Cycloconverter-type high frequency link inverter for photovoltaic application

Abstract

The abundance solar energy in this country has triggered the interest of researchers to develop local products to be used in the solar photovoltaic (PV) systems. Although the development of solar cell itself is somewhat far from target, the power converter design is well within reach. This paper presents a dc to ac power converter which can be suitably fitted in a solar PV system. The topology is an isolated cycloconverter-type high frequency link inverter that consists of three arms of bidirectional switches at the transformer secondary. The inverter has the advantages of light weight and reduced switch count. Furthermore, to overcome high voltage surge problem and power device switching loss, the natural commutation method that enables soft switching operation is applied. To verify the viability of the scheme, a low-power laboratory prototype is constructed. The prototype inverter is able to supply a near sinusoidal output voltage with a total harmonic distortion of less than 1%. The total power conversion efficiency reaches 86% when the output power is beyond 300W.