A Five-Level Unidirectional Rectifier for Medium Input Voltage High-Power Chargers

Abstract

This paper proposes a new unidirectional three-phase five-level rectifier that is suitable for the rectifier unit of off-board chargers for electric vehicles or trams. The proposed rectifier is featured with a simple architecture, fewer devices and lower voltage stress across each power device, in addition to the high-quality power factor correction (PFC) function. These characteristics render it especially suitable for the chargers with medium voltage input, high-voltage and high-power output to meet the growing demand for fast charging of electric vehicles. The voltage loop and the current loop based on carrier modulation are used to control the proposed topology. According to the design prototype, the scaled down simulation model was built-in MATLAB/Simulink to verify the feasibility of the proposed rectifier topology. The simulation results prove that the PFC function works well, the rectifier has good dynamic characteristics, and the devices suffer low voltage stress under the condition of medium voltage input.