Opposite Triangle Carrier Method for Common-Mode Voltage Reduction in Dual Three-Phase Motor Drive

This paper proposes a common-mode voltage (CMV) reduction algorithm by using carrier changing and compensation voltage injection in a dual three-phase motor. A conventional CMV reduction algorithm is based on the sawtooth carrier-based sinusoidal pulse width modulation (SC-SPWM). Even if this method reduces the CMV, it fails to totally remove it while resulting in a lower voltage utilization rate compared to space vector pulse width modulation (SVPWM). The proposed method in this paper uses an opposite triangle carrier-based SVPWM (OTC-SVPWM) to reduce the magnitude of the CMV, and improve the voltage utilization. The compensation voltage is injected into each winding group in order to reduce the change frequency of the CMV. In addition, additional compensation term is added to the current controller feedforward term to improve the phase current characteristics. The simulation results are provided to show the performance of the proposed method in reducing the CMV.