An Isolated Buck-Boost Type High-frequency Link Photovoltaic Microinverter

This paper introduces a new topology and the associated control method of an isolated, high-frequency ac link inverter for photovoltaic applications. The circuit, which uses a buck-boost interface on the dc side and a half-bridge cycloconverter on the ac side, works on the principle of controlling the amount of charge delivered to the output over a switching period. The proposed circuit has advantages of low device count, soft-switching operation of switches and absence of reactive power flow. Circuit operation and details of the charge control algorithm are discussed followed by some relevant simulation and experimental results, that validate the approach.