages during the high vltage utput nnetin based upn MIL-STD-12. Page D-4 shws the utput line urrents in amperes rrespnding t the high vltage utput. The required internal DC link vltages are alulated n page D-5 based upn the arhiteture. The respetive average DC link urrents are shwn in the lwer table n D-5. The table n page D-6 reviews the DC link harateristis with a resnant link inverter appliatin. Page D-7 shws the peak 1

38 urrents in the pwer transistrs. Page D-8 has a table that summarizes the same infrmatin fr the lw vltage utput nfiguratin. The summing transfrmer apprah uses nnetins n the sendary t renfigure its utput. The internal DC link vltage remains the same, as des the peak transistr urrents, fr the rrespnding utput pwer levels at the high vltage utput nfiguratin. It shuld be nted that these alulatins are intended t prvide rugh rder f magnitude mparisns at the preliminary design stage. They exlude ertain fatrs suh as effiieny and magneti mpnent exitatin urrents. They may be nsidered reasnable t within 10%. The tables used fr the high utput vltage nfiguratin basially establishes the vltage ratings f the pwer semindutrs. The tables rrespnding t the lw vltage utput establish the urrent handling requirements f the pwer semindutrs. 2

39 Ü N " l e JZ s» s- s - - < 2 a a>~ C "Ö *> C Q. -2--g is "5. 2.= 5 IS. 8 ^ (D a 2 Q- <2 ** <D I i <D as w T s» a si III f s e Sfe ü t s Q. ^ a in < es. S. - 5 «5 S «= las «.0 I 8 f? $ #.<» B >>! 2 «> a! -e 10 a (0 > UJ. 1 Q.7i C J 5. es D.. es H a es s. H» > u " Q. H U PH -eei 2 es H 5 (D 18 " t f.ii He f l S % > 5 5 t <D z i i ff g i UIJ I I "5 Q je 1=1 S- 0) 9 10 S *± ih "es.e 5 S.f? "5 f- w w- -^ a>?* es _ i. js?.b: S"g a) "a ^ < Q a (S If J2 I l I 5 "5 «'8 I a = a SP. a. >% u Ü " a (0 (0 r u >. LLI H 10 % J= t- 5 = ±ä _l X is _l I I I»- <D.f <=«2 0) p s.? IE V) ^- "» ^^ _fr 5 C (D > -S, m J«IZ I I I a. i_ r- 9.e a i_ T 1 8-S j ff SiSft * r* ils 1 1 ^ CS Q. 'S 'S P- Q. s S 0 T a I IS 0 10 a es F 5 (0 g es S.IK= tj a 2 E S U a». s C T ID t 8 Q (0 t Z I a» 0) - u 0. es *i Q. C 5 II _1 10 (0-2 C 11 S-S X I I S ">"»"= I 08 <B g CM 1 >. 1 a u t 0 E -a 9r Ü I =5 Z X I at ID 2 L_ "=1 a. 1= s l) 0 f a *i 0 Q.TJ C!" s-s 8 uj E E w 5 UJ UJ Jj "S E zed AC grid sysh ut requiring large se ntrlled (0 ±i L a.f 5? : 'S S " 0?Sg, IE <D Q. I 0 : IS R- CS Ü «J s 5= (0 E s I 8*. E Q?? 5 fe TD 0 S e «Ü E <» 8 S ^ a. l-s-j gtj-g t (0 F E = Q- <B g 0 0 ^-S.: z 0X0 I ener n ut ng, ph '&_ J2 t_ IC ts E.u m.ms "^ Q.-CI < s^? D. -5 SWS S Q- 0 5 C i= 111 fet _ E es " at il :== 2 UJ 1 Ü I I I >- e It a ü a a a: E E I* s S--H s a 2 ü " es I 5 ID C 2.1 es u a S E a $ at 2 T 1 5 I f g» 50SCL g es ja a. ü >. E "^ ii:.e 01.E * ^S f? C C) T f p s " Ü 0 >. (0 0 CS n X CN Mi

