Development of synchronized voltage modulation techniques for seven-phase voltage source inverters

The use of synchronized Pulse Width Modulation PWM techniques have been studied in the last years in order to minimize the voltage/current harmonics generated by the power converter, for situations where low switching frequencies are required. This paper introduces a set of PWM techniques for 7-phase drives that meets seven phase symmetry, half-wave symmetry and quarter wave symmetry. The switching pattern are designed from the space vector perspective, in order to meet the requirements. Switching patterns, output voltage and current spectra corresponding to introduced methods are presented and their effectiveness are validated by simulation results. The minimum switching frequency that can be achieved is 7 times the fundamental frequency.