Energy device with an extended dynamic range on current readings
First Claim
1. An energy device for measuring the delivery and generation of electrical energy from an energy supplier to a shared energy grid through an electric circuit, the energy device comprising:
- a sensor configured to sense a current or a voltage of the electric circuit and configured to generate digital samples indicative of the current or voltage;
a microprocessor coupled with the sensor, configured to receive the digital samples, and configured to generate a measurement signal in response to the samples;
wherein the measurement signal is indicative of energy through the electric circuit to within an accuracy of 1.0% allowable error in energy over a 10 mA to 20 A current with a power factor near unity; and
wherein the sensor and the microprocessor are further configured so that the measurement signal generated therefrom satisfies each of at least four accuracy categories, wherein each of the at least four accuracy categories are operable to satisfy at least one standard and cover the dynamic range of 10 mA to 20 A.
1 Assignment
0 Petitions
Accused Products
Abstract
Systems and methods are disclosed for accurately measuring delivered or supplied electrical energy over an extended range of values. In one embodiment, a meter for monitoring the energy at a remote site includes a current sensor for measuring the current supplied to or from the site, and a microprocessor that generates output readings with an enhanced accuracy over a wide range of outputs in response to digital samples received from the sensor. In a one implementation, the meter is configured to provide readings with an accuracy that satisfies the standards IEC 60687 1A 0.5S, IEC 60687 5A 0.5S, ANSI C12.20 Class 20 0.5, and ANSI C12.20 Class 2/10 0.5. In another implementation, the meter is configured to provide readings with an accuracy that satisfies the standards IEC 60687 1A 0.2S, IEC 60687 5A 0.2S, ANSI C12.20 Class 20 0.2, and ANSI C12.20 Class 2/10 0.2.
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Citations
41 Claims
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1. An energy device for measuring the delivery and generation of electrical energy from an energy supplier to a shared energy grid through an electric circuit, the energy device comprising:
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a sensor configured to sense a current or a voltage of the electric circuit and configured to generate digital samples indicative of the current or voltage; a microprocessor coupled with the sensor, configured to receive the digital samples, and configured to generate a measurement signal in response to the samples; wherein the measurement signal is indicative of energy through the electric circuit to within an accuracy of 1.0% allowable error in energy over a 10 mA to 20 A current with a power factor near unity; and wherein the sensor and the microprocessor are further configured so that the measurement signal generated therefrom satisfies each of at least four accuracy categories, wherein each of the at least four accuracy categories are operable to satisfy at least one standard and cover the dynamic range of 10 mA to 20 A. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An energy device for measuring the delivery and generation of electrical energy from an energy supplier to a shared energy grid through an electric circuit, the energy device comprising:
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a sensor coupled with the electric circuit, operative to sense a current in the electric circuit, and operative to generate a signal indicative of the current; and an output interface coupled to the sensor and configured to provide an energy measurement in response to the signal indicative of the current; wherein the sensor and the output interface are operable in at least four accuracy categories, the four accuracy categories defining an extended dynamic range; and further wherein the energy device is operative to provide the energy measurement when the current is between 10 mA to 20 A within 1.0% allowable error in energy. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. An energy monitoring device comprising:
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a current sensor adapted to measure a current in a power delivery circuit and to generate a digital sensor signal indicative of energy in the power delivery circuit; wherein the current sensor is configured to generate the digital sensor signal with an accuracy of; 0.5% allowable error in energy for values of the current from 50 mA to 20 A with a power factor of about unity, and 1.0% allowable error in energy for values of the current from 2 mA to about 50 mA with a power factor of about unity; wherein the current sensor is operative to satisfy a plurality of accuracy categories. - View Dependent Claims (29, 30, 31, 32, 33)
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34. An energy monitoring device comprising:
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a current sensor adapted to measure a current in a power delivery circuit and to generate an analog sensor signal indicative of the current; wherein the current sensor is adapted to sense the current over a plurality of N current ranges, wherein N is an integer greater than one; an analog-to-digital converter, wherein the analog-to-digital converter has an input range for analog inputs; a plurality of X amplification circuits, wherein X is an integer greater than one, further wherein each amplification circuit is coupled to the current sensor and to the analog-to-digital converter; wherein in response to the analog sensor signal, each amplification circuit is configured to generate a separate amplified signal, the X amplification circuits thereby generating X amplified signals; wherein each of the X amplified signals substantially spans the input range of the analog-to-digital converter for a separate one of the N current ranges; wherein the analog-to-digital converter is configured to receive the amplified signals and to generate digital samples in response to the amplified signals; wherein the current sensor, the analog-to-digital converter, and at least one of the amplification circuits are operative in combination to generate the digital samples for values of the current as low as 2 mA at 1.0% allowable error in energy; wherein the current sensor, the analog-to-digital converter, and at least one of the amplification circuits are operative in combination to generate the digital samples for values of the current as high as 20 A at 0.5% allowable error in energy; and a selector circuit coupled to the analog-to-digital converter, wherein the selector circuit is adapted to select digital samples based on a selected one of the X amplified signals when the analog sensor signal is in a corresponding one of the N current ranges. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41)
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Specification