Automatic non-linear phase response calibration and compensation for a power measurement device
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Accused Products
Abstract
Phase delay compensation sweep may be used in determining correct phase delay compensation of measured currents for substantially matching a measured apparent power to an expected apparent power over an operating range of current values of a current transformer (CT). A frequency sweep may also be used in determining correct phase delay compensation of each measured current in applications having multiple frequencies. Phase delay compensation for each CT current value may be stored in a phase delay compensation look-up table during the phase delay compensation sweep calibration and recalled from the look-up table during operational power measurements. Phase delay compensation for each CT current value and each frequency of that current value may be stored in a phase delay compensation look-up table during the phase delay compensation sweep calibration and recalled from the look-up table during operational power measurements.
63 Citations
16 Claims
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1-12. -12. (canceled)
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13. A method for automatic non-linear phase response calibration and compensation for a power measurement device, said method comprising the steps of:
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a) entering an expected apparent power value (PAE) and a calibration point N;
b) storing the PAE and the calibration point N;
c) starting a sweep calibration for determining phase delay compensation, wherein the sweep calibration comprises;
1) determining voltage and current values;
2) calculating an apparent power (PA) from the voltage and current values;
3) comparing the PAE and the PA, wherein;
i) if the PA is less than the PAE, then decreasing a phase delay of the current value and returning to step
2),ii) if the PAE is less than the PA, then increasing the phase delay of the current value and returning to step
2), andiii) if the PA is substantially equal to the PAE, then saving the current value and the phase delay to address N of a look-up table. - View Dependent Claims (14)
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15. A method for automatic non-linear phase response calibration and compensation for a power measurement device, said method comprising the steps of:
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a) entering an expected apparent power value (PAE) and calibration points M and N;
b) storing the PAE and the calibration points M and N;
c) starting a sweep calibration for determining phase delay compensation, wherein the sweep calibration comprises;
1) determining voltage and current values, and frequency;
2) calculating an apparent power (PA) from the voltage and current values;
3) comparing the PAE and the PA, wherein;
i) if the PA is less than the PAE, then decreasing a phase delay of the current value and returning to step
2),ii) if the PAE is less than the PA, then increasing the phase delay of the current value and returning to step
2), andiii) if the PA is substantially equal to the PAE, then saving the current value and the phase delay to address N of a look-up table, and the frequency to address M of the look-up table. - View Dependent Claims (16)
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Specification