Research On Electric Energy Measurement Of Micro-grid Including Charging Piles For Electric Vehicles

Electric vehicle charging piles are composed of power electronic devices and belong to high-power,non-linear loads.When electric vehicles are connected to the microgrid for charging,it will have a greater impact on the power quality of the microgrid and bring about problems in the accuracy of power measurement.This article takes the three-phase uncontrollable rectification charging pile as the research object,and analyzes the impact of the electric vehicle using the three-phase uncontrollable rectification charging pile connected to the microgrid to charge the microgrid energy measurement.The types of electric vehicle charging piles and their respective advantages and disadvantages are introduced.The specific theoretical analysis and experimental simulation of the harmonic characteristics of the three-phase uncontrollable rectifying charging piles are carried out.The main harmonics of the th ree-phase uncontrollable rectifying charging piles are explained.The number of waves is 6k ?1(k =0,1,2,).Laid the foundation for the following research.The principle of energy measurement in the presence of harmonics is described.Introduced several current energy metering schemes,and analyzed in detail the calculation method of energy metering error when harmonics existed,indicating that the current energy metering method could not achieve fairness and reasonableness of energy metering Sex.Preparations are made for studying the impact of electric vehicle charging on the microgrid and charging on energy measurement.According to the existing metering methods,the typical AC microgrid model specifically analyzes the electric power metering cau sed by the electric vehicle at the same position,different power,different position,same power,different position and different power when connected to the charging.Impact,the results show that the location of the electric vehicle access and the different access power have different effects on the energy measurement.In view of the shortcomings of the existing metering methods,the combined algorithm of fast Fourier transform and wavelet transform is used to realize the microgrid energy metering after the electric vehicle is connected.The algorithm can more accurately detect the harmonic components generated by electric vehicle charging piles,and its adaptability and measurement accuracy have been significantly improved compared with traditional algorithms.The feasibility of the algorithm is verified by simulation experiments,which provides a certain theoretical support for electric energy measurement of microgrid with electric vehicle charging piles.