System and method for digitally compensating frequency and temperature induced errors in amplitude and phase shift in current sensing of electronic energy meters
First Claim
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1. A method of compensating for temperature-induced phase shift in an energy meter, comprising:
- obtaining a temperature reading from a temperature sensor within the energy meter;
converting the temperature reading to a digital signal;
converting the digital signal to a degrees of phase shift value;
providing the degrees of phase shift value to a processor in the energy meter; and
adjusting the output of the processor responsive to the degrees of phase shift value.
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Abstract
The phase shift in an electronic energy meter is compensated for by obtaining temperature and frequency readings in the meter and using these readings in a digital signal processor (DSP) residing within the electronic energy meter. The frequency and temperature compensation is performed to each phase calibration and the result is stored in the DSP. To reduce the possible influence of noise in the system, the compensated DSP values are filtered to provide a smoothing of the data.
75 Citations
36 Claims
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1. A method of compensating for temperature-induced phase shift in an energy meter, comprising:
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obtaining a temperature reading from a temperature sensor within the energy meter;
converting the temperature reading to a digital signal;
converting the digital signal to a degrees of phase shift value;
providing the degrees of phase shift value to a processor in the energy meter; and
adjusting the output of the processor responsive to the degrees of phase shift value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of compensating for frequency-induced phase shift in an energy meter, comprising:
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obtaining a line frequency reading from the energy meter;
converting the line frequency reading to a value in engineering units;
converting the value to a degrees of phase shift value;
providing the degrees of phase shift value to a processor in the energy meter; and
adjusting the output of the processor responsive to the degrees of phase shift value. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method of compensating for temperature-induced phase shift and frequency-induced phase shift in an energy meter, comprising:
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obtaining a temperature reading from a temperature sensor within the energy meter;
converting the temperature reading to a first digital signal;
converting the first digital signal to a first degrees of phase shift value;
providing the first degrees of phase shift value to a processor in the energy meter;
obtaining a line frequency reading from the energy meter;
converting the line frequency reading to a value in engineering units;
converting the value in engineering units to a second degrees of phase shift value;
providing the degrees of phase shift value to the processor in the energy meter; and
adjusting the output of the processor responsive to the first degrees of phase shift value and the second degrees of phase shift value. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A system for compensating for temperature-induced phase shift in an energy meter, comprising:
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a temperature sensor for obtaining a temperature reading;
an analog to digital converter for receiving the temperature reading from the temperature sensor and converting the temperature reading to a digital signal;
a processor for receiving the digital signal from the converter and converting the digital signal to a degrees of phase shift value, the processor adjusting its output responsive to the degrees of phase shift value; and
a current transformer for sensing current provided to the energy meter, wherein the temperature sensor is disposed on the current transformer. - View Dependent Claims (23, 24)
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25. A system for compensating for line frequency-induced phase shift in an energy meter, comprising:
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a processor for obtaining a line frequency reading; and
an analog to digital converter for receiving the line frequency reading from the processor and converting the line frequency reading to a value in engineering units, wherein the processor receives the value in engineering units from the converter, converts the value in engineering units to a degrees of phase shift value, and adjusts its output responsive to the degrees of phase shift value. - View Dependent Claims (26)
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27. A system for compensating for temperature-induced phase shift and frequency-induced phase shift in an energy meter, comprising:
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a temperature sensor for obtaining a temperature reading;
a processor for obtaining a line frequency reading; and
an analog to digital converter for receiving the temperature reading from the temperature sensor and converting the temperature reading to a first digital signal, and for receiving the line frequency reading from the processor and converting the line frequency reading to a value in engineering units;
wherein the processor receives the first digital signal and the value in engineering units from the converter, converts the first digital signal and the value in engineering units to first and second degrees of phase shift values, and adjusts its output responsive to the first and second degrees of phase shift values. - View Dependent Claims (28, 29, 30, 31)
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32. An apparatus comprising a storage device that stores software that compensates for temperature-induced phase shift and frequency-induced phase shift in an energy meter and performs the acts of:
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obtaining a temperature reading from a temperature sensor within the energy meter;
converting the temperature reading to a first digital signal;
converting the first digital signal to a first degrees of phase shift value;
obtaining a line frequency reading from the energy meter;
converting the line frequency reading to a value in engineering units;
converting the value in engineering units to a second degrees of phase shift value; and
adjusting the output of a processor in the energy meter responsive to the first degrees of phase shift value and the second degrees of phase shift value. - View Dependent Claims (33, 34, 35, 36)
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Specification