Development Of Three-phase Power Quality Analyzer Based On DSP&ARM

Currently, It is recommended to take long time online monitoring so that the power quality status of power system and large electricity customers could be traced and comprehensive recorded. This project is based on this situation.Firstly, the corresponding measurement theory is represented via the main design work of this project. Not the derivation and analysis but the realization of various parameters measurement theory is mainly introduced in this section. It is clearly explained that how to realize fast Fourier transform in digital signal processor. The discrete principle of IEC flicker measurement which is an important guarantee for achieving desired measurement function is also discussed. After fast Fourier transform is completed, the unbalanced ratio of three-phase could be easily calculated according to the corresponding formula. Measurement of voltage sag and swell is achieved by dq0 coordinate transformation method based on instantaneous reactive power theory.Secondly, the hardware circuit and software design of double CPU power quality analyzer is introduced according to the related measurement principle. The timing of data acquisition and calculation which proves that digital signal processor could meet the real-time requirement is analyzed. In design of hardware circuit section two highlights are represented. One point is the design of programmable gain amplifier using DAC which results in lower cost and higher performance. The other is that the whole system is powered by a single +5V power supply. Thus the power supply of system design becomes easier and reduces costs. In software design section details of DSP algorithm are explained.μC/OS-II kernel is ported in ARM which is the control center of whole system. After this task scheduling and porting analysis are also involved.Finally, experimental results of three-phase power quality analyzer based on single DSP which proves the correction of design are analyzed. Therefore the double CPU power quality analyzer based on the three-phase power quality analyzer is feasible. It could meets the real-time demands of power quality online monitoring in accuracy.