Performance Comparison of Different Multi-Carrier Based PWM Approaches for Cascaded H-Bridge Inverter-Fed Induction Motor Drives

This paper presents the performance of a three-phase seven-level Cascaded H-Bridge (CHB) inverter fed induction motor drive, operated at an open loop v/f control mode, taking into account three modulation techniques that use three different modulating signals. By using triangular carrier waves, this study implements multicarrier PWM strategies including Phase-shifted (PS), Level-shifted (LS) (including alternative phase opposition disposition (APOD), phase opposition disposition (POD), and phase disposition (PD). Total harmonics distortion (THD), total power losses of switching devices, efficiency, and junction temperature for a seven-level CHB inverter, while operating an induction motor at v/f control mode at rated load conditions, employing different modulation signals for different modulation indices are achieved. In addition, the Phase Disposition strategy results in reduced harmonic distortion, while the Phase shifted PWM strategy generates higher junction temperatures as a result of its high-power losses. The simulation is done for a three-phase seven-level CHB inverter-fed induction motor drive in the PLEXIM simulink platform.