Residential Electric Vehicles Charging Control Strategy In The Smart Grid

The energy crisis and environmental pollution has become the two major problems in the world. With the continuous deterioration of the environment and depletion of non-renewable energy, electric vehicles encounter an unprecedented development opportunity. However, large-scale of electric vehicles connecting to the grid disorderly would cause serious shocks to the grid, especially when the load curve is already in the peak, which will lead to the charging power peak add to load peak. And it is not good for the power system stable safety and economy operation.The purpose of this thesis intends to propose the control strategy to solve the negative impact of large-scale electric vehicles into the grid. By reading a lot of literature, firstly we conclude and analyze the current researches on electric vehicle charging control, the technology of electric vehicle charging in the smart grid and the charging service model. Based on the comparison and analysis, we propose two novel optimization charging control methods applied in large-scale residential electric vehicle charging control method.Firstly, considering the stochastic nature of electric vehicles charging activities, three important factors of the electric vehicle charging process are taken into account and studied, including the characteristics of electric vehicle battery, the start time of electric vehicle charging and the initial state-of-charging of electric vehicle battery. Based on the above three factors, we built the charging load model of the single electric vehicle, then by The Central Limit Theorem, we can get multiple electric vehicles charging load model.Then, based on the electric vehicle charging load model, we present a residential electric vehicles charging optimization scheduling strategy to minimize the variation of total power load in the specified time period. And then we propose an approximate evaluation method for the corresponding optimization problem. The simulation results illustrate that the proposed electric vehicles charging scheduling strategy will reduce the total power load curve difference of peak and valley, and the proposed method is very promising to improve the daily load profile of power system.What’s more, based on the above electric vehicle charging load model and resident electric vehicles charging optimization scheduling method, we propose the resident electric vehicles charging optimization scheduling strategy under the electricity market environment. We built and analyse the electric vehicle charging load demand response optimization model, which can optimize the electric vehicle charging cost and optimize the power system. The simulations further illustrate and verify the validity of the proposed charging optimization method.To conclude, this paper built the electric vehicle charging load model considering the stochastic nature of electric vehicles charging activities, then we propose the residential electric vehicles charging optimization scheduling strategy based on the probability method. What’s more, we propose the residential electric vehicles charging optimization scheduling strategy under the electricity market environment. By the simulations, we further illustrate and verify the validity of the proposed methods.