POWER METER HAVING COMPLEX QUADRATURE OUTPUT CURRENT AND VOLTAGE FILTERS
First Claim
1. A power measurement system comprising:
- a current measurement circuit for measuring a current through a load;
a first bandpass filter having a bandpass filter response formed by complex non-conjugate poles, wherein the first bandpass filter has an input coupled to an output of the current measurement circuit and provides complex current output components indicative of real and imaginary portions of the current, and wherein the first bandpass filter response rejects one of a positive or a negative half of a complex frequency spectrum;
a voltage measurement circuit for measuring a voltage across terminals of the load;
a second bandpass filter having a response substantially identical to the bandpass filter response, wherein the second bandpass filter has an input coupled to an output of the voltage measurement circuit and provides complex voltage output components indicative of real and imaginary portions of the voltage; and
a processing system for receiving the complex current output components and the complex voltage output components and providing at least one indication of a power provided to the load.
1 Assignment
0 Petitions
Accused Products
Abstract
A power meter having complex quadrature output current and voltage filters provides power measurements in high amplitude and frequency variation and/or high jitter environments without requiring high computational overhead. A pair of filters, one for voltage and one for current each have a response determined by complex non-conjugate poles. The response of the filters is such that only the positive or negative half plane of the complex frequency spectrum is passed and provide complex outputs representing the real and imaginary parts of both the current and voltage. At least one indication of a power delivered to a load is computed from the complex current and voltage outputs, which may be the real and/or reactive power.
27 Citations
21 Claims
-
1. A power measurement system comprising:
-
a current measurement circuit for measuring a current through a load; a first bandpass filter having a bandpass filter response formed by complex non-conjugate poles, wherein the first bandpass filter has an input coupled to an output of the current measurement circuit and provides complex current output components indicative of real and imaginary portions of the current, and wherein the first bandpass filter response rejects one of a positive or a negative half of a complex frequency spectrum; a voltage measurement circuit for measuring a voltage across terminals of the load; a second bandpass filter having a response substantially identical to the bandpass filter response, wherein the second bandpass filter has an input coupled to an output of the voltage measurement circuit and provides complex voltage output components indicative of real and imaginary portions of the voltage; and a processing system for receiving the complex current output components and the complex voltage output components and providing at least one indication of a power provided to the load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method of measuring electrical power supplied to a load, comprising:
-
first measuring a current through the load; first filtering a result of the first measuring with a bandpass filter response formed by complex non-conjugate poles to provide complex current output components indicative of real and imaginary portions of the current; second measuring a voltage across terminals of the load; second filtering a result of the second measuring with the bandpass filter response, to provide complex voltage output components indicative of real and imaginary portions of the voltage; and processing the complex current output components and the complex voltage output components to compute at least one indication of a power provided to the load. - View Dependent Claims (12, 13, 14, 15, 16, 18, 19)
-
-
17. The method of claim 17, wherein the detecting is performed by multiplying the imaginary portion of the result of the given one of the first or second filtering with the input provided to the given one of the first or second filtering, and wherein the adjusting adjusts the coefficients of the bandpass filter response by rotating a set of fixed pole values by multiplying each of the set of fixed pole values by a complex adjustment value determined in conformity with the detected deviation from the quadrature relationship.
-
20. A power measurement system comprising:
-
a current measurement circuit for measuring a current through a load; a first analog-to-digital converter for converting an output of the current measurement circuit to a digital current value; a voltage measurement circuit for measuring a voltage across terminals of the load; a second analog-to-digital converter for converting an output of the voltage measurement circuit to a digital voltage value; and a digital signal processing system for receiving the digital current value and the digital voltage value and filtering each of the digital current value and the digital voltage value with a bandpass filter response formed by complex non-conjugate poles, wherein the bandpass filter response rejects one of a positive or a negative half of a complex frequency spectrum, and wherein the digital signal processing system combines a result of the filtering of the digital current value and a result of the filtering of the digital voltage value to determine an indication of a power provided to the load.
-
-
21. A computer program product comprising computer readable storage media containing program instructions for execution by a digital signal processing core, the program instructions including program instructions for:
-
first receiving a representation of a current through a load; first filtering a result of the first measuring with a bandpass filter response formed by complex non-conjugate poles to provide complex current output components indicative of real and imaginary portions of the current; second receiving a representation of a voltage across terminals of the load; second filtering a result of the second measuring with the bandpass filter response, to provide complex voltage output components indicative of real and imaginary portions of the voltage; and processing the complex current output components and the complex voltage output components to compute at least one indication of a power provided to the load.
-
Specification