Research On High Efficiency Power Converter For Electric Vehicle

Electric vehicles are the development direction of vehicles in the future because of their advantages of energy-saving, low-noise, low-cost and so on. However, many factors, such as its mileage short, charging inconvenient, short battery life, etc, hinder spreading and popularization of electric vehicles. Nowadays, because battery technology of electric vehicles has yet made no headway, so we do nothing but endeavor to improve the efficiency for power converter electric vehicles and develop charging devices which are new and convenient.According to the practical need of electric vehicles, a42V/14V converter and a mounted charger for electric vehicle are designed in this paper. The development background of electric vehicles and research status of vehicle mounted power converters are introduced firstly in chapter one. Synchronous rectification technology and phase shifted ZVS full bridge converter are introduced briefly too. Chapter two is the design of42V/14V converter whose main circuit uses synchronous rectifier Buck converter, analyzing the operating principle of main circuit and finishing the design of control circuit and the choice of parameters and loss calculation of main circuit component. In chapter three, the prototype of42V/14V converter are introduced, and experimental waveforms are given, and field measured maximum efficiency of prototype reaches up to93.14%. Chapter four is the design of a mounted charger for electric vehicle. The main circuit of mounted charger for electric vehicle employ phase shifted ZVS full bridge converter and adopts two charging ways of constant-current and constant-voltage. Therefore, its control structure is simple and it has few damage to batteries. The protection circuit, charging indication circuit and a stop indication circuit are designed in this chapter too. Finally, a summary of the paper is given.The main circuit of42V/14V converter uses synchronous rectification technology, by which power loss is greatly reduced. The main circuit of mounted charger for electric vehicle employ phase shifted ZVS full bridge converter. Due to adopting soft switching technology and synchronous rectification technology, two power converters can achieve a high conversion efficiency. Electric vehicle can save the electrical energy stored in the battery and extend its mileage by using DC/DC converter of high efficiency. Then, light and small vehicle mounted charger may supply an electric vehicle with electrical energy conveniently in time. Therefore, the combination of the both metheds can improve the performances of electric vehicles and be beneficial to spreading and popularization of electric vehicles.