Rogowski Coil Mutual Inductor Crosstalk Compensation

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Solution Overview

Problem

Electronic mutual inductors based on Rogowski coils suffer from interphase crosstalk, leading to inaccurate output voltages due to magnetic field coupling between phases, which affects the accuracy of current measurement.

Innovation Solution

A method to determine the coefficients of mutual induction and crosstalk induction for each phase, using a compensation coefficient to correct the output voltage of each phase, compensating for interphase interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the physical distance between three-phase currents is reduced due to mechanical size limitations, then the electronic mutual inductor achieves compact size, but interphase crosstalk increases causing measurement inaccuracy

Engineering Contradiction:

Improvesize of electronic mutual inductorVSAvoidaccuracy of current measurement

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent measures the crosstalk induction coefficients between phases and uses these previously harmful interphase couplings as compensation parameters. By quantifying the crosstalk effects and applying compensation algorithms, the system converts the harmful magnetic field coupling into useful correction data, enabling accurate measurements despite compact dimensions

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the mathematical parameters of the output signal by applying compensation coefficients that account for interphase crosstalk. The compensation process modifies the voltage output parameters to eliminate crosstalk effects, transforming the raw inaccurate measurements into corrected accurate current values

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If Rogowski coils are placed closer together to reduce device size, then manufacturing compactness is improved, but magnetic field coupling between phases increases causing crosstalk

Engineering Contradiction:

Improvecompact structure fabricationVSAvoidinterphase crosstalk

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent performs preliminary measurement of crosstalk induction coefficients during the manufacturing or calibration phase. By pre-characterizing the magnetic field coupling between phases and storing compensation coefficients, the system prepares correction data in advance that can be applied during operation, eliminating crosstalk without requiring physical separation of coils

Inventive Principle:

Principle #10Preliminary action

3Speed

If the output voltage directly reflects primary current without compensation, then real-time performance is maintained, but measurement accuracy deteriorates due to crosstalk

Engineering Contradiction:

Improvereal-time response speedVSAvoidaccuracy of voltage output

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent implements a feedback compensation mechanism where the measured crosstalk coefficients are used to adjust the output voltage in real-time. The compensation algorithm continuously corrects the voltage output based on the relationship between phases, maintaining both real-time performance and measurement accuracy through dynamic parameter adjustment

Inventive Principle:

Principle #23Feedback

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 provides accurate secondary-side voltage values corresponding to actual primary-side current values, enhancing measurement precision and real-time performance.

Implementation Method 1

The theoretical bases for measuring a current with a Rogowski coil is Faraday's law of electromagnetic induction and Ampere's circuital law, wherein, when the measured current passes through the center of the Rogowski coil along the axis, a magnetic field that changes accordingly is generated within the volume enclosed by the annular winding

Methodology Applied

Scientific EffectFaraday's law of electromagnetic induction: Electromagnetic Induction

Implementation Method 2

Due to electromagnetic induction, the magnetic field generated by the current in each phase will be coupled to the Rogowski coils of the other two phases and generate a corresponding induced voltage

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250383376A1Method and apparatus for electronic mutual inductor, and electronic mutual inductor

Publication Date: 2025.12.18 SIEMENS AG

AI summary

A method and apparatus for electronic mutual inductance, and an electronic mutual inductor. The method includes: determining a coefficient of mutual induction of a Rogowski coil of each phase of the electronic mutual inductor and determining crosstalk induction of each phase to the Rogowski coils of other phases; based on the corresponding coefficient of mutual induction and crosstalk induction of each phase, acquiring a compensation coefficient for an output voltage of the secondary side of that phase. The compensation coefficient is used to compensate for a real-time output voltage value of the secondary side of the electronic mutual inductor to acquire a compensation voltage value that corresponds to an actual current value of the primary-side device. This allows the actual current value of the primary-side device to be accurately acquired.