In-Conductor Magnetometer for Crosstalk-Resistant Current Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional current sensing techniques face challenges such as high cost, complexity, and limited accuracy due to crosstalk from extraneous magnetic fields, especially in high-current applications where magnetic field strength exceeds the sensing range of high-precision sensors.
Innovation Solution
The placement of a magnetometer with a sensor interface circuit inside the periphery of a conductor structure allows for the use of higher sensitivity sensors like fluxgate, AMR, GMR, and TMR sensors, reducing crosstalk and occupying less space, while generating output signals representing longitudinal current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple magnetic sensors are disposed around the outside of the conductor to cancel interference, then current measurement accuracy is improved, but cost and device complexity increase significantly
Solution Approach 1:
Instead of placing sensors outside the conductor to measure magnetic fields, this patent inverts the approach by placing a magnetic sensor inside the conductor where the magnetic field from extraneous sources is minimal. The sensor measures the magnetic field generated by current flow directly at the conductor's center, eliminating the need for complex interference cancellation algorithms and multiple sensors.
Solution Approach 2:
The patent extracts the magnetic sensor from the external environment and places it within the conductor's interior. This extraction removes the sensor from the problematic external magnetic field environment, allowing single-sensor operation without the need for multiple external sensors and their associated signal processing complexity.
2Measurement precision
If multiple magnetic sensors are used around the conductor to reduce crosstalk, then measurement accuracy improves, but space occupancy increases
Solution Approach 1:
The patent inverts the conventional sensor placement by moving the sensor from the external perimeter area to the internal center area of the conductor. This single internal sensor position occupies minimal space compared to multiple external sensors distributed around the conductor, while still achieving high measurement accuracy.
3Measurement precision
If high precision magnetic sensors are used to measure high current, then measurement accuracy is limited, but sensor cost increases
Solution Approach 1:
The patent changes the spatial parameter of sensor placement from external to internal position within the conductor. This parameter change allows the use of higher sensitivity sensors that can operate in lower magnetic field environments, enabling accurate measurement of high currents without requiring excessively complex or expensive sensor systems.
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
This approach enables cost-effective, accurate current sensing with reduced crosstalk and space occupancy, utilizing higher sensitivity sensors within the conductor structure to improve measurement accuracy.
Implementation Method 1
magnetic sensor technology has been developed in which one or more sensors are placed near a current-carrying conductor to detect the magnetic field strength, and the amount of current flow is estimated based on the sensed field strength
Implementation Method 2
The magnetic sensors in certain embodiments are fluxgate sensors including a magnetically susceptible core structure as well as an excitation winding and at least one sense winding formed around the core structure
Implementation Method 3
Placement of the magnetometer within the conductor facilitates use of higher sensitivity sensors such as fluxgate sensors, anisotropic magnetoresistive (AMR) sensors
Implementation Method 4
fluxgate sensors, anisotropic magnetoresistive (AMR) sensors, gigantic magnetoresistive (GMR) sensors
Implementation Method 5
gigantic magnetoresistive (GMR) sensors, a tunneling magnetoresistive or tunneling magnetoresistance (TMR) sensors
Data Source
Figure 1
Figure 2~3
Figure 4~7
AI summary
Conductor apparatus (100) includes a bus bar conductive structure (110) and a magnetometer (120). The conductive structure conducts current along a longitudinal direction (102) and has an outer periphery extending between first and second longitudinal ends (111, 112). The magnetometer includes an array of at least two magnetic sensors located on a single integrated circuit at least partially within the outer periphery of the conductive structure. The individual magnetic sensors have an associated sensing direction transverse to the longitudinal direction of the conductive structure. A sensor interface circuit coupled to the magnetic sensors generates at least one output signal or value representing longitudinal current flow in the conductive structure based at least partially on at least one signal from the magnetic sensors. Multiple wires (122) are electrically connected to the sensor interface circuit and extend outside the outer periphery of the conductive structure.