Design And Research On A 3KW Bi-directional AC/DC Converter Based On V2G Technology

With the development of electric vehicles,a large number of new energy which connects to the grid will affect the normal operation on traditional power grid.Therefore,smart grid and V2G has been widely studied.By unified scheduling power grid,the power grid operation can be optimized,the cost can be reduced and the reliability can be improved.Power electronics converter plays an important role in V2G technology.Because it turns the power flow between grid and electric vehicle into a reality.This graduation thesis introduces design and research on bi-directional AC/DC converter based on V2G concept.The first chapter introduces the development of V2G technology and smart grid.And then single stage and double stage AC/DC converter has been studied.The second chapter designs the hardware.The parameters of circuit and the efficiency of AC/DC converter has been calculated.This chapter focuses on the LCL filters analysis.The third chapter calculates the control loop of AC/DC converter.The discretization analysis of AC/DC converter is also considered.The steady requirement is answered.And then it introduces self-adaptive frequency method based on SOGI PLL.The simulation based on PLECS software verifies it.This chapter also makes an analysis on the zero cross distortion and the control strategy to eliminate it.Finally the experiment result including AC/DC,DC/AC and bidirectional switching is shown.Chapter four introduces a modified control strategy which adopts an extra variable to control reactive power to make sure the power factor is always 1 or-1 during bidirectional switching.The simulation and experiment verifies the control strategy.Chapter five makes a review on the bidirectional AC/DC converter and it introduces the future work.