International Journal of Advance Engineering and Research Development. Speed Control of Induction Motor fed by PWM inverter by Vector Control Method

Transcription

1 Scientiic Journal o Impact Factor(SJIF): International Journal o Advance Engineering and Reearch Development Volume 2,Iue 6, June e-issn(o): p-issn(p): Speed Control o Induction Motor ed by PWM inverter by Vector Control Method Ujjwal Kumar 1, K. P. Singh 2 1,2 Department o Electrical Engineering, MMMUT,Gorakhpur, India Abtract- The peed control method or induction motor ed by PWM voltage ource inverter i being introduced in thi paper. LC ilter i being ued at inverter output terminal to reduce the voltage pike. Oberver are ued to etimate the lux and torque to reduce the number o meaurement and ultimately cot o etup. No additional voltage or current meaurement are needed or vector control o the induction motor. Keyword PWM voltage ource inverter, Induction Motor, LC ilter, Oberver. I.INTRODUCTION The output voltage o PWM voltage ource inverter contain voltage pule with harp pike. I thee pule are altered uddenly then there will be bearing current and high voltage tre in motor inulation. The Ocillation at witching requency caue additional loe and acoutic noie. LC ilter remove thi phenomenon. There will be no need o EMI hielding o motor ince voltage o inverter i nearly inuoidal. The high pa iltered tator voltage ha been ued to correct the voltage reerence, and a multi-loop eedback controller ha been propoed. Here we have to keep number o meaurement low in order to obtain cot aving and reliability. In thi paper the peed control method or induction motor ed by PWM voltage ource inverter i preented. II.PRINCIPLE OF CONTROL S YSTEM The principle o control ytem i explained by the block diagram a hown in igure1.the inverter output voltage u A i iltered by LC ilter and the induction motor i ed by iltered voltage u S. The inverter current i A, the angular peed ω m o the rotor and the dc link voltage u dc are the only meaured quantitie, wherea tator voltage and current o motor are etimated by an oberver. The ytem i controlled by neted control loop in rotor lux reerence rame. Fig.1. Principle o Control Sytem [1] Filter and Motor Model In a reerence rame rotating at angular peed ω, the equation o LC ilter are di RL 1 A j i i S A ( u u S A ) dt L L (1) du 1 j u ( i i A S ) dt C All right Reerved 561

2 International Journal o Advance Engineering and Reearch Development (IJAERD) Where L i the inductance and R L i the erie reitance o the inductor, C i the capacitance o the ilter. The motor control i baed on the model in ynchronouly rotating rotor lux rame. The tator and rotor voltage equation in thi reerence rame are d dt (3) d r 0 R i j( ) R R m r dt (4) u Ri j S Repectively, where Ψ and Ψ r are the tator and rotor lux linkage. R and R R are the tator and rotor reitance, i R i the rotor current and ω m i the electrical angular peed. [2] Cacade Control Fig. 2. Complex ignal low diagram o cacade control In the LC ilter control, the innermot control loop govern the inverter current i A by mean o a PI controller, and the tator voltage i governed by a P-type controller in the next control loop. In both control loop, decoupling term are ued to compenate the cro-coupling caued by the rotating reerence rame. The motor control i baed on vector control and orm two outermot loop o the cacade control. Thetator current i controlled by a PI-type controller with crocoupling compenation, and the rotor peed i governed by a PI-controller. In addition, a PI-type rotor lux controller i ued. [3] Obervability The obervability o the ytem can be invetigated uing M O 2 3 T [ C CA CA CA ] (5) The ytem i obervable i the rank o the obervability matrix i equal to the number o tate [4]. [3]Full Order Oberver The mot eential part o the control i a ull-order oberver, which i implemented in the etimated rotor lux reerence rame, i.e., in a reerence rame where Ψ R = Ψ R + j0. the oberver i deined a x = Ax + Bu A + K(i A i A ) Where etimated tate are marked by the ymbol ^ and K = [k 1 k 2 k 3 k 4 ] T i the oberver gain vector. The digital implementation o the ull-order oberver baed on the conventional orward Euler dicretization caue intability at higher peed. Other alternative, uch a the backward Euler method or the bilinear tranormation, hold the tability but are more complicated to implement. A imple ymmetric Euler method ha been ound to be an eective and Reliable dicretization method in electromechanical imulation [5] and ull-order lux oberver [6]. The oberver gain vector K can be elected in many way. The election can be baed on the pole placement method, or a imple contant gain can be ued, a will be preented in the ollowing. 1). Pole Placement In the pole placement method, the pole o the etimation error dynamic are placed to deired location. Becaue the ytem model i time variant, the pole placement hould be carried out at every calculation tep. However, thi would increae the computing time o the proceor dramatically. Apractical olution i to ue gain cheduling: the All right Reerved 562

