Research on methods of distortion spectrum analysis for aircraft VFAC power system

A lot of power electronic conversion devices are used in the variable frequency AC power system. Harmonic pollution and voltage distortion have serious impact on power quality, and voltage distortion spectrum is an important indicator to measure the electric power quality of aircraft. The distortion spectrum is analyzed for aircraft VFAC power system. The frequency ranged 360 ~ 800Hz brings a wider frequency range distortion spectrum according to MIL-STD-704F. Based on digital filtering technology, the paper proposes a distortion spectrum testing method. The test system can collect synchronous voltage signal by PXI high-speed data acquisition card. The characteristics of digital notch filter are analyzed by simulation, and Butterworth notch filter with four orders is designed for filtering out fundamental component of the distortion voltage. Experimental results show that this test method can extract the fundamental frequency, calculate distortion factor, obtain distortion spectrum. The feasibility and reliability of the test system are verified.