Apparatus and method for monitoring power
First Claim
1. A power monitor for monitoring power associated with a periodic signal comprising:
- sampling means for sampling said signal during an observation window, said window including a plurality of cycles of said signal, to generate a plurality of voltage-current sample sets; and
timing means, coupled to said sampling means, for timing the sampling of said signal such that said voltage-current sample sets are distributed in time at different time positions from cycle to cycle within said observation window relative to the beginning of each cycle.
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Accused Products
Abstract
A power monitor, for determining real and imaginary power associated with one or more line signals, samples a plurality of line cycles during an observation window to generate a plurality of voltage-current sample sets for each line cycle. The sampling of the sample sets is timed such that the voltage-current sample sets are taken at different relative time positions. The power monitor stores incoming voltage-current sample data in one memory area and concurrently analyzes sample data already stored in another memory area. Deletion of sample data is not permitted until transient analysis of such data is complete.
In another embodiment, the power monitor includes a working data memory area coupled to the sampling circuitry such that the sample sets occurring during each observation window are stored in the working data memory area in interleaved fashion to simulate a single cycle of data. This power monitor further includes a transient data area, coupled to the sampling circuitry, for storing the sample sets occurring during an observation window in a non-interleaved or sequential fashion. Power analysis is conducted on the sample sets in the working data memory area unless a power transient is sensed. Upon sensing a transient, data from the transient data area is provided for analysis.
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Citations
32 Claims
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1. A power monitor for monitoring power associated with a periodic signal comprising:
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sampling means for sampling said signal during an observation window, said window including a plurality of cycles of said signal, to generate a plurality of voltage-current sample sets; and timing means, coupled to said sampling means, for timing the sampling of said signal such that said voltage-current sample sets are distributed in time at different time positions from cycle to cycle within said observation window relative to the beginning of each cycle.
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2. A power monitor for monitoring power associated with a periodic signal comprising:
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sampling means for sampling said signal during an observation window, said window including a plurality of cycles of said signal, to generate a plurality of voltage-current samples sets; and timing means, coupled to said sampling means, for timing the sampling of said signal such that a non-integer number of sample sets are taken per cycle so that from cycle to cycle within said observation window said voltage-current sample sets are taken at different relative time positions with respect to the beginning of each cycle of said observation window.
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3. A power monitor for monitoring power associated with a periodic signal during an observation window, said window including a plurality of cycles of said signal, said method comprising:
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timing means for dividing each cycle time of said signal into a plurality of time intervals; sampling means, coupled to said timing means, for taking voltage and current samples during each of said time intervals to generate a plurality of voltage-current sample sets during each cycle of said observation window, said voltage-current sample sets being generated at different time positions during each cycle of said signal relative to the beginning of each cycle of said signal; memory means, coupled to said sampling means, for storing said voltage-current sample sets; and microprocessor means, coupled to said memory means, for determining the real and imaginary power associated with said signal from the sample sets stored in said memory means.
