Performance Enhancement of Shunt Active Power Filter Using a Kalman Filter-Based ${{{\rm H}}_\infty }$ Control Strategy

This paper proposes a Kalman filter (KF)-based H
_∞
control scheme for a three-phase shunt active power filter (SAPF) system. For the current control loop, a H
_∞
controller is designed with a mixed sensitivity approach for achieving stability and high-disturbance rejection in the SAPF system. A new current reference scheme is also proposed that employs KF to avoid synchronization circuit and proportional integral (PI) controller loop resulting in a reliable and cost-effective SAPF system. This reference scheme can self-regulate the dc-link voltage by a fast and adaptive estimation of the source reference current with power system perturbations raised in source or load sides. The efficacy of the proposed KF-H
_∞
control algorithm is evaluated through comparison with an existing PI and PI plus vector PI (PI-PIVPI) algorithm and then validated with experimental studies pursued using a dSPACE1104. From the obtained experimental results, it is observed that the proposed SAPF significantly outperforms the existing PI-PIVPI in terms of exhibiting robustness to modeling uncertainties and insensitivity to grid perturbations such as harmonics, measurement noise, and phase angle jump. Thus, the power quality improvement is achieved in terms of perfect current harmonics cancellation as well as power factor improvement.