40 1- Ü 1 1 i i i es H a es Sa H >> Ml a ". H U es H 1 e '* ) IE C a- ID VI C a 1 ) IE C % t; 1 <=?.2 g.1 S -.2> v. l l <D > T J= «'S Ü.* es Heavier weight assiated with utput XFMR - DC ntent n XFMR primary auses saturatin - Can use in $ nfiguratin - Islatin thru XFMR intrinsi t design - Cmmn grund fr pwer devies - Gd fr lw vltage sures - New tehnlgy (unprved) - Lw pwer level appliatins due t resnant urrents being muh greater then lad urrents - Vltage limitatins (utput & DC Link) - High mpnent stress with high pwer - Cmplex AC inverter swithes, use 4 dides & trans, 2 trans. & 2 dides, r 2 SCRs - New tehnlgy 'I ) s= Ü _ <D C es 1 iü D) <C Ü V) C es Ü r >- -J s K I -. <D g ' m CB I <D m 8. Push-Pull Inverter (XFMR Cupled) _i a e es V) ID n d Li >. a> r Li. ) I

41 s - Can use XFMR leakage indutane as an integral part f utput filtering - XFMR may be designed fr pulse frequeny using ertain arhitetures, thus reduing size - Can use this apprah with mst tplgies - Can use this apprah with mst tplgies - Use bak plane type rak plug in nnetrs - This an apply t mst all PFC Tplgies being reviewed. i I- H >> M 'S ft H U v. I <D (A < 'a> 1 - XFMR utput emulates typial generatr utput nnetin apability - Prvides full range f utput nnetin apability - N DC mpnent pssible in utput - Prvides "effetive" paralleling f utput stages t inrease ttal utput pwer apability - Needs disrete utput indutr fr utput filtering - Limited utput nnetin apability, will impse nstraints - Needs additin f NFT t ver all utput nnetins f MIL-STD-12 r verrated mpnents (V*l harateristis) - Ptential minimal DC mpnent in utput - Ptential large DC mpnent in utput during inverter failure mdes _l I.2> ) ' a. >> «j E 05 I - Expandability - Cnfigurability - Imprved lgisti supprt - Lwer st - Cmmn mpnents - Paralleling apability prvided by mdular design intrinsially allws MEPS paralleling peratin - Expensive develpment apprah - Expensive prdutin sts - High Life Cyle Cst - High lgistial supprt requirement v. 1 H.2> E <» > S 5 *l if ^ 1 5 (D GENERAL PFC TPLGY Transfrmer Cupled utput Diret Cnverter utput Mdular Arhiteture Unique Arhitetures fr Individual Pwer Ranges

42 i 1 a «- a> in. 4-* l_ " s«.a.a 51-5 h-< i 0) " es u H ^> M " & H U CM u es H i s.i f 2* SI <D (0»? fig if 2 g. UJ 1 " Ü g (D C a. E.n > I 1 (0 tf) t a> 1 _1 1 e ) (0 a> 8 Q. E Ü l - High effiieny - Sft swithing (lw stress) >- -J Q ui a ft «0 ID m 17. Resnant DC Cnverter

43 4... TPLGY DESCRIPTINS Funtinal blk diagrams rrespnding t eah f the fllwing tplgy desriptins are lated in Appendix C. The blk diagrams detail the majr elements f eah apprah and shw their basi pwer internnetins. The fllwing desriptins present general nepts, and signifiant harateristis abut eah apprah where appliable. Sme alternatives require little r n explanatin. The desriptins are targeted at presenting harateristis related t the seletin f ptimum nfiguratins fr use in a HFA-PFC system. Detailed shematis and perating desriptins are nt the bjetive f this task, but may be fund in tehnial jurnals and mdern textbks n pwer nversin. Mst f these tplgies have been available fr quite a perid f time. The inrease in pwer handling apability f semindutrs brings ertain tplgies int favr peridially. Additinally, high speed digital ntrl tehniques help t prvide imprvement in the designs that make them effetive t use. A-PFC Tplgy The fllwing tplgies are well suited t appliatin in < > nverters. Many f the < > ptins are built arund the basi < > inverter bridge. This is illustrated in Figure 6 fr referene. This shemati is used fr all "( > UTPUT BRIDGE"s shwn in the blk diagram. Figure 6. Fundamental Three Phase Inverter Bridge 7

