独立运行微网中含不平衡负载的控制方法研究

Study on the Control Method of Islanding Running Microgrid Under Unbalanced Loads

基于分布式电源(DG)在d,q,0坐标系下的模型,设计了解耦的电压电流双闭环比例积分(PI)控制器,分析了不对称负载对逆变器输出的影响,并提出了不受频率波动影响的正负序列分离方法,给出了逆变器在负载不平衡时消除零序和负序电压对逆变器输出影响的控制策略;在负载分配方面,对传统的下垂控制进行了改进,提出了一种可更好实现并联逆变器之间负载分配的算法。最后,进行了基于PSIM的仿真以及实验研究,结果表明相较于传统的控制方法,改进算法能使基波功率分配不受影响且整个系统功率能得到精确分配。

Based on the model of distributed generation (DG) supply in d ,q ,0 coordinate system, a decoupling voltage and current double closed loop proportional integral (PI) controller is designed, and the effect of asymmetric load on the output of inverter is analyzed.A positive and negative sequence separation method is proposed, which is not affected by frequency fluctuation, and the control strategy of eliminating the influence of zero sequence and negative sequence voltage on the output of inverter when the load is unbalanced is given.In the aspect of load distribution, the traditional droop control is improved, and a better algorithm for load distribution between parallel inverters is proposed. Finally ,the simulation and experimental research based on PSIM are carried out.The results show that com? pared with the traditional control method, the improved algorithm can make the fundamental power distribution unaffected and the power distribution of the whole system accurate.