![ ISSN: 2088-8694
IJPEDS Vol. 4, No. 3, September 2014 : 321 – 328
326
Figure. 9 Stator current of Induction motor
The above Figures represents the simulation results of the phase current dynamics during torque
reversal. We can see that the change in the three currents Ia, Ib , and Ic caused by the torque reversal is very
fast. And when the torque reversal is happened at the time instant of 1sec then the three phase output current
and the stator current are having the phase reversal.
4. CONCLUSION
The direct torque control of induction motor is done and, the torque is in the controlled range. Since
there are losses the torque is in controlled by using the discreet space vector modulation technique.
Simulation of the system is done by using MATLAB/Simulink and the output waveforms are obtained. And
from the waveforms the inferences are made which gives positive result regarding the control strategy of the
induction motor.
REFERENCES
[1] I Takahashi, T Noguchi. A new quick-response and high-efficiency control strategy of an induction motor. IEEE
Transactions on Industrial. Appications. 1986; 1(5): 820–827.
[2] SA Zaid, OA Mahgoub, K El-Metwally. Implementation of a new fast direct torque control algorithm for induction
motor drives. IET Electrical Power Applications. 2010; 4(5): 305 313.
[3] C Patel, RPPA Day, A Dey, R Ramchand, KK Gopakumar, MP Kazmierkowski. Fast direct torque control of an
open-end induction motor drive using 12-sided polygonal voltage space vector. IEEE Transactions on Power
Electronics. 2012; 27(1): 400–410.
[4] Y Zhang, J Zhu. Direct torque control of permanent magnet synchronous motor with reduced torque ripple and
commutation frequency. IEEE Transactions on Power Electronics. 2011; 26(1): 235–248.
[5] Y Zhang, J Zhu. A novel duty cycle control strategy to reduce both torque and flux ripples for DTC of permanent
magnet synchronous motor drives with switching frequency reduction. IEEE Transactions on Power Electronics.
2011; 26(10): 3055–3067.
[6] KD Hoang, ZQ Zhu, MP Foster. Influence and compensation of inverter voltage drop in direct torque-controlled
four-switch three-phase PM brushless AC drives. IEEE Transactions on. Power Electronics. 2011; 26(8): 2343–
2357.
[7] S Bolognani, L Peretti, M Zigliotto. Online MTPA control strategy for DTC synchronous-reluctance-motor drives.
IEEE Transactions on. Power Electronics. 2011; 26(1): 20–28.
[8] G Foo, MF Rahman. Direct torque and flux control of an IPM synchronous motor drive using a backstepping
approach. IET Electronics in Power Applications. 2009; 3(5): 413–421.
[9] WC Lee, TK Lee, DS Hyun. Comparison of single-sensor current control in the dc link for three-phase voltage-
source PWM converters. IEEE Transactions.on Industrial. Electronics, 2001; 48(3): 491–505.
[10] JT Boys. Novel current sensor for PWM AC drives. Proceedings of Electronics in Power Appicationsl. 1988; 5: 27–
32.
[11] F Petruzziello, G Joos, PD Ziogas. Some implementation aspects of line current reconstruction in three phase PWM
inverters. Proceedings of 16th IEEE Annual Conference. Industrial Electronics Society. Pacific Grove, CA. 1990; 4:
1149–1154.
[12] F Blaabjerg, JK Pedersen. An ideal PWM-VSI inverter using only one current sensor in the dc-link. Proceedings of
5th International Conference on Power Electronics and Variable-Speed Drives, London, U.K. 1994; 5: 458–464.](https://image.slidesharecdn.com/062apr145641ijpeds-paperedit-171213034948/85/Analysis-of-Direct-Torque-Control-of-Industrial-Drives-using-Zone-Shifting-SVM-6-320.jpg)
![IJPEDS ISSN: 2088-8694
Analysis of Direct Torque Control of Industrial Drives using Zone-Shifting SVM (Vicky Jose)
327
[13] F Blaabjerg, JK Pedersen, U Jaeger, P Thoegersen. Single current sensor technique in the DC link of three-phase
PWM-VS inverters: A review and a novel solution. IEEE Transactions on. Industrial. Applications. 1997; 33(1):
1241– 1253.
