Transformer-less High-Gain DC-DC Converter with SiC Cascode JFETs for High-Voltage Applications

Abstract

Wide-bandgap (WBG) semiconductor devices bring numerous advantages to power converters due to their inherent superior switching characteristics and high performance under harsh operating conditions. Currently, traditional silicon switching devices are approaching their practical limits in terms of meeting requirements for fast-switching, high-voltage, and high-temperature operations. To overcome the limitations of the existing Si technologies, silicon carbide (SiC) power devices are selected because they exhibit a wider bandgap energy with a lower on-state resistance and therefore are effectively able to improve the power density and increase efficiency of power conversion in high-switching and high-temperature environments. This paper presents an efficient transformer-less high-gain floating boost converter equipped with SiC cascode JFETs for high-voltage applications. The switching energies of both Si and SiC cascode JFET devices are evaluated using a double-pulse test (DPT) technique at different switch currents, gate resistances, and junction temperatures. In addition, the efficiency of the converter design with SiC power devices is investigated and tested at different switching frequencies and input voltages and compared with the Si-based converter. The results reveal that the SiC power devices utilized in the converter significantly reduce the total semiconductor loss and improve overall converter efficiency.