VECTOR CONTROL OF INDUCTION MOTOR DRIVE BY USING THE CONSTANT SWITCHING FREQUENCY CURRENT CONTROLLER FOR REDUCED RIPPLE

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1 Acta Electotechnica et Infomatica, Vol. 3, No. 3, 203, 27 33, DOI: /aeei VECTOR CONTROL OF INDUCTION MOTOR DRIVE BY USING THE CONSTANT SWITCHING FREQUENCY CURRENT CONTROLLER FOR REDUCED RIPPLE M. RAMA PRASAD REDDY, T. BRAHMANANDA REDDY,Membe, IEEE, B. BRAHMAIAH EEE Depatment, Si Vaavi Engineeing College, T.P. Gudem, A. P, India, EEE Depatment, G. Pulla Reddy Engineeing College (Autonomou), Kunool, A. P, India, Guntu College of Engineeing, Guntu, A. P. India. ABSTRACT Thi pape peent a novel and imple vecto contol algoithm fo induction moto dive. The claical vecto contol and diect toque contol algoithm give the decoupled contol. But, the claical vecto contol algoithm ue efeence fame tanfomation, which inceae the complexity of the algoithm fo implementation. Wheea the diect toque contol i imple fo the implementation by uing the lookup table appoach, but, it give lage teady tate ipple in toque, flux and cuent. Hence, to ovecome the dawback of both vecto contol and diect toque contol, the popoed method combine the pinciple of both vecto contol and diect toque contol. In the popoed algoithm, the d- and q-axe efeence cuent ae geneated a pe the pinciple of vecto contol algoithm and vecto baed hyteei compaato integated with look-up table ae ued a pe the pinciple of diect toque contol. Moeove, to educe the toque ipple, a novel contant witching fequency cuent contolle i popoed. To validate the popoed method numeical imulation have been caied out and compaed with the exiting algoithm. The imulation eult how the effectivene of the popoed technique. Keywod: Diect Toque Contol, Induction moto, witching table, vecto contol. INTRODUCTION Nowaday in many indutial application DC dive ae eplaced by induction moto dive due to thei numeou advantage like low maintenance and low weight volume atio. But, DC dive have advantage like high tating toque and decoupled contol of toque and flux. To achieve chaacteitic of DC moto in induction moto dive both toque and flux ae to be contolled independently. Thi independent contol o decoupled contol can be achieved in induction moto by uing field oiented contol. With the advent of vecto contol o field oiented contol (FOC) technique, the induction moto became popula in vaiable peed dive application []. The invention of the FOC bought a enaiance in the high pefomance peed contol of induction moto dive. To impove the pefomance of vecto contol tategy, many technique have been popoed in [2]-[4]. Though vecto contol algoithm achieve a decoupled contol with good tanient epone, the complexity involved in the technique i moe due to the eveal tanfomation. To achieve the decoupled contol with educed complexity, late the diect toque contol (DTC) ha been developed by Takahahi [5]. The DTC diectly contol the both toque and flux without tanfomation by uing the hyteei contolle and lookup table. Moeove, the enitivity to the paamete vaiation i alo le when compaed with the FOC. The detailed compaion between FOC and DTC ha been dicued in [6]. Though, the DTC give good dynamic epone, it give lage teady tate ipple in toque, flux and cuent. Wheea, the FOC give le teady tate ipple when compaed with the DTC. The claical cuent contol algoithm ue the hyteei contolle fo the geneation of witching pule. To educe the complexity involved in the implementation of cuent contolle, a novel and imple appoach ha been peented in [7] by uing the lookup table appoach. Moeove, to achieve the contant witching fequency, a contant cuent contolle i peented in [8]-[9] in which, the cuent eo ignal will be compaed with the tiangula caie ignal. Hence, to ovecome the dawback of FOC and DTC, thi pape peent a new field oiented contol o vecto contol cheme, which combine the pinciple of both vecto contol and DTC. To educe the toque ipple futhe and to maintain a contant witching fequency, a imple cuent contolle i intoduced to eplace the conventional hyteei compaato. By pope election of the cuent contolle paamete, the evee voltage vecto election i avoided duing toque eduction. The popoed algoithm ue ophiticated lookup table to geneate the PWM ignal to the invete. Moeove, the popoed method doe not equie efeence fame tanfomation and give good teady tate and tanient pefomance. 2. CONVENTIONAL VECTOR CONTROL In the FOC, the decoupled contol can be achieved by tanfeing all the quantitie to ynchonou efeence fame and eolving the tato cuent vecto a toque poducing cuent component iq and flux poducing cuent component i d. The electomagnetic toque expeion fo an induction moto i given a T e = 3 P L 2 2 L m ( ψ i ψ i ) d q q d To achieve decoupled contol, id i oiented along the oto flux linkage vecto, and the iq i pependicula to the oto flux vecto. Thu, the entie oto flux i aligned along d-axi and hence the q-axi flux component will () ISSN (online),

