Asymmetric cascaded converter for solar PV applications

Solar photovoltaic energy systems have received increasing attention during the last years due mainly to the cost reduction of solar panels and the availability of power converters specifically designed for these applications. Small scale photovoltaic plants have been installed to fed houses and small business whether connected to the grid or stand-alone. In the latter case, the converter must provide a high quality output voltage even with non-linear loads. In this paper the design and control scheme of an asymmetric cascaded converter for small scale PV applications is shown. The converter proposed is based on a main stage which provides the active power to the load and a secondary stage that generates the reactive power compensation. It is shown that this asymmetric converter can work with higher voltage ratios than previously published asymmetric converters and can generate high quality output voltages for both linear and non-linear three-phase loads. The proposed converter is analysed and design guidelines are given. Results that shown the performance of the converter and its control system are presented.