A buck-boost based DC/AC converter for residential PV applications

The single stage architecture is often preferred to realize grid connected Photo-Voltaic generators for residential applications. In fact,by halving the power processing steps, the power losses can be considerably reduced if compared with those of a two stage configuration. However, single stage power conditioners are generally unable to boost the voltage of the PV modules, therefore, they feature a narrower input voltage range. A new approach to design a power conditioner for grid connected PV plants for residential applications is presented in this paper. It is based on the series connection between a buck-boost converter,and the PV array. According to such an approach, the buck-boost converter processes only a fraction of the inverter input power, while always operating in conditions of high efficiency. Experimental tests show that the proposed solution features an efficiency level very close to that of a single stage power conditioner, but owns a voltage boosting capability, similar to that of a two stage configuration.