Design Of Verification System For Direct Current Charging Pile Of Electric Vehicle

With the continuous development of social economy,environmental issues have gradually entered the public’s field of vision.Compared with traditional fuel vehicles with no exhaust emissions,low carbon and environmental protection,electric vehicles have developed rapidly in recent years,and the number of supporting charging facilities has also increased exponentially.The electric energy meter in the electric vehicle charging pile is a measuring instrument for trade settlement.The Measurement Law stipulates that this type of measuring instrument needs to be periodically verified to ensure the fairness of the transaction and the vital interests of both parties to the transaction,and the regular verification is carried out by the government measurement administrative department in accordance with the verification Regulations are mandatory.Existing verification methods can be divided into verification methods based on physical standards and datadriven verification methods according to whether physical standards are needed.The advantages of verification methods based on physical standards are high accuracy and reliability,but the disadvantage is that they are affected by physics.Space constraints,low verification efficiency,unable to meet the growing demand for verification of charging piles.The advantage of the data-driven verification method is that the verification can be completed online and remotely,with good real-time performance and high efficiency.The disadvantage is that the accuracy is lower compared to the verification method based on the physical standard device.Based on the above situation,this subject has designed an electric vehicle DC charging pile verification system that can improve the verification efficiency.First,starting from the requirements of the verification system,the requirements of the verification system are analyzed in combination with the verification procedures,and the overall plan of the verification system combining on-site verification based on the physical standard device and remote pre-verification based on data-driven is proposed,and the verification system is divided.There are two parts: on-site verification device and remote pre-verification system.Secondly,according to the demand analysis of the on-site verification device,the on-site verification device was designed in detail from the three aspects of machinery,hardware and software,and the development and assembly of the on-site verification device were completed.Thirdly,the remote pre-verification system is designed and developed.In the part of remote pre-verification,this subject proposes a propagation-type charging pile verification method.The method first calibrates the part of the charging pile that is used more frequently.The calibrated charging pile is used as a reference,and the difference between the electric vehicle BMS(Battery Management System)system and the charging pile in the charging process data is used to measure the same voltage and current difference to complete the estimation of the voltage and current measurement error of the electric vehicle BMS.The car will use the charging behavior of different charging piles to complete the estimation of the voltage and current measurement errors of other charging piles,and further estimate the electric energy measurement errors of the charging piles to be inspected,so as to achieve the purpose of remote pre-verification.Finally,this subject has carried out related tests on the on-site verification device and the remote pre-verification system.The test results show that the voltage and current measurement errors of the on-site verification device meet the requirements specified in the 0.5%;the maximum voltage error estimation of the preverification system The average value is 0.124 V,the average maximum current error is1.728 A,and the average maximum electric energy error is estimated to be 1.52%,which can improve the verification efficiency of the charging pile to a certain extent.