[14] HG Joo, MJ Youn, HB Shin. Estimation of phase currents from a DC-Link current sensor using space vector PWM
method. IEEE Transactions of Power Systems. 2000; 28(3): 1053–1069.
[15] JF Moynihan, S Bolognani, RC Kavanagh, MG Egan, JMD Murphy. Single sensor current control of AC servo
drives using digital signal processors. Proceedings of 5th
European. Conference on Power Electronics Applications,
Brighton, UK. 1993; 5: 415–421.
[16] M Riese. Phase current reconstruction of a three-phase voltage source inverter fed drive using a sensor in the dc
link. Proceedings of Power Converse Intelligent Motion Conference. 1996: 95–101.
[17] TM Wolbank, P Macheiner. An improved observer-based current controller for inverter fed AC machines with
single DC-link current measurement. Proccedings of IEEE Power Electronics Spectrum Conference, Cairns,
Australia. 2002: 1003–1008.
[18] TM Wolbank, P.Macheiner. Scheme to reconstruct phase current information of inverter fed AC drives. IEEE
Electronics Letter. 2002; 38(5): 204–205.
[19] TM Wolbank, P Macheiner. Current controller with single DC link current measurement for inverter fed AC
machines based on an improved observer structure. IEEE Transactions on Power Electronics. 2004; 19(6): 1526–
1527.
[20] H Kim, TM Jahns. Phase current reconstruction for AC motor drives using a DC link single current sensor and
measurement voltage vectors. IEEE Transactions on Power Electronics. 2006; 21(5): 1413–1419.
[21] R Rajendran, Dr N Devarajan. A Comparative Performance Analysis of Torque Control Schemes for Induction
Motor Drives. International Journal of Power Electronics and Drive Systems. 2012; 2(2): 177-191.
[22] G Venu Madhav, YP Obulesu. Low Voltage Ride-Through of Doubly Fed Induction Machine using Direct Torque
Control Strategy. International Journal of Power Electronics and Drive Systems. 2013; 3(1): 95-104.
BIBLIOGRAPHY OF AUTHORS
Vicky Jose received his B.Tech. degree in Electrical and Electronics Engineering from Kerela
University, Kerela, India. Presently he is pursuing M.Tech in Power Electronics and Drives from
Karunya University, Coimbatore, Tamil Nadu, India. His present research interests are Neural
Networks and Fuzzy Logic, Special machines, Application of Soft Computing Technique.
K. Vinoth Kumar received his B.E. degree in Electrical and Electronics Engineering from Anna
University, Chennai, Tamil Nadu, India. He obtained M.Tech in Power Electronics and Drives
from VIT University, Vellore, Tamil Nadu, India. Presently he is working as an Assistant
Professor in the School of Electrical Science, Karunya Institute of Technology and Sciences
(Karunya University), Coimbatore, Tamil Nadu, India. He is pursuing PhD degree in Karunya
University, Coimbatore, India. His present research interests are Condition Monitoring of
Industrial Drives, Neural Networks and Fuzzy Logic, Special machines, Application of Soft
Computing Technique. He has published various papers in international journals and conferences
and also published four textbooks. He is a member of IEEE (USA), MISTE and also in
International association of Electrical Engineers (IAENG).
