Magnetic Field Current Measurement with Interference Cancellation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for measuring electrical current in electronic circuits are either energy inefficient or introduce unwanted resistance, and non-contact magnetic field-based methods face interference from external magnetic fields, making accurate current measurement challenging.

Innovation Solution

A current measurement system utilizing multiple magnetic field sensors arranged in a predetermined configuration to measure magnetic fields associated with current conductors, combined with a processor implementing a Taylor series expansion algorithm to cancel interference terms and calculate current amplitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage measurement across a resistor is used to measure current, then current measurement is achieved, but energy efficiency deteriorates and unwanted resistance is added to the current path

Engineering Contradiction:

Improvecurrent measurementVSAvoidenergy efficiency

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent replaces the electrical measurement method (voltage across resistor) with a magnetic field-based measurement method. Magnetic field sensors detect the magnetic field generated by current flow, enabling current measurement without introducing resistance or energy loss into the electrical circuit.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic field sensors as an intermediary between the current conductor and the measurement system. These sensors detect the magnetic field produced by the current without directly contacting or interfering with the current path, thus avoiding energy loss and unwanted resistance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If voltage measurement across a resistor is used to measure current, then current measurement is achieved, but unwanted resistance is added to the current path

Engineering Contradiction:

Improvecurrent measurementVSAvoidunwanted resistance

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces direct electrical contact measurement with non-contact magnetic field measurement. This substitution eliminates the need for resistors in the current path, thereby removing the harmful effect of unwanted resistance while maintaining measurement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Magnetic field sensors serve as an intermediary that enables current measurement without introducing resistance into the current path. The sensors detect the magnetic field externally, preventing any harmful resistance from being added to the circuit.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If non-contact magnetic field measurement is used, then energy efficiency is improved and unwanted resistance is avoided, but measurement accuracy deteriorates due to external magnetic field interference

Engineering Contradiction:

Improveenergy efficiencyVSAvoidmeasurement accuracy

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The patent divides the measurement system into multiple magnetic field sensors positioned at different locations. By segmenting the measurement function across multiple sensors, the system can differentiate between the magnetic field generated by the current conductor and external magnetic field interference, thereby improving measurement accuracy while maintaining energy efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements signal processing that uses feedback from multiple magnetic field sensors to cancel out external interference. The system processes the differential signals from multiple sensors to extract the true current-related magnetic field component, effectively removing the impact of external magnetic field interference on measurement accuracy.

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 system provides accurate, energy-efficient current measurement by mitigating interference from external magnetic fields, ensuring precise calculation of current amplitudes in current conductors without adding resistance.

Implementation Method 1

current through a current conductor, such as a metal trace, creates a magnetic field that is sensed by a magnetic sensor

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS10598700B2Magnetic field-based current measurement

Publication Date: 2020.03.24 TEXAS INSTRUMENTS INC

AI summary

One example includes a current measurement system. The system includes at least two magnetic field sensors positioned proximal to and in a predetermined arrangement with respect to a current conductor, each of the magnetic field sensors being configured to measure magnetic field associated with a current flowing in the current conductor and provide respective magnetic field measurements. The system also includes a current measurement processor configured to implement a mathematical algorithm based on a Taylor series expansion of the magnetic field measurements to calculate an amplitude of the current based on the mathematical algorithm.