基于虚拟电机的V2G新型充放电控制策略

为了提高电动汽车车辆到电网(V2G)的稳定性,增强其友好互动,设计了一种新型电动汽车V2G充放电模型,并提出了基于虚拟电机的电动汽车V2G充放电控制策略。电动汽车DC接口采用虚拟直流电机控制,电网AC接口采用虚拟同步电机控制。与传统V2G结构相比,在两侧接口处采用隔离型双向DC/DC变换器连接。在此基础上,对于虚拟直流电机的参数整定,根据电动汽车初始电池荷电状态(SOC)确定阻尼系数以决定电动汽车组的功率分配,并根据SOC的变化实时调节虚拟惯量以提高电动汽车参与电网频率调节的能力。在不同电网状态下对具有不同初始SOC的电动汽车采用所提控制策略进行仿真测试,结果表明,该策略能够在兼顾电动汽车用户需求的同时,有效协调V2G功率双向流动,并减少并网点谐波电流,进而维持电网稳定运行。

Novel Charging and Discharging Control Strategy of V2G Based on Virtual Machine

In order to improve the vehicle-to-grid (V2G) stability and enhance the friendly interaction between electric vehicle and power grid, a new type of V2G charging and discharging model for electric vehicle is designed. An electric vehicle V2G charging and discharging control strategy based on virtual machine is proposed. The DC interface of electric vehicle is controlled by the virtual DC machine. The AC interface of grid connection is controlled by the virtual synchronous machine. Compared with the traditional V2G structure, an isolated bidirectional DC/DC converter is used to connect the two side interfaces. On this basis, for the setting of virtual DC machine parameters, the damping coefficient is determined according to the initial state of charge (SOC) of each electric vehicle to determine the power distribution of electric vehicle group. The virtual inertia is adjusted in real time according to the change of SOC to improve the ability of electric vehicle to participate in grid frequency regulation. The simulation test of electric vehicles with different initial SOCs is carried out under different grid conditions. The simulation results show that the strategy can effectively coordinate the two-way power flow between electric vehicle and power grid while taking into account the needs of electric vehicle users, and reduce the harmonic current of the grid-connected point, thus maintaining stable operation of power grid.