Researching On The Strategy Of Vehicle To Grid

In recent years, the electric vehicle technology and vehicletogird(V2G) technology have received extensive attention all over the world. In order to meet the requirements of smart grid and improve themanagement level of power grid and electric vehicle network, we need to build a comprehensive and coordinatedelectric vehicle operation control system. Because of the ability to store electrical energy,electric vehicles can be charged during the valley load or low price period, and it can be discharged through the charging and discharging devices during the peak load orhigh price.The time of exchanging the mode of charging and discharging is very short, so electric vehicles have the ability to stabilize the distributed power fluctuations and voltage drift generated by distributed generation units. Appropriate polices can effectively solve the problemsofV2G, it is effectiveto promote the development of smart grid, and also can reduce the series of problems caused by V2G.Firstly, the paper givestheresearch status ofV2G around the worldfrom the angels ofeconomy and power network operation, and then introduces the basic concepts of electric vehicle and V2G.The game between the power company and PHEV usersbecomesmore and morefrequently and closely. The power priceis the role ofleverage.The paper takes into account the smooth grid equivalent loadfluctuations of the supply side and the benefitsof the user side, uses the comprehensive price reaction curve and electricity elastic matrix to represent the PHEV users’ charging and dischargingelastic characteristics, establishes the mathematical model. Reasonable charging and discharging peak-valleyprice is proved to be effective by the example to smooth system load, while the PHEV users’ economic benefits is met.The paperhas analyzedthe distributed charging and discharging model of electric vehicleswhich consider the randomness and particularity of PHEV users’ behavior. Considering the effects of price and discounted cost of the battery, a load shifting scheduling strategy is used to guide the electric vehicle users to charge during the low load periods and discharge during thepeak loadperiods. In order to analyze PHEV users’ behavior, the concept of the gametheory is usedto create a distributed charging and dischargingmodel whose Nash equilibrium is solved to get the optimal scheduling policy. Through the analysis, if the control strategy and control level are set reasonably, electric vehiclescan effectively regulate the system load and optimize the operation condition of the system. At the same time, battery isanexpensive component of the vehicles, unhealthy charging and discharging behaviorwill affect its life, and we should pay more attention on it. The mode of battery swap station combined with micro-grid has been discussed in the paper.In the mode,battery swap station can satisfy the EVusers’ energy demand, and micro-grid is more flexible and schedulable.Based on the multi-agent system of micro-grid,the paper analyzesthe micro-grid energy schedule strategy. Considering micro-grid and battery swap station as economic community, the paperestablishes cooperative economic dispatch model.Through the numerical simulation, the micro-gird with battery swap station support the main grid with energy during the peak load period, and canget electric power efficiently during the low load period. At the same time, battery swap station can effectively reduce their operating costs, even make some profits.With the popularization and development of smart grid and electric vehicles, the study about influence and control of V2G will become more and more popular. During the process of development and innovation, there will be many new problems. In order to find more rational, effective and specific way to arrange V2G, we needdeeper and furtherresearch.