3.6 kW High Efficiency SiC-based HV/LV DC/DC Converter for EVs

Abstract:
Electrical Vehicles (EVs) employ a DC/DC converter to power auxiliary loads with lower voltages from the high-voltage battery. In this work, a SiC based 3.6kW high-voltage (HV) to low-voltage (LV) auxiliary power supply (APS) converter is designed based on silicon carbide (SiC) technology to achieve high efficiency. SiC devices enable higher switching frequencies, leading to the development of power-dense converters. A phase-shifted full-bridge (PSFB) topology is chosen for this application. The design details a PSFB-based DC/DC converter for EVs with 800V DC bus voltage, employing state-of-the-art, automotive grade 1200V SiC MOSFETs to demonstrate the advantages of SiC for superior efficiency and power density. A comprehensive design procedure is provided to support the chosen topology and components. Finally, a thorough simulation and analytical analysis are performed across the entire input and output voltage range.