Reliability Assessment of a WBG-based Interleaved Bidirectional HV DC/DC Converter for Electric Vehicle Drivetrains

Abstract

As Wide Bandgap (WBG)-based semiconductors are being widely used in Electric Vehicles (EVs) drivetrains, it becomes essential to assess the reliability of the WBG-based power electronics converters (PEC). Nevertheless, the ageing response of WBG-based converters in the EVs throughout a complete mission-profile has remained a significant concern for Automotive Original Equipment Manufacturers (OEMs). This paper presents a reliability assessment of a WBG-based Interleaved Bidirectional high-voltage (HV) DC/DC Converter (IBC) for EV-drivetrains. The reliability of IBC is assessed stepwise using a standard mission-profile based on a reliability estimation toolchain that simulates the thermal wear-out of failure-prone components like the semiconductor’s module and DC-link electrolytic capacitor. A modified rainflow algorithm is used to count the thermal stress, swings and expansion of the active and passive components on the IBC system. Outcomes of this article depict that the DC-link capacitor and the upper MOSFET of the half-bridge module are the most failure-prone components when the EV is driven using the dynamic WLTC mission-profile. Moreover, experimental results have presented the accuracy of the electro-thermal modelling by operating 30kW IBC prototype at different load conditions.