Power Measurement In A Two-Wire Load Control Device
First Claim
1. A two-wire load control device for controlling an amount of power delivered from an AC power source to an electrical load, the load control device comprising:
- a controllably conductive device that operates in a non-conductive state during a first portion of a half-cycle of an alternating current (AC) waveform and in a conductive state during a second portion of the half-cycle;
a voltage measuring circuit that measures a voltage across the two-wire load control device during the first portion of the half-cycle;
a signal generator that generates a complementary voltage waveform that approximates a voltage across the load during the second portion of the half-cycle, wherein the complementary voltage waveform is based on the voltage measured across the two-wire load control device during the first portion of the half-cycle;
a current measuring circuit that measures a current supplied to the load from the two-wire load control device during the second portion of the half-cycle; and
a control circuit that computes an estimated amount of power consumed by the load based on the complementary voltage waveform and the current supplied to the load during the second portion of the half-cycle.
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Accused Products
Abstract
A two-wire load control device may be configured to compute an accurate estimate of real-time power consumption by a load that is electrically connected to, and controlled by, the two-wire load control device. The load control device may be adapted to measure a voltage drop across the device during a first portion of a half-cycle of an AC waveform provided to the device. The device may be further configured to estimate a voltage drop across the load during the second portion of the half-cycle. The estimated voltage drop may be based on the measured voltage drop. The device may be further configured to measure a current supplied to the load during a second portion of the half-cycle. The device may be configured to estimate power consumed by the load based on the measured current and the estimated voltage drop.
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Citations
30 Claims
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1. A two-wire load control device for controlling an amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a controllably conductive device that operates in a non-conductive state during a first portion of a half-cycle of an alternating current (AC) waveform and in a conductive state during a second portion of the half-cycle; a voltage measuring circuit that measures a voltage across the two-wire load control device during the first portion of the half-cycle; a signal generator that generates a complementary voltage waveform that approximates a voltage across the load during the second portion of the half-cycle, wherein the complementary voltage waveform is based on the voltage measured across the two-wire load control device during the first portion of the half-cycle; a current measuring circuit that measures a current supplied to the load from the two-wire load control device during the second portion of the half-cycle; and a control circuit that computes an estimated amount of power consumed by the load based on the complementary voltage waveform and the current supplied to the load during the second portion of the half-cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A two-wire load control device for controlling an amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a controllably conductive device that operates in a non-conductive state during a first interval of a half-cycle of an alternating current (AC) waveform and a conductive state during a second interval of the half-cycle; and a control circuit adapted to; measure a voltage across the two-wire load control device during a first portion of the half-cycle; compute an estimated voltage across the load during a second portion of the half-cycle based on the voltage measured across the two-wire load control device during the first interval of the half-cycle; measure a current supplied to the load during the second portion of the half-cycle; and compute, based on the estimated voltage and the measured current, an estimated power consumed by the load during the second portion of the half-cycle. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A two-wire load control device for controlling an amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a controllably conductive device electrically configured to allow an alternating current to be delivered from the AC power source to the load during a portion of a half-cycle of an AC waveform provided from the AC power source to the load control device; and a control circuit configured to compute an estimated amount of power consumed by the load based on a current supplied to the load during the portion of the half-cycle and an estimated voltage across the load during the portion of the half-cycle. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A method for estimating power consumption of an electrical load in a load control system, the load control system including a two-wire load control device for controlling an amount of power delivered from an AC power source to the electrical load, the load control device having a controllably conductive device that operates in a non-conductive state during a first portion of a half-cycle of an alternating current (AC) waveform supplied to the two-wire load control device and in a conductive state during a second portion of the half-cycle, the method comprising:
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measuring a voltage across the two-wire load control device during the first portion of the half-cycle; generating a complementary voltage waveform that approximates a voltage across the load during the second portion of the half-cycle, wherein the complementary voltage waveform is based on the voltage measured across the two-wire load control device during the first portion of the half-cycle; measuring a current supplied to the load from the two-wire load control device during the second portion of the half-cycle; and computing an estimated amount of power consumed by the load based on the complementary voltage waveform and the current supplied to the load during the second portion of the half-cycle. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A load control device for controlling an amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a controllably conductive device that operates in a non-conductive state during a first portion of a half-cycle of an alternating current (AC) waveform and in a conductive state during a second portion of the half-cycle; a voltage measuring circuit that measures a voltage across the load control device during the first portion of the half-cycle; a signal generator that generates a complementary voltage waveform that approximates a voltage across the load during the second portion of the half-cycle, wherein the complementary voltage waveform is based on the voltage measured across the load control device during the first portion of the half-cycle; a current measuring circuit that measures a current supplied to the load from the two-wire load control device during the second portion of the half-cycle; a control circuit that computes an estimated amount of power consumed by the load based on the complementary voltage waveform and the current supplied to the load during the second portion of the half-cycle; a power supply adapted to draw a power supply current from the AC power source and coupled to the control circuit through the electrical load for generating a direct current (DC) voltage to power the control circuit; and
a load terminal adapted to be connected to the load for conducting the current supplied to the load and the power supply current.
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Specification