基于自抗扰控制的并网逆变器环流抑制策略

Circulating current suppression strategy of grid-connected inverter based on active disturbance rejection control

谐波交互是影响微网正常运行的主要扰动之一,为此带来的谐波谐振和谐波环流等问题备受关注。环流抑制是确保微网系统可靠工作的关键技术,为应对双闭环PI控制受扰动情况下抑制环流效果不佳,提出了一种基于自抗扰控制的多逆变器并联环流抑制策略,由线性扩张状态观测器对扰动进行估计并进行反馈补偿,配合独有的带宽法调参改善多逆变器并联均流控制效果。文章的主要内容是:建立了逆变器拓扑结构,进行环流的数学物理机理分析,通过两台逆变器并联在并网情况下的MATLAB仿真,证明了并联系统在扰动存在的条件下,自抗扰控制对环流有较好的抑制能力,使系统有很好的动态响应性能和均流效果,提高了并联系统的抗扰能力和可靠性。

Harmonic interaction is one of the main disturbances affecting the normal operation of microgrid.The problems of harmonic resonance and harmonic circulation have attracted much attention.Circulating current suppression is the key technology to ensure the reliable operation of micro-grid system.In order to deal with the poor effect of circulating current suppression under the disturbance of double closed-loop PI control,a multi-inverter parallel circulating current suppression strategy based on active disturbance rejection control is proposed.The disturbance is estimated and feedback compensated by linear extended state observer,combining with the unique bandwidth method,the control effect of parallel current sharing of multiple inverters is improved.The main contents of this paper are as follows:the topology of inverter is established and the mathematical and physical mechanism of circulating current is analyzed.Through the MATLAB simulation of two inverters connected in parallel under the condition of grid connection,it is proved that under the condition of disturbance,the active disturbance rejection control has a good ability to suppress the circulating current,so that the system has a good dynamic response performance and current sharing effect,which improves the disturbance rejection ability and reliability of the parallel system.