Shunt active power filter line current control based on T-S fuzzy model

In single-phase shunt active power filter (SAPF), there are several methods to obtain the best reference control current. The theory of instantaneous reactive power has been successfully used in three-phase symmetrical and asymmetrical power systems, but it is too complicated to apply into single-phase power systems because of complex coordination converting by single-phase to three-phase and then being reverted. One-cycle control or equivalent method can deal with single-phase SAPF control in a good way, but the PI controller also seems too difficult to adjust, and it may cause system unstable while in wide range used. In this paper, the application of Takagi-Sugeno (TS) type fuzzy logic controllers for single-phase SAPF line current control is proposed. This type of fuzzy controller provides a wide range of control gain variation by including both linear and non-linear terms in the consequent part of the fuzzy rule base. The TS fuzzy controllers are quite general in that they use arbitrary input fuzzy sets, any type of fuzzy logic, and the general defuzzifier. 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. Computer simulation tests on a single-phase power system indicate the significant performance of this new TS fuzzy controller for a single-phase SAPF.