Research and design of digital power quality analysis system based on mixed radix FFT

Abstract

This paper is dedicated to the research on the digital analysis system of the power quality which is greatly deteriorated by the development of power electronic technology and the widespread application of nonlinear loads. Researchers at home and abroad have done many studies on the measurement of the power quality indicators and have proposed many measuring methods which are too complex to be used in practice. This paper proposes a hardware detection method for frequency measurement and a digital harmonic analysis method based on mixed radix fast Fourier transform (FFT) for the measurement of harmonics, and adopts a frequency-domain analysis method based on mixed radix FFT to measure the fluctuations and flicker of voltage. Compared with other measuring methods, the measuring methods proposed in this paper are simpler and more reliable, and they have fewer complex mathematical calculations and a better real-time performance. Finally, a real-time digital power quality analysis system was designed and implemented in the laboratory by using ARM processor and mixed radix FFT algorithm. After that, we tested the system by using the relay protection tester, in the laboratory, and the experimental results showed that the power quality analysis system designed satisfied the requirement of IEC61000-4-30 standard.