Research And Design Of The DC/DC Converter For Electrical Vehicle Application

As the popularity of electric vehicles and intelligent vehicle systems, the demand of low-voltage DC power supply for electric vehicles is growing, and this is one of the most important applications of EV lithium ion battery. A low-voltage DC power supply is needed for the lead acid battery, intelligent control system, as well as the large number of low-voltage electronics devices (such as instruments and lighting equipments, etc) of EV. The rated voltage of the power supply of these devices is usually12V, and the total current of these loads is large, which up to over100A. The rate of change of the load is very high when these operation status of these devices change. Therefore, to devlelop a low-voltage high-current DC/DC converter with high efficiency and stability for EV application is neccesary.Small size and high power density and efficiency are the key purpose to develop a low-voltage high-current DC/DC converter for EV application. As a result, high-frequency technology, soft switching technology, current doubler rectification technology, and synchronous rectification technology are adapt to reduce the volume and to improve the efficiency of the converter, and these technologies are development direction of modern DC/DC converters. A phase-shifted full-bridge DC/DC converter with current doubler and synchronous rectifier is adapted to meet the requiments of low-voltage and high-current. The control method is current mode control, good effect and fast dynamic response. And the control chip is the phase-shifted full-bridge soft switching PWM controller UCC28950of TI, which is the latest green phase-shifted full-bridge controller with synchronous rectification function, and meets the requiments of automotive applications.Based on the detailed theoretical analysis of the principle and operation modes of the topology, the detailed design processes of every part of the converter are given in this article. Then a prototype is developed based on the simulation verification.As the popularity of electric vehicles and intelligent vehicle systems, the demand of low-voltage DC power supply for electric vehicles is growing. The advantages of the DC/DC converter designed in this article are small size, high power desity and effiency, and good dynamic response, etc. And this DC/DC converter is modular designed for automotive applications. The application prospect is sure to be good.