The Research On The Charger Of The Electric Vehicle

To meet the requirement of the electric vehicles project on the battery charger for our laboratory, this thesis designs an intelligent charger for the lithium battery group applied to the electric vehicle. With the research of the development status of the charger and the character of the lithium battery, we determine to adapt the two-step charger strategy with the first constant current and then constant voltage. Besides it, full bridge topology is adapted for the main circuit. The thesis firstly presents the detailed course of the calculation for the main circuit and then introduces the design course of the control circuit. To generate constant output current or voltage, the control circuit adapts the double closed-loop PI regulator. Apart from it, the protect circuit is designed to keep output off the over-voltage or over-current. To enhance the intelligent degree of the charger, CAN communication circuit is designed to transfer the relative charger data to the central signal processing unit of the electric vehicle and receives the command on real time. Due to the high power of the charger, the design of the thermal treatment has been implemented to obtain the stability of the system. At the last, we debug the circuit and do experiment to approve the rationality of the design.