T-S Fuzzy Controller Design Based on LMI for a Shunt Active Power Filter System

In this paper, a Takagi-Sugeno fuzzy model (T-S fuzzy model) is proposed for a single-phase shunt active power filter (APF) to improve line power factor and to reduce line current harmonics. The proposed active power filter controller forces the supply current to be sinusoidal with low current harmonics and in phase with the line voltage. To design fuzzy controllers, bilinear model of the active power filter system are represented by T-S fuzzy modeling and the so-called parallel distributed compensation (PDC) is employed to design fuzzy controllers from the T-S fuzzy models. For the designed fuzzy control system, the problem of finding stable feedback gains and a common Lyapunov function is solved by linear matrix inequality (LMI) via MATLAB. To verify the proposed APF system, a digital signal controller (dsPIC30F4012) is adopted to implement the algorithm of the T-S fuzzy control and an 1-kVA laboratory prototype APF is built to test the feasibility. Simulation and experimental results are provided to verify the performance of the proposed APF system.