S. Suresh Kumar received his B.E. degree in Electrical and Electronics Engineering from
Bharathiar University, Coimbatore, Tamil Nadu, India in 1992. He has obtained M.E. from
Bharathiar University, Coimbatore, Tamil Nadu, India in 1997. He has received doctoral degree
from Bharathiar University, Coimbatore, Tamil Nadu, India in 2007. Presently he is working as a
Professor and Head of the department for Electrical and Electronics Engineering in Karunya
Institute of Technology and Sciences (Karunya University), Coimbatore, Tamil Nadu, India. He
is having 17 years of teaching experience from PSG College of technology. His present research
interests are Electrical Machines and Power Quality. He has already published 107 papers in
international journals and international conferences. He is a member of IEEE (USA), ASE
ISCA, MCSI, and MISTE and also in International association of Electrical Engineers.](https://image.slidesharecdn.com/062apr145641ijpeds-paperedit-171213034948/85/Analysis-of-Direct-Torque-Control-of-Industrial-Drives-using-Zone-Shifting-SVM-7-320.jpg)
Analysis of Direct Torque Control of Industrial Drives using Zone-Shifting SVM
- 1. International Journal of Power Electronics and Drive System (IJPEDS) Vol. 4, No. 3, September 2014, pp. 321~328 ISSN: 2088-8694 321 Journal homepage: http://iaesjournal.com/online/index.php/IJPEDS Analysis of Direct Torque Control of Industrial Drives using Zone-Shifting SVM Vicky Jose*, K.Vinoth Kumar*, S. Suresh Kumar**, Nithin. T. Abraham*, Dona Maria Mathew* * Department of Electrical and Electronics Engineering, School of Electrical Sciences, Karunya University, Tamilnadu, India ** Department of Electronics and Communication Engineering, Dr.NGP.Institute of Technology, Coimbatore, Tamilnadu, India Article Info ABSTRACT Article history: Received Jan 17, 2014 Revised Apr 2, 2014 Accepted Apr 19, 2014 Direct Torque Control of Induction Motor has gained popularity in industrial applications mainly due to its simple control structure from its first introduction in 1986. Here the direct torque control (DTC) of induction motor with zone shifting space vector modulation (SVM) has been done. It uses a simple phase current re-construction algorithm for three phase induction motor (IM). The phase current re-construction algorithm is done by using information from the current that is from the phases between the inverter and the induction motor. The proposed algorithm is robust and very simple. It uses the AC current to get the stator current for estimating the motor flux and the electromagnetic torque. By evaluating through the torque value and the current the controlling of induction motor is done. The simulation results are also given which supports the direct torque control strategy of the induction motor (IM). Keyword: Direct Torque Control Induction motor Space vector modulation Zone shifting Strategy Copyright © 2014 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: K.Vinoth Kumar, Department of Electrical and Electronics Engineering, School of Electrical Sciences, Karunya University, Coimbatore – 641114, Tamilnadu, India Email: kvinoth_kumar84@yahoo.in 1. INTRODUCTION The concept of direct torque control of the induction motor (IM) has been started and gained popularity in the field of industrial sector. The DTC method is having similarities with the field-oriented control despite a simple structure. In fact the DTC control is having the closed loop control of the electromagnetic torque and the flux without using the current loop or the shaft sensors. In DTC method the information about stator current and DC-link voltage which is used with the inverter switches states to get the values of flux and electromagnetic torque. The paper “Direct Torque Control of IPM synchronous motor using back stepping approach” by G.Foo and M.F.Rahaman, and the paper “Incorporating control trajectories with the direct torque control scheme of interior permanent magnet synchronous motor drive” by M.E.Haque and M.F.Rahaman explains current sensing by the use of galvanically isolated current sensor and the Hall effect sensor. The current measurement is done by using these sensors but the disadvantage is the cost, encumbrance and non-linearity. Another paper by D.W.williams and T.C.Green “Derivation of motor line-current waveforms from the dc-link current of an inverter” here single current sensor operation has been proposed to reconstruct the phase current from dc link current sensor. Another main approach is based on estimation of phase using prediction-correction algorithms by T.M.Wolbank and P.Machiener “An improved observer-based current controller for inverter fed AC machines with single DC-link current measurement”. Having the defect of additional computational burden
