Research Of Vehicle Charger Based On Phase Shift Full Bridge Soft Switching Technology

With the deepening energy crisis and environmental pollution problems, electric vehicle is becoming a mainstream automobile development because of its zero pollution and zero emission. At the same time, vehicle companies and scientific research institutions pay high attention to vehicle charger, and it gains rapid development as a core component of electric vehicle. In the course of development, the traditional hard-switching PWM vehicle charger technology is brutally eliminated due to its high energy loss and low efficiency, so soft-switching technology becomes the focus of today's vehicle charger research instead of hard-switching. In this context, the paper proposes and implements a vehicle charger design based on phase-shifted full-bridge ZVZCS soft-switching technology by researching and summarizing. It solves many existing problems in the hard-switching PWM vehicle chargers.Firstly, this article introduces controlling method, topology and design parameter of phase shift full bridge ZVZCS converter. Then it gives a detail analysis of working principle for this kind converter focusing on phase shift controlling method and lagging arm series diode circuit.On this basis, the paper completes the hardware circuit design of vehicle charger, including active power factor correction circuit, phase shift full bridge ZVZCS soft-switching circuit, MOSFET driving circuit, phase shift controlling circuit, MCU controlling circuit and sensor detection circuit. Among them, the article gives a detailed introduction for designing key components in phase shift full bridge ZVZCS soft-switching circuit. In addition, the paper uses Saber to build simulation models with the combination of hardware circuitry and components design for the above parameters, then it completes the critical circuit simulation. Results show that the hardware circuit of the proposed design works well.In the design of software systems, the paper use C language to complete the controlling program design in Keil MDK integrated compiler environment, and to generate a visual control interface for PC software using Labview. Of course, detail design process and realization principle of the software system are described.Finally the vehicle charger is completed according to above hardware and software system design. And an appropriate test platform based on parameters indicators is set up to test its performance. The test results show that the design of the vehicle charger achieves normal functioning of ZVZCS soft-switching. Full output power of the system is up to 1.55 KW with 94% conversion efficiency, 0.97 power factor constant, 260~420V voltage output range, 0~5A current output range, 0.47% voltage error, 0.89% voltage ripple, and 1% current error. All these indicators are expected to meet the design requirements of the mainstream market level.