ANN Current Controller Based on PI-Fuzzy Adaptive System for Shunt Power Active Filter

This paper deals with the use of triphase shunt active filter which is able to compensate current harmonics, reactive power, and current unbalance produced by nonlinear loads. To perform the identification of disturbing currents, a very simple control method is introduced. It’s formed by a DC voltage regulator and a balance between the average power of load and the active power supplied by the grid. The output current of the voltage source inverter (VSI) must track the reference current. This is done by a neural controller based on a PI-Fuzzy adaptive system as reference corrector. Also to regulate the DC link capacitor voltage a fuzzy logic adaptive PI controller is used. 1. Introduction Due to the increased use of nonlinear electrical loads, such as power electronics supplies, harmonics currents are generated in the level of these loads and injected back to the grid causing its voltage distortion at harmonics currents’ frequencies. The distorted voltage generates distorted currents which will be absorbed by sensitive loads and causing losses in the lines. Also, the most consuming electrical power loads are almost inductive, and then they contribute to the degradation of grid power factor at the point of common connection (PCC). Conventionally, passive filters were adopted for the reduction of harmonics and to improve power factor; therefore, they have the disadvantages such as fixed frequency compensation, resonance, and large size. These limitations were avoided by the use of active filters which utilized a switch-mode power electronic converter to supply harmonic currents equal to those in the load currents. The main objective of the power active filter (PAF) is to compensate reactive power, current harmonics, neutral current, and unbalancing of nonlinear loads by injecting compensating currents. Almost, the method-based instantaneous active and reactive power (pq method) [1] is currently performed for disturbing current identification. The major disadvantages of a bloc identification-based pq method are essentially as follows:(i)it is not effective under distorted and unbalanced mains voltages conditions;(ii)the time delays introduced by pass filters, which are used to separate the average and oscillating parts of powers, degrades the dynamic performance of active filter;(iii) this method requires more computational calculation. The controller of the PAF is comprised of an inner current loop which actively shapes the line currents and an outer voltage control loop which regulates the magnitude of the line currents. This paper presents the