Direct Power Control System of Voltage-Type PWM Rectifiers. Chun-ming ZHOU*

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1 016 International Conference on Alied Mechanic, Electronic and Mechatronic Engineering (AMEME 016) ISBN: Direct Power Control Sytem of Voltage-Type PWM ectifier Chn-ming ZHOU* College of Mechatronic Engineering, Eatern Liaoning Univerity, Dandong, China, *Correponding athor Keyword: PWM rectifier, Voltage orientation, Direct power control, Dal-cloed loop. Abtract. According to the mathematical model of voltage-type PWM rectifier nder the ynchrono rotating coordinate ytem, the power mathematical model are etablihed baed on voltage orientation. By analyzing the characteritic of the direct power control ytem, the doble-cloed loop trctre with power voltage-qare oter loop and power internal loop i derived in the paper. To olve the accracy of coordinate change, the deign of a ingle-phae voltage ignal phae-locked loop i deigned to obtain the accrate voltage phae. The theory i validated by MATLAB imlation experiment. The relt how that the deigned control ytem ha good dynamic and tatic performance and can atify the reqirement of voltage-type rectifier. Introdction PWM rectifier ha the advantage of low net ide crrent harmonic, nit power factor, bidirectional energy flow and DC voltage controlled, which can realize "green tranformation" of the electricity and can olve the "eliminating harmonic and reactive power" problem fndamentally[1-3]. It ha a broad alication propect in high power ninterrptible power ly, for qadrant AC inverter, the rlacement of the traditional power ytem, reactive power compenation, olar power, AC/DC tranmiion ytem, and other field. PWM rectifier have indirect crrent control and direct crrent control trategy. Indirect crrent control trategy i imple, bt the dynamic repone i low, and there are large DC and AC harmonic, which i enitive to ytem parameter [4,5]. Direct crrent control trategy can obtain good dynamic characteritic. Intantaneo power i alied to PWM rectifier cloed-loop control ytem make voltage-type PWM rectifier ha the advantage of higher power factor, low crrent harmonic ditortion rate, imple control algorithm and control ytem etc[6]. In thi paper, on the bai of detailed analyi of mathematical model, the direct power control ytem i deigned, and then, the dynamic and tatic characteritic and the ability to reit ditrbance of control ytem i validated by ing MATLAB imlation experiment. Mathematical Model of Voltage-type PWM ectifier Mathematical Model of Voltage-type PWM ectifier Baed on The Synchrono otating Coordinate Sytem The trctre of three-phae voltage-type PWM rectifier i hown in figre 1. The main circit inclde power ly, indctor, DC ide capacitor and rectifier-bridge. We take A phae for example, the other two phae i ame a it. Each bridge arm conit of for witch tbe VTA 1, VTA, VTA 3, VT A4 and for anti-parallel freewheeling diode VDA 1, VDA, VDA 3, VD A4 and clamped-diode DA 1, D A. e a, e b, ec i grid electromotive force, i a, i b, i c i AC ide crrent, Let UC 1 UC Udc /. AC ide KVL eqation in d-q coordinate ytem i hown a follow: di di d q du dc PL L id ed Liq Vd, L iq eq - Lid Vq, idc C dt dt dt U dc (1)

2 Where i c i capacitance crrent and i L i load crrent. Mathematical Model of Boot-type PWM ectifier Baed on Power In voltage orientation d qframe, 0 e Sbtitting it into (1), it follow that 1 p ed edvd Lq LS L 3 1 q edvq Lp LS L 3 e d q i contant, Intantaneo power i 3 p e i, 3 q e i, () d d d q ae be O ce ia VTA1 VTA L VTA3 V a a DA1 DA VTB1 VT C1 VTB VTC VTB3 V b b DB1 DB VTC3 cv c idc DC1 DC U dc P Z U dc C 1 C i L Load el hae Amplitde detection Phae detection f e inpt _ VTA4 VTB4 VT C4 e otpt N Figre 1. Diode-clamped three-level PWM rectifier. Figre. PLL baed on phae voltage. Deign of Control Sytem of Voltage-type PWM ectifier Dal-cloed Deign of Power Loop and Voltage Loop Dal-cloed control ytem i compoed of dc voltage-qare oter loop and power inner loop. From the formla (), d-axi and q-axi exit copling in the power model. The method of the feed forward i adopted to eliminate copling power. PWM modle i rlaced by mall inertial link, power inner loop i PI reglator, the open-loop tranfer fnction i follow that KPWM ( k k pi / ) Gp () (0.5T 1)( L) Let L k k, k K pi K PWM, it follow that (3) K Gp () (0.5T 1) Voltage-qare oter loop i PI reglator too, the tranfer fnction i follow that KvpKL ( vv 1) Gv () (0.5 C 1)( (0.5T 1) K) vv L Let 0.5C, it follow that vv L KvpK Gv () 0.5 C( (0.5T 1) K) (4) (5) (6)

