Three-phase Unity-Power-Factor VIENNA Rectifier with Unified Constantfrequency

Transcription

1 0- Three-phse Unity-Power-Ftor VIENNA Retifier with Unified Constntfrequeny Integrtion Control Chongming Qio nd Keyue M. Smedley Deprtment of Eletril nd Computer Engineering Uniersity of Cliforni, Irine, CA 9697 Tel: ( , Fx: ( , emil: ui.edu Astrt: A Unified Constnt-frequeny Integrtion (UCI ontroller for three-phse three-swith three-leel retifier (VIENNA with unity-power-ftor-orretion is proposed. One dntge of the VIENNA retifier is tht the swith oltge stress is one hlf of the totl output oltge so tht MOSFETs n e used. The proposed ontrol pproh is sed on oneyle ontrol nd fetures gret simpliity nd reliility: ll three phse will e power ftor orreted using one integrtor with reset long with seerl flips-flops, omprtors nd logi nd liner omponents. It does not require multipliers to sle the urrent referene ording to the output power leel s used in mny other ontrol pprohes. In ddition, the input oltge sensor is eliminted. It employs onstnt swithing frequeny modultion tht is desirle for industril pplitions. The proposed ontroller n operte y sensing either the indutor urrents or the swithing urrents. If the swithing urrents re sensed, the ost is further redued euse swithing urrents re esier to sense ompring with indutor urrents. The proposed pproh is supported y experimentl results. Introdution Trditionl diode retifiers nd thyristor retifiers drw pulsed urrent from the min, using signifint urrent hrmonis pollution. The interntionl stndrds presented in IEC or EN imposed hrmoni restritions to modern retifiers, whih stimulted foused reserh effort on the topi of unity power ftor retifiers. Among the reported three-phse retifier topologies, three-phse three-swith three-leel retifier (VENNA retifier []-[] is n ttrtie hoie euse its swith oltge stress is one hlf of the totl output oltge so tht fst swithes suh s MOSFETs n e used. In this pper, Unified Constntfrequeny Integrtion (UCI ontroller sed on one-yle ontrol [4]-[7] is proposed for this retifier. The proposed ontroller employs onstnt swithing frequeny modultion nd is ery simple tht re ery desirle for industril pplitions. Assuming tht the retifier is operted in Continuous- Condution-Mode (CCM, generl eqution tht reltes the input phse oltge nd duty rtios of swithes is deried from n erge model. Bsed on one of the solutions nd using One-Cyle ontrol, UCI ontroller is proposed for the VIENNA retifier with the following fetures: Constnt swithing frequeny. Simple nd relile. This ontroller is omposed of one integrtor with reset long with some flips-flops, omprtors, nd some logi nd liner omponents. No need for multipliers tht re required to sle the urrent referene ording to the lod leel s used in mny other ontrol pprohes. No -phse oltge sensors re required. The proposed ontrol pproh n e hieed y sensing either the indutor urrents or the swithing urrents. If the swithing urrents re sensed, the ost is further redued euse swithing urrent is esier to sense ompring with indutor urrents. Proposed Unified Constnt-frequeny Integrtion ontroller for the -phse VIENNA retifier V V V O L L O Dp D n A Dp Dn L B L L Dp S S Dn Fig.. The -phse VIENNA retifier nd its swithing yle erge model. The shemti nd its swithing yle erge model for the VIENNA retifier re shown in Fig.. The erge etor oltge t nodes A, B, C referring to the neutrl point O equl the phse etor oltges minus the oltge ross the indutors L, L, L, whih is gien y A B C S C N N E E

