Abstract
DC-link capacitors in high-power converters are most susceptible to degradation from self heating due to the fact that its current contains large switching-frequency ripple. To mitigate DC-link current ripples of three-phase neutral point clamped (NPC) converters, a novel phase-disposition (PD) pulse width modulation (PWM) is proposed by mixing several variants of existing PD schemes. Comprehensive analysis of both bipolar and unipolar modulation schemes are performed. Both numerical simulations and hardware experiments are conducted to illustrate the effectiveness of the proposed mixed PD modulation schemes.