Research And Design Of Electric Vehicle Charging System Based On SOC Values

Nowadays, Vehicle charger of the new energy vehicles are too expensive,low efficiency and the charging control method is simple. Some related equipment of the electric vehicle is less install. Vehicle charger could not charge the battery based on charging performance curve strategies. Battery charging excessively lead to the short age of battery life. For those reasons, this paper proposes five stage charging curve method based on SOC optimization. Design a 1500 W half-bridge resonant LLC Vehicle charger. The result of the experimental test shows that the vehicle charger operate stably, the output parameters are in line with the input parameters, and it enhance the efficiency than similar products by 2%.The main contents of this thesis as follows: 1. Studied the basic principle of charging a lead-acid battery and charging methods to optimize the charging strategy. Using the current time integral method and the Calman filter algorithm to estimate the battery state optimization. Accurate detection of battery state for Real time. 2. Design the APFC(Active Power Factor Correction) and the main power DC-DC converter circuit. This paper focusing on the control algorithm of the voltage and current double closed loop PID. The DSP real-time adjustment of the charging state based on the data collected by the SOC state, which reduces the switching losses of MOSFET, the main power converter working in soft switching state. Finally, we measured output voltage waveform stability and low ripple. 3. Over-voltage, over-current, over temperature and other conditions are detected the charger stops working or operating by reducing power.