配电静止同步补偿器补偿电流优化重复控制策略

比例—积分与重复控制相结合的电流控制策略可以有效地提高配电静止同步补偿器的无功功率和谐波补偿精度,并抑制装置自身由于死区、电网畸变等影响在输出电流中产生的低次谐波,由于传统重复控制器设计引入周期延时环节,导致装置动态时性能不佳,稳定性差。针对这一问题进行改进,提出基于误差调节及改进内模的优化重复控制,利用滞环比较器和衰减器构成误差调节器,在指令或负载切换等动态过程中,根据无功轴电流误差幅值对重复控制器输入信号进行动态调节,减小重复控制对比例—积分前馈通路的影响,并根据三相电网在同步旋转坐标系下谐波电流特性,采用改进内模减小周期延时,提高装置动态性能和稳定性。仿真和实验结果验证了提出方法的可行性和实用性。

An Optimal Repetitive Control Strategy of Compensation Current for Distribution Static Synchronous Compensator

The combination of proportional-integral (PI) and repetitive control strategy for the distribution static synchronous compensator (DSTATCOM) is able to improve the compensation accuracy of reactive power and harmonic and suppress the low-order harmonic in the output current generated by itself due to dead time, grid harmonic, etc. In order to eliminate the effect of fundamental delay caused by the controller and improve the dynamic performance and stability, the optimal repetitive control based on error adjustment and the advanced internal model is designed. The input signal of the repetitive controller is dynamically regulated by hysteresis and attenuator according to the error amplitude of the reactive axis. It can reduce the influence of the repetitive controller on the feed-forward path and improve the response speed. According to the harmonic characteristics of the three-phase grid in the synchronous rotating coordinate, the advanced internal model is introduced to reduce the cycle delay to improve the response speed and stability. Simulation and experimental results have verified the feasibility and practicality of the method. This work is supported by National Natural Science Foundation of China (No. 51177147) and Zhejiang Key Science and Technology Innovation Group Program (No. 2010R50021).