考虑电动汽车灵活储能的交直流混合微电网功率协调控制策略

Power Coordinated Control Strategy of AC-DC Hybrid Microgrid Considering Flexible Energy Storage for Electric Vehicles

孤立交直流混合微电网集中储能荷电状态趋近充、放电临界值,容易引发微电网及其子网功率越限,从而导致系统供电不可靠。在此背景下,该文提出了一种考虑电动汽车灵活储能的交直流混合微电网功率协调控制策略。首先,根据交直流混合微电网及其子网功率盈缺状态,同时考虑混合储能中传统集中和灵活储能之间协调配合,将交直流混合微电网运行模式划分为正常、临界平衡和功率越限3种。在此基础上,根据储能荷电状态不均衡或异常、子微网越限等非正常状态进一步划分工况,以将控制目标进行细分。接着,通过分析电动汽车灵活储能、传统集中储能与互联接口变换器在同一时间尺度下的响应优先级,设计混合储能功率分配和互联接口变换器功率传输原则,并提出系统运行模式及工况间平滑切换方法。最后,基于MATLAB/Simulink搭建的交直流混合微电网仿真模型验证了所提控制策略的有效性。

Conventionally it is difficult to avoid the centralized energy storage in an isolated AC-DC hybrid microgrid because the state of the charges tends to be the critical charge/discharge,which may lead to the unreliable power supply of the system.Aiming at this problem,a power coordination control strategy of the AC-DC hybrid microgrid considering the flexible energy storage of the electric vehicles is proposed.First,according to the power surplus and deficit states of a AC-DC hybrid microgrid and its subnets,and considering the coordination between the traditional centralized energy storage and the flexible energy storage in the hybrid energy storage,the operation modes of the AC-DC hybrid microgrid are divided into three types:the normal,the critical balance and the power off-limit modes.On this basis,according to the differences of the control targets in each mode,the detailed operating conditions are further divided.Then,by analyzing the response priorities of the EV flexible energy storage,the traditional centralized energy storage and the interconnected interface converter at the same time scale,the principles of the hybrid energy storage power distribution and the interconnected interface converter power transmission are designed,and the smooth switching methods between the system operation modes and working conditions are proposed.Finally,an AC-DC hybrid microgrid simulation model based on the MATLAB/Simulink is used to verify the effectiveness of the proposed control strategy.