Recursive integral proportional–integral control based on membership cloud for active power filter

A recursive integral proportional-integral (RIPI) control based on membership cloud theory applied in active power filter (APF) is proposed. The parallel and integral parameters of RIPI are modulated by the cloud model theory firstly. The rule generator with X-term two-dimensional (2D) cloud generator as forward cloud generator and Y-term 1D cloud generator as backward cloud generator is built for cloud reasoning. The outputs from the rule generator are dealt with to obtain their numerical values. The system controlling performance is analysed, which is compared with the recursive integral PI based on fuzzy theory. Simulation and experimentation are done and the results verify the feasibility and good performance of the proposed controlling method. The APF can suppress harmonic currents well.