Research On Reactive Power Compensation Of Electric Vehicles Charging Station

A large amount of reactive power has a bad impact on the quality of the grid voltage nowadays and a large number of electric vehicles charging devices who produce those reactive power influence the quality of the grid, devices’ safety and the economic benefits of electricity.General reactive power compensation devices can not dynamically compensate the reactive power which is changing rapidly. As an effective reactive power compensation device, static var generator(SVG) is able to compensate the instantaneous reactive power. This paper is aimed at researching on reactive power compensation for electric vehicles charging station.This article introduces the history and current situation of development of reactive power compensation and analyzes the principle of SVG and establishes mathematical model. It studies the method of the reactive current extraction algorithm which set the frequency without PLL based on instantaneous reactive power theory. this method can extraction reactive current accurately without PLL, completely unaffected by the voltage distortion and frequency effects. for asymmetric systems which containing negative sequence component, this paper further researched the positive sequence, negative sequence dynamic reactive power detection algorithm. This paper analyzes the principle of battery and charging device and simplifies it’s topology and establishes mathematical model. Based on the reactive power compensation theory, this paper research reactive power compensation strategies for electric vehicles charging station which produces capacitive reactive power. This paper simulates the system in conditions of constant load and flexible load respectively using software simulink and confirm the reliability of dynamic compensation of this system.