Switching Ripple Characteristics of Space Vector PWM Schemes for Five-Phase Two-Level Voltage Source Inverters - Part 2: Current Ripple

Flux harmonic distortion factors (HDFs) of two space vector pulse width modulation (SVPWM) schemes, aimed at sinusoidal output voltage generation with five-phase voltage source inverters, have been evaluated in Part 1 of this paper. Analytical considerations and numerical integration have been applied in order to determine the switching properties of the considered SVPWM methods. It has been shown that the SVPWM based on four large vectors leads to a considerably higher overall per-phase flux HDF than the method based on two large and two medium space vectors. The purpose of the second part of the paper is to relate flux HDFs to the current ripple and current total harmonic distortion and thus explore further switching characteristics of the two SVPWM techniques. The applied approach is based on simulation and experimentation, in conjunction with the subsequent fast Fourier transform of the waveforms, so that all the results for the ripple are obtained using a methodology completely different from the one in Part 1. Relationships that correlate the current ripple and the flux HDFs are established, and it is further shown that the current ripple can be easily calculated from the flux HDF values of Part 1 if the relevant leakage inductances of the two planes are known. Hence, the complete theory of Part 1 is fully verified by both simulation and experimentation. It is also shown that, in certain cases, the SVPWM based on four large vectors may lead to a smaller current ripple despite a considerably higher flux HDF.