A Novel Method for Selective Harmonic Elimination and Current Control in Multilevel Current Source Inverters

One of the most important problems in power electronic, especially inverters, is its switching. The amplitude of the harmonics can be reduced by using of multilevel inverters. So it leads to decrease of output current total harmonic distortion (THD). In the multilevel current source (MLCSI) the entire harmonics cannot be removed and some of them can be appeared in the output current. This paper presents a novel method in which combination of chops and short circuit pulses are positioned in such a way that lower order harmonics are eliminated selectively besides current magnitude modulation with minimum switching frequency. Generalized equations which show the relationship of various PWM-SHEM parameters to the position of short circuit pulses and the number of chops per 360 degrees are provided and discussed in details. To verify proposed method, a sample multilevel current source inverter has been designed and simulated in PSPICE. Copyright (C) 2010 Praise Worthy Prize S.r.l. - All rights reserved.