Based On The Arm Of Power Quality Monitor System Software Design And Implementation

In industrial production, the application of non-linear and impact of electronic equipment bring a large number of harmonics, voltage fluctuation and flicker pollution to the grid, resulting in the reduction of power quality. In order to ensure power quality regulation and governance, the research and development of high-precision power quality analysis equipment is particularly important.In the paper, the development status of power quality analyzer in the domestic and international is researched. According to the embedded technology, the design concept is proposed which adopts ARM9as processor core and uc/OS-Ⅱ embedded operation system as software core, the system owns measurement, storage and display in one set.Firstly, according to the measurement requirement in GB, the measuring method on frequency, the basic electrical parameters and harmonics are described, especially focusing on the measurement principle of FFT harmonic analysis and flicker of voltage fluctuation. In the FFT spectrum analysis, synchronous sampling and hanning window function theory are adopted to eliminate the picket fence effect and spectral leakage in the spectral analysis. Owing to the difficulties in the realization of IEC flicker instrument, the paper proposes a method which uses FFT of discrete data processing instead of time-domain algorithm.Secondly, in the part of system software design, on the basis of the transplantation of uc/OS-Ⅱ to ARM, the detail introduction of software architecture which designed based on uc/OS-Ⅱ core is proposed, and the tasks such as collection, calculation, storage, display and so on are allocated reasonably.Finally, the basic parameters and harmonic parameters experiments are designed to test the measurement accuracy. By analyzing the test data, voltage Rms error is less than0.5%. The frequency accuracy is guaranteed within0.01Hz. Owing to defects in the system’s inherent noise and synchronization, the harmonics error can achieve less than5%only in the first30th. The results show that the research and development of the equipment basically realize the intended design goals, but need to continue to improved the accuracy and functionality.