Performance Analysis of an Active Power Filter Utilizing Cascaded H-Bridge Multilevel Inverter with Unified Constant-frequency Integration Control

Abstract

The recent years have seen an increase in non-linear loads that are known to generate harmonics in the source current of an electrical network. To overcome this issue, instead of using passive filters, active power filters (APF) have been introduced to inject harmonic currents of the same amplitude and in the reverse order of the phase current harmonics in the load into the network. In an attempt to improve the effectiveness of APF in source current harmonics compensation, this paper presents the performance analysis on the use of cascaded H-bridge multilevel inverter (CHMI) with Unified Constant-Frequency Integration (UCI) as an APF in a single-phase system. A simulation study conducted using MATLAB/Simulink on the APF has shown improved source current total harmonic distortion (THD) as the CHMI number of output voltage levels is increased.