2 28 Vecto Contol of Induction Moto Dive by Uing the Contant Switching Fequency Cuent become zeo. Hence, the toque expeion can be expeed a given in (2). T 3 2 P L ( ψ i ) m e = d q 2 L (2) Hence, the total oto flux can be given a in (3). ψ =ψ d = Lmid (3) Fom (3), it can be obeved that the oto flux i diectly popotional to i d and i maintained contant. Hence, the toque linealy depend on i q, and povide a toque epone a fat a the i q epone. Baed on calculation of oto flux poition angle the vecto contol algoithm can be claified a diect and indiect vecto contol algoithm. In many indutial application, the indiect vecto contol algoithm i popula. In indiect vecto contol the lip fequency and oto flux linkage poition angle can be evaluated fom (4) and (5). L R m ω l = iq (4) Lλ ( ω + ωl ) θ = θ + θl = = ω (5) 3. PROPOSED VECTOR CONTROL In the popoed indiect vecto contol algoithm the electomagnetic toque equation given in (2) can be modified a 3 P Lm T e = λ i inδ (6) 2 2 L whee δ i the angle between tato cuent and oto flux linkage vecto. Fom (6), it can be obeved that the toque can be vaied by vaying the δ. Hence, fat toque contol can be achieved by changing δ in the equied diection. Fo a hot time inteval, the oto flux linkage vecto i almot unchanged in pace due to oto inetia. Hence, the apid change of electomagnetic toque can be poduced by otating the tato cuent vecto in the equied diection accoding to the efeence toque. By ignoing the tato eitance dop, the tato voltage can be expeed a given in (7). dψ v = (7) The tato and oto flux linkage pace vecto of an induction moto can be expeed a given in (8) and (9). ψ (8) = L i + Lmi ψ (9) = L i + Lmi Fom (9), the expeion fo oto cuent can be calculated a L i m = ψ (0) L i By putting (0) in (8), the tato flux linkage vecto expeion can be obtained a in (). 2 Lm Lm ψ = Li + ψ i () L L Fo hot time duation, by auming the oto flux linkage vecto a contant, the voltage expeion can be implified a follow. v dψ = = L 2 m L L di = σl di (2) whee σ i the leakage coefficient of induction moto. Fom (2), fo a hot time inteval of t, the tato cuent vecto can be obtained a i = σl v t Thu, the tato cuent pace vecto move by (3) i in the diection of the tato voltage pace vecto at a peed popotional to magnitude of voltage pace vecto. By electing a uitable voltage vecto it i then poible to change the tato cuent in the equied diection. Decoupled contol can be achieved by acting on the id and i q component of the tato cuent vecto. Thee two component ae diectly popotional to the component of the tato voltage vecto in the ame diection. By auming a low motion of the oto flux linkage pace vecto, if an active voltage vecto i applied in fowad diection then it caue apid movement of i and toque inceae with δ. On the othe hand, when a zeo voltage vecto i ued, i become tationay and the electomagnetic toque will deceae, ince oto flux continue to move in the fowad diection lowly and the angle δ deceae. Thu, the peed of the tato cuent vecto can be egulated by uing the diffeent voltage vecto in each ampling time peiod a hown in Fig.. Thi i the baic pinciple of opeation of the popoed vecto contol algoithm. Movement with active fowad vecto Stop with zeo vecto Movement with active backwad vecto Rotate continuouly Fig. Movement of tato cuent vecto unde the influence of voltage vecto The election of the voltage vecto can be done by uing the concept of diect toque contol (DTC). In the claical DTC, fo the election of uitable voltage vecto, a thee-level hyteei contolle fo toque loop and a two-level hyteei contolle fo flux loop ae conideed. Same a DTC, in the popoed vecto contol ISSN (online),