44 PFC-1 «j) Resnant DC Link Many reent variatins f this knwn tplgy are nw surfaing with the renewed interest due t the high pwer apability f semindutrs. The primary advantage f this tplgy is that it prvides sft swithing f the pwer transistrs. Whih redues swithing lsses in the pwer semindutrs. This prvides tw prinipal benefits. verall nverter lsses are redued and the swithing transistrs experiene lwer swithing stresses. The later assures peratin well within the Safe perating Area (SA) f the pwer transistrs. An additinal benefit is redued EMI due t swithing harateristis having a quasi-sinusidal edge instead f the hard swithing square wave. ne aveat is that additinal lsses are intrdued in the resnant iruit that must be weighed against the redued swithing lsses. The priniple f peratin is t reate a resnating vltage n the DC link that ranges frm zer t apprximately twie the input vltage. Tehniques are pssible t rever sme f the resnant energy and redue the peak resnant vltage. This helps t redue the sustaining vltage requirements f the mpnents. Cmpliatins with this tehnlgy inlude high urrents in the resnant iruit. These must be muh larger then the lad urrent t maintain a resnating link vltage. All the resnant energy must flw thrugh the resnant iruit, usually requiring partiular attentin t apaitr seletin and appliatin. This high urrent rrespnds t new lsses in the resnant iruit elements whih an be mprised f indutrs, apaitrs, and semindutrs. The peak urrent thrugh the utput transistrs inreases t ammdate fr the lss f urrent at the edges f the traditinal square wave peratin. utput vltage regulatin is ahieved thrugh a mbinatin f varying the resnant link frequeny t adjust the impedane f the resnant iruit, and seleting an apprpriate pulse pattern in the utput. Stability ntrl ver large lad variatins is diffiult. This usually fres the peratin int a quasiresnant mde f peratin. The benefits f resnant peratin are nw realized depending upn lad. Mitigating DC ntent in the resnant nverter utput puts anther ntrl lp int the mplex regulatin sheme. High resnant link frequenies aid in reduing resnant iruit mpnents, but there is a pratial limitatin. As frequeny inreases, indutr designs get mre mplex, and skin effet begins t play a large fatr in magneti design. The pwer semindutrs have realisti swithing limits. MCT's are apable f apprximately 20 khz, and IGBT's an perate up t 40 khz. The resnant DC link requires a Neutral Frming Transfrmer (NFT) when perated in njuntin with an HFA that has n neutral nnetin suh as a variable relutane mahine. This is neessary in rder t prvide a neutral referene, and grunding prtetin f equipment and persnnel. Due t their additinal iruitry and ntrl mplexity, Resnant link nverters usually beme advantageus when the iruit design stresses exeed the apability f available pwer semindutrs. PFC-2 < > Stepped Wavefrm / Summing Transfrmer Inverter The summing transfrmer inverter is based arund the standard $ utput Bridge. Eah utput bridge is effetively a < > inverter. Using a transfrmer t sum the utputs f multiple bridges an raise the utput pwer rating f a PFC t very high levels. The utput f the individual bridges are phase shifted in rder t redue utput harmnis. This tehnique wrks n the prinipal f a mre traditinally knwn harmni neutralizatin nverter, whih used single leg bridge utputs - phase shifted t minimize harmni ntent. The harmni neutralizatin nverter shuld nt be nfused with the harmni 8