2 , ( < iwhen d(( < =0 0 iwhen diwhen Ed d d, S S,, = = isign dvisign dv, ( isign < =0 ( Eisign =e e ir ir Re (( = m ivisign disign d (, 0- & = & jwl i& L & = & jwl i& L ( & = & jwl i& L L is the indutne of the input indutors nd w is the line ngulr frequeny if we ssume tht the indutne for r r r ll three-phse is sme. The symols i, i, i signify indutor urrent etors. The indutne L is ery smll with regrds to the line frequeny rition, sine the indutors re designed for swithing frequeny opertion. For 60Hz utility system, the oltges ross the indutor jwl r is ery smll ompring with the phse oltge, i L thus n e negleted. Therefore, the eqution ( n e pproximtely simplified s & & & & & &, = V = V = V gp gp gp sin sin sin L L L ( wt ( wt + 0 ( wt (, re yle erge of the oltge t nodes A,B,C referring to node O nd V gp re pek of the phse oltge. For three-phse system, it holds tht = ( + Eqution ( leds to = (4 + The oltges t nodes A, B, C referring to the neutrl point O re gien y = = = ---(5 Comintion of eqution (4 nd (5 yields = ( (6 Sustituting eqution (6 nd ( into (5 results in ( ( = ( Simplifition yields = (7 For the VIENNA retifier, if the onerter opertes in CCM, the erge node oltges in eh swithing yle re gien y respetiely. Simplifition yields of indutor urrents. For exmple, re duty rtios of swithes ( (8 Sustitution eqution (8 into eqution (7 yields depends on the polrity -----(0 Eqution (0 shows the inherent reltionship etween the duty rtios nd the input phse oltge in CCM ondition. For three-phse retifier with unity-power-ftor, the ontrol gol is gien y ( is the emulted resistne tht reflets the output power leel. Sustitution of the oe eqution into (0 nd simplifition yield ---(

3 Rs Vm mr V += += miki dviki dv,k K siri K + K=sR ;0 = s ms miri dviri = = i ii sign i(( i i, (( = Lpk mlpk dv e = 0= 0- is the equilent urrent sensing resistor nd the output of the feedk error ompenstor. is ( Sine the mtrix in eqution ( is singulr, there is no unique solution. One simple solution n e found s ( (4 re onstnt. Prmeters n e determined y sustituting the oe eqution in eqution ( whih results in the following: prmeter n e ny rel numer, while prmeter stisfies the following (5 For -phse system, it holds tht Comintion of the oe two equtions yields. Selet rewritten y. The eqution (4 n e (6 With the ssistne of the following equtions, the oe eqution n e simplified s shown in eqution (7 --(7 This is the ontrol key eqution for the VIENNA retifier. The solute lue of urrent n e relized y using three full-we retifier iruits. No oltge sensors re required. The implementtion n e hieed y sensing either indutor urrents or swithing urrents. Replement of the ontrol implementtion equtions: with pek indutor urrent results in the Fig.. Shemti of proposed -phse PFC ontroller for VIENNA retifier y sensing pek indutor urrents nd its opertion weforms. Eqution (8 n e relized y one integrtor with reset s well s some logi nd liner omponents. The proposed ontroller s well s its opertion weforms for pek indutor urrent sensing re shown in Fig. ; the

4 =τst pd D, i i i n 0-4 integrtion time onstnt equls the swithing period, i.e.. Fig.. Experimentl -phse VIENNA retifier. Experimentl erifition In order to erify the onept, kw prototype of -phse VIENNA retifier with proposed ontrol pproh using pek indutor urrent sensing ws uilt. The VIENNA retifier in the experiment is shown in Fig.. The experimentl ondition is s follows: -phse input filter indutne is 88uH; input filter pitne is uf; min indutne is.4mh; diodes, et re MUR800; the three min swithes re implemented with two MOSFETs in series kto-k. The input oltge is 0Vrms. The output oltge is 485V. The output resistne is ohm nd the output power is kwtts. The swithing frequeny is 00kHz. The experimentl weforms re shown in Fig. 4. Fig. 4 shows three-phse indutor urrents; Fig. 4 shows the phse oltge nd phse urrent. The mesured THD is 6.5% while the input oltge hs out 4% THD itself.. Phse A oltge nd urrent. Upper ure: input oltge, 0V/di; sensed through 0V: 6V trnsformer Bottom ure: input Phse A urrent, 5A/di. Fig. 4. Experimentl weforms for -phse VIENNA retifier with proposed ontrol pproh. 4 Extension of the proposed ontrol pproh y sensing swithing urrents The VIENNA retifier with unity-power-ftor n lso e implemented y sensing swithing urrent, whih osts less ompring with indutor urrent sensing. One possile implementtion of swithing urrent sensing is illustrted in Fig. 5. Three-phse input urrents. R:, 5A/di. Horizontl: 5ms/di., 5A/di. R:, 5A/di. R:

