Common-Mode Voltage Reduction Of Nine Switch Converter Fed Dual Three-Phase Load System Using Reverse Carrier Scheme

Pulse width modulated (PWM) converter fed motor drive system builds a common-mode voltage (CMV). CMV causes electromagnetic interference, leakage current through the motor bearing, and deterioration of stator winding, leading to unusual operation and premature failure of the drive system. For the first time, this paper discusses a simple reverse carrier sine triangular pulse width modulation (RCSPWM) in a three-phase nine switch inverter (NSI) fed load system to reduce CMV. In this scheme, the median of three modulating references is compared with the reverse triangular carrier to avoid zero vectors that cause peak CMV. Compared to conventional sine pulse width modulation (SPWM) and interleaved carriers (IC) (ICSPWM), the CMV peak in RCSPWM reduced to ±VDC/6 from ±VDC/2. MATLAB simulation results are supported to validate the claim of the proposed PWM scheme.