Modified RPWM Strategy Based on Level-Shifted Random Carrier and Power Balance to Reduce the PWM Voltage Noise in Three-Phase CHB Inverters

Aimed at the pulse width modulation (PWM) voltage noise and power imbalance in three-phase cascaded H-Bridge (CHB) inverters, a modified random PWM (RPWM) strategy, named power-balanced RPWM (PB-RPWM) is proposed this paper. The PB-RPWM strategy mainly includes three steps: (1) signals are generated by compared wave with level-shifted carriers; (2) circularly distributed between CHB units logic operation method, then driving of switching devices produced; (3) used to control inverter. Under spectra line become uniform continuous, that is, can be effectively reduced. output single H-bridge unit contain basic voltages within 3/2 TA, balance realized. When conventional non-random strategies, has lower smaller total harmonic distortion (THD). (LS-PWM) balanced performance. effectiveness feasibility verified abundant simulations experiments.