Study On Coordinated Charging Strategy For Household Electric Vehicles

With the energy shortage and environmental pollution becoming more and more serious,most countries in the world are accelerating the research of electric vehicles to alleviate the problems caused by traditional fuel vehicles.At present,the difficulty of popularizing electric vehicles in a wide range is how to quickly realize the electric energy supply,which is closely related to the battery materials,structure,charging methods and so on.Firstly,the energy replenishment of electric vehicles in our country advocates the way of "switching is the main,charging is auxiliary",with the influence of automobile manufacturers,power suppliers and social technology progress,etc."Switching is the main" is gradually weakening,the way of energy replacement is gradually weakening,the charging mode has become the main trend of development.How to realize fast charging under the condition of the lowest battery damage has become a hot topic of research.After briefly introducing AC charging and DC charging,this paper considers that only DC charging can realize fast charging,and then studies the topology and control strategy of DC charging.the three-phase bridge rectifier circuit is analyzed theoretically,and a MATLAB simulation model of voltage and current double closed-loop is built based on space vector control strategy and decoupling control.At the same time,in order to ensure the accuracy of DC charging measurement,factors affecting the accuracy of measurement were studied.Based on the analysis of different factors,a test model was built to verify the error effects of different factors and different algorithms.and the 6k±1 harmonics generated by three phase bridge structure and six pulse rectification are estimated.Finally,under a actual charging environment,the DC charging voltage will have ripple disturbance after rectification,especially in the case of voltage fluctuation,large DC ripple disturbance not only affects the accuracy of measurement,but also affects batteries charging quality.In order to solve those problems above,this paper proposes a charging method to improve the charging quality of electric vehicles,we design specific control circuits,and build a verification test model,the final simulation results demonstrate the effectiveness of the proposed method.