变采样速率在电能质量监测系统中的应用

FFT算法(离散傅氏变换的快速算法)在电能质量检测和分析中应用最成熟,但在实际中由于硬件方面的原因,很难满足采样点数N为2的幂次方。传统方法提出通过"补零"的方式来满足这一条件,但当实际采样点数偏离条件较大时,"补零"的方式不再适用。针对这一问题,提出变采样速率的方式,并以DSP外扩A/D为核心的硬件设计的基础上,在采样电压和电流信号之后,采用先插值后抽取的方式,结合软件方法改变采样点数满足使用FFT算法的条件。该方法易于实现,且精度较高,可方便应用于三相系统和非三相系统,具有广泛的工程应用前景。通过Matlab仿真实验结果验证了该采样方法的可行性和有效性。

Application of Variable Sampling Rate Method in the Power Quality Monitoring System

FFT algorithm has been widely used in power quality detection and analysis, however, due to the disadvantages of hardware in the practical application, it is difficult to meet the requirement that the sampling points N is powers of 2. Although proposed the means of ＂zero padding＂ to meet the conditions with traditional method, when the deviation of actual sampling points from the condition is rather big, ＂zero padding＂ is not applicable. In order to solve this problem, this paper puts forward the way of variable sampling rate, extracting after interpolating. It is used after sampling the voltage and current signals which is based on the hardware design with A/D converter AD73360 and high-performance digital signal processor TMS320F2812. It is from the aspects of software that can change sampling points to meet the conditions of using FFT algorithm. This method is easy to implement and with high precision. And it can be easily applied to three-phase system and non-three-phase system, so that it has a good prospect of engineering application. The simulation results verify the validity and effectiveness of the proposed sampling method.