独立光储直流微网母线电压分层协调控制策略

Hierarchical Coordinated Control Strategy for Bus Voltage of Isolated PV/Storage Hybrid DC Microgrid

提出一种基于双蓄电池储能系统的电压分层协调控制策略,以储能系统为主体协调控制母线电压稳定。根据母线电压的变化范围将系统的动态调节过程划分为稳态阶段与暂态阶段。稳态阶段下,采用双蓄电池组共同协调工作方式,解决了负载突变导致单组蓄电池充放电电流过大,易引起过流故障的问题;暂态阶段下,采用基于改进下垂控制的双蓄电池组轮换协调工作方式,解决了单组蓄电池荷电状态(State of Charge,SOC)达到上、下限后,出现过充或过放情况引起的蓄电池损坏问题。利用Matlab/Simulink平台分别对系统的两种动态调节过程进行仿真,验证各阶段下所提出的工作方式的有效性,并通过单、双蓄电池组的对比,验证所提出控制策略的合理性与优越性。

In an isolated PV/storage hybrid DC microgrid,maintaining bus voltage stability plays an important role in ensuring the safe and reliable operation of the system.In this paper,a hierarchical coordinated control strategy for voltage based on double batteries energy storage system is proposed.The strategy takes energy storage system as the main body to coordinate bus voltage stability control.According to the variation range of bus voltage,the dynamic regulation process of the system is divided into steady stage and transient stage.Under the steady state,the co-coordinated working mode of double batteries is adopted to solve the problem of overcurrent fault caused by excessive charging and discharging current of single battery due to sudden load change.Under the transient stage,the rotate coordinated working mode of double batteries based on improved droop control is adopted to solve the battery damage caused by over charge or over discharge when the SOC of single batteries reaches the upper or lower limits.Two kinds of dynamic adjustment processes of the system are simulated by using MATLAB/Simulink platform.The effectiveness of the proposed working methods at each stage is verified.The rationality and superiority of the proposed control strategy are verified by comparing single battery and double batteries.