3 Acta Electotechnica et Infomatica, Vol. 3, No. 3, alo, a 3-level and 2-level hyteei contolle can be conideed fo toque component and flux component cuent contolle. But, a thee-level toque component cuent hyteei contolle will give vaiable witching fequency opeation, which will caue moe ipple in the teady tate toque. Hence, to ovecome thi dawback, in thi pape a contant witching fequency baed cuent contolle i popoed. The tuctue of the popoed toque component cuent contolle i a hown in Fig. 2. Fig. 2 Block diagam of the popoed cuent contolle The popoed toque component cuent contolle conit of two tiangula caie ignal, which ae 80 o out of phae each othe, two compaato and one popotional integal (PI) contolle. The abolute value of the dc offet fo the tiangula wavefom ae et to half of thei peak to peak value. Becaue of the two oppoite caie ignal (uppe and lowe), the output of the popoed cuent contolle i imila to that of a theelevel hyteei compaato. Hence, the output value of the popoed cuent contolle ae, 0 o -. Thi mean that imila voltage vecto and look-up table, a in the conventional DTC dive, can be ued. The value of the intantaneou output of the toque component cuent contolle ( S q ) i given by (4). Sq = 0,, fotc Cuppe foclowe < Tc < Cuppe, fotc Cuppe (4) The block diagam of the popoed vecto contol algoithm i a hown in Fig. 3. Fig. 3 Block diagam of the popoed vecto contolled induction moto dive A in conventional vecto contol, the toque cuent component ( i q ) and flux cuent component ( i d ) of tato cuent, ae at ynchonouly otating efeence fame. The eo ignal of d-axi and q-axi tato cuent will be given to epective cuent contolle. The d-axi cuent contolle conit of two-level hyteei contolle. The digitized output of d-axi cuent contolle can be obtained a if id id i then S d = and if id id + i then S d =0. The digitized output value of the popoed q-axi cuent contolle can be obtained fom (4). Then, the digitized output value of the d- and q-axe cuent contolle and oto flux angle will be given to the lookup table a input. Baed on thee thee input, the uitable voltage vecto can be elected fom the lookup table. The lookup table fo the popoed vecto contol algoithm i given in Table.. The elected voltage vecto will be applied to the VSI fed induction moto dive in ode to keep the cuent eo within limit. Table. Optimum voltage vecto witching table Secto S d S q I II III IV V VI V 2 V 3 V 4 V 5 V 6 V V 7 V 0 V 7 V 0 V 7 V 0 V 6 V V 2 V 3 V 4 V 5 V 3 V 4 V 5 V 6 V V 2 V 0 V 7 V 0 V 7 V 0 V 7 V 5 V 6 V V 2 V 3 V 4 ISSN (online),

4 30 Vecto Contol of Induction Moto Dive by Uing the Contant Switching Fequency Cuent 4. SIMULATION RESULTS AND DISCUSSION To validate the popoed vecto contol algoithm numeical imulation tudie have been caied out in Matlab-imulink envionment. Fo the imulation tudie the moto paamete ae taken a R =.57Ω, R =.2 Ω, L m =0.65H, L =0.7H, L =0.7H and J=0.089Kg-m 2. Moeove, fo the imulation eult equal band wih have been conideed fo the hyteei band in the popoed and exiting cuent contolled vecto contolled dive. The imulation eult of claical vecto contol algoithm ae hown in fom Fig.4 to Fig.9. The imulation eult of popoed vecto contol algoithm ae hown in fom Fig.0 to Fig.5. Fig. 6 Hamonic pecta of tato cuent in claical vecto contol algoithm Fig. 4 Stating tanient of claical vecto contol algoithm baed induction moto dive Fig. 7 Tanient duing the tep change in load (a 25 N-m load i applied at 0.5 ec and emoved at 0.7 ec) fo claical vecto contol algoithm baed induction moto dive Fig. 5 Steady tate plot of claical vecto contol algoithm baed induction moto dive Fig. 8 Tanient duing the peed eveal (fom +000 pm to -000 pm) fo claical vecto contol algoithm baed induction moto dive ISSN (online),

5 Acta Electotechnica et Infomatica, Vol. 3, No. 3, Fig. 9 Tanient duing the peed eveal (fom -000 pm to +000 pm) fo claical vecto contol algoithm baed induction moto dive Fig. 2 Hamonic pecta of tato cuent in popoed vecto contol algoithm Fig. 0 Stating tanient of popoed vecto contol algoithm baed induction moto dive Fig. 3 Tanient duing the tep change in load (a 25 N-m load i applied at 0.5 ec and emoved at 0.7 ec) fo popoed vecto contol algoithm baed induction moto dive Fig. Steady tate plot of popoed vecto contol algoithm baed induction moto dive Fig. 4 Tanient duing the peed eveal fo popoed vecto contol algoithm baed induction moto dive ISSN (online),

