Coreless Current Sensor with Conductor Cutouts for Flux Density
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Solution Overview
Problem
Traditional magnetic current sensors with ferrous cores are bulky, costly, prone to non-linearity and offset errors due to saturation and remanence effects, and require larger sizes for high power applications, which increases phase shift and magnitude attenuation.
Innovation Solution
A coreless sensor device with an electric conductor of flat elongated shape featuring cutout portions that increase electric current density and magnetic flux density, allowing for a magnetic sensor to be positioned next to the conductor to measure the magnetic field effectively, while maintaining small dimensions and low insertion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a ferrous core (field concentrator) is used in magnetic current sensors, then the flux density is amplified and galvanic isolation is achieved, but the sensor becomes bulky, costly, and prone to non-linearity and offset errors
Solution Approach 1:
The patent removes the ferrous core (field concentrator) from the sensor structure, extracting the problematic component that causes bulkiness, cost, and measurement errors. The solution measures flux density directly from the conductor without requiring an iron core, thereby eliminating saturation and remanence effects while maintaining measurement capability.
Solution Approach 2:
The patent replaces the mechanical/physical iron core structure with a direct measurement approach using a magnetic sensor (e.g., Hall sensor) positioned near the conductor. This substitution eliminates the need for ferromagnetic materials and their associated problems, achieving galvanic isolation through the air gap between the conductor and sensor rather than through a closed magnetic circuit.
2Reliability
If coreless current sensors are used to avoid ferrous core drawbacks, then non-linearity and offset errors are eliminated, but the available flux density at the sensitive elements is significantly reduced
Solution Approach 1:
The patent positions the magnetic sensor in advance at an optimized location near the conductor where the magnetic field is strongest. By pre-positioning the sensor in the region of highest flux density, the system maximizes the available signal before measurement occurs, compensating for the lack of field concentration that would otherwise be provided by a ferrous core.
3Measurement precision
If the magnetic sensor is placed close to the conductor to measure flux density, then measurement sensitivity is improved, but the sensor dimensions and insertion resistance increase
Solution Approach 1:
The patent repositions the magnetic sensor from a traditional close-contact arrangement to a lateral arrangement next to the conductor. This dimensional change allows the sensor to measure the magnetic field component perpendicular to the conductor surface, enabling effective measurement while maintaining greater spatial separation and reducing insertion resistance requirements.
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 solution achieves a lower phase shift and magnitude attenuation, enabling efficient current measurement in high power applications with smaller dimensions and reduced costs, comparable to core-based sensors.
Implementation Method 1
a magnetic sensor for measuring a magnetic field that is created by an electric current flowing through the electric conductor
Implementation Method 2
This residual portion forms a narrowed section that has to be passed by an electric current when flowing through the electric conductor. Accordingly, the electric current density is increased at this narrowed residual portion, resulting in an increased flux density of the magnetic field emanating from the flowing electric current
Data Source
AI summary
This disclosure concerns a sensor device including an electric conductor including a flat elongated shape. The electric conductor includes at least one cutout portion extending along the width of the electric conductor (200), the cutout portion extending from a first longitudinal side of the electric conductor towards an opposite second longitudinal side of the electric conductor, wherein a residual portion of the electric conductor remains between the cutout portion and the second longitudinal side of the electric conductor. A magnetic sensor is provided for measuring a magnetic field emanating from the electric current flowing through the electric conductor, wherein the magnetic sensor is arranged next to the electric conductor opposite the cutout portion.