A High-Frequency-Link Photovoltaic Inverter

This paper presents the operation and design of a differential-mode current-fed zero-current-switching (ZCS) based voltage-doubling photovoltaic (PV) inverter[1]. It does not need a) 60-Hz transformer, b) front-end dc/dc converter, and c) can boost a low-voltage (30-60V) input to a 120V/60 Hz output using a unity-turns-ratio transformer because of the added voltage gain of the topology. Further, because the operation is differential mode, a previously proposed ZCS scheme[2] retains its effectiveness for the new inverter. The inverter requires a smaller high-frequency transformer because of a) 100-kHz switching, b) bipolar transformer current and voltage in every switching cycle, and c) the transformer sees only half of the input current at any given instant. Analysis, design and simulation results of the inverter are provided here.