6 32 Vecto Contol of Induction Moto Dive by Uing the Contant Switching Fequency Cuent REFERENCES Fig. 5 Tanient duing the peed eveal fo claical vecto contol algoithm baed induction moto dive Fom the imulation eult, it can be obeved that the popoed vecto contol algoithm give good tanient epone imila to the claical vecto contol algoithm. Moeove, fom the teady tate imulation eult, it can be obeved that the popoed algoithm give educed teady tate toque ipple and cuent ipple. Alo, fom the hamonic pecta of line cuent, it can be obeved that the popoed algoithm give educed hamonic ditotion when compaed with the claical vecto contol algoithm. 5. CONCLUSIONS The decoupled contol tategy fo induction moto dive give fat tanient epone. The conventional vecto contol technique give bette dynamic pefomance but the complexity involved i moe due to the efeence fame tanfomation and PWM pocedue. Hence, to educe the complexity, a new vecto contol algoithm i popoed by combining the pinciple of both vecto contol and diect toque contol. The popoed vecto contol technique ue lookup table and eliminate the ue of efeence fame tanfomation and PWM pocedue. Moeove, to educe the toque ipple in teady tate a novel contant witching fequency baed cuent contolle ha been popoed. Fom the imulation eult it can be obeved that the popoed algoithm give good tanient pefomance imila to the claical vecto contol algoithm and give bette pefomance in teady tate when compaed with the claical vecto contol in tem of toque and cuent ipple duing teady tate opeation. [] BLASCHKE, F.: The pinciple of field oientation a applied to the new tanvecto cloed loop contol ytem fo otating-field machine, Siemen Review, 972, pp [2] LEONHARD, C. W.: 30 yea of pace vecto, 20 yea of field oientation, 0 yea of digital ignal poceing with contolled AC-dive, a eview (Pat). EPE Jounal, No., July 99, page [3] LEONHARD, W.: 30 yea of pace vecto, 20 yea of field oientation, 0 yea of digital ignal poceing with contolled AC-dive, a eview (Pat 2). EPE Jounal, No. 2, Oct, 99, page [4] SANTISTEBAN, J. A. STEPHAN, R. M.: Vecto contol method fo induction machine: an oveview, IEEE Tan. On Education, vol. 44, no. 2, pp , May 200. [5] TAKAHASHI, I. NOGUCHI, T.: A new quickepone and high-efficiency contol tategy of an induction moto, IEEE Tan. Ind. Applicat., vol. IA- 22, no. 5, Sep/Oct 986, pp [6] CASADEI, D. PROFUMO, F. SERRA, G. TANI, A.: FOC and DTC: Two Viable Scheme fo Induction Moto Toque Contol IEEE Tan. Powe Electon., vol. 7, no. 5, Sep, 2002, pp [7] KAZMIERKOWSKI, M. P. DZIENIAKOWSKI, M. A. SULKOWSKI, W.: Novel Space Vecto Baed Cuent Contolle fo PWM-Invete, IEEE Tan. Powe Electonic, vol. 6, no., Jan, 99, pp [8] IDRIS, N. R. N. YATIM, A. H. M.: Diect toque contol of induction machine with contant witching fequency and educed toque ipple, IEEE Tan. Ind. Electon., vol. 5, no. 4, Aug 2004, pp [9] TOH, C. L. IDRIS, N. R. N. YATIM, A. H. M.: Contant and high witching feqeuncy toque contolle fo DTC dive, IEEE Tan. Powe Electon. Lette, vol. 3, no. 2, June 2005, pp Received Augut 7, 203, accepted Septembe 20, 203 BIOGRAPHIES M. Rama Paad Reddy eceived the Bachelo of Engineeing degee in Electical & Electonic Engineeing fom Kanataka Univeity of Dhawad in 999 and Mate degee fom JNTU Kakinada in He i peently puuing Doctoal degee fom JNTU, Hydeabad. Cuently, woking a an Aociate Pofeo in Si Vaavi Engineeing College, Tadepalligudem, A.P. Hi aea of inteet ae in powe ytem, Powe electonic contol of dive. ISSN (online),

7 Acta Electotechnica et Infomatica, Vol. 3, No. 3, D. T. Bahmananda Reddy gaduated fom Si Kihna Devaaya Univeity, Anantapu in the yea 200. He eceived M.E degee fom Omania Univeity, Hydeabad, India in the yea 2003 and Ph.D fom J.N.T.Univeity, Hydeabad in the yea He i peently woking a Pofeo and Head of Electical and Electonic Engineeing Depatment, G. Pulla Reddy Engineeing College (Autonomou), Kunool, India. He peented moe than 00 eeach pape in vaiou national and intenational confeence and jounal. Hi eeach aea include PWM technique, DC to AC convete and contol of electical dive D. B. Bahmaiah eceived the Bachelo of Technology degee in Electical & Electonic Engineeing fom JNTU, Hydeabad in 979, and Mate degee fom National Intitute of Technology, Waangal in 982 and Ph.D fom JNTU, Hydeabad in 200. He i peently woking a Pincipal of Piyadahini Intitute of Technology, Tiupati. He peented many eeach pape in vaiou national and intenational jounal and confeence. Hi eeache aea include ae in Electical Machine and Powe Electonic Dive. ISSN (online),