A novel high performance utility interactive photovoltaic inverter system

This paper presents a novel photovoltaic inverter system that can achieve not only a sinusoidal AC output current synchronized with the utility line voltage but also a generation power control on each of the photovoltaic modules connected in series. The proposed inverter system is composed of a half bridge inverter and novel generation control circuit that can compensate for the reduction in output power caused by the shadow covering the photovoltaic modules. The proposed generation control circuit can make the operation point on each of the photovoltaic modules correspond to the maximum power point individually, and the generation power control on each of the photovoltaic modules is executed only by detecting the total output power of the photovoltaic system. Furthermore, the low frequency ripple voltages on the series-connected DC bus capacitors caused by the utility interactive inverter operation are reduced owing to the effect of the generation control circuit. Hence, the average value of photovoltaic generation power is much increased. The effectiveness of the proposed system is confirmed experimentally and through simulation results.