考虑分段充电的实用型电动汽车概率负荷模型

随着电动汽车发展的规模不断扩大,车辆的充电负荷将成为电网负荷的重要组成.由于自身充电行为的随机性,电动汽车充电负荷难以用传统的负荷模型进行描述.文章针对停车场内的电动汽车充电负荷,提出了一种考虑分段充电特性的实用型充电负荷概率模型.研究了单台电动汽车电流型分段充电负荷模型,在此基础上利用蒙特卡洛抽样模拟多台电动汽车的随机充电过程;通过最小二乘法对模拟的电动汽车充电负荷特性进行辨识,得到等值充电负荷模型参数集;考虑电动汽车进站时刻、充电时长占比等因素,结合分段模型参数辨识值得出各参数的概率分布特性,将停车场的充电负荷等效为一个变系数的负荷模型.利用实测出行规律的统计数据,在Matlab/Simulink中对该模型进行仿真验证负荷模型参数的有效性.仿真结果表明,文章建立的负荷模型简洁清晰地描述了充电行为随机的电动汽车充电负荷特性,可应用于规模化电动汽车充电负荷的实际工程计算中.

A Practical Probability Load Model of Electric Vehicles Considering Charging by Stages

With the expansion of the development scale of electric vehicles, the load of charging vehicles into the power grid will become an important part. Because of the random charging behavior, it is hard to describe the charging load of EV (Electric Vehicle) with the traditional load model. In this paper, aiming at the charging load of electric vehicles in parking lots, a practical probability load model of EV considering the segmental charging characteristics is proposed. Firstly, the current-mode charging load model and its parameter identification of a single EV considering two-stage charging characteristics are studied. Based on this, Monte Carlo sampling method is used to simulate the random charging process of multiple EVs. Then the charging load characteristics of EVs are identified by least-square method, and the parameters set of equivalent charging load model is obtained. Finally, considering the factors such as the arrival time and the proportion of charging time, and combining the two-stage load model identified parameters, the probabilistic distribution characteristics of each parameter can be obtained. And the charging load of EV in parking lot is equaled to a variable coefficient load model. The model is simulated in MATLAB/Simulink by using the statistical data of the actual travel law to verify the validity of load model parameters. The simulation results show that the established load model considering the randomness of charging behavior in this paper describes the charging load characteristics of EVs concisely and clearly. It can be applied to the actual engineering calculation of charging load of large-scale EVs.