Parallel-Input Series-Output Z-Source Converters for High Voltage DC Power Supplies

High Voltage DC power supplies typically employ a high voltage high frequency transformer to step-up the voltage generated by a high frequency inverter. Generally, the step-up ratio of the transformers is high and therefore the effect of the stray capacitance and inductance values is amplified, deteriorating the inverter operation. LCC converters utilizing these stray capacitors are suggested to generate soft switching for better efficiency, but this increases the complexity. Also, the varying nature of the stray capacitance may complicate the control. In this paper, a modular, Parallel-Input Series-Output converter utilizing two z-source dc-dc converters is proposed to step a 350V input to generate 2-kV, 2-kW output. Simulation and experimental results prove that impedance source converters which are generally used in renewable energy applications can also be used at high voltage applications.