A Multifunctional Integrated Three-Level Inverter for Electric Vehicle Application

This paper demonstrates a highly integrated 4-in-1 power electronics solution for 800V electric vehicle applications. combines the functionalities of on-board charging, DC boost charging, motor traction, and high-voltage/low-voltage power conversion, all within a single housing. A high level of integration is achieved by using motor windings for charging and a specially designed three-port transformer that magnetically couples high-voltage (HV) and low-voltage (LV) batteries while maintaining galvanic isolation. Additionally, the SuperBox system utilizes a three-phase open-ended-winding machine to facilitate both three-phase and single-phase AC charging. The dual-bank DC/DC architecture allows for the seamless integration of a redundant auxiliary power module, ensuring autonomous and functional safety. During AC charging mode, the T-type three-level (3L) inverter is repurposed as a Vienna three-phase Power Factor Correction (PFC) for three-phase on-board charging or as a totem-pole PFC for single-phase on-board charging. The three-phase motor windings are reused as the PFC coils. In DC boost charging mode, the T-type 3L inverter functions as a boost converter, converting the 400V DC charger input to the 800V battery voltage. A Triple Active Bridge (TAB) converter is implemented to achieve HV-to-HV and HV-to-LV DC/DC conversion and can also operate as a Dual Active Bridge (DAB) converter during DC boost charging and traction modes. Finally, the 3L T-Type inverter is used to drive the motor during the traction mode of operation. Additionally, the 3L T-type inverter is used to drive the motor during traction mode. Detailed design, optimization, and simulation results for each mode of operation will be presented to validate the control and efficiency of the integrated system. Finally, the system is benchmarked against conventional non-integrated solutions to demonstrate improvements in cost, volume, and weight.