Performance of a 4- switch, 3-phase inverter fed induction motor (IM) drive system

Transcription

1 Perforance of a 4- switch, 3-phase inverter fed induction otor (IM) drive syste Prof. P.S.Phutane 1, Prof. Suraj R.Karpe 2 Assistant Professor, Dept. of lectrical n, S.B.Patil ollee of nineerin, Indapur, Maharashtra, India 1 Assistant Professor, Dept. of lectrical n, S.B.Patil ollee of nineerin, Indapur, Maharashtra, India 2 ABSTRAT: This project proposes the perforance of a 4- switch, 3-phase inverter fed induction otor (IM) drive syste for hih perforance industrial drive systes. In the proposed realization, instead of a usual 6-switch three-phase inverter (SSTPI) a 4-switch three-phase inverter (FSTPI) is used. A cost effective FSTPI fed IM drive usin Field-Oriented-ontrol and Space-Vector PWM controller (with new control SVPWM approach) is ipleented in real tie. This reduces the cost of the inverter, the switchin losses, and the coplexity of the control aloriths and interface circuits to enerate 6 PWM loic sinals. Furtherore, the proposed control approach reduces the coputation for real-tie ipleentation. In this paper, a siulation odel of the drive syste is developed and analyzed in order to verify the effectiveness of the approach. The coplete vector control schee for the IM drive fed fro the proposed 4S3P inverter is ipleented in real-tie usin diital sinal processor for a prototype 1 hp otor. Theoretical and experiental results of the proposed drive verify the robustness of the drive. A perforance coparison of the proposed IS3P inverter fed drive with a conventional 6S3P inverter fed drive is also ode in ters of speed response and total haronic distortion (THI)) of the stator current. Siulation results show that the proposed drive syste provides a fast speed response and ood disturbance rejection capability. The desined inverter fed IM drive is found suitable considerin its cost decrease and the robustness. Keywords: State FPGA-Field Proraable Gate Array, FSTPI- Four Switch Three Phase Inverter, IM-Induction Motor, PWM- Pulse Width Modulation, THD-Total Haronic Distortion. I.INTRODUTION Over the year s induction otor (IM) has been utilized as a workhorse in the industry due to its easy build, hih robustness, and enerally satisfactory efficiency. By tradition, 6-switch 3-phase inverters have been widely used for variable speed IM drives. The last work on FSTPI for IM drives investiated the perforance of a 4-switch, 3-phase inverter fed cost effective induction otor in real tie, which has been ipleented by vector control.a standard three-phase voltae source inverter utilizes three les [six-switch three-phase voltae source inverter, with a pair of copleentary power switches per phase. The FSTPI structure enerates four active vectors in the plane, instead of six, as enerated by the sstpi topoloy. A reduced switch count voltae source inverter [four switch three-phase voltae source inverter uses only two les, with four switches. Several articles report on fstpi structure reardin inverter perforance and switch control. This paper presents a eneral ethod to enerate pulse width odulated (pw) sinals for control of four-switch, three phase voltae source inverters, even when there are voltae oscillations across the two dc-link capacitors. The ethod is based on the so called space vector odulation, and includes the scalar version. This perits to ipleent all alternatives, thus allowin for a fair coparison of the different odulation techniques. The proposed ethod provides a siple way to select either three, or four vectors to synthesize the desired output voltae durin the switchin period. In the proposed approach, the selection between three or four vectors is paraeterized by a sinle variable.the influence of different switchin patterns on output voltae syetry, current wavefor, switchin frequency and coon ode voltae is exained. The paper also discusses how the use of the wye and delta connections of the otor windins affects the ipleentation of the pulse width odulator. II.PROPOSD THNOLOGY The block diara of the proposed syste is shown in Fi.1.The drive syste consists of a 3 phase A supply, 3 phase Diode bride Rectifier, 3 phase four switch Inverter, 3-phase Induction Motor and controlled circuits. The standard A power supply is converted to a D by usin a 3-phase diode bride rectifier. A voltae source FSTPI is used to convert the D voltae to the controlled A voltae. The output of FSTPI is fed to 3-phase induction otor. VHDL prora is used in Xilinx software to enerate the controlled PWM pulses at different duty ratio for FSTPI to drive the Induction Motor at different speeds. opyriht to IJARI 970