- 2. ISSN: 2088-8694 IJPEDS Vol. 4, No. 3, September 2014 : 321 – 328 322 to drive system. The paper’s by M. Bertoluzzo, G. Buja, and R. Menis, “Direct torque control of an induction motor using a single current sensor,” and E. Peralta-Sanchez, F. Al-rifai, and N. Schofield, “Direct torque Control of permanent magnet motors using a single current sensor,” is only dealing with the DTC method of IM and PMSM. In this paper the phase current is measured from the phases. And based on the sensed phase current DTC method is done and switching happened. DTC method is mainly based on the switching. The switching table gives the optimal inverter switching state for the inverter. By the use of voltage and the current obtained from the current and voltage sensing parts is used to deduce flux and electromagnetic torque. The voltage and current hysteresis controller determine voltage required to drive the flux and torque for the particular time. The basic block diagram is given below as Figure 1. Figure 1. Basic DTC From the voltage and current appropriate magnitude current and voltage are to be obtained. From these electromagnetic torque and flux are estimated, a hysteresis control is done and voltage vectors to be applied are obtained from the switching table. The torque and flux can be deduced from the following equations, ∅ (1) 3 2P (∅ ) (2) Figure 2. DTC sectors and inverter voltage vectors
- 3. IJPEDS ISSN: 2088-8694 Analysis of Direct Torque Control of Industrial Drives using Zone-Shifting SVM (Vicky Jose) 323 Table 1. Basic DTC switching table ∅ Sec I Sec II Sec III Sec IV Sec V Sec VI 1 1 V5 V6 V1 V2 V3 V4 0 V3 V4 V5 V6 V1 V2 0 1 V6 V1 V2 V3 V4 V5 0 V2 V3 V4 V5 V6 V1 2. DIRECT TORQUE CONTROL STRATEGY Figure 3. Sector selection Figure 4. Proposed model DTC strategy is quite different from that of the field orientation control (FOC) or vector control, which does not need complicated coordination transformations and decoupling calculation. Here a simple current re-construction algorithm is done by using current sensor. The stator currents and the dc-link voltages
- 4. ISSN: 2088-8694 IJPEDS Vol. 4, No. 3, September 2014 : 321 – 328 324 are sampled and based on the sampled voltage and current torque and flux are created. These torque and flux are again undergone transformations to form voltage and current that is used for switching. The switching is done by using space vector switching method. On the first implementation the control system should be able to generate more voltage vectors; this could be achieved by applying at each cycle period voltage vectors at specified interval of time. This leads to a space vector modulation (SVM). In improving the DTC method look up table and adjusting the stator flux sector which is taken from 0 0 0 60to (given in Figure 3) (by zone shifting strategy) instead of -30 and +30 degree as of basic DTC schemes. The proposed DTC method is given in the Figure 4. The switching table and the voltage vector are given in Table 2, and Figure 5. Table 2. Switching table Flux error position Torque error position Sec I Sec II Sec III Sec IV Sec V Sec VI 1 1 V2 V3 V4 V5 V6 V1 0 V7 V0 V7 V0 V7 V0 -1 V6 V1 V2 V3 V4 V5 0 1 V3 V4 V5 V6 V1 V2 0 V0 V7 V0 V7 V0 V7 -1 V5 V6 V1 V2 V3 V4 Figure 5. Voltage Vector SVM techniques have several advantages that are offering better DC bus utilization, lower torque ripple, lower Total Harmonic Distortion (THD) in the AC motor current, lower switching losses, and easier to implement in the digital systems. At each cycle period, a preview technique is used to obtain the voltage
