Research And Implementation Of Portable AC Charging Pile Metrological Verification And Test System

With the increasing popularity of electric vehicles,charging piles are increasing year by year.It is essential to carry out regular verification in strict accordance with the metrological verification regulations and test specifications and standards proposed by the AQSIQ to ensure the safety and standardization of charging pile products.However,the domestic mainstream function of the product and test content is unitary,which cannot integrate all test functions of measurement verification,communication protocol consistency,and interoperability.High precision electric energy acquisition technology depends on foreign products.Given the above situation,this thesis intends to study an AC charging pile measurement verification and on-site inspection test system integrating high-precision measurement verification and interoperability test.The main research contents are as follows:1.Designing the overall scheme of AC charging pile measurement verification and interoperability test system,based on the analysis of AC charging pile charging workflow and test measurement specifications.Firstly,analyzing the charging workflow,verification regulations,test specifications,and test requirements of AC charge piles and electric vehicles.Then,designing the overall scheme of AC charging pile verification and interoperability test system.It takes high-precision electric energy measurement as the core,an electric vehicle AC charging interface analog circuit as the bridge,and programmable automatic test software as the carrier.2.Designing a high-precision AC energy econometric model according to the error analysis of three-phase AC energy measurement.Firstly,analyzing the influence of threephase AC signal frequency fluctuation,harmonic interference,and electric energy integration on high-precision measurement error.Then designing the corresponding digital filter according to measurement error and accuracy requirements,To determine the high-precision measurement scheme of three-phase AC energy combined with fixed frequency sampling + digital filter + zero-crossing detection technology.On this basis,design and implement the high-precision AC energy metering software and hardware modules.3.Designing an AC charging interface analog circuit for the electric vehicle by taking the vehicle pile charging process and interoperability test as the criterion.It is essential to build a simulation environment of electric vehicles to realize the interoperability test of the AC charging pile.This thesis designed an AC charging interface analog circuit to meet the functions of charging process control and simulations of abnormal charging.Including Electrical signal monitoring of the charging control circuit,which plays the role of a bridge for interoperability tests.4.Designing and implementing the metrological verification and interoperability testing software to meet the requirements of programmable and automatic testing.It is appropriate to divide the functions of the test system into three parts: creating test files,executing test processes,and saving test results in the software design of the AC charging pile test system.Therefore,an automatic test software should integrate hardware control,logic synthesis,human-computer interaction,and other functions.This part will design a hierarchical test software,formulate the implementation strategies of each level,and propose a programmable test item creation method.