Active Power Measurement Without Load Voltage Sensing
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Solution Overview
Problem
Measuring active power in electrical circuits with both resistive and reactive components is challenging due to the phase difference between load voltage and current, often requiring complex and expensive systems that include load voltage measurement.
Innovation Solution
A system and method that determine active power by measuring line voltage and load current, eliminating the need for load voltage measurement, using a digital processing device to synchronize and process these signals to calculate active power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load voltage measurement is included to accurately measure active power, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the load voltage measurement component from the power measurement system. By using only line voltage and load current measurements, the system removes the complexity and cost associated with load voltage sensing while maintaining accurate active power measurement through digital processing of the remaining signals.
Solution Approach 2:
The patent changes the measurement parameters from three (line voltage, load voltage, load current) to two (line voltage, load current). This parameter reduction is compensated by advanced digital processing algorithms that calculate active power using the relationship between line voltage, load current, and their phase difference, eliminating the need for direct load voltage measurement.
2Measurement precision
If load voltage measurement is included to accurately measure active power, then measurement precision is improved, but expense increases
Solution Approach 1:
The patent removes the load voltage measurement subsystem, eliminating the associated costs of voltage sensors, isolation equipment, and calibration systems. The expense reduction is achieved while preserving measurement accuracy through computational methods that process line voltage and load current signals.
Solution Approach 2:
The patent replaces expensive hardware-based load voltage measurement with a more economical software-based calculation approach. By using digital processing of readily available line voltage and load current signals, the system achieves the same measurement function at lower cost, effectively substituting costly physical measurement components with computational algorithms.
3Measurement precision
If three measurements (line voltage, load voltage, load current) are taken to measure active power, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent simplifies the measurement process by removing the load voltage measurement step. Operators only need to connect line voltage and load current sensors, eliminating the complex task of measuring load voltage and dealing with phase differences between load voltage and current. This reduces installation complexity and operational burden while maintaining measurement accuracy.
Data Source
Figure 1
AI summary
A system for use in determining the active power used in an electrical circuit (100) is provided. The system includes an electrical circuit (100) comprising both reactive and resistive components (106, 108), and a digital processor (110) connected to the electrical circuit (100), the digital processor configured to collect synchronized samples of a line voltage across the electrical circuit (100) and a load current through the electrical circuit (100). The digital processor processes the synchronized samples of the line voltage and the load current to determine an active power used in the electrical circuit (100).