An Improved Half-bridge Type Active Power Filter for Aircraft Power Grids

Great harmonics and reactive current has been brought to aircraft power grids because of much more nonlinear avionics' application with the proposal of concept of “more electric aircraft” and “all electric aircraft”. To fulfill the high power quality and reliability of aircraft power grids, an improved power converter topology of active power filter (APF) is proposed. It is configured by 6 independent split half-bridges consist of one diode and one power switch, in place of the traditional 3 bridge-arms within two power switches. The salient feature of the aeronautic APF using the improved half-bridge power converter is that the inevitable “shoot-through” path during each upper and lower power switch is absolutely eliminated. Furthermore, the original bipolar compensation current is decomposed into two parts of unipolar ones with the novel configuration. The operation principle and mathematical model of the novel APF is analyzed, meanwhile, the correlative key techniques including current control strategy and dc-link voltage control are described as well. Finally, both simulation and experimental results have demonstrated that the improved half-bridge type APF is good in harmonic reduction and reactive power compensation.