Power-related amount measurement device

PROBLEM TO BE SOLVED: To solve the problem wherein the calculation for power related amounts has errors, if the voltage signal input, current signal input, and A/D converter are influenced by the magnitudes of voltage and current to be detected, the frequency of the voltage and current to be detected, and an operating temperature. SOLUTION: This power-related amount measuring device is set with primary straight lines, beforehand; changes in the characteristics of a voltage signal input; a current signal input whose parameters are the effective value of voltage Vrms_1; the effective value of current Irms_1, and the power supply frequency, and changes in the characteristic of the A/D converter, whose parameter is its temperature. The device is so formed as to correct the changes in the characteristics, by updating the coefficients of an amplitude phase correction matrix being used at regular operations, at a fixed time intervals. COPYRIGHT: (C)2004,JPO&NCIPI