An improved robust model predictive and repetitive combined control for three-phase four-leg active power filters with fixed switching frequency

Abstract

An improved robust model predictive control (MPC) method for a three-phase four-leg active power filter (APF) is proposed in this paper. First, the decoupling model in abc coordinates of the four-leg APF is derived, and then an optimal control law is also deduced based on the calculation of the partial derivation of the cost function, which is composed of the current tracking error and control quantity with a weighted coefficient. In addition, repetitive control (RC) is introduced to eliminate the prediction error inherent in the model. Finally, the influence of control parameters on the stability of the system is analyzed by the Jury stability criterion, the performance of the proposed method has also been investigated with the perturbations of the filter inductor parameters, and strong robustness, fixed switching frequency and rapid dynamic response of the whole system can be obtained. Simulation and experimental results show the effectiveness and feasibility of the proposed method.

Keywords

• Active power filter (APF)
• Robust model predictive control (MPC)
• Optimal control law
• Four-leg inverter