A novel circuit topology for grid-connected photovoltaic (PV) system is proposed. The basic circuit consists of a Buck-Boost converter and a current mode high-frequency link inverter. Working in the discontinuous mode of the capacitive/ inductive current, the Buck-Boost converter can realize the maximum power point track (MPPT) of the PV module without loss. The high-frequency link inverter transforms the output power from Buck-Boost converter into AC power, which is compatible with grid connection. The top...