US 4,131,847 A · Device for measuring active and/or reactive component of AC current or AC power

Abstract

A device for measuring the active component and reactive component of AC current or AC power comprising a first detector detecting AC voltage of an AC circuit, a second detector detecting AC current flowing through the AC circuit, a phase shifter shifting the phase of the detected AC voltage by .pi./2, first switch selectively transmitting one of the detected AC voltage and the phase-shifted AC voltage, a signal generator generating a pulse signal lasting over a selected one half cycle of the two opposite half cycles constituting one cycle of the detected AC voltage transmitted through the first switch, a second switch responsive to the pulse signal to permit transmission of an AC voltage corresponding to the detected AC current, and a circuit computing the active or reactive component of the root mean square value of the AC current or power of the AC circuit on the basis of the AC voltage permitted to transmit through the second switch thereby providing an output signal representing the result of computation.

Claims14

Dependent claims

A device for measuring active and/or reactive component of AC current comprising:

first means for detecting an AC voltage of an AC circuit;
second means for detecting an AC current flowing through the AC circuit;
third means for generating a pulse signal lasting over a selected one-half cycle of the two opposite half cycles constituting one AC cycle of the AC output voltage of said first means;
fourth means connected to said second and third means for controlling transmission of the output AC signal of said second means in response to said pulse signal;
and
fifth means connected to said fourth means for delivering the signal corresponding to the signal controlled by said fourth means as an output signal.

3 more elements

A device for measuring active and/or reactive component of AC power comprising:

first means for detecting an AC voltage of an AC circuit;
second means for detecting an AC current flowing through the AC circuit;
third means for generating a pulse signal lasting over a selected one-half cycle of the two opposite half cycles constituting one AC cycle of the AC output voltage of said first means;
fourth means connected to said second and third means for controlling transmission of the output AC signal of said second means in response to said pulse signal;
fifth means connected to said fourth means for producing a signal corresponding to the signal controlled by said fourth means;
sixth means for converting the AC voltage detected by said first means into a signal representing the linear transform of said detected AC voltage;
seventh means for multiplying the output signal of said fifth means by the output signal of said sixth means;
and
eighth means connected to said seventh means for delivering a signal corresponding to the output signal of said seventh means as an output signal representing the result of measuring.

6 more elements

Dependencies are inferred from the claim text.

Device for measuring active and/or reactive component of AC current or AC power

Life of this patent

Device for measuring active and/or reactive component of AC current or AC power

Life of this patent

Abstract

Claims14