Closed Loop Topology of Converter for Variable Speed PMSM Drive

Transcription

1 Closed Loop Topology of Converter for Varable Speed PMSM Drve Devang B Parmar Assstant Professor Department of Electrcal Engneerng V.V.P Engneerng College,Rajkot, Gujarat, Inda Abstract- The dscontnuous mode operaton (DCM) of all sngle-swtch topologes s most sutable for low power applcatons, somewhere these converters there outstandng characterstcs of power factor correcton usng a very smple control scheme wth only one voltage feedback loop. The Permanent Magnet Synchronous Motor s used to construct low power ratng applcaton such as Refrgerator, Washng Machne, House-hold applances, Medcal Equpment, Wde speed range of servo drves and ndustral robots. CCM fly back converter sustans the same voltage stress as, but less current stress than ts DCM counterpart, when delverng the same output power. As for output voltage performance, both CCM and DCM fly back converters perform equally well n terms of output voltage regulaton. In the lght of effcency, the CCM fly back converter s superor to ts DCM complement, whch suffers from the larger conducton and swtchng losses. Index Terms - Power Qualty, Total Harmonc Dstorton. Topology of Fly back AC-DC Converter, Hgh Frequency Isolaton, Permanent Magnet Synchronous Motor. I. CLOSED LOOP OF PMSM DRIVE SYSTEM The motor drve conssts of four major components, the motor, nverter, control unt and the poston sensor. The components are connected n closed loop operaton as shown n fgure 1.1. [1] Inverter Ia Ib Ic PM Motor Load Poston Sensor DC Source Ia Ib Ic Control Input Controller Rotor Poston Fgure 1.1 Closed loop PMSM Motor Drve. II PROBLEM IDENTIFICATION The PMSM used to buld small power ratng applcaton devces such as Refrgerator, Washng Machne, House-hold applances, Medcal apparatus, Wde speed range of servo drves and ndustral robots. PMSM drves are use for ts hgh effcency, fast dynamc response and small sze etc. For the functon of PMSM Drve frst necesstate exchangng AC supply power to DC power wth rectfer crcut and then DC power to varable magntude and changeable frequency AC power to feed PMSM. PMSM works on two mode vector control mode as well as drect torque control mode of operaton. At ths tme we are wth vector control PMSM. Here for converson of AC-DC we cannot use smple rectfer crcut whch s shown n fgure 1.2. Snce n ths crcut large value of capactor s necessary whch drawn a large value of small narrow pulse current. As we get the capactor voltage dstncton s nearly constant. But due to ths current we obtan the supply voltage poor n condtons of hgh value of Total Harmoncs Dstorton low value of Power Factor Dsplacement Factor and poor Dstorton Factor. These large harmonc currents not only produce dstorton other than also create conducted and radated Electromagnetc Interference. Ths dffculty becomes supplementary severe when all the strategy are organzaton n sngle phase supply [1-3]. IJEDR Internatonal Journal of Engneerng Development and Research ( 381

