LCL并网逆变器改进型重复控制策略

An Improved Repetitive Control Strategy for Grid-connected Inverters with LCL Filter

对于采用"比例—积分(PI)+重复控制"的LCL并网逆变器控制系统进行了详细分析,并指出其动态性能仍有待进一步改善并且其补偿函数形式复杂,实现困难。结合零相位误差跟踪控制和干扰观测器,提出了一种改进型重复控制策略。一方面,利用零相位误差跟踪控制原理改善了重复控制系统的动态性能并且其补偿函数设计简单;另一方面利用干扰观测器克服了零相位误差跟踪控制参数依赖性强的缺点。最后,仿真和实验表明,与"PI+重复控制"相比较,所提控制策略在保证稳态控制精度的同时能够获得更好的动态性能,并且同样具有鲁棒性强的优点。

The control systems of grid-connected inverters with LCL filter based onproportion-integration(PI)and repetitive control 'are analyzed in detail.And it is pointed out that its dynamic performance has yet to be further improved and its compensation function form is complex while difficult to achieve.By using the zero phase error tracking control and disturbance observer(DOB),an improved repetitive control strategy is proposed.The use of the zero phase error tracking control can improve the dynamic performance of the system and its compensation function can be easily designed.On the other hand,the use of DOB can overcome the parameter dependence shortcomings of zero phase error tracking control.Finally,simulations and experiments show that,compared withPI and repetitive control',the proposed control strategy can yield a better dynamic performance and,while ensuring the steady-state control accuracy,it also has the advantage of strong robustness.