Adaptive Selective Compensation for Variable Frequency Active Power Filters in More Electrical Aircraft

The work presented here investigates an adaptive current controller for active power filters for aircrafts power networks, which compensate selected load current harmonics. The attention is focused on the load current harmonic compensation when the fundamental frequency varies over a wide range (typically between 360 Hz and 800 Hz as in new generation aircrafts) and the harmonics produced by distorting loads (such as the 5th and the 7th) are above the achievable current loop bandwidth. Compared with previously reported resonant controllers, this work proposes an adaptive leading angle compensation in the resonant filter, which-by compensating the variable process delay-is potentially able to guarantee the theoretical current control stability when the selected frequency is up to the Nyquist frequency. However, the presence of intermodulation, i.e., distortion introduced due to the compensation of frequencies approaching the Nyquist limit, introduces an additional distortion, which limits the maximum compensation frequency. Experimental results are presented to demonstrate the effectiveness of the proposed system.