Research On Electric Vehicle Intelligent Charging Pile System

With the improvement of people’s living standard, more and more attentions are paid to environmental problems incurred by increasing of car amount. It’s clear that electric cars due to its environmental protection feature, which permitted zero emission, stands for the trend of auto industry. Many countries are increasing money supply to research on electric car currently. However, the charging facilities development should be also valued while the developing of electric cars. Charging piles have been put into operation in many areas as petrol stations for electric cars. However, the user experience of charging piles is not so satisfied as most of users are boring about long charging time. To address this issue, strongly promotions on fast charging piles is an inevitable choice. This paper focused on intelligent charging pile system of electric cars so as to make the charging process faster and more intelligent, which are of great significance on the development of electric car industry.The charging strategy of intelligent charging pile is the key research content of the paper, the selection of charging strategy directly affects the charging effect of intelligent charging piles. Nowadays, lithium iron phosphate battery is often used as the power battery of electric vehicle, the paper takes the lithium iron phosphate battery as an example to study the charging strategy of intelligent charging pile. The charging strategy of intelligent charging piles is based on the segmented charging, which is different charging methods at different charging stages. In the third section of the positive and negative pulse charging, fuzzy controller calculates the negative pulse strength, in order to achieve the best effect of depolarization. Experiments show that it can significantly improve the charging speed, prolong the service life of the lithium iron phosphate battery.In this paper, the hardware of the intelligent charging pile is designed in detail, including the design of the charging unit circuit and the design of the signal acquisition unit. According to the charging unit design. Firstly, for three-phase alternating current of rectification and filtering, the reason why the use of three-phase power as intelligent charging power supply, it is because the three-phase power can provide intelligent charging pile the current. Then the output DC power DC-AC-DC transform, in the transformation by controlling the IGBT to adjust the size of the output current. Finally, the discharge depolarization circuit is designed, which can be realized without loss. On the signal acquisition unit, designed three circuits used to collect the current, voltage and temperature of the battery charging process, and provide the necessary information for the charging strategy.The related functions of the intelligent charging pile prototype are tested, and the intelligent charging pile can work normally, and the design requirements are completed.