Improved PWM Methods to Reduce the Common Mode Voltage of the Five-Phase Open-Winding Drive Topology

Abstract

With the phase angle and shape modifications for carriers, two improved carrier-based pulse width modulation (CPWM) methods with common-mode voltage (CMV) suppression effects for the five-phase open-winding drive topologies are introduced. Theoretical analysis reveals that, by employing reversed triangular carriers for two inverters under the carrier-reversed PWM (CRPWM), CMV contributions of two bridge legs belonging to the same phase can be cancelled, realizing the zero CMV effect. By dynamically employing positive and negative sawtooth carriers for all bridge legs under the carrier-switching PWM (CSPWM), the CMV contribution of each inverter can be reduced, decreasing both the amplitude and step frequency of the CMV. Current qualities and dead-time effects on CMV under the above PWM methods are analyzed. Moreover, performances of two PWM methods are verified by experiments implemented on a five-phase open-winding topology with the induction motor load.

Keywords

• multi-phase machine
• common mode voltage
• carrier-based PWM