2 Fgure 1.2 Basc Block Dagram of PMSM Drve drectly connected wth power supply. III MODELLING OF VECTOR CONTROLLED PMSM DRIVE SYSTEM Fgure1.2 shows the block dagram of the vector controlled PMSM drve system. It conssts of control scheme wth proportonal plus ntegral (PI) speed controller, feld weakenng controller, d-axs current calculaton, vector controller, Pulse Wdth Modulated (PWM) Current Controller (CC), voltage source nverter and PMSM. 1) PI speed controller: The nput to the PI speed controller s the speed error motor speed r ( k) ( k) ( k) ( k) (1) e r r. Ths error s estmated at the wth samplng nstant as: ( k e ) between reference speed ωr(k) and the The error s processed n the PI speed controller and the output of the controller s gven by the reference torque samplng nstant as: Tk T k K p e k e k KI e k ( -1) { ( ) - ( -1)} ( ) (2) Tk at kth Where KP and KI are the proportonal and ntegral gans of the PI speed controller, respectvely. After lmtng the output of the PI controller ( Tk ) s taken as reference torque ( T ref ). 2) Reference wndng current generaton: The quadrature, drect axs and three-phase reference motor wndng currents are generated usng the output of the speed controller and the rotor poston. The followng are the equatons for the reference currents [4]: The flux component of reference stator current ( d d 0 for r b and (3) [{ - }/{ ( L - L )}] for d f b r r d q r b The torque component of the reference stator current ( ) can be defned as: d ) can be obtaned from reference torque (Tref) as: Where Kt s motor torque constant, Ld and Lq are q-axs and d-axs nductances and PMSM. The reference three-phase currents for the stator wndng can be represented as: Where s the rotor angular poston n electrcal rad/sec. r f s the flux produced by rotor magnets of These reference currents ( a b c ) are compared wth sensed wndng currents ( a b c) and the current errors are fed to the PWM current controller. IJEDR Internatonal Journal of Engneerng Development and Research ( 382

3 Fgure 1.3 PSIM Smulaton of PMSM Drve drectly connected wth Fly back converters. Fgure 1.4 Output current, Reference speed, dc-lnk voltage. Fgure1.5 s1 s2 s3 swtchng pulse of nverter. After Smulaton and Analyss of AC-DC Fly back Converter for Varable Speed PMSM drve for Power Qualty Improvement, we get Total Harmonc Dstorton of Supply current s varyng from % to % for 20% to 100% load. [7-9]. Power Factor of PMSM wth Fly back Converter Connected for 20% to 100% load s to The desgn and hardware mplementaton of the fly back converter for 12V, 5W output has been done. The unversal swtchng mode power supply works properly for the nput range of the 85 VAC to 265 VAC.As the nput voltage vares from 85 VAC to 265 VAC, the output of the fly back converter s accurately mantaned at 12 V. The Controller n the Feedback Loop ensures the constant output voltage of 12 V. The crcut s desgned n such a manner that t can delver a maxmum current of 400mA. TABLE I SIMULATION PARAMETER SPECIFICATION AND INPUT DATA OF FLYBACK CONVERTER FED PMSM DRIVE SYSTEM Sr. No. Parameter Value 1. Input Peak Voltage (V s) 325V 2. Output Voltage (V dc) 120V 3. Rated Power of Converter (P n) 900W 4. Swtchng Frequency of PWM Voltage Controller of Fly back Converter (f s) 50kHz 5. Rated Output Power of PMSM (P out) 600W 6. Stator Resstance (R e) 0.195Ώ 7. Inductance d-axs (L d) 0.45mH 8. Inductance q-axs (L q) 0.45mH 9. Back EMF Constant (K 0) 18.66V/KRPM 10. Poles (P) 6 IJEDR Internatonal Journal of Engneerng Development and Research ( 383

