Design and Control of A High Power Density Three-Phase Flying Capacitor Multilevel Power Factor Correction Rectifier

Abstract

Three-phase rectifiers with Power Factor Correction (PFC) at kilowatt levels are widely used in applications such as electric vehicle (EV) charging and data center power delivery and so on. The Flying-Capacitor Multilevel (FCML) converter has great potential to improve the performance of three-phase rectifiers due to the smaller required inductance and the use of high-energy-density [] ceramic capacitors. While high performance single-phase ac-dc FCMLs have been demonstrated, three-phase FCMLs with PFC function have unique characteristics and challenges, which are addressed in this work through the hardware and control design of a high performance three-phase FCML PFC rectifier, which has been tested up to 6.1 kW, 208 Vac to 400 Vdc, achieving peak efficiency of 98.5% and effective inductor switching frequency of 1 MHz.