3 International Journal o Advance Engineering and Reearch Development (IJAERD) gain vector i calculated in advance a a unction o the angular peed o the rotor, and interpolation between tabulated valuei ued during the operation. The pole alo depend on the angular lip requency ω r = ω ω m a the etimated rotor lux reerence rame i ued. I the gain obtained or no-load operation are ued, the lip requency aect only the imaginary part o the oberver pole. Thereore, the aumption o ω r = 0 in the pole placement method doe not caue tability problem. 2). Simple Contant Gain The oberver become relatively imple when the real-valued gaink = [k ] T i elected. III. S IMULATION RES ULTS The behavior o the ytem wa invetigated by mean o computer imulation with MATLAB/Simulink otware. The data o a 2.2-kW our-pole induction motor (400 V, 50 Hz), given in Table I, were ued or the imulation. The ampling requency o 5 khz wa equal to the witching requency. The LC ilter wa deigned to have a cuto requency o 566 Hz in order to meet a rule o thumb that the cuto requency hould be about one decade below the witching requency and one decade above the nominal undamental requency [7]. The undamental-requency voltage drop in the ilter inductance wa choen to be le than 5 % o the nominal voltage in the nominal operating point [8]. The ilter parameter are alo given in Table I. The bandwidth o the controller were 500 Hz or the inverter current, 250 Hz or the tator voltage, 150 Hz or the tator current, 15 Hz or the rotor peed, and 3 Hz or the rotor lux a hown in Table 1. TABLE1.PARAMETERS OF THE MOTOR AND THE LC FILTER MOTOR PARAMETERS Stator Reitance, R S Rotor Reitance, R R Stator Tranient Inductance, L S Magnetizing L M Inductance, Total Moment o inertia, J Rated S peed, n N Rated Current, I N Rated Torque, T N VALUES 3.67 Ω 1.65 Ω H H kgm r/min 5 A 14.6 All right Reerved 563

4 International Journal o Advance Engineering and Reearch Development (IJAERD) LC FILTER PARAMETERS Inductance, L Capacitance, C 8.0mH 9.9µF VALUES Serie Reitance, R L 0.1Ω The behaviour o motor peed and torque variation with time i hown in ig. 3 and ig. 4. Fig. 3: Variation o motor peed Fig. 4: Variation o torque with time IV.CONCLUS ION When the inverter output voltage i iltered by an LC-ilter, the vector control o an induction motor can be baed on neted control loop. Simulation reult how that the propoed control method operate correctly. The oberver gain can be elected by mean o pole placement, or a contant gain can be ued. Reerence [1] Bimal K. Boe, Modern Power Electronic and AC Drive, PHI, 2012 [2] M. H. Rahid, Power Electronic, 2010 [3] JanneSalomäki and JormaLuomi, Vector Control o an Induction Motor Fed by a PWM Inverter with Output LC Filter, 1992 [4] G.F. Franklin, J. D. Powell, and A. Emami-Naeini, Feedback Control o Dynamic Sytem, 4th ed., Prentice Hall, Upper Saddle River, NJ, 2002 [5] J. Niirane, Fat and accurate ymmetric Euler algorithm or electromechanical imulation, in Proc. lectrimac 99,Liboa, Portugal, Sept. 1999, pp [6] M. Kojima, K. Hirabayahi, Y. Kawabata, E.C. Ejiogu, and T Kawabata, Novel vector control ytem uing deadbeat controlled PWM inverter with output LC ilter, in Con. Rec. IEEE/IAS Annu Meeting, vol. 3, Pittburgh, PA, Oct. 2002, pp. All right Reerved 564

5 International Journal o Advance Engineering and Reearch Development (IJAERD) [7] Nabae, H. Nakano, and Y. Okamura, A novel control trategy o the inverter with inuoidal voltage and current output, in Proc. IEEEPESC 94, vol.1,taipei, Taiwan, June 1994, pp [8] R. Seliga and W. Koczara, Multiloop eedback control trategy in ine wave voltage inverter or an adjutable peed cage induction motor drive ytem, in Proc. EPE 2001, Graz, Autria, Aug. 2001, CD-ROM. [9] M. Hinkkanen and J. Luomi, Parameter enitivity o ull-order lux oberver or induction motor, IEEE Tran. Ind. Applicat. vol. 39, July/Aug. 2003, pp [10] J. Steinke, C. Stulz, and P. Pohjalainen, Ue o a LC ilter to achieve a motor riendly perormance o the PWM voltage ource inverter, in Proc. IEEE IEMDC 97, Milwaukee, WI, May 1997, pp. TA2/4.1-TA2/4.3 [11] C. Xiyou, Y. Bin, and G. Yu, The engineering deign and the optimization o inverter output RLC ilter in AC motor drive ytem, in Proc. IEEE IECON'02, vol. 1, Sevilla, Spain, Nov. 2002, pp [12] M. Carpita, D. Colombo, A. Monti, and A. Fradilli, Power converter iltering technique deign or very high peed drive ytem, preented at the EPE Con., Graz, Autria, [13] Ph. Lataire, White paper on the new ABB medium voltage drive ytem, uing IGCT power emiconductor and direct torque control, EPE J., vol. 7, no. 3 4, pp , Dec [14] T. Kawabata, T. Miyahita, and Y. Yamamoto, Dead beat control o three phae PWM inverter, IEEE Tran. Power Electron., vol. pp , Jan [15] P. Va, Electrical Machine and Drive. Oxord, U.K.: Oxord Science, 1992, pp [16] B. C. Kuo, Digital Control Sytem. New York: Holt, Rinehart and Winton, [17] AH. Bonnett, "Analyi o the Impact o Pule-Width Modulated Inverter Voltage Waveorm on AC Induction Motor, " IEEE Tranaction on indutry Application, vol32, no 2, pp ,MarcWApnl 1996 [18] M. Salo and H. Tuua, A vector controlled current-ource PWM rectiier with a novel current damping method, IEEE Tran. Power. Electron. vol. 15, no. 3, pp , May [19] P. Eichenberger and M. Junger, Predictive vector control o the tator voltage or an induction machine drive with current ource inverter, in Proc. 28th Annu. IEEE Power Electronic Specialit Con., vol. 2, 1997, pp All right Reerved 565