4 11. Moment of Inerta (J) Kg-m Statc Frcton (T f) 0.14N-m 13. Swtchng Frequency of PWM Current Controller of VSI (f c) 10kHz 14. PI Speed Controller Gans (K p, K I) 0.9, DESIGN PARAMETERS OF FLYBACK CONVERTER 15 PI Voltage Controller Gan (K pdc, K dc) 0.3, Voltage Rato M Turn Rato of Transformer n 4 18 Duty Rato D Conducton Parameter K Crtcal Value of Conducton Parameter 0.30 of Converter K crt 21 Inductance L m 0.2mH 22 Flter Capactance C f 200nF 23 Output Capactance C dc 3000µF TABLE II RESULT DATA Sr. No %Load %THD of Is Power Factor 1 20% % % % % IV CONCLUSION Applcaton of Permanent Magnet Synchronous Motor drves are used owng to ts hgh effcency, fast dynamc response and small sze. For the operaton of PMSM Drve, AC provde s converted nto DC supply usng rectfer path and then DC supply s converted addcted to varable magntude and varable frequency AC supply wth help of nverter to feed PMSM. Hgh value of Total Harmoncs Dstorton (THD), low value of Power Factor (PF), Dsplacement Factor (DPF), and poor Dstorton Factor (DF) are some problems of usng smple rectfer crcut. These problems can be reduced by usng Fly back converter. The Fly back converter be able to be use n ether n CCM or DCM but f converter s used n CCM mode then t cannot sustan current stress as t can be sustaned n DCM mode. PMSM operates on two modes - vector control mode and drect torque control mode. In ths thess, Smulaton and Analyss of vector controlled PMSM usng AC-DC Fly back Converter n DCM mode s done for power qualty mprovement. The sngle swtch topologes can be preferred n sequence of fly back, Zeta, Cuk, and SEPIC converter. Because Zeta and fly back converter topologes provde addtonal protecton besde n excess of current and nrush current as compare to Cuk and SEPIC converter topologes. Furthermore, the fly back converter topology requre only a capactor as an output flter and the Cuk converter topology requres smaller core, and has lower core and copper losses. V REFERENCE [1] R.Dhaouad and N.Mohan, Analyss of Current Regulated Voltage Source Inverters for PMSM Drves n Normal and Extended Speed Range, IEEE Trans. on Energy Converson, vol.5, no.1, pp , March [2] P. Freere, P. Pllay, Desgn andevolutonof Current Controllers For PMSM Drves /90/ $ IEEE. [3] C. Larouc, J.P. Ferreux, L. Gerbaud, J. Roudet and J. Barbaroux, Control of a fly back converter n power factor correcton mode: compromse between the current constrants and the transformer volume, n Proc. IEEE APEC, 2002, vol.2, pp [4] Mhaela Moscalu, Petre-Danel Ionescu, AlnMoscalu, AC/DC Flyback converter wth low swtchng delay 8 th Internatonal Conference on Development And Applcaton Systems Suceava, Romana, May 25-27,2006. [5] C. Larouc, J.P. Ferreux, L. Gerbaud, J. Roudet and J. Barbaroux, Control of a flyback converter n power factor correcton mode: compromze between the current constrants and the transformer volume, n Proc. IEEE APEC, 2002, vol.2, pp [6] B. Sngh, S. Sngh, A. Chandra and K. Al-Haddad, Comprehensve Study of Sngle-Phase AC-DC Power Factor Corrected Converters wth Hgh Frequency Isolaton, IEEE Trans. Industral Informatcs (TII), vol. 7, no. 4, pp , Nov [7] P. Freere, P. Pllay, Desgn And Evaluton Of Current Controllers For PMSM Drves /90/ $ IEEE. [8] Maran K. Kazmerczuk, Pulse-wdth Modulated DC DC Power Converters Wrght State Unversty [5] Sanjeev Sngh, Bhm Sngh, Improved Power Qualty Flyback Converter fed PMBLDCM Drve IEEE [9] Bhm Sngh, Ganesh Dutt Chaturved, Comparatve Performance of Isolated Forward and Flyback AC-DC Converters for Low Power Applcatons IEEE Dayton, Oho, USA@ 2008 John Wley & Sons, Ltd. IJEDR Internatonal Journal of Engneerng Development and Research ( 384

5 [10] R. Erckson, M. Madgan and S. Snger, Desgn of a Smple Hgh-Power-Factor Rectfer Based on the Flyback Converter, n Proc. IEEE APEC 90, 1990, pp [11] R.Dhaouad and N.Mohan, Analyss of Current Regulated Voltage Source Inverters for Permanent Magnet Synchronous Motor Drves n Normal and Extended Speed Range, IEEE Trans. on Energy Converson, vol.5, no.1, pp , March IJEDR Internatonal Journal of Engneerng Development and Research ( 385