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4. A power monitor for monitoring power associated with a periodic line signal having a plurality of cycles comprising:
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reference signal generating means, synchronized in frequency and phase with said line signal, for generating a reference signal which is a multiple of said line signal and which exhibits an integer number of pulses for each cycle of said line signal; sampling means for sampling said line signal at a selected sampling frequency during an observation window, said window including a plurality of cycles of said line signal, to generate a plurality of voltage-current samples sets during each cycle of said line signal, said sampling means having a plurality of outputs at which samples are held respectively, each of said sample sets including at least one voltage sample and at least one current sample; divider means, coupled between said reference signal generating means and said sampling means, for dividing said reference signal down to determine said selected sampling frequency such that from cycle to cycle within said observation window said voltage-current sample sets are distributed in time at different time positions relative to the beginning of each cycle; multiplexing means, coupled to the plurality of outputs of said sampling means, for multiplexing the samples within each sample set at the outputs of said sampling means by sequentially providing said samples to an output of said multiplexing means, thus generating a multiplexed sample signal; analog to digital converter means, coupled to the output of said multiplexing means, for converting said multiplexed sample signal to a digital sample signal; and microprocessor means, coupled to said analog to digital converter means, for processing said digital sample signal to determine the real and imaginary power associated with said line signal during said observation window. - View Dependent Claims (5)
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6. A power monitor for monitoring power associated with a periodic line signal over a plurality of cycles comprising:
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first, second and third memory areas; sampling means for sampling voltage and current of said line signal over a plurality of observation windows to generate incoming sample data, an observation window including a predetermined number of cycles of said line signal; means for alternatingly storing incoming sample data in said first and second memory areas during respective sequential observation windows; microprocessor means, coupled to said first, second and third memory areas, for performing analysis on the sample data stored in said first memory area while incoming sample data is being stored in said second memory area, said microprocessor means subsequently performing analysis on the sample data stored in said second memory area while incoming sample data is being stored in said first memory area; and transient sensing means for determining if sample data in a present observation window contains transient data and, if so, causing incoming sample data in a next observation window following said present observation window to be stored in said third memory area. - View Dependent Claims (7, 8)
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9. A method of monitoring power associated with a periodic signal comprising the steps of:
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sampling said signal during an observation window including a plurality of cycles of said signal to generate a plurality of voltage-current sample sets during each cycle of said signal; and timing the sampling of said signal such that said sample sets are generated at different relative time positions from cycle to cycle with respect to the beginning of each cycle of said observation window. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method of monitoring power associated with a periodic signal during an observation window, said window including a plurality of cycles of said signal, said method comprising the steps of:
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dividing each cycle into a plurality of time intervals having substantially equal duration; taking voltage and current samples during each of said time intervals of each of said cycles to generate voltage-current sample sets at different relative time positions from cycle to cycle of said signal with respect to the beginning of each cycle of said observation window; storing said voltage-current sample sets in a memory; and determining the real and imaginary power associated with said signal from the samples thus stored. - View Dependent Claims (17)
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18. A method of monitoring power associated with a periodic signal during an observation window, said window including a plurality of cycles of said signal, said method comprising the steps of:
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taking voltage and current samples during first and second observation windows of said signal to generate a plurality of voltage-current sample sets per cycle of said first and second observation window; storing the voltage-current sample sets taken during said first observation window in a first memory area; analyzing the samples in said first memory area to determine the power associated therewith while during said second observation window storing voltage-current samples taken during said second observation window in a second memory area; determining if any of said voltage-current samples sets represent transients in said signal; designating one of said first and second memory areas as a transient memory area when transient data is determined to be stored therein; storing in a third memory area the sample sets occurring in a next observation window subsequent to an observation window during which a transient was determined to have occurred; and preventing use of one of said first and second memory areas designated as said transient memory area until the transient data therein is analyzed. - View Dependent Claims (19, 20, 21)
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22. A power monitor for monitoring power associated with a periodic signal comprising;
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sampling means for sampling said signal during an observation window, said window including a plurality of cycles of said signal, to generate a plurality of voltage-current sample sets, each sample set containing at least one voltage sample and at least one current sample taken substantially at the same time; timing means, coupled to said sampling means, for timing the sampling of said signal by said sampling means such that said voltage-current sample sets are distributed throughout each cycle of said observation window; a working data memory area, coupled to said sampling means, for storing the sample sets occurring during an observation window in interleaved fashion to simulate a single cycle of data; and a transient data area, coupled to said sampling means, for storing the sample sets occurring during an observation window in sequential fashion. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A method for monitoring power of a substantially periodic signal comprising the steps of:
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sampling said signal during an observation window, said window including a plurality of cycles of said signal, to generate a plurality of voltage-current sample sets, each sample set containing at least one voltage sample and at least one current sample taken substantially at the same time; timing the sampling of said signal such that said voltage-current sample sets are distributed throughout each cycle of said observation window; storing in interleaved fashion in a first memory area the sample sets occurring during a particular observation window so as to simulate a single cycle of data in said first memory area; and storing in sequential fashion in a second memory area the sample sets occurring during said particular observation window. - View Dependent Claims (30, 31, 32)
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Specification