Silicon Carbide Multilevel Converters for Grid-Connected PV Applications

Abstract

To fulfill the space and weight requirements of the photovoltaic systems, an all-SiC transformer less dc-dc multilevel converter based on the Cockcroft-Walton voltage multiplier capable of providing high voltage conversion ratios without an extremely high duty cycle has been realised. The evaluation of converter performance utilising SiC devices have been detailed and presented. The converter offers self-balancing which maintains the same output at all output levels, reducing the complexity of the control strategy. SiC Schottky diodes were used to achive lowest reverse recovery and fast switching while evaluating the high voltage and high frequency performance of the SiC MOSFET in the multilevel boost converter.