A three-phase three-level (NPC) shunt active power filters controlled by different controllers which can compensate current harmonics generated by nonlinear loads is presented in this paper. Three-level inverters and intelligent controllers have been successfully employed in several power electronic applications these past years. An ANN and fuzzy current controllers are adopted for three-level (NPC) shunt APF to improve the performances of the conventional control scheme. These controllers are proposed to simplify the complicated conventional hysteresis controller and to improve compensation capability of APF. The reference current signals required to compensate harmonics use the synchronous reference current detection method. This technique is easy to implement, require few calculations and achieves good results. To maintain the dc voltage across capacitor constant and reduce inverter losses, a proportional integral voltage controller is used. The simulation is performed using Matlab-Simulink and SimPowerSystem toolbox. The results obtained in transient and steady states under various operating conditions show the effectiveness of the proposed shunt APF based on these intelligent current controllers compared to the conventional scheme.

Keywords: Artificial neural network (ANN), Fuzzy logic, Harmonic current compensation, Power quality improvement, Shunt active power filter (SAPF), Three-level neutral point clamped (NPC) inverter