Abstract
This paper presents laboratory test results of the Dominant Harmonic Active Filter (DHAF) prototype. The DHAF system achieves harmonic isolation at the dominant harmonics using square-wave active filter inverters. The key advantages of the DHAF system are the low rating and low bandwidth requirements of the active filter inverter. Such characteristics allow cost-effective and viable applications of the DHAF system to mitigate harmonic problems for high-power nonlinear loads (10-100 MW and above). Several practical situations, including source-sink resonance, ambient harmonic interferences, and unbalanced grid voltages are applied to the DHAF prototype to validate its performance. The operation principles of the DHAF system and the synchronous-reference-frame-based controller are discussed to explain how harmonic isolation at the dominant harmonics is accomplished. A design example of the DHAF system for a 20-MVA rectifier load at an industrial site is also given to illustrate its application.