IJREE – Volume 5 Issue 4 Paper 3


Author’s Name :  D Lakshmi Devi

Volume 05 Issue 04  Year 2018  ISSN No: 2349-2503  Page no: 9 – 12



A multilevel inverter topology for a four-pole induction-motor drive is presented in this paper, which is constructed using the induction-motor stator winding arrangement. A single dc source with a less magnitude when compared with conventional five-level inverter topologies is used in this topology. Therefore, power balancing issues (which are major challenges in conventional multilevel inverters) are minimized. As this configuration uses a single dc source, it provides a path for zero-sequence currents because of the zero- sequence voltages present in the output, which will flow through the motor phase winding and power electronic switches. To minimize these zero-sequence currents, sine–triangle pulse width modulation (SPWM) is used, which will shift the lower order harmonics near to switching frequency in the linear modulation region. However, in the case of over modulation, harmonic voltages will be introduced close to the fundamental frequency. In this regard, a modified SPWM technique is proposed in this paper to operate the drive in the over modulation region up to the modulation index of 2 /3. The proposed quad two-level inverter topology is experimentally verified with a laboratory prototype on a four-pole 5-hp induction motor. Experimental results show the effectiveness of the proposed topology in the complete linear modulation region and the over modulation region.


Back-to-Back Converter, Dynamic Performance, Induction Machine Drives, Open-End Winding and Unity Power


  1. S. Das, G. Das, P. Purkait, and S. Chakravorti, “Anomalies in harmonic distortion and Concordia pattern analyses in induction motors due to capacitor bank malfunctions,” in Proc. Int. Power Syst. Conf., Dec..27– 29, 2009, pp. 1–6.
  2. R. Spee and A. K. Wallace, “Comparative evaluation of power factor improvement techniques for squirrel cage induction motors,” IEEE Trans. Ind. Appl., vol. 28, no. 2, pp. 38–386, Mar./Apr. 1992.
  3. N. H. Malik and A. A. Mazi, “Capacitance requirements for isolated self -excited induction generators,” IEEE Trans. Energy Convers., vol. EC-2, no. 1, pp. 62–69, Mar. 1987.
  4. M. Ermis, Z. Cakir, I. Cadirci, G. Zenginobuz, and H. Tezcan, “Selfexcitation of induction motors compensated by permanently connected capacitors and recommendations for IEEE std 141-1993,” IEEE Trans. Ind. Appl., vol. 39, no. 2, pp. 313–324, Mar./Apr. 2003.
  5. L. Ruan, W. Zhang, and P. Ye, “Unity power factor operation for threephase induction motor,” in Proc. 3rd Int. Power Electron. Motion Control Conf., 2000, vol. 3, pp. 1414–1419.
  6. E. R. Laithwaite and S. B. Kuznetsov, “Cage-rotor induction motor with unity power factor,” IEEE Proc. B Elect. Power Appl., vol. 129, no. 3, pp. 143–150, May 1982.
  7. E. R. Laithwaite and S. B. Kuznetsov, “Test results obtained from a brushless unity-power-factor induction machine,” IEEE Trans. Power App. Syst., vol. PAS-100, no. 6, pp. 2889–2897, Jun. 1981.
  8. “Discussion on unity-power-factor induction motors,” IEEE Proc. Elect. Power Appl., vol. 130, no. 1, pp. 60–68, Jan. 1983.
  9. F. J. T. E. Ferreira and A.T. Almeida, “Novel multi flux level, three phase, squirrel-cage induction motor for efficiency and power factor maximization,” IEEE Trans. Energy Convers., vol. 23, no. 1, pp. 101–109, Mar. 2008.
  10. M. V. Aware, S. G. Tarnekar, and A. G. Kothari, “Unity power factor and efficiency control of a voltage source inverter-fed variable-speed induction motor drive,” IEE Proc. Elect. Power Appl., vol. 147, no. 5, pp. 422–430. Sep. 2000.
  11. M. Morimoto, K. Sumito, S. Sato, K. Oshitani, M. Ishida, and S. Okuma, “High efficiency, unity power factor VVVF drive system of an induction motor,” IEEE Trans. Power Electron., vol. 6, no. 3, pp. 498–503, Jul. 1991.
  12. S. Kwak and H. A. Toliyat, “Comparison and assessment of current source- inverter-fed induction motor drive systems with unity power factor,” in Proc. IEEE 29th Annu. Ind. Electron. Soc. Conf., Nov. 2–6, 2003, vol. 1, pp. 232–237.