- 5. IJPEDS ISSN: 2088-8694 Analysis of Direct Torque Control of Industrial Drives using Zone-Shifting SVM (Vicky Jose) 325 space vector required to e actly compensate the flux and torque errors. The torque ripple for this SVMDTC is significantly improved and switching frequency is maintained constant. The two switching states (SA and SB) ar named active switching states.SA indicates the inverter switching states (001), (100), or (010) and SB indicates the inverter switching states (101), (110) or (011). In DTC, with the space vector PWM technique, the DTC transient performance and robustness are preserved and the steady state torque ripple is reduced. Moreover, the inverter switching frequency is constant and totally controllable. 3. SIMULATION RESULTS & DISCUSSIONS The simulation for the proposed DTC method is done by the MATLAB/SINULINK model based on power system toolbox. Based on the simulation outcome the behavior of the proposed DTC method is analyzed and concluded. The specifications of the induction motor in this study are as follows. min1.1 , 415 , 50 , 1415 , 6.03 , 6.085 ,r n n n s rp kw u v f Hz R R 2 29.9 , 29.9 , 489.3 , 0.011787 .ls lr mL mH L mH L mH J Kg m Figure 6 shows the variations of the motor torque in the proposed control scheme. First, the machine is fluxed with a zero reference torque, then at 0.25s, we set the torque reference to 3.5 Nm (50% of the rated torque) and a torque inversion is made at 1s. Torque Reference : 0 3.5 -3.5 Time : 0 0.25 1 (sec) Figure 6. Torque dynamic Figure 7. Circular flux trajectory Figure 8. Phase currents dynamic during torque reversal
- 6. ISSN: 2088-8694 IJPEDS Vol. 4, No. 3, September 2014 : 321 – 328 326 Figure. 9 Stator current of Induction motor The above Figures represents the simulation results of the phase current dynamics during torque reversal. We can see that the change in the three currents Ia, Ib , and Ic caused by the torque reversal is very fast. And when the torque reversal is happened at the time instant of 1sec then the three phase output current and the stator current are having the phase reversal. 4. CONCLUSION The direct torque control of induction motor is done and, the torque is in the controlled range. Since there are losses the torque is in controlled by using the discreet space vector modulation technique. Simulation of the system is done by using MATLAB/Simulink and the output waveforms are obtained. And from the waveforms the inferences are made which gives positive result regarding the control strategy of the induction motor. REFERENCES [1] I Takahashi, T Noguchi. A new quick-response and high-efficiency control strategy of an induction motor. IEEE Transactions on Industrial. Appications. 1986; 1(5): 820–827. [2] SA Zaid, OA Mahgoub, K El-Metwally. Implementation of a new fast direct torque control algorithm for induction motor drives. IET Electrical Power Applications. 2010; 4(5): 305 313. [3] C Patel, RPPA Day, A Dey, R Ramchand, KK Gopakumar, MP Kazmierkowski. Fast direct torque control of an open-end induction motor drive using 12-sided polygonal voltage space vector. IEEE Transactions on Power Electronics. 2012; 27(1): 400–410. [4] Y Zhang, J Zhu. Direct torque control of permanent magnet synchronous motor with reduced torque ripple and commutation frequency. IEEE Transactions on Power Electronics. 2011; 26(1): 235–248. [5] Y Zhang, J Zhu. A novel duty cycle control strategy to reduce both torque and flux ripples for DTC of permanent magnet synchronous motor drives with switching frequency reduction. IEEE Transactions on Power Electronics. 2011; 26(10): 3055–3067. [6] KD Hoang, ZQ Zhu, MP Foster. Influence and compensation of inverter voltage drop in direct torque-controlled four-switch three-phase PM brushless AC drives. IEEE Transactions on. Power Electronics. 2011; 26(8): 2343– 2357. [7] S Bolognani, L Peretti, M Zigliotto. Online MTPA control strategy for DTC synchronous-reluctance-motor drives. IEEE Transactions on. Power Electronics. 2011; 26(1): 20–28. [8] G Foo, MF Rahman. Direct torque and flux control of an IPM synchronous motor drive using a backstepping approach. IET Electronics in Power Applications. 2009; 3(5): 413–421. [9] WC Lee, TK Lee, DS Hyun. Comparison of single-sensor current control in the dc link for three-phase voltage- source PWM converters. IEEE Transactions.on Industrial. Electronics, 2001; 48(3): 491–505. [10] JT Boys. Novel current sensor for PWM AC drives. Proceedings of Electronics in Power Appicationsl. 1988; 5: 27– 32. [11] F Petruzziello, G Joos, PD Ziogas. Some implementation aspects of line current reconstruction in three phase PWM inverters. Proceedings of 16th IEEE Annual Conference. Industrial Electronics Society. Pacific Grove, CA. 1990; 4: 1149–1154. [12] F Blaabjerg, JK Pedersen. An ideal PWM-VSI inverter using only one current sensor in the dc-link. Proceedings of 5th International Conference on Power Electronics and Variable-Speed Drives, London, U.K. 1994; 5: 458–464.