3 Formla (5) and (7) i tned with the econd order and third order optimal etting, repectively. PI parameter vale of power inner loop and voltage oter loop are derived. Deign of Phae-locked Loop (PLL) Phae information play a crcial role in PWM rectifier control ytem. Grid voltage phae i obtained by ingle phae voltage ignal PLL in thi paper. The PLL i divided into amplitde detection and phae detection and the trctre of the phae-locked loop i hown in figre. Phae detection link i only one inpt ignal e p _ inpt. The otpt i grid phae, freqency f and e p _ otpt. The trctre of amplitde detection i hown in figre 3. Let ideal voltage ign i eideal co( ), from figre 3, it follow that 1 ef The etimation vale of correction coefficient can be expreed a follow (7) 1 k, e ke co( ) e 1 inpt a F (8) The trctre of amplitde detection i hown in figre 4. Let grid phae actal vale i, the ' etimation grid phae i ' 1 ' ' e inpt in( ) in( ) (9) When 0, the etimate of the grid freqency hold be increaed to lock the phae of power grid. When 0, the etimate of the grid freqency hold be redced to lock the phae of power grid. e a e ideal - Low-Pa filter 1 k 1/ e inpt e inpt in( ) 1 in( ) - PI 50 f co( ) e opt Figre 3. The chematic of amplitde-loop. Figre 4. The chematic of phae-loop. Simlation of Control Sytem The parameter ed in imlation are hown a grid ide rated line voltage i 380 V, rated power i 3 kw, indctance i 11.7 mh, DC-b capacitance i 4400 F, DC-b voltage i 600 V, rated load i10 ohm, ampling freqency i 10 khz and control freqency i khz. We imlate the ytem by the Matlab/Simlink. The chematic diagram i a followed. Fig.5 how the DC b voltage waveform. The rectifier tart at 1t econd with the lope given vale. The DC b voltage achieve tability after 0. econd, the overhoot i abot 1v. The load i added from no-load to fll load ddenly at nd econd. From Fig.5, we can ee that the DC b voltage i redced abot 60V nder the condition of dden increae load. Bt, we can alo ee that the DC b voltage will recovery to given vale within 0.3, which prove that the rectifier ha a good dynamic performance to fll load. Fig.6 how the teady tate waveform of crrent and harmonic

4 ditortion rate after fll load. From fig.6, we can ee the waveform i better, harmonic ditortion rate i abot THD = 5.53%. A phae voltage and crrent waveform of grid ide are hown in Fig.7 and Fig.8 when the rectifier work in rectification and energy feedback, repectively. A een in fig.7, the direct power control trategy can realize nit power factor rectifier, and have a better follow peed. It i hown in fig. 8, the rectifier load feedback energy to the network ide at 3rd econd. After a hort adjtment, the phae difference of voltage and crrent become 180 º from the ame phae. From the imlation, we can ee the rectifier can realize two-way flow of energy. The waveform of intantaneo active power and intantaneo reactive power are hown in Fig.9. It can be een that the actal vale can reach on given vale and withot p and down of amplitde. Fig.10 i the amplitde and phae waveform of grid ide voltage ignal. It can be een whether the inpt ignal mtation or not, it can obtain good phae ignal. All thi embodie the phae-locked loop ha a good tracking performance. Figre 5. DC-b voltage waveform. Figre 6. The wave of crrent in teady tate and THD. Figre 7. Grid-ide voltage of A phae when rectification. Figre 8. Grid-ide crrent of A phae when energy feedback. Smmary We deign the direct power control ytem voltage-type PWM rectifier baed on voltage orientation. Engineering deign method i ed to tne the parameter of the qare oter loop and power inter loop. A ingle-phae voltage ignal phae-locked loop i deigned to acce grid voltage phae accrately to olve the angle accracy in coordinate tranformation of the control ytem. The imlation relt how the control ytem ha a good dynamic and tatic performance and the harmonic ditortion rate i mall. It can realize nit power factor rectifier and two-way flow of energy.

5 Figre 9. Intantaneo active power and reactive power. Figre 10. The relation between grid-ide voltage and phae. Acknowledgement Thi reearch wa financially orted by Liaodong Univerity Fondation of China nder 015QN009 and 015JC005. eference [1] Malinowki, Kazmierkowki, Trzynadlowki. A Comparative Stdy of Control Techniqe for PWM ectifier in AC Adjtable Speed Drive, IEEE Tranaction on Power Electronic.18(6): , 010. [] Tongzhen Wei. A Novel Direct Power Control Method of Three-Phae Active ectifier in Indtrial Drive Sytem, Proceeding of ICMA , 010. [3] Jihe Wang, Hade Li, Liming Wang. Direct Power Control Sytem of Three Phae Boot Type PWM ectifier, Proceeding of the CSEE, 6(18):54-60, 006. [4] Wei Chen, Ynping Zo, Lijan X. Direct Power Control for Netral-point-clamped Three-level PWM ectifier, in IEEE International Conference on Indtrial Technology, 1(5):897-90:005. [5] Jihe Wang, Hade Li. A New Direct Power Control Strategy of Three Phae Boot Type PWM ectifier, Proceeding of the CSEE, 7(3): , 005. [6] Zheng Zheng, Cong Wang. eearch on Direct Power Control Strategy for PWM ectifier, International Conference on Ftre Power and Energy Engineering, 010:95-98.