45 eliminatin, whih is a swithing ntrl algrithm used in a ((> bridge t eliminate speified harmnis frm the utput. The main advantage f this apprah is that is allws the utput bridges t be effetively paralleled withut atually paralleling disrete pwer semindutrs. Appendix D, PFC-2 shws a 6 bridge nfiguratin, prduing a 6 step utput wavefrm. These steps are then filtered using an utput filter. utput lad is equally shared amng the bridges prvided that the summing transfrmer is balaned and the turns ratis are equal. utput vltage regulatin is perfrmed by lsed lp ntrl f the HFÄ utput. The inverter utput bridges perate in a fixed ndutin duty yle. Frequeny is set by a preise internal timing referene sillatr. The majr drawbak t this tehnique is the weight f the utput transfrmer. ne aspet f the transfrmer design that may be used t redue weight is that the effetive perating frequeny is equal t the utput frequeny multiplied by the number f steps in the utput wavefrm. This results frm the steps being applied t the transfrmer appearing as pulses. The transfrmer perates as a pulse transfrmer. The perating frequeny is muh higher then the 60 Hz, and the resulting transfrmer may be muh smaller. The use f the utput transfrmer prvides an eletrially islated inverter utput with a neutral that may easily be referened t the mmn grund struture. This nverter is nt nfigurable as a 1$ utput due t the summing tehniques f the transfrmer primary. N DC ntent is pssible in the PFC utput with this nfiguratin. PFC- <j» Pulse Width Mdulated Inverter The Pulse Width Mdulated (PWM) inverter is an extensin f the < > utput bridge. It is a mmnly applied and well knwn tplgy. This nfiguratin is used t prvide a diret bridge utput t an utput filter. ne basi mde f peratin is t ntrl swithing f the pwer transistrs t synthesize a sinusidal utput after filtering. utput regulatin is perfrmed by a dediated vltage regulatr that may mpare a sample f the utput wavefrm t a referene vltage, thus generating an errr signal fr PWM ntrl. Several apprahes are pssible inluding mdulated arrier, ptimum respnse (bang-bang), and prgrammed wavefrm. Preise vltage and frequeny regulatin is pssible. Swithing f utput vltage levels frm 120 t 240 VAC may be perfrmed by the PWM tehnique. 1< > r < > peratin is determined by the dwell between phases and the utput nnetin. Cmpensatin t mitigate utput DC ntent is required. System neutrals and grunding are easily defined with this arhiteture. A apaitr divider netwrk may be used arss the internal DC link t establish a grund referene fr the nverter utput. The tehnique is als mpatible with the VRM design. PFC-4 < > High Frequeny Link (AC Inverter) The high frequeny link AC inverter uses the basi < > utput bridge, but replaes eah pwer swith with a bidiretinal swith. The link vltage is a high frequeny AC vltage. Cntrl algrithms establish a pwer swithing sequene that passes psitive prtin integral half yles f the AC link vltage t the utput. The pattern synthesizes an AC utput by "gating" the AC link half yles t emulate a lw frequeny AC utput. An integral number f half-yles are used t avid any DC ntent in the utput. 9

46 Eah bidiretinal swith must be mpsed f ne transistr and fur dides, r tw transistrs and tw dides. The verall nverter has the same quantity f pwer semindutrs, with essentially the same rating as the nventinal input bridge / utput bridge arrangement. Ptential advantages f this apprah are eliminatin f swithing lsses sine the pwer swithes are swithed at the zer rssings f the AC bus. A resnant AC link iruit is required t perate at the input frequeny. Cntrl algrithm's are very mplex fr this apprah and require high speed mputatinal apability. Additinally, ntrl during lw pwer fatr is diffiult. PFC-5 Phase Cntrlled Cnverter (Cylnverter) Is the lassi thyristr based AC t AC nverter. PFC Tplgy The fllwing tplgies are well suited t 1( > nverters. They were reviewed t assess their appliatin fr the ne phase generatr set utput requirements. Cnsideratin was given t renneting them t als supprt the 1< > / $ rennetin riteria speified in ML-STD-12. Mst f these tplgies an be applied in tripliate with a 120 phase shift in the frequeny ntrl t prvide a $ nfiguratin. PFC-6 Half Bridge The half bridge effetively perates as ne bridge leg utput f the < > PWM inverter. An additinal requirement is a neutral frming apaitr nnetin. The $ PWM inverter has the intrinsi ability t perate with the three utputs paralleled as a 1< ) inverter. PFC-7 Full Bridge This arhiteture has a high mpnent unt when used as in a three phase bridge nfiguratin. Requires an islatin transfrmer t grund ne side f the utput, r fr use with a lad that has ne side grunded. PFC-8 Push-Pull Inverter (XFMR Cupled) The push-pull inverter design requires an utput transfrmer. The magneti design may be based upn the fundamental perating frequeny f the inverter, thus reduing its size. PFC-9 Resnant DC Link The 1< > resnant DC link inverter perates in a similar fashin as the $ nfiguratin. PFC-10 High Frequeny Link The 1( > High Frequeny AC link inverter perates in a similar fashin as the < > nfiguratin. 40

