A double‐modulation‐wave discontinuous pulse‐width‐modulation for dead‐time‐effect elimination and switching‐loss reduction in two‐level power converters

Abstract

Abstract High current qualities and high efficiencies are always two important characteristics for power converters. However, it is challenging to achieve the two targets simultaneously. In this paper, the dead‐time‐effect elimination pulse‐width‐modulation (PWM) for improving current qualities and the discontinuous PWM (DPWM) for reducing switching losses are combined, proposing a double‐modulation‐wave DPWM. An additional modulation wave is added, whose amplitude is adjusted according to the current polarity. By utilizing the added drive pulses in the current freewheeling stage, the proposed double‐modulation‐wave DPWM successfully reduces the dependence on the current polarities. The overmodulation phenomenon brought by the added modulation wave is analysed, which is proved to be negligible for achieving the maximum modulation index of 1.15. Finally, the effectiveness of the proposed double‐modulation‐wave DPWM is experimentally verified at a switching frequency of 40 kHz.

Keywords

• DC–AC power convertors
• harmonic distortion
• pulse width modulation