Research of harmonic measuring based on virtual instrument

Two new instantaneous harmonic current measuring methods are introduced,they are the method based on DFT(Discrete Fourier Transform) digital filter and the method based on re-sampling theory and digital mean filter. Both are simulated with Matlab,and results show that the following and real-time performances of digital filter are improved while the veracity is kept. The dynamic performances of both methods are experimented on personal computer with LabVIEW and data acquisition card,which verifies the correctness of the simulative results. Applying the harmonic measuring method based on fast Fourier transform,a virtual harmonic measuring instrument is designed in LabVIEW environment. It may be used in harmonic analysis and suppression.