High-Voltage Measuring Unit Self-Correction via Signal Injection
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Solution Overview
Problem
High-voltage measuring units face inaccuracies due to manufacturing tolerances, aging effects, and temperature variations in high-voltage power systems, leading to measurement errors.
Innovation Solution
A method involving the injection of a periodic signal into a voltage divider to separate and correct the sensing signal, using a correction signal derived from the injection signal's attenuation, allowing for impedance variation compensation without requiring high-accuracy materials or manual calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage divider with high impedance upper dipole is used to achieve galvanic insulation and high voltage measurement, then safety and insulation are improved, but measurement precision deteriorates due to manufacturing tolerances, aging effects, and temperature variations
Solution Approach 1:
The patent introduces a feedback mechanism where a correction signal is generated based on the sensed voltage and used to adjust the measurement. The correction signal is derived from the difference between the expected and actual voltage divider ratios, continuously compensating for drift in the upper dipole impedance without compromising the galvanic insulation.
Solution Approach 2:
The patent changes the parameter being measured from the raw sensed voltage to a corrected voltage that accounts for impedance variations. By monitoring the voltage divider ratio and applying corrections based on this monitored parameter, the system maintains measurement precision despite changes in the upper dipole impedance over time or with temperature.
2Measurement precision
If high-accuracy materials and manual calibration are used to improve measurement precision, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a self-calibrating system where the measurement unit automatically compensates for its own errors. The correction signal is generated internally based on the sensed voltage and predetermined correction values, eliminating the need for external manual calibration or specialized high-accuracy materials. The system serves its own calibration needs through the automated correction process.
3Measurement precision
If high-accuracy materials are used to reduce measurement errors, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive high-accuracy materials with standard, lower-cost components. Instead of relying on expensive precision resistors that maintain stable ratios, the system uses conventional materials combined with an automated correction algorithm. The correction values can be stored in inexpensive memory and applied through simple circuitry, making the overall system cheaper to manufacture while maintaining or improving accuracy.
Data Source
AI summary
The present application relates to a method for providing a corrected measuring signal indicating a high voltage on a high-voltage node (HV), including: injecting a periodic injection signal into a voltage divider coupled between the high-voltage node (HV) and a reference potential; obtaining a sensing signal at a sensing node (S) of the voltage divider, wherein the sensing signal depends on the periodic injection signal; from the sensing signal, separating a first sensing signal portion resulting from the high voltage and a second sensing signal portion resulting from the periodic injection signal; and depending on the second sensing signal portion, correcting the first sensing signal portion corresponding to the high-voltage signal in order to obtain the corrected measuring signal.