Research Of Harmonic Analysis Method Based On ARM And Virtual Instrument

With the development of modern industry,all kinds of power electronie devices have been widely used,the power system is also having a significant increase in non-linear loads,making the power system harimonic pollution more and more serious.It has so serious deterioration of power quality,endangering the power system security,and impacting the user's normal work. The main basis and final goal of harmonic studies are harmonic analysis,harmonic detection and suppression.This is necessary to protect the safety of the power operation.Presently the main method of hamonics analysis is the Fourier transform and the wavelet transform. Fourier transform is the basic of modern hamonics analyze. However Fourier transform needs longer time to collect and process the signal. Further more,there are grid-effect and frequency-leak in the processing,which leads to inferior real-time and precision. Wavelet transform is the new method which has being researched nowadays.With this new method,the local characters of signals can be analyzed exactly, and the real-time and precision of harmonics analysis can be improved too.This paper introduces the basic concept of hamonic, hamonic source and hamonic hazards, and then it investigates the methods of harmonic analysis,such as the methods of Fast Fourier transform,Prony's method, wavelet transform method,and the various methods are compared. The emphasis of paper is that according to wavelet packet decomposition algorithms,the power system harmonic current,voltage RMS derived from wavelet transform coefficients. It constructs a real-time gathering of electrical power system based on Magic ARM2410 experiment platform.The core board of the experiment platform is used as the main control unit,it is composed the whole system with the board of AD which is made by ourself. We the WinCE embedded system.When the system is initialed, the voltage and current signal flow into the mutual inductors. Under the control of the main S3C2410 chip, the data acquisition circuit wafer gather it.Then we can analyse the signal by eVC++ programming. Also, we can send the data to PC through the serial port, then we can do a further process by using the virtual instrument technology. Through simulation experiments, we confirrmed that wavelet packet transform can bring a more exact analysis of the local charicteristics of signals, so as the real-time and precision of harmonic analysis can be improved too.