An adaptive Discontinuous Pulse Width Modulation (DPWM) method for three phase inverter

This paper presents an adaptive Discontinuous Pulse Width Modulation (DPWM) method for three phase inverter. A common-mode (CM) signal is injected in the modulation wave to realize the DPWM and the waveform of the injected CM signal is modulated according to the modulation index of the inverter. This feature can lower the equivalent CM voltage source in the low modulation index case to avoid the oscillation without increasing the CM choke. In high modulation index case, the proposed DPWM can realize the same switching loss reduction effect as conventional DPWM methods. The implementation of the proposed DPWM method is explained. A detailed analysis of proposed DPWM method and conventional DPWM methods is presented. The simulated results shows that the proposed DPWM method achieves a balance between efficiency and stability in wide modulation index range.