A robust adaptive strategy for improving harmonic compensation in shunt active power filters

This paper investigates the use of a robust adaptive control strategy for improving the harmonic compensation in shunt active power filters (SAPF). This control scheme is applied on the filter current control loop and is based on an adaptive pole placement control strategy integrated to a variable structure control scheme (VS - APPC). This control strategy forces the supply currents to be sinusoidal with low harmonics contents. The advantage of proposed VS - APPC over conventional proportional-integral (PI) control is more flexibility, adaptive and robustness to the system parametric uncertainties or unmodeled disturbances introduced by non linear random loads. Moreover, the proposed control strategy can self-tune the controller gains which assures the system stability. Furthermore, the use of this proposed control scheme enhance performance of SAPF with fast transient response. The feasibility of the proposed control system is validated by simulation and experimental results.