Sliding mode control of a shunt hybrid active power filter based on the inverse system method

• The shunt hybrid active power filter is linearized and decoupled.
• The external dynamics is exponentially stabilized at its reference state.
• The zero dynamics can be stabilized by a novel PI controller.
• The proposed control strategy is effective to eliminate harmonics.

In this paper, an inverse system method based sliding mode control strategy is proposed for the shunt hybrid active power filter (SHAPF) to enhance the harmonic elimination performance. Based on the inverse system method, the d-axis and q-axis current dynamics of the SHAPF system are firstly linearized and decoupled into two pseudolinear subsystems. Then a sliding mode controller is designed to reject the influence of load changes and system parameter mismatches on the system stability and performance. It is proved that the current dynamics are exponentially stabilized at their reference states by the controller. Moreover, the stability condition of the zero dynamics of the SHAPF system is presented, showing that the zero dynamics can be bounded by adding an appropriate DC component to the reference of the q-axis current dynamics. Furthermore, a proportional-integral (PI) controller is employed to facilitate the calculation of the DC component. Simulation and experimental results demonstrate the effectiveness and reliability of the SHAPF with the proposed control strategy.