直流微电网并联储能系统改进下垂控制策略

Improved Droop Control Strategy for Parallel Energy Storage System of DC Microgrid

针对直流微网中并联储能系统采用传统下垂控制时,在系统电流精确分配和公共母线电压稳定中存在的问题,该文提出一种改进下垂控制策略。该方法通过引入变换器耦合点的电流和负载电压信息,确定下垂控制补偿量,将其以负补偿形式引入下垂控制,解决了因线路阻抗产生的电流分配影响,实现母线电压稳定;同时为消除变换器本身参数误差对下垂控制带来的影响,通过增加电流控制算法,修正变换器电压设定点,提高了电流分配精度。通过Matlab/Simulink仿真和实验证明,所提控制策略有效解决了电流分配精度问题,保持了系统电压稳定;且无需在变换器之间建立通信连接,极大地提高了系统的可扩展性和稳定性。

Aiming at the problems in the precise distribution of system current and the stability of the common bus voltage when the parallel energy storage system in the DC microgrid adopts traditional droop control,an improved droop control strategy is proposed.This method determines the droop control compensation amount by introducing the current and load voltage information of the converter coupling point,and introduces it into the droop control in the form of negative compensation,suppressing the influence of the current distribution caused by the line impedance,and realizing the bus voltage stable.At the same time,in order to eliminate the influence of the converter’s own parameter error on the droop control,the converter voltage set point is corrected by adding the current control algorithm and the current distribution accuracy is improved.Through Matlab/Simulink simulation and experiments,it is proved that the proposed control strategy can effectively solve the circulating current problem in the system and keep the system voltage stable;there is no need to establish a communication connection between the converters,which greatly improves the scalability and stability of the system.