47 General PFC Tplgy The fllwing variatins may apply t mst all f the tplgies nsidered t this pint. PFC-11 Transfrmer Cupled utput If an utput transfrmer is perated at the fundamental 60 Hz line frequeny, its size will be very large and prelude its appliatin due t lss f weight advantages. This ptin is nly feasible where higher fundamental frequenies are pssible. The utput filter assiated with this arhiteture is usually smaller then that required by the diret nverter utput sine a prtin f the filtering may be derived frm the leakage indutane f the transfrmer. PFC-12 Diret Cnverter utput This apprah uses an utput filter in series with the $ utput bridge. Like the previus example, the utput filter magnetis must be perated at a high frequeny mmensurate with the inverter peratin t maintain weight savings advantages fr its appliatins. PFC-1 Mdular Arhiteture The Mdular Arhiteture apprah requires that frequeny and phase infrmatin pertaining t the utput vltage be mmuniated t the mplementary mdules. This may be amplished thrugh a disrete internnet r thrugh internnets in the munting rak. PFC-14 Unique Arhitetures fr Individual Pwer Ranges Eah previus alternative may be applied in a unique design fr eah pwer range. The mdular apprah appears ptimum, but is nt required fr the implementatin f an HFA-PFC System. Unique designs uld be reated fr the 20 kw, 40 kw, and 60 kw levels, fr instane. There is n rrespnding blk diagram fr this alternative, as it is essentially eah f the alternatives previusly disussed MPUTER MDELS AND SIMULATINS Cmputer simulatins were perfrmed n the < > Summing transfrmer arhiteture t demnstrate sme iruit simulatin apability during this prjet. A set f data was generated fr 1 bridge, 2 bridge, 4 bridge, and 6 bridge nfiguratins. Cmputer simulatins take a large amunt f time t effet a realisti mdel where data has signifiant meaning. The simulatins were limited t the ne apprah during the Phase I effrt. It wuld have be easy t spend all the prjet time fusing n the simulatin f ne arhiteture, let alne attempting t perfrm simulatins n all the variatins. The simulatins presented fr this phase f the prjet d nt represent ptimized detailed designs. They are intended t demnstrate the iruit peratin alng with sme f the idisynrasies f the arhiteture simulated. These simulatins wuld be an integral part f a design undertaken t pursue develpment f the HFA-PFC System. Simulatin results are lated in Appendix E. The shemati fr the 6 bridge Summing Cnverter is shwn in the first setin. The bridge nfiguratin in this shemati is idential t 4, 2, and 1 bridge 41

48 simulatins. Simulatins were als perfrmed n nverter iruits with and withut an utput filter t shw the redutin in harmni ntent as the number f steps inreases, and the rrespnding redutin in utput filtering requirements. The send setin in Appendix E shw the simulatin results f a 6 bridge summing nverter arhiteture with an utput harmni filter. The utput pwer rating is 100 kw. The first set f data shws the harmni dempsitin f the utput wavefrm. The plts that fllw are titled, and represent a harmni spetrum f the utput vltages, line-t-neutral utput vltages, line-t-line utput vltages, expanded plts f utput vltages, and line urrents. The next setin shws the same infrmatin fr the same nverter nfiguratin at apprximately n lad. The fllwing setin simulates the idential 6 bridge nfiguratin, but withut an utput filter. The utput pwer level is 100 kw. The respetive data is inluded in this setin. The wavefrm smthing apparent in the utput vltage plts is due t the simulated leakage indutane f the utput transfrmer. As will be seen with the next set f plts, this smthing is lad dependent sine the leakage indutane is effetively in series with the utput nnetins. The next setin simulates the same "filterless" iruit at apprximately n lad. The disrete summatin f the square wave mde utput bridges may be seen in the stepped appearane f the utput wavefrms. Althugh, this utput appears very jagged, its atual ttal harmni distrtin is apprximately 4.8%. The leakage indutane filtering effet has a dereasing affet n the utput wavefrm as the lad urrent dereases. Frm these simulatins, it may be seen that a small amunt f utput filtering is required. The last setin in Appendix E shws the utput vltage wavefrm fr the different bridge nfiguratins f the summing nverter. An imprtant result f the simulatins is an analysis f the utput harmni ntent fr varius summing nverter nfiguratins. Table 1 summarizes the results fr a 6 bridge nfiguratin with and withut an utput filter fr varius lads. This infrmatin was derived frm the tabular PSPICE utput where a Furier analysis is perfrmed n a partiular nde. 42

