An Enhanced Second Carrier Harmonic Cancellation Technique for Dual-Channel Enhanced Power Generation Centre Applications in More-Electric Aircraft

The more-electric aircraft concept has made the extraction of electrical power from both high-pressure shaft and low-pressure shaft of the aircraft engine essential for future aircraft. With each shaft driving one electrical generation channel, an advanced dual-channel enhanced power generation system can be formed. This article aims to address the power quality issues of this dual-channel power generation system, specifically focusing on the reduction of harmonics on a common dc bus. A simplified model to estimate second carrier harmonic of dc current in two-level converters is developed and reveals the fact that while this second carrier harmonic component magnitude can be determined by modulation index and dc-link current, its phase angle is solely dependent on the angle of carrier signals. Based on the developed model and these key findings, a new harmonic cancellation method is proposed through active power sharing and phase angle shifting of the carrier signals within different power sources. The method has demonstrated high robustness and is effective under different fundamental frequencies and power sharing ratio. Both simulation and experimental results are presented in this article to validate the proposed harmonic model and the enhanced cancellation method.