Analysis and design of solar power system interface utility using ZVS converter

In the present work, the development of a grid-connected ZVS inverter with a reduced number of power conversion stages and fewer passive components for single-phase photovoltaic applications, suitable for conversion from low-voltage (40-60V) DC to high voltage AC (230VAC;RMS) at average power levels of 175 W and below, (the design specifications given inTable I) is presented. The circuit topology is based on a full-bridge ZVS inverter with an auxiliary circuit, a high-frequency transformer, and a novel half-wave cyclo-converter. The ZVS converter employs an asymmetric auxiliary circuit to provide the reactive current to the full-bridge semiconductor switches, which guarantees ZVS at the switching instants of the MOSFETs. The main operational characteristics of this topology are identified and analyzed, and a multidimensional control technique is applied, firstly to determine the optimum value of the reactive current injected by the auxiliary circuit to guarantee ZVS and secondly for an improved realization of the proposed architecture that enables reduced device losses compared to other realizations along with flexible control, enabling very high efficiencies to be achieved.