Research And Design Of On-site Test Device For DC Charging Pile With Temperature Drift Suppression

In recent years,in order to deal with the environmental pollution and energy shortage,domestic major cities have promoted the development of electric vehicle industry,DC charging piles and other infrastructures have been vigorously built and promoted too.However,as the construction of DC charging piles is in the early stage of development,there are still some problems.For example,the quality of charging piles are badly different;installed charging piles are affected by the long-term working environment which make the measurement accuracy reduce,the performance of the charging pile fail.As a kind of metering device,the accuracy of the DC charging pile is closely related to the rights and interests of electric vehicle owners and power supply companies.So development the field detection of the DC charging pile,research the high efficiency detection device suitable for the large temperature range of the charging pile in the field are of great significance to maintain the normal work of the charging pile and ensure the rights and interests of vehicle owners and power supply enterprises not damaged.Firstly,the system structure and charging principle of DC charging pile are analyzed,and the measurement and testing rules are studied,combining with the requirements of on-site testing environment,the detection methods of working error,indication error,payment error and clock indication error are determined.Based on this,the whole scheme and technical index of the testing device are designed.The traditional detection technology is mainly used in the laboratory environment,but the corresponding equipment is lack the consideration of the large working temperature range and the temperature drift under high current.In order to solve this problem,the measurement field calibration technology with temperature drift suppression is studied,and the method of measuring current and voltage by using zero flux sensor and precision platinum resistance are put forward.These study make the accurate measurement performance of DC charging pile in the field accomplished.A set of non-vehicle charger field detection device with temperature drift suppression technology is developed.The front end plate,sampling template,power management,BMS(Battery Management System)and other hardware modules are selected and designed,the hierarchical network model is optimized to build the communication protocol between the load and the detection device,the device software is designed based on C#language,and the guided man-machine interface is established.The application verification and field experiment of the testing device are carried out,and some charging piles in Jiangxi province are tested on the spot by using the results of the project.The experiment results showed that within the test temperature range required by the regulations,the detection device meets the requirements of the average temperature coefficient of the 0.05 grade device and 0.1%accuracy of on-site detection.The researched results have a strong application value,the performance of DC charging piles under the condition of wide temperature range in the field can be accurately tested according to the testing regulations.