A Novel SPWM-based Common-mode Voltage elimination Modulation Method for Dual Three-phase Motors

Common-mode voltage (CMV) is one of the major concerns in modern motor drive techniques. To alleviate the CMV issue, a series of different pulse width modulation (PWM) methods have been proposed, which are particularly effective when the motor phases have even numbers, such as six phases. This paper proposes a new modulation method based on the traditional sinusoidal PWM (SPWM) to fully eliminate the CMV in a dual-three-phase motor drive system, thereby helps the sizing shrinking of the CM choke. Both mathematical models and experiments indicate its effectiveness in the full linearity range of the modulation index. Such a method has been implemented in the field-programmable gate array (FPGA) to widen its control bandwidth.