New Start-Up Scheme for HF Transformer Link Photovoltaic Inverter

Safe start-up procedure is critical for the reliable operation of power converters. The challenges in start-up schemes of high-frequency transformer link inverters involve precharge of the capacitors without significant inrush currents and overvoltages. The precharge is normally followed by enabling of the closed-loop control. The overvoltage or inrush current problems in conventional start-up schemes available in the literature are identified in this paper. A new start-up scheme is proposed which achieves the objectives of limiting inrush current and start-up overvoltages. This method does not require any additional dedicated precharge circuitry. The proposed scheme is validated using simulation and experimental results which agree with the theoretical prediction.