A single-phase current source PV inverter with power decoupling capability using an active buffer

This paper proposes a new circuit configuration and a control scheme for a single-phase current source inverter with a power decoupling circuit which is called as the active buffer. The proposed inverter achieves low-DC-input voltage ripple and also provides sinusoidal current that can achieve unity power factor, without large passive components in DC bus such as smoothing inductors and electrolytic capacitors, which are conventionally required in order to decouple the power pulsation caused by single-phase power source. In this paper, the fundamental operations of the proposed inverter are demonstrated experimentally. From the experimental results, the input voltage ripple is 8.87% and the output current THD is 4.24%. In addition, the output power factor over of 99% and a maximum efficiency of 94.9% are obtained. Finally, it is confirmed that the maximum power density of the conventional circuit and the proposed circuit are 2.75 kW/L at the switching frequency 70 kHz and 4.86 kW/L at the switching frequency 80 kHz, respectively.