49 Table 1. Six - Bridge Cnverter utput THD Perent Ttal Harmni Distrtin (%THD) utput Pwer Unaltered utput Filtered utput 17 kw kw kw kw kw kw kw apprx 0 kw A mparisn %THD f the different bridge nfiguratins is shwn in Table 14. Table 14. N Lad utput %THD fr Varius utput Bridge Cnfiguratins utput Bridge Cnfiguratin Unfilter utput (%THD) 6 Bridge Bridge Bridge Bridge 0.55 As an be seen, the abve simulatins are quite invlved, and nsume a large amunt f prjet time. Simulatins f all pssible nfiguratins wuld have been impratial at this pint f neptual design and preliminary design stages. The simulatins are required during a detailed design phase in rder t ptimize the detailed iruit designs, and assist in validating design and peratin. Simulatins will als prve invaluable during prttype fabriatin and test. 4

50 4.4. HF A APPRACH PTIMIZATIN A review f High Frequeny Alternatr (HFA) tehnlgy was undertaken using riteria and evaluatin tehniques similar t thse used in the aerspae industry. Primary nsideratins fr evaluating weight redutins in generatr tehnlgy are the speed range and the rrespnding appliable mahine design. The net result f this effrt shws a signifiant pprtunity t prvide substantial weight and size redutins with respet t the generatr. The results f this wrk task are summarized in the Table 15. The table shws the preferred mahine tehnlgy appliable t a rrespnding pwer range. The pwer ranges supprt the mdular nept fr the standard family f generatr sets established earlier. They are idential t the pwer ranges used under the PFC setin. It is imprtant t nte that the pwer range values reflet the pwer level at the utput f the engine generatr set. The atual pwer utput f the HFA is slightly higher by the amunt equivalent t the PFC lsses. Fr instane the HFA required fr the 20 kw system will have an utput f apprximately 21.7 kw. A majr generatr weight redutin is pssible thrugh peratin at higher speeds. The andidate speed ranges f generatr peratin are well within the perating apabilities f their respetive tehnlgy. Mehanial designs are valid in these speed ranges, as many turbines engines use rtrs with similar and larger mments f interia, and supprt bearings, t handle the lading and speeds seen by the HFA. The HFA weights are based upn the mdular HFA-PFC design nept. The weights given in the table rrespnd t the basi mdule HFA fr the respetive pwer range. Fr instane, the kw range weight is fr the 20 kw mahine that may be nfigured in parallel, as desribed under the HFA-PFC setin, t yield 40 r 60 kw utput. These weights are nsidered nservative in the aerspae industry, espeially when nsidering the perating speeds. Reent tehnlgy trends prvide pwer densities as high as lb/kva fr il led mahines. Air led mahines have als experiened inreased pwer density t 1.07 lb/kva frm levels f 2.5 kva in the 1950's. Air ling tehniques were seleted fr HFAs in the range frm 0.5 t.0 kw based upn their simplisti design. Air ling yields a slightly larger design and lwer pwer density. Cmpared t the urrent systems, a signifiant imprvement is realizable. il led HFAs are used in the higher pwer ranges in rder t yield signifiant weight savings ver air led mahines. Signifiant HFA ptins are shwn that have the ptential t ntribute t additinal weight savings when nsidering the entire system. This primarily invlves using the HFA as an eletri starter fr engine start funtin. The Swithed Relutane Mahine (SRM) tehnlgy almst prvides this peratin as an intrinsi funtin t the design. The SRM exitatin tehnique is idential in bth generatr mde and mtr mde. The prime differene is where the exitatin is applied relative t the angular psitin f the rtr. Sme f the tehnlgy appliatins will atually hange in the future as thers beme mre favrable. Fr example, ne f the realisti limiting fatrs with variable relutane tehnlgy appliatins is the pwer semindutrs used t exite the mahine. As their pwer rating inreases, they will be apable f supprting the VRM tehnlgy. At this pint, the VRM tehnlgy will mve int favr fr the highest pwer appliatin f kw. Likewise, as the st f permanent magnet material is redued with inreased use, the PM tehnlgy mahine may mve int the 5-15 kw range in rder t take advantage f a redued quantity f pwer semindutrs in the assiated PFC. 44

