Single-phase composite PWM voltage source converter

This paper proposes a novel circuit of a single-phase voltage source converter. A pulsewidth modulation (PWM) strategy is utilized to obtain a sinusoidal input current. The proposed circuit has an auxiliary arm for the bridge circuit and can be operated by a composite PWM strategy which contributes to reduce the ripple in the current. Moreover, the novel circuit has an LC series resonance circuit in the DC side. The DC capacitance necessarily installed in the converter can be greatly reduced by applying the resonance circuit and the constant DC voltage is achieved. The experimental and the theoretical results in the rectifier operation of the converter are shown. The steady state waveforms in the inverter operation with the photovoltaic in the DC side are given. The experiments show that the proposed converter can be used for a single-phase utility interactive photovoltaic system