A multi-level PWM technique has been developed to reduce the lower order harmonic distortion. The implementation of the existing control strategies has been found to affect the switch utilization and increase the losses. The Variable Frequency Carrier Band (VFCB) has been found to equalize the number of switching at all levels and contributes to reducing the losses besides allowing uniform dissipation of power in the switching devices. The existing SHPWM methods create inferior harmonic spectrum and unequal utilization of devices. Therefore, a new Pulse Width Modulation (PWM) strategy, with the view to ensure that the power devices at all the levels are switched equal number of times is proposed in this paper. The MATLAB-based simulation response and its experimental validation are included to highlight the fact that there is a significant enhancement in harmonic power distribution besides contributing to reduce the switching losses and improve the efficiency.
N. Kamalakannan, A. Arulvizhi, J. Jayashree
Harmonics, modulation, multilevel inverter, THD, VFCB
- Agelidis V. G. and Calais M. (1998) ‘Application specific harmonic performance evaluation of multicarrier PWM Techniques’, in Proc. IEEE PESC’98, pp. 172–178.
- Chen Y., Mwinyiwiwa B., Wolanski Z., and Ooi B. T.(1997) ‘Regulating and equalizing DC capacitance voltages in multilevel STATCOM’,IEEE Trans. Power Delivery, vol. 12, pp. 901–907.
- Corzine K.A. Wielebski M.W. Peng F.Z. and Wang J. (2004) ‘Control of cascaded multilevel inverters’, IEEE Transactions on Power Electronics, Vol. 19, No. 3, and pp.732–738.
- Choi N. S., Cho J. G., and Cho G. H. (1991)’A general circuit topology of multilevel inverter’, in Proc. IEEE PESC’91, pp. 96–103.
- Choi N. S., Cho G. C., and Cho G. H. (1993) ‘Modeling and analysis of a static var compensator using multilevel voltage source inverter’, in Conf. Rec. IEEE-IAS Annu. Meeting, pp. 901–908.
- Fracchia M., Ghiara T., Marchesoni M., and Mazzucchelli M. (1992)’Optimized modulation techniques for the generalized N-level converter’, in Proc. IEEE PESC’92, pp. 1205–1213.
- Liu H. L. and Cho G. H.( 1994)’Three-level space vector PWM in low index modulation region avoiding narrow pulse problem’, IEEE Trans. Power Electron., vol. 9, pp. 481–486.
- R.W, Steimer P and Steinke J.K.(1994) ‘Five-level GTO inverters for large induction motor drives’, IEEE Trans. Ind. Applicat., vol. 30, pp. 938–944.
- Menzies R. W. and Zhuang Y. (1995) ‘Advanced static compensation using a multilevel GTO thyristor inverter’, IEEE Trans. Power Delivery, vol. 10, pp. 732–738.
McGrath B.P. and Holmes D.G. (2002) ‘Multicarrier PWM strategies for multilevel inverters’, IEEE Transactions on Industrial Electronics, Vol. 49, No. 4, pp.858–867.