Influence of DC Link Capacitance on Power Efficiency of Single-Phase Inverter

The capacitor sizing for the capacitive DC link of a single-phase inverter is usually based on a pre-determined voltage ripple limitation, ripple current capability, and/or energy storage requirement. Nevertheless, it is lack of justifications of the pre-determined criteria. This paper aims to investigate the dependency between the DC-link capacitance and the converter-level efficiency of a single-phase inverter. The major sources of the converter power loss, i.e., IGBTs, capacitors, and inductors, are quantitatively modeled considering the varying DC-link voltage. It provides an additional dimension to optimize the capacitor selection for capacitive DC links. The theoretical analyses are verified by both simulations and experiments.