The Research And Circuit Design Of Electric Vehicle On-board Charger

With the shortage of energy and the environmental pollution becomes more and moreserious, electric vehicles are becoming the hot topic of automotive industry research、development and utilization because of its superb features of environmental protection andenergy saving.Charging module is a vital part of electric vehicle and its technology level plays a keyrole in the development of electric vehicles industry. Currently, there are two kinds ofcharging method: off-board charging and on-board charging. Due to the high cost ofconstruction and large area involved in, the former one can not meet the users’ need; Whilethe latter one has technical difficulties in charging reliability、efficiency、precision. So it is akey point to design on-board charging equipment of high efficiency, low loss and high safetyfactor.In this paper, the circuit designing process of on-board charger is introduced. The methodof modularization can simplify the design. The part of hardware circuit has four modules:multi-output auxiliary power supply whose control IC is FAN4800; program-controlledswitching power supply based on ISL6754and STM32F100C8T6whose topology is fullbridge phase shift in primary side and synchronous rectification in secondary side; main DCoutput module which has several functions such as combine the power modules and sendsome alarm signals to the MCU when voltage and current signals are unusual; the core controlboard based on STM32F105RCT6which consists of power, the communication interface ofRS485and CAN, the control guide circuit which is linked to charging device on the land. Inaddition, the basic structure of main program software used to control system of chargingdevice is introduced simply in this paper.. The charging device makes use of the groundsignal、the data measured by voltage sensor and current sensor and the battery status to adjustoutput power in real time. So using this method can improve the intelligence, reliability andsafety of charging system effectively.At last, the feasibility of the circuit design of each module and the rationality of wholestructure of the charger is verified by testing the on-board charger module by module.