Multi-Loop Control of a Current-Source Active Power Filter for Harmonics Mitigation in Distribution Systems

Nonlinear loads, such as those with semiconductor or iron-core devices, can produce voltage and current harmonics that may lead to malfunctions in power systems. This paper proposes a multi-loop control strategy for enhancing power quality in electrical distribution systems using a current-source active power filter (CSAPF). The proposed control strategy employs cascaded dc-side and ac-side current loops supplemented with a virtual interface impedance that introduces appropriate resonance damping. CSAPFs offer inherent voltage boosting and current protection capabilities than active power filters with voltage-source converters. Moreover, the proposed active power filter can parallel multiple modules to meet higher power requirements. Simulation results conducted in MATLAB environment demonstrate the effectiveness of the presented control approach in suppressing unwanted harmonic components in power systems.