An Improved Linear Active Disturbance Rejection Control for UPQR to Optimize Series Side THD

To further improve the compensation ability and dynamic response performance of the series side of the united power quality regulator, an improved control strategy based on linear active disturbance rejection is proposed in this paper. A high-order linear extended state observer is introduced to the structure of the traditional linear active disturbance rejection control, which reduces the estimation error of the total disturbance and improves the dynamic characteristics of the controller. Although the linear active disturbance rejection controller can achieve an excellent signal-tracking effect, it has a sizeable steady-state error. This paper analyzes the root causes of the steady-state error and proposes a feedforward-based active disturbance rejection control strategy to reduce the steady-state error. The performance of the proposed improved active disturbance rejection control is analyzed, and the simulation model is built to verify the effectiveness of the proposed method.