Harmonic Compensation for Current Measurement Accuracy
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Solution Overview
Problem
Existing current sensors provide false readings due to harmonic distortion in source currents, leading to inaccurate measurements and increased costs from oversized equipment to compensate for power dissipation.
Innovation Solution
A measurement module that uses harmonic compensation factors, sampling at different rates to determine and apply a harmonic compensation factor to current measurements, minimizing distortion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing current sensing techniques are used, then measurement simplicity is maintained, but measurement precision deteriorates due to false readings from harmonic distortion
Solution Approach 1:
The patent segments the current measurement process into multiple sampling rates (first sampling rate for normal operation, second sampling rate for harmonic detection). By dividing the measurement into different rate components, the system can detect harmonic distortion without requiring complete redesign of the entire measurement system, thus improving precision while limiting complexity increase
Solution Approach 2:
The patent applies partial action by using a higher second sampling rate only during specific intervals when harmonic distortion is suspected or detected, rather than continuously. This allows the system to maintain measurement precision when needed while avoiding the constant complexity and resource consumption of high-rate sampling, resolving the contradiction between accuracy and system complexity
2Reliability
If devices are oversized to compensate for power dissipation, then reliability improves, but loss of energy increases due to increased power dissipation
Solution Approach 1:
The patent implements feedback by continuously monitoring current measurements at different sampling rates and using harmonic compensation factors to adjust the reported current values. This feedback mechanism provides accurate real-time current information, enabling the system to operate reliably with properly sized equipment rather than oversized equipment, thus reducing power dissipation while maintaining reliability
Solution Approach 2:
The patent changes the parameter of sampling rate dynamically - using a first sampling rate for normal conditions and switching to a second, higher sampling rate when harmonic distortion is detected. This parameter change allows the system to maintain reliability through accurate measurement without the energy penalty of continuously operating at high sampling rates or using oversized equipment
Data Source
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AI summary
A measurement module uses harmonic compensation factors to minimize the effects of harmonic distortion in measurements of a source current by a current sensor of the module. The module samples at a first sampling rate, measurements of the source current to generate a first current measurement. The module samples at a second sampling rate higher than the first sampling rate, for an interval of time, measurements of the source current to generate a second current measurement. The module determines a harmonic compensation factor based, at least, on a difference between the first current measurement and the second current measurement. The module determines a reported current computed as a function of at least the first current measurement, the difference between the first current measurement and the second current measurement, and the harmonic compensation factor. The reported current represents a magnitude of the source current adjusted by the harmonic compensation factor.