Design Of High-Power Charging For Electric Vehicles Based On VIENNA Rectifier

With the rapid development of electric vehicles,high-power charging pile as an important supporting equipment is becoming more and more popular.The high-power charging pile has a large demand for power supply.Many small and medium-sized units or some residential areas may have insufficient power supply capacity.The high-power charging pile with energy storage provides a solution for low-cost expansion of power supply capacity.In this paper,the main circuit of high-power charging pile and its control strategy are described and analyzed from the perspective of engineering application;Aiming at the problem that the power supply capacity cannot meet the installation requirements of high-power charging pile,a main circuit structure of high-power charging pile with energy storage based on unidirectional DC/DC converter is proposed.The main circuit structure of electric vehicle high-power charging pile is mainly composed of AC/DC rectifier and DC/DC converter.The AC/DC rectifier designed in this paper selects VIENNA rectifier,which is more suitable for high-power engineering applications,and selects full bridge LLC DC/DC converter as the DC to DC converter module.In this paper,the operation principle of VIENNA rectifier circuit is analyzed and the mathematical model is established.The PI regulator double closed loop control strategy is adopted,specifically the current input from the AC side of the inner loop control circuit and the voltage output from the outer loop control circuit.The circuit is simulated.This paper introduces the topology of the full-bridge LLC DC/DC converter,and analyzes the working principle of the circuit with the simulation waveform;The PI regulator is used for phase shifting control to realize constant current charging of the power battery.The effectiveness of the control strategy is verified through simulation.In this paper,a main circuit structure of high-power charging pile with energy storage battery is proposed,which is different from the structure using bidirectional DC/DC converter.In this structure,the charging and discharging function of energy storage battery is realized through unidirectional DC/DC converter;The paper discusses the working mode and control strategy of the main circuit structure.The power distribution of the charging pile is designed,and the system diagram of the distribution box of the charging pile is given.The simulation experiment is carried out for the cascade of VIENNA rectifier and full bridge LLC DC/DC converter.At the same time,the simulation verification is carried out for the simultaneous charging of electric vehicle battery by mains and energy storage battery under one charging module.