5 =Lpk = SL Si dii (( = = Spk mspk mir dvir dv E600 fmh L.4, 0,= Lpk sv kw PkHz ( Fig. 5. Illustrtion of swithing urrent sensing with urrent trnsformer for VIENNA retifier. One leg of VIENNA retifier. Swithing urrent sensing. When the indutor opertes in CCM, the reltionship etween the indutor urrent nd swithing urrent is gien y Eqution ( shows tht -PFC for VIENNA retifier n e relized y sensing swithing urrent. The shemti for the ontrol lok is shown in Fig. 6. Simultion results re shown in Fig. 7. The simultion onditions re s follows: the input phse oltge is 0Vrms; the output oltge is ;. The mesured THD is % (9 nd ---(0 Reple the indutor pek urrent with swithing urrent in eqution (8 yields Fig. 7. Simultion results for -PFC for VIENNA retifier with pek swithing urrent sensing. Opertion weforms of the ontroller.. Simulted indutor urrent weforms. Fig. 6. Shemti of -PFC ontroller for VIENNA retifier with pek swithing urrent ontrol. The ontrol sed on pek swithing urrent sensing is more sensitie to noise. Sensing erge swithing urrent is n lterntie solution. Reple the erge indutor urrent in eqution (8 with erge swithing urrent in eqution (0 yields

6 (( = = S ms mir dvir dv ( md V s s ( The item n e relized with two integrtors with reset. The shemti of ontrol lok for VIENNA retifier with erge swithing urrent sensing is shown in Fig. 8 nd simultion results re shown in Fig. 9. Fig. 9. Simulted weforms for -phse VIENNA retifier with erge swithing urrent sensing.. Opertion weforms of ontrol lok.. Simulted three-phse indutor urrent wefroms. The simultion onditions re: the input oltge is 0Vrms, the output oltge is 600V; the swithing frequeny is 0KHz, the power is 6KW; nd the mesured THD is 0.%. Fig. 8. The shemti of ontrol lok for -PFC VIENNA retifier with erge swithing urrent sensing. 5 Conlusion In this pper, three-phse three-swith three-leel (VIENNA retifier with unity power ftor is inestigted. A generl eqution tht reltes the reltionship etween input phse oltge nd swith duty rtios is deried. Bsed on one of the solutions nd using One-Cyle Control, new -phse PFC ontroller is proposed. The proposed ontroller is omposed of one or two integrtors with reset long with seerl omprtors nd flip/flops. No multipliers nd input oltge sensors re required. The ontroller employs onstnt frequeny modultion tht is desirle for industril pplitions. An experimentl iruit of kw VIENNA retifier with pek urrent sensing ws uilt to erify the onept. Ner unity power ftor ws mesured in ll three phse. The proposed ontroller n e implemented y sensing either indutor urrents or swithing urrents. The ontroller is ery simple nd relile. Referenes: [] Kolr, J.W, Drofenik.; Zh, F.C. Current hndling pility of the neutrl point of three-phse/swith/leel oost-type PWM (VIENNA retifier. PESC 96 Reord. p.9-6 ol.. [] Kolr, J.W; Zh, F.C. A noel three-phse utility interfe minimizing line urrent hrmonis of high power teleommuntions retifiers modules, IEEE Trns on Industril Eletronis, ol. 44, IEEE, Aug P [] Kolr, J.W, Ertl, H; Zh, F.C. Design nd experimentl inestigtion of three-phse high power density high effiieny unity-power-ftor PWM (VIENNA retifier employing noel integrted power semiondutor module. APEC 96, Sn Jose, CA. IEEE, 996, p.54- ol.. [4] Smedley, K. nd Cuk, S. One-yle ontrol of swithing onerter, PESC, 99. [5] Li, Z, nd Smedley,K.M. A Generl Constnt Frequeny Pulse- Width Modultor nd Its Applitions. IEEE Trnstions on Ciruits nd Systems I: Fundmentl Theory nd Applitions, ol 45.(no.4, IEEE, April, 998.P [6] Qio, C. nd Smedley, K.M. A Generl Three-Phse PFC Controller. Prt I for retifiers with Prllel-onneted Dul Boost Topology, IEEE IAS 99. [7] Qio, C. nd Smedley, K.M. A Generl Three-Phse PFC Controller. Prt II for retifiers with Series-onneted Dul Boost Topology, IEEE IAS 99.