- 7. IJPEDS ISSN: 2088-8694 Analysis of Direct Torque Control of Industrial Drives using Zone-Shifting SVM (Vicky Jose) 327 [13] F Blaabjerg, JK Pedersen, U Jaeger, P Thoegersen. Single current sensor technique in the DC link of three-phase PWM-VS inverters: A review and a novel solution. IEEE Transactions on. Industrial. Applications. 1997; 33(1): 1241– 1253. [14] HG Joo, MJ Youn, HB Shin. Estimation of phase currents from a DC-Link current sensor using space vector PWM method. IEEE Transactions of Power Systems. 2000; 28(3): 1053–1069. [15] JF Moynihan, S Bolognani, RC Kavanagh, MG Egan, JMD Murphy. Single sensor current control of AC servo drives using digital signal processors. Proceedings of 5th European. Conference on Power Electronics Applications, Brighton, UK. 1993; 5: 415–421. [16] M Riese. Phase current reconstruction of a three-phase voltage source inverter fed drive using a sensor in the dc link. Proceedings of Power Converse Intelligent Motion Conference. 1996: 95–101. [17] TM Wolbank, P Macheiner. An improved observer-based current controller for inverter fed AC machines with single DC-link current measurement. Proccedings of IEEE Power Electronics Spectrum Conference, Cairns, Australia. 2002: 1003–1008. [18] TM Wolbank, P.Macheiner. Scheme to reconstruct phase current information of inverter fed AC drives. IEEE Electronics Letter. 2002; 38(5): 204–205. [19] TM Wolbank, P Macheiner. Current controller with single DC link current measurement for inverter fed AC machines based on an improved observer structure. IEEE Transactions on Power Electronics. 2004; 19(6): 1526– 1527. [20] H Kim, TM Jahns. Phase current reconstruction for AC motor drives using a DC link single current sensor and measurement voltage vectors. IEEE Transactions on Power Electronics. 2006; 21(5): 1413–1419. [21] R Rajendran, Dr N Devarajan. A Comparative Performance Analysis of Torque Control Schemes for Induction Motor Drives. International Journal of Power Electronics and Drive Systems. 2012; 2(2): 177-191. [22] G Venu Madhav, YP Obulesu. Low Voltage Ride-Through of Doubly Fed Induction Machine using Direct Torque Control Strategy. International Journal of Power Electronics and Drive Systems. 2013; 3(1): 95-104. BIBLIOGRAPHY OF AUTHORS Vicky Jose received his B.Tech. degree in Electrical and Electronics Engineering from Kerela University, Kerela, India. Presently he is pursuing M.Tech in Power Electronics and Drives from Karunya University, Coimbatore, Tamil Nadu, India. His present research interests are Neural Networks and Fuzzy Logic, Special machines, Application of Soft Computing Technique. K. Vinoth Kumar received his B.E. degree in Electrical and Electronics Engineering from Anna University, Chennai, Tamil Nadu, India. He obtained M.Tech in Power Electronics and Drives from VIT University, Vellore, Tamil Nadu, India. Presently he is working as an Assistant Professor in the School of Electrical Science, Karunya Institute of Technology and Sciences (Karunya University), Coimbatore, Tamil Nadu, India. He is pursuing PhD degree in Karunya University, Coimbatore, India. His present research interests are Condition Monitoring of Industrial Drives, Neural Networks and Fuzzy Logic, Special machines, Application of Soft Computing Technique. He has published various papers in international journals and conferences and also published four textbooks. He is a member of IEEE (USA), MISTE and also in International association of Electrical Engineers (IAENG). S. Suresh Kumar received his B.E. degree in Electrical and Electronics Engineering from Bharathiar University, Coimbatore, Tamil Nadu, India in 1992. He has obtained M.E. from Bharathiar University, Coimbatore, Tamil Nadu, India in 1997. He has received doctoral degree from Bharathiar University, Coimbatore, Tamil Nadu, India in 2007. Presently he is working as a Professor and Head of the department for Electrical and Electronics Engineering in Karunya Institute of Technology and Sciences (Karunya University), Coimbatore, Tamil Nadu, India. He is having 17 years of teaching experience from PSG College of technology. His present research interests are Electrical Machines and Power Quality. He has already published 107 papers in international journals and international conferences. He is a member of IEEE (USA), ASE ISCA, MCSI, and MISTE and also in International association of Electrical Engineers.
- 8. ISSN: 2088-8694 IJPEDS Vol. 4, No. 3, September 2014 : 321 – 328 328 Nithin T.Abraham received his B.Tech. degree in Electrical and Electronics Engineering from Karunya University, Coimbatore, Tamil Nadu, India. Presently he is pursuing M.Tech in Renewable Energy Technologies from Karunya University, Coimbatore, Tamil Nadu, India. His present research interests are Neural Networks and Fuzzy Logic, Special machines, Application of Soft Computing Technique. Dona Maria Mathew received his B.Tech. degree in Electrical and Electronics Engineering from Kerela University, Kerela, India. Presently he is pursuing M.Tech in Power Electronics and Drives from Karunya University, Coimbatore, Tamil Nadu, India. His present research interests are Neural Networks and Fuzzy Logic, Special machines, Application of Soft Computing Technique.