51 E a. * ü-- 55 Q p - 8 C 'a> -a * jr- C T" * 5 III a. W w 5 1 m 1 >" Ü "5 UJ E d Q. ^ (0 <D >fr * a> CM CM Ü i T UJ.Q C ü Ü 45 CM" > *r~ LU VI a e ' #y. a. < * a es H Ul E Ü (D a. ^ «5 JC ' s : <tf h- a: 1 CM ZJ UJ 1 a Ü Ü s S? CM a. > CM UJ E Ü a. 1 Ö 55 ^ i <* ) a: ^_ XT T5 UJ I T XJ C Ü 4? CM > CM UJ AC as ) a. E a. " en I E w m " *- in r- i 1 < i t Weight, lbs (Base Mdular Unit fr Pwer Range) a>. G" 'S C u 1 <0 s 1

52 IDENTIFICATIN F ALTERNATE TECHNLGIES HFA alternate tehnlgies inlude a variety f eletri mahine tehnlgies, and a subset f tehnlgies appliable arss the variety f eletri mahines. The mprehensive set f mahine tehnlgies available fr implementing HFA designs is t numerus t inlude in this reprt. Therefre, a sample f likely andidates was dwn seleted fr evaluatin. These inlude: Permanent Magnet A favrable tehnlgy knwn fr mpat size and light weight designs. Variable Relutane Well knwn tehnlgy that is seeing a renewed interest due t the inreased apability f the pwer eletrnis needed fr exitatin and nversin. Wund Rtr Brushless DC This is a traditinal synhrnus generatr using a dubly fed nfiguratin with rtr exitatin upled by eletrmagneti means. These mahine tehnlgies are explained in further detail later in this setin. Unique harateristis f eah mahine are disussed, as well as speial nsideratins fr appliatin f eah tehnlgy where appliable. The subset f tehnlgies appliable t the mahines being evaluated inlude: perating speed Cling tehniques Generatr ple nfiguratin utput phase nfiguratin Future trends As previusly desribed, the single largest fatr attributing t weight redutin is the inreased HFA perating speed. This is based upn the fat that magneti material peak perating flux dereases as frequeny inreases fr a given re size and pwer level. By inreasing the perating speed, the HFA fundamental perating frequeny is inreased, and the weight an be redued fr the same utput pwer rating The weight relatinship is inversely prprtinal t the perating frequeny, negleting re lsses. Realisti upper limits are enuntered when windage, re lss, and ndutr skin effet at high frequenies assiated with high speed is taken int aunt. Typial 4 ple, 60 Hz generatrs perate at 1800 rpm. Present day 2 ple, 400 Hz airraft generatrs perate at 24,000 rpm. The HFA-PFC nept allws even higher perating speeds sine the utput frequeny is nditined by the PFC. perating speeds as high as 60,000 rpm are neivable and inline with turbine engine mahinery velities. The perating speeds evaluated during this prjet (up t 44,000 rpm) are up t 24 times the urrent nminal speeds. Present APU turbine engines perate between 40,000 and 60,000 rpm having rtr masses similar t the HFA rtr masses being nsidered. An alternative t inreasing generatr speed is t inrease the ple unt f the mahine. Dubling r quadrupling the ples wuld theretially redue the generatr magneti material weight by half and a quarter, respetively. While these are reasnable weight redutins, they are nt ptimized. Inreasing the number f ples beynd this is generally nsidered impratial frm a physial layut perspetive. Additinally, the PFC weight will be inreased substantially t aunt fr inreased input filtering required fr the lwer input frequeny. As will be seen in the setins desribing the individual mahine tehnlgy, eah has its wn speed limiting fatr. Speial nsideratins must be given t the mehanial designs f these high speed mahines. Upper speed limits n mahines based n mehanial parameters inlude windage lsses, 46

