Three-Level NPC Shunt Active Filter Powered by a Hybrid Fuel-Cell/Battery DC Bus Voltage

This paper concerns the application of a NPC three-level shunt active power filter for damping harmonic disturbances from a three-phase feeder. The main contribution of the article is the elaboration of an algorithm dedicated to manage the energy in the hybrid fuel cell/battery DC bus feeding the SAPF. Design of active and passive components is presented. The control circuit is based on the SRF algorithm for detecting the reference harmonic currents and on the phase-shifted carrier-based PWM technique for gating signals generation. Moreover, dimensioning of the SAPF input DC bus voltage and AC output current PI regulators are provided. The study is validated through computer simulations using MATLAB/Simulink. The checked THDs of the feeder voltage and current, power factor and current unbalance rate, demonstrate a satisfying improvement in the power quality of the feeder.