The research on phase-shift method of reactive power

Phase-shift method is one way of reactive power measurement, in the method, the input voltage or current is to phase-shift at first, then the multiplier which is used to calculate the active power will be used to calculate the reactive power. There are two ways to carry out phase-shift, the one is the way which is based on the sampling points, the other one is to use Hilbert filter. First of all, the principle of the two methods is expatiated in this paper, and then, they are designed and simulated on MATLAB, and the Hilbert filter method is verified on a FPGA chip of EP2C50 while there is no one else who has carried out the method on FPGA chip. The results show that the method based on sampling points is limited in practical application, but the Hilbert filter method has the advantages of Phase-shift accuracy and high precision measurement, it is used widely.