Kalman Filter-Based Control System for Power Quality Conditioning Devices

A new control scheme based on the Kalman filter and the linear quadratic regulator (LQR) is proposed to improve the performance of power quality conditioning devices. Grid perturbations such as load variations, frequency deviation, voltage distortion, line impedance, unbalance, and measurement noise are taken into account. A new model of the plant is developed that allows the use of the LQR controller with a better performance. This new controller structure is feasible thanks to an algorithm based on the Kalman filter (KF), which estimates the state space variables at the point of common coupling, used in the proposed control system. This algorithm is also responsible for generating the references for the controller. The proposed control system was implemented using a digital signal controller. Extensive tests and experimental results are presented in order to verify the performance of the proposal.