| 摘要 |
PURPOSE:To enable a direct measurement with an arithmetic controller eliminating the necessity of any analog instrument by computing an instantaneous power portion at each sampling in such a manner tht the number of sampling is so determined as to be zero pulsated components containing the instantaneous power portions. CONSTITUTION:Voltage and current information is provided in a digital value from an analog-digital converter 17 to match a sampling cycle and memorized and updated sequentially with a shift register 21. The contents of each register of the shift register 21 are taken as measured value proportional to an effective power VIcostheta via a multiplier 22, an adder 23 and a divider 24 and the like. Thus, the sampling and the computation made at an appropriate cycle enables the measurement of an effective power in such a manner as to zero the pulsated components during the addition thereof. This eliminates any analog instrument thereby enables a direct measurement with an arithmetic controller such as microcomputer. |
