Sensor Data Correction for Rogowski Coil Nonlinear Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Low-voltage circuit breakers face challenges in accurately measuring current and voltage due to the non-linear transfer function of Rogowski transducers, leading to amplitude-dependent errors, which affect the accuracy of energy data acquisition and compliance with PMD standards.
Innovation Solution
A method for correcting sensor data using a functional correlation between physical quantity values and correction values, determined through multi-point calibration, allowing for continuous adjustment and interpolation to achieve precise corrections, thereby improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a Rogowski transducer with analog integrator is used for current measurement, then the device achieves a compact structure and potential isolation, but the non-linear transfer function causes amplitude-dependent errors in the measured signal
Solution Approach 1:
The patent applies parameter changes by implementing a digital integrator with adjustable integration parameters and a correction factor that can be dynamically modified. The system changes the integration time constant and applies amplitude-dependent correction factors to compensate for the non-linear transfer function, thereby improving measurement accuracy while maintaining the compact Rogowski transducer structure
Solution Approach 2:
The patent replaces the analog integrator with a digital integrator implemented in microprocessor or FPGA. This substitution allows for precise control of the integration process through software, enabling dynamic adjustment of integration parameters and application of correction algorithms to compensate for non-linearities, thereby improving measurement accuracy without increasing physical complexity
2Measurement precision
If a digital integrator is used to improve measurement accuracy, then the linearity of the transfer function improves, but the computational complexity and resource consumption increase
Solution Approach 1:
The patent applies partial action by implementing a corrected integration algorithm that only processes the necessary portion of the signal with full computational effort. Instead of continuously applying complex correction algorithms, the system uses a simplified integration method for normal operating conditions and activates more computationally intensive correction only when amplitude-dependent errors are detected, thereby balancing accuracy with resource consumption
Solution Approach 2:
The patent implements dynamics by making the integration parameters and correction factors adaptive rather than fixed. The system dynamically adjusts the integration time constant and correction factor based on the instantaneous amplitude of the measured signal, allowing the digital integrator to maintain high accuracy across varying operating conditions while optimizing computational resource usage through conditional processing
3Measurement precision
If multi-point calibration is performed to determine correction factors, then the accuracy of measured values significantly improves, but the calibration process time and resource consumption increase
Solution Approach 1:
The patent applies preliminary action by performing the multi-point calibration process during the manufacturing or initial setup phase, storing the resulting correction factors in the device's memory. This allows the calibration to be done once under controlled conditions with sufficient time and resources, while during normal operation the pre-determined correction factors are applied without requiring additional calibration time, thus achieving high accuracy without continuous calibration overhead
Solution Approach 2:
The patent applies copying by creating a lookup table or stored functional relationship from the multi-point calibration results. Instead of performing the full multi-point calibration process during each measurement, the system copies the essential correction information into a compact data structure that can be quickly referenced and applied, thereby maintaining high measurement accuracy while significantly reducing the time and computational resources required during normal operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method significantly enhances the accuracy of measured values, reducing errors by approximately five times, ensuring compliance with PMD standards and maintaining resource efficiency by continuously updating correction factors.
Implementation Method 1
Rogowski coils output a voltage proportional to the differential current
Data Source
AI summary
Values of a physical quantity acquired by a sensor unit are corrected with a correction value. A functional correlation) exists between the values of the physical quantity and the correction value. At least one value of the physical quantity acquired by the sensor unit is corrected by applying a correction value to it determined by way of the functional correlation. A new correction value is determined by way of the functional relationship on the basis of the at least one value of the physical quantity captured by the sensor unit. Finally, at least one value of the physical quantity acquired by a sensor unit is corrected by applying the new correction value to it.