53 mehanial integrity, and bearing ratings. Anther imprtant nsideratin fr high speed peratin is bearing tehnlgy and their lubriatin tehniques. il lubriated bearings perate well in the high speed ranges. Grease paked bearings are usually appliable t abut 15,000 t 18,000 rpm maximum. Mahine ling tehniques are anther mmn design aspet amng the HFA types. Several fundamental apprahes are available inluding air led, il led, and liquid led. The simplest apprah is usually air ling, whih is als the least effiient. Air ling may be amplished by impinging air flw diretly thrugh the enter f the HFA This tehnique has drawbaks when the system is perated in a hstile envirnment suh as dust. Freign matter an erde eletrial insulatin, ause partiulate matter buildup, and eventually ause a dieletri breakdwn. If the system is perated in a high humidity r wet envirnment, this will aelerate dieletri breakdwns by ingesting water. These diffiulties may be averted by using a lsed frame design with a nvetin ling tehnique t draw heat frm the mahine internals and transfer it t the frame r ase. Here it may be dissipated t the ambient thrugh ling fins whih imprve the heat transfer effiieny. The lw thermal effiienies assiated with heat transfer in air require large surfae areas fr dissipating heat. This ntributes t a larger mahine design. Air ling als presents a nflit with high speed peratin and the use f traditinal grease paked bearings in air led designs. Upper speed ranges are typially limited t abut 18,000 rpm. il lubed bearings, with the added mplexity f integrating an il lubriatin system and seals, must be used t extend the perating speeds. New erami bearing tehnlgy may be used t eliminate lubriatin requirements in the future. Fred air led mahines must prvide a sure f ling air. If a fan is designed as an integral mpnent, nsideratin must be given t the mahine perating speed. Fans rtating at high velities prdue high levels f high frequeny nise. An alternative is t use an air pump perating frm a lw speed take-ff frm the engine t supply a high vlume air flw. Natural nvetin ling and ling fins may be used t aid in remving lsses frm the statr and husing. il ling an prvide additinal weight savings by imprving heat transfer harateristis, and allwing the ling interfaes t be smaller. In sme ases a 50% redutin in weight is pssible ver the equivalent air led mahine. Cling effiieny is imprved by passing il diretly thrugh the mahine. This may be in passages arund the statr, thrugh the rtr, r interleaved with the statr windings. il led mahines prvide a lsed design t the atmsphere, eliminating intrusin by freign ntaminants. il ling an be perfrmed by an individual system that is dediated t the HFA with a heat exhanger t the atmsphere, r t the main engine radiatr. ptinally, the HFA may have a shared il system with the engine and gearbx. il ling tehniques prvide a means fr lubriating bearings and flushing partiulate matter t prvide lng life. Tw basi types f il led mahines are pssible. Spray ling disperses il n the rtr and slings it ff t prvide statr ling. Cndutin ling direts il flw thrugh passages near and arund windings and laminatins t extrat heat. Spray ling is usually a simpler mahine that desn't require as many dynami seals as the ndutin led mahine when rtr windings must be led. The spray led tehniques are mre favrable fr BLDC mahines. SRM and PM designs are easily mpatible with ndutin ling sine the statr and statr windings are f primary nern. il led mahines prvide an integral means fr bearing lubriatin. il led mahines are a mmn appliatin in the aerspae mmunity. Cndutin il led mahines are very mmn in military airraft where all attitude peratin is imprtant. Engine lant is very similar t the ndutin il led apprah. This tehnique wuld take the ndutin ling priniples frm il led systems and apply them t the mahine frame f a PM mahine r SRM where the priniple nern is in ling the statr windings and statr. The mahine husing must have passages as an integral part that are in prximity t the statr stak Shared engine lant is irulated thrugh these passages t remve heat frm the statr and windings via ndutin thrugh the statr. The PM mahine and SRM are ideal andidates fr this type f ling. This apprah has the large advantage f nt requiring any speial ling hardware, and may diretly integrate with the engine. The engine radiatr must be sized t ammdate and dissipate the additinal heat rejetin. As 47