Magnetic Current Sensor Calibration for Multi-Phase Interference

Solution Overview

Problem

Magnetic cores used in current sensing systems add cost, weight, and mechanical constraints, and existing calibration methods for magnetic interference are inefficient in multi-phase power systems.

Innovation Solution

A calibration method that determines coupling coefficients by measuring magnetic fields from multiple conductors with simultaneous multi-phase currents, using zero sequence currents to break perfect correlation and calculate interference components, allowing accurate current measurements without magnetic cores.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If magnetic cores are used in current sensing systems, then magnetic field shielding and interference reduction are improved, but cost, weight, and mechanical constraints increase

Engineering Contradiction:

Improvemagnetic field interferenceVSAvoidsystem weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent removes the magnetic core from the current sensing system, extracting the harmful weight and mechanical constraints while retaining current sensing capability through alternative means (measuring magnetic field components and applying calibration coefficients to compensate for interference).

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical magnetic core shielding approach with a computational approach using calibration coefficients and signal processing to eliminate magnetic interference, substituting physical protection with mathematical compensation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If magnetic cores are used in current sensing systems, then magnetic field shielding and interference reduction are improved, but cost increases

Engineering Contradiction:

Improvemagnetic field interferenceVSAvoidsystem cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent removes the magnetic core from the current sensing system, extracting the harmful weight and mechanical constraints while retaining current sensing capability through alternative means (measuring magnetic field components and applying calibration coefficients to compensate for interference).

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical magnetic core shielding approach with a computational approach using calibration coefficients and signal processing to eliminate magnetic interference, substituting physical protection with mathematical compensation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If traditional calibration methods are used in multi-phase power systems, then calibration process is simplified, but calibration accuracy and efficiency deteriorate due to perfect correlation between phase currents

Engineering Contradiction:

Improvecalibration process complexityVSAvoidcalibration accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary anti-action by introducing zero sequence currents before the actual calibration measurement, which breaks the perfect correlation between phase currents and creates the necessary conditions for accurate coupling coefficient determination.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent changes the electrical parameters of the calibration process by superimposing zero sequence currents on the phase currents, altering the current waveforms to have different frequencies and phases, thereby breaking the correlation that prevents accurate calibration in multi-phase systems.

Inventive Principle:

Principle #35Parameter changes

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

Improves calibration efficiency and accuracy by characterizing interference components, reducing inaccuracies in multi-phase power systems, and enabling precise current measurements.

Implementation Method 1

receiving, from a sensor proximate a first conductor, a sensor signal representing a measurement of a magnetic field produced based on a first current flowing in the first conductor and a second current flowing in a second conductor

Methodology Applied

Scientific EffectMagnetic field measurement: Magnetic Field

Data Source

PatentUS12560661B2Magnetic current sensor calibration

Publication Date: 2026.02.24 TEXAS INSTRUMENTS INC

AI summary

In one example, a calibration method includes receiving, from a sensor proximate a first conductor, a sensor signal representing a measurement of a magnetic field produced based on a first current flowing in the first conductor and a second current flowing in a second conductor, the first current including first and second current components having different frequencies, and the second current including third and fourth current components, the third current component phase shifted from, and having the same frequency as, the first current component and the fourth current component having a different frequency from the third current component, determining reference values of the first and second currents, and based on the sensor signal and the reference values of the first and second currents, determining for the sensor, a plurality of coupling coefficients representing magnetic field coupling between the first and second conductors.