Current Sensor With Multi-Point Flux Cancellation for Offset Wires
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Solution Overview
Problem
Existing current sensors face challenges in accurately measuring currents when the conducting wire is not centered within the magnetic core, leading to errors due to non-uniformly distributed magnetic flux and residual magnetic flux saturation.
Innovation Solution
A current sensor design featuring multiple magnetic sensors, amplifiers, feedback coils, and a current detector that cancels magnetic flux by combining feedback currents from multiple coils, allowing for accurate measurement regardless of the conducting wire's position relative to the magnetic core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnetic sensor is used to detect magnetic flux in the magnetic core, then the device complexity is low, but the measurement precision deteriorates when the conducting wire is not centered
Solution Approach 1:
The magnetic core is divided into multiple predetermined portions, with each portion monitored by a dedicated magnetic sensor. This segmentation allows independent detection of magnetic flux in different regions, enabling accurate measurement even when the conducting wire is not centered in the magnetic core.
Solution Approach 2:
Each magnetic sensor is positioned to detect magnetic flux in a specific predetermined portion of the magnetic core. By assigning local detection responsibilities to individual sensors, the system captures spatial variations in magnetic flux distribution, improving measurement accuracy for off-center wire positions.
2Measurement precision
If multiple magnetic sensors and feedback coils are used to cancel non-uniform magnetic flux, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The system employs feedback coils connected to amplifiers that receive signals from magnetic sensors. The feedback mechanism generates compensating magnetic fields to cancel non-uniform magnetic flux distributions, thereby maintaining measurement accuracy across different wire positions within the magnetic core.
Solution Approach 2:
Multiple magnetic sensors are integrated with corresponding amplifiers and feedback coils to form a unified feedback system. The combined output currents from multiple feedback coils work together to cancel non-uniform magnetic flux, achieving improved measurement precision through coordinated operation of multiple components.
3Measurement precision
If the magnetic core size is increased to accommodate centered wire positioning, then the measurement precision improves, but the volume of the device increases
Solution Approach 1:
Instead of relying on a single centralized detection point, the system transitions to multi-dimensional spatial detection by placing multiple magnetic sensors at different predetermined portions of the magnetic core. This dimensional expansion in sensor arrangement enables accurate measurement without increasing magnetic core size.
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 sensor effectively cancels non-uniformly distributed magnetic flux without increasing size, ensuring high accuracy in current measurement even when the conducting wire is offset from the center, and includes a resistor to detect the current based on combined coil currents.
Implementation Method 1
When a current to be measured flows in a conducting wire, a magnetic field is generated around the conducting wire due to the effect of electromagnetic induction
Implementation Method 2
a plurality of magnetic sensors each configured to detect magnetic flux in a predetermined portion of the magnetic core
Implementation Method 3
each of the plurality of feedback coils is wound around the magnetic core and passes the current outputted by the corresponding amplifier in a direction that cancels the corresponding magnetic flux in the predetermined portion of the magnetic core
Data Source
AI summary
A current sensor includes a magnetic core that can be arranged to surround a conducting wire through which a current to be measured flows, magnetic sensors each configured to detect magnetic flux in a predetermined portion of the magnetic core, amplifiers arranged in correspondence with the magnetic sensors, feedback coils arranged in correspondence with the magnetic sensors, and a current detector that detects the current to be measured based on a current yielded by combining currents flowing through each of the feedback coils. Each of the amplifiers amplifies an output of the corresponding magnetic sensor and outputs a current corresponding to the output of the corresponding magnetic sensor. Each feedback coil is wound around the magnetic core and passes the current outputted by the corresponding amplifier in a direction that cancels the corresponding magnetic flux in the predetermined portion of the magnetic core.