Research on two-stage on-board charging system based on IPOP LLC resonant converter

In this paper, a two-stage on-board charging system based on IPOP LLC resonant converter is proposed. The front stage uses a three-phase VSR, which can realize the PFC function and provide a stable DC voltage to the rear stage. The rear stage adopts IPOP LLC resonant converter, low output current ripple, output a wide range of DC voltage, the soft switch over the full load range, and the system efficiency is high. Voltage current double closed-loop control is used for the front stage converter and outputs stable DC voltage. The rear stage converter adopts variable frequency voltage regulation control and phase shift current sharing control, which reduces the volume of the filter capacitor and improves the overall performance and power density of the on-board charging system. A 3.3 kW system simulation model is built to prove the correctness of the theoretical analysis and parameter design method.