New Start-up Scheme for HF Transformer Link Photovoltaic Inverter

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