并联型储能系统孤网运行协调控制策略

Cooperative Control for Parallel-Connected Battery Energy Storage System of Islanded Power System

储能系统为含波动性可再生能源、负荷扰动大的孤网系统实现系统稳定提供了一种有效的方法。通过多个子储能系统的并联可提高储能系统的容量,即并联型储能系统。分析了并联型储能系统工作原理,根据电池系统工作特性并结合传统下垂控制,提出了基于电池荷电状态的负荷分配控制策略,即外环功率协调控制。同时,考虑到下垂控制存在固有静态误差、中低压电网线路阻抗不完全为纯感性等因素,提出了含线性补偿环的电压幅值-频率控制策略,即内环电压控制。仿真和实验结果表明,在不同带载情况下,该系统不仅能维持系统电压幅值和频率稳定、且能有效地分配负荷功率,进而提高电池均衡管理能力。

As a valid alternative,battery energy storage system（BESS） is an effective method to maintain the stability of islanded power system consisting of fluctuant renewable energy sources（RES） and load disturbances.Parallel-connected battery energy storage system（P-BESS） will supply high capacity when BESSs are connected in parallel.The operational principle of P-BESS is analyzed.On the basis of the analysis of operating characteristic of battery system and traditional droop control,a new method based on state of charge（SOC） of battery system is proposed to share load power,named power cooperative control outer loop.Moreover,considering an inherent static error in droop control and the impedance being not pure inductance in middle or low voltage grid,an inner loop control strategy based on linear compensating loop is presented,named voltage amplitude and frequency control.Simulation and experimental results show that not only the voltage and frequency of the system can be kept at desired level,but the load powers can be shared effectively regardless of various loads by the proposed method,which contributes to the balance management of battery system.