2 Fi(1.) Block diara of coputational schee I. FSTPI Well The power circuit of the FSTPI fed Induction Motor drive is shown in Fi. 2 The power inverter has 4 switches, S1, S2, S3 and S4 and a split capacitor. The two phases a and b are connected to the two les of the inverter, while the third phase c is connected to the centre point of dc link capacitors, 1 and 2 The value of the capacitances 1 and 2 are equal. Vc1 and Vc2 are the voltae across the D link capacitors (Vc1=Vc2). Vdc is the voltae across the capacitor 1 and 2 (Vdc =Vc1+Vc2)., Fi(2.) FSTPI with Induction Motor III. PWM Generation in Two-Le Inverter Usin XILINX FPGA PWM sinals are enerated fro the Spartan-3 processor by writin VHDL prora to control these 4 switches The phase voltae is deterined by the duty cycle of the PWM sinals. The switchin sinal paraeters naely switchin frequency, the duty ratio and the nuber of pulses are easily controlled via VHDL prorain lanuae. The tiin of PWM pulses are enerated by usin equations A sall dead-tie is iven between switchin off the upper switch and switchin on the lower switch and vice versa. This ensures that both switches are not conductin when they chane states fro on to off, or vice versa. For the induction otor drive, the three phase voltae references in a balanced set are iven by equation. V as = V cos ωtn. V bs = V cos wt 2π 3 V cs = V cos wt + 2π 3 V ac = V as V cs = 3V cos wt π 6 V bc T 1 = T s = V bs V cs = 3V cos wt π 2 + V ac T 2 V s dc opyriht to IJARI 971

3 T 2 = T s + V bc T 2 V s dc In this paper the scalar odulation schee is adopted since it is siple and easy. The scalar odulation uses the phase voltaes in calculatin the switchin tie. Since the two phases of the induction otor are connected to the inverter les and the third phase is connected to the neutral point of the dc link, the line-to-line voltae can be used for the PWM instead of the phase voltae. The c phase is connected to the neutral point. Fro qns. the two line-to-line voltae references are iven by A Novel Ipleentation of Xilinx FPGA Based Four Switch Three Phase IGBT Inverter Fed Induction Motor Drive Usin PWM. IV. Siulation Work and Results Diital coputer siulation odel of FSTPI fed induction otor drive has been developed by usin SIMULINK MATLAB. The siulation work has been perfored for this drive syste at different load conditions. Weihted total haronic distortion (THD) has been used to evaluate the perforance of the FSTPI with load and without load conditions in this siulation work. This FSTPI fed drive syste consists of a three-phase diode bride rectifier, a split capacitor, four switch three phase inverter and 3- phase squirrel cae Induction Motor. Input supply voltae: 3-phase, 415 V (rs), 50 Hz; Induction Motor: 5 hp 415 V, 50 Hz, 1430 rp. The coplete siulink block diara of syste is shown in Fi. This block diara consists of 2 blocks. Switchin pulses block enerates the PWM pulses for 4- switches of FSTPI at the terinals Out1 to Out4 and FSTPI with IM block contains Diode bride rectifier, FSTPI and IM. Vabc and Iabc block is used to display the 3-phase voltae and current wavefors. The Siulation circuit diara of the drive syste is shown in Fi. This circuit contains 3-phase input A power supply, diode bride rectifier, split capacitor, 4-IGBT switches and 3-phase 3hp IM. The 3-phase output currents of FSTPI ia, ib and ic with IM are shown in Fi.7. The output line voltae wavefor Vab of FSTPI is shown in Fi. The speed and torque characteristics of induction otor with and without load are shown It is observed that the speed increases linearly and reaches the rated speed (1430 rp) at steady state in 0.75 sec. At startin the torque increases and reduces to a iniu value when the speed reaches the rated value. In Fi.7 the sae torque and speed curve is shown with full load at 10 N-. The Total Haronic Distortion (THD) with load and without load conditions is shown in Fi.11 and Fi.12. It is found that THD without load is 9.32% and with load is 8.24%. Discrete, Ts = 5e-005 s powerui Scope 1 c1 SaU SbU Vin A Vabc Iabc B a b c V&I <Rotor current ir _a (A)> <Stator current is _a (A)> <Rotor speed (w)> -K- rp ir,is (A) c2 SaL T A B Asynchronous Machine SI Units 3 N (rp ) SbL w Pulses is_abc Fi (3.) Siulink diara opyriht to IJARI 972

