基于电流观测与重复控制的逆变器多环控制策略研究

Study on Multi-loop Control Strategy of Inverter Based on the Current Observation and Repetitive Control

提出一种基于电流观测与重复控制的单相逆变器多环控制策略。内层双环控制器采用输出电压和电容电流反馈,通过电容电流观测器实现了电流内环最小拍控制,可实现系统的快速动态响应,解决了负载突增时电压跌落的问题。基于此又增加了外层重复控制,采用FIR数字滤波器替代传统二阶低通滤波器作为重复控制补偿器,不仅简化了设计过程而且提高了系统稳态精度和抗非线性负载扰动能力。试验结果表明该策略可兼具动态响应快、稳态波形精度高和鲁棒性强等特性,适用于交流稳压器等需要高性能电压输出控制的场合。

A single-phase inverter multi-loop control strategy, which based on current observation and repetitive control, was proposed. The inner dual-loop controller selected the output voltage and capacitive current as feedback quantities. In order to realize the current-loop minimum beat control, capacitive current observer was established. This approach could increase the dynamic response and eliminate the voltage droop. FIR digital filter was adopted as repetitive control compensator, aiming to simplify design process and improve the steady state accuracy and the ability to suppress nonlinear load disturbance. Finally, the experimental results demonstrate that the proposed strategy can achieve rapid dynamic response, high tracking accuracy and strong robustness. Consequently, this control strategy is suitable for the critical applications, especially for the requirements of high quality output voltage control.