Research And Design Of Power Quality System Based On DSP

Electricity is not only a sign of the second industrial revolution,but also a symbol of the human society entering the age of electricity.As a kind of widely used clean energy,the utilization degree of the electricity is the important embodiment of a country's science and technology.With the development of the power of the electronics technology,kinds of non-linear loads are greatly applied.Therefore,it gradually deteriorates the power quality of electric grid.In order to improve the quality of power supply in power network,there is an urgent need for the monitor of parameter of electric power quality,such as harmonic,frequency,RMS,three-phase unbalance,voltage sag,etc.This paper describes the significance of the detection of power quality and the necessity of it.It introduces the basic concept of power quality and summarizes the domestic and international standards of power quality detecting,studying on the parameter of power quality and the basic principle and algorithm of detecting deeply.Based on the national standards of design requirements,this paper gives a design of power quality detector at the core of TMS320F2812,and introduce the design of hardware and software specificly.For harrmonic detection,this paper uses the traditional fast Fourier(FFT)algorithm for steady-state harmonic measurement since the correlation detection premise.In order to improve the precision of harmonic detection,the author window the sampling points.The process of digital filtering and hardware filtering method is applied to detect the voltage fluctuation and flicker.Applied in the voltage sag frequency tracking algorithm(improved dq transform method)can be more accurate to obtain the phase angle jump value.In terms of hardware,by the use of high-performance DSP and high-speed and high-precision A/D converter,it meets the demands of the system in the aspect of sampling data accurately and real-time.Frequency tracking algorithm and phase selection circuit to ensure that the FFT transform to meet the demands of synchronous sampling,it can reduce the leakage of frequency spectrum.The system structure is based on the DSP.It benefits from the advantages of the DSP in the data processing and in the external controlling.Base on our designed system and other related experimental instruments and tools,the entire system is tested through vast amount of data.The result of test and the analysis of error indicate that this system can effectively detect the power quality parameters and meet the expected design goal.