4 Fi (4.) Stator & Rotor current Fi (5.) Speed charactristics opyriht to IJARI 973

5 Fi( 6.)Torque haracteristics Fi (7.) Switchin haracteristics opyriht to IJARI 974

6 V. ONLUSION A cost effective FSTP inverter fed PMSM drive has been siulated and successfully ipleented. This paper presents a coplete odel developent and analysis for four switch three phase inverter fed synchronous reluctance otor drive. The results obtained and presented in this work indicate that the proposed control schee produces very fast response of the SynRM drive. A coparison of perforances for the proposed FSTP inverter fed SynRM drive with conventional SSTP inverter fed drive has also been ade in ters of speed response, torque response, and three phase currents under identical operatin conditions. The drive also shows ood perforance in speed operation under the effect of load disturbances, paraeter variation, and reversal of speed. The proposed control schee with low cost ipleentation is suitable for coercial applications. An FPGA based ipleentation of FSTPI fed IM drive usin PWM control is successfully carried out in siulation and real-tie experient. MATLAB SIMULINK is used for siulation and the hardware. Ipleentation is carried out usin SPARTAN-3 processor. VHDL (Very hih speed description lanuae) prora is developed in XILINX to enerate the controlled PWM pulses to drive the syste. A Ipleentation of Xilinx FPGA Based Four Switch, three Phase IGBT Inverter Fed Induction Motor Drive Usin PWM 433. The proposed FSTP inverter fed PMSM drive is found acceptable considerin its cost reduction and other advantaeous features. VI. AKNOWLDGMNT We take this opportunity to express our deepest ratitude and appreciation to all those who have helped us directly or indirectly towards the successful copletion of this paper. RFRNS [1]. Bose B.K., Power lectronics and A Drives, nlewood liffs, NJ: Prentice Hall, 1986 [2]. Frede Blaabjer,, Siurdur Freysson, Hans-Henrik Hansen, and S. Hansen A New Optiized Space-Vector Modulation Stratey for a oponent-miniized Voltae Source Inverter I Trans. on Power lectronics, Vol. 12, No. 4, July 1997, pp [3]. Jaehon Ki, Jinseok Hon, and Kwanhee Na, A urrent Distortion opensation Schee for Four-Switch Inverters, I Trans. Power lectronics, vol. 24, no. 4, pp , April [4]. Maurício Beltrao de Rossiter orrea and ursino Brandão Jacobina, A General PWM Stratey for Four-Switch Three-Phase Inverters, I Transactions on Power lectronics, vol. 21, no. 6, pp , Noveber [5]. M. N. Uddin, T. S. Radwan, and M. A. Rahan, Fuzzy-loic-controller-based cost-effective four-switch three-phase inverter-fed PM synchronous otor drive syste, I Trans. Ind. Appl., vol. 42, no.1, pp , Jan./Feb [6].. T. Lin,. W. Hun, and. W. Liu, Position sensorless control for four-switch three-phase brushless D otor drives, I Tran. Power lectronics, vol. 23, no. 1, pp , Jan BIOGRAPHY Prof. Pravin S.Phutane is workin as Assistant Professor in the dept. of lectrical n. at S.B.Patil ollee of enineerin, Indapur. Prof.Suraj R. Karpe Phutane is workin as Assistant Professor in the dept. of lectrical n. at S.B.Patil ollee of enineerin, Indapur. opyriht to IJARI 975