A Switching Method for Improving Lifetime of DC-Link Capacitors in Hybrid ANPC Inverters

This paper presents a switching strategy for improving lifetime of DC-link capacitors in photovoltaic (PV) hybrid active neutral-point-clamped (ANPC) inverters. The DC-link capacitor current ripples should be reduced, because the high current ripples of the capacitors cause high thermal stress and short lifetime of the capacitors. To reduce the DC-link current ripples, the switching sequence of the conventional space vector pulse width modulation (SVPWM) method is replaced with the proposed switching sequence. By applying the proposed method, the DC-link current ripples are reduced substantially. The effectiveness of the proposed method was verified by simulation results.