Switched control of shunt active power filter based on parameter estimation

To deal with the operating characteristic of the three-phase shunt active power filter (SAPF), a control strategy is proposed based on the switched system theory. Firstly, the switched dynamic model and the error dynamic model of the three-phase SAPF is established. Then according to the stability analysis of the SAPF, an original switching control strategy is proposed; Moreover, in order to attenuate the effect of parameter perturbations, the discrete switched affine system model of APF is presented, the parameters of the system matrix of the SAPF are estimated online using the Least Square Method (LSM), the single-step prediction of the reference current is implemented using the Lagrange interpolation formula. An optimized switching rule is proposed to guarantee the optimal performance during each control period. Finally, simulation results show that the harmonic current in power grid can be suppressed in the case of parameters perturbation more effectively with the proposed strategy.