Study On The Control System Based On Expert Fuzzy PID For A Multi-module Electric Vehicle Charger

With the reduction of oil resources and the deterioration of the ecological environment, the electric vehicle industry has been rapidly developing, aiming at energy saving and environmental protection. Electric vehicle charger is an important facility for the power supply of electric vehicles, and so is an important prerequisite for the industrialization and marketization of the electric vehicle. Because it has many kinds of electric vehicle batteries on the market, modularity is the inevitable trend of charger. During the multi-module charger(MC) charges, since the difference between the output characteristics of a single power supply module, it appears the problem of current uneven and total output error after multi-module parallel. Combined charger actual functional requirements and the overall design scheme, the control strategy and algorithm based on expert fuzzy PID are developed. Then the charger control system hardware, software and experimental testing is completed.This paper studies the design of high-power MC control system, namely the concrete design of hardware and software based on the overall design. Charger control system hardware is based on AT91SAM9G45. According to the modular design, hardware design of the main control section, integrated charging power supply module, communication section and peripheral equipment is completed. According to the construction of the hardware platform, function modules such as expert fuzzy PID control, communication control, man-machine interface and other software have been designed. And the key point of this paper is the control strategy and algorithm. The hardware platform and software design of the MC control system are aiming at security and stability.The main features and innovations of the dissertation are as follows: The introduction of digital communication technology such as CAN bus. through the study of the lithium battery charging characteristics and charging method, The fuzzy PID control are employed to adjust the MC output error. Meantime combined with digital current sharing control, the charging process is more precise and intelligent. Appling of sub-charging strategy can effectively improve battery charging speed and prolong life.In the end, through the simulation and prototype test, the results demonstrate: the MC control system meet the functional requirements and performance indicators. Control strategy, hardware and software are reasonable and effective.