Current Measuring Device with Flux Concentrator
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Solution Overview
Problem
Existing current measuring devices for electrical vehicle applications face challenges in adaptability to various conductor geometries, accuracy, and resistance to electromagnetic interference, with prior solutions being bulky, prone to poor insulation, and having suboptimal signal-to-noise ratios.
Innovation Solution
A contact-less current measuring device featuring a U-shaped flux concentrator and dual magnetic sensors, allowing flexible adaptation to any conductor geometry, enhancing accuracy by concentrating magnetic fields and dividing measurement ranges for precise current detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large wound-type transformer is used to transform the magnetic field into current and voltage, then the measurement function is achieved, but the device occupies a lot of space and has poor insulation against high voltages
Solution Approach 1:
The patent replaces the traditional mechanical wound-type transformer with a magnetic core and winding assembly that transforms the magnetic field into electrical signals through electromagnetic induction. This substitution maintains the measurement function while reducing the overall device size and improving insulation performance against high voltages.
2Adaptability or versatility
If an open loop current sensor with ferromagnetic core is used, then the device is easy to adapt to different bus bar geometries, but the signal-to-noise ratio is poor due to EMI sensitivity
Solution Approach 1:
The patent introduces a magnetic core as an intermediary element between the conductor and the Hall sensor. This magnetic core concentrates and guides the magnetic field lines, enhancing the magnetic field strength at the sensor location while filtering out external electromagnetic interference, thereby improving the signal-to-noise ratio without compromising adaptability to different bus bar geometries.
3Measurement precision
If a shunt sensor is used to measure current through voltage drop, then the measurement is contact-based, but the device requires welding in the middle of the bus bar which reduces adaptability
Solution Approach 1:
The patent replaces the contact-based shunt sensor method with a contactless Hall effect sensing system. The magnetic core and Hall sensor assembly detects the magnetic field generated by the current-carrying conductor without requiring physical contact or welding, thereby maintaining measurement accuracy while significantly improving adaptability to various conductor configurations and geometries.
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 provides a compact, reliable, and accurate current measurement system that is easy to implement in various power electronics applications, reducing errors and improving adaptability to different conductor configurations while resisting external magnetic interference.
Implementation Method 1
a first magnetic sensor (2) adapted to sense, in a first current range, a magnetic field generated by a current flowing through the conductor (7)
Implementation Method 2
a flux concentrator (4) received by the board (5), wherein the first magnetic sensor (2) is disposed between the side portions (4a, 4c) of the flux concentrator (4) to converge a flux generated by a current flowing through the conductor (7) towards the first magnetic sensor (2)
Data Source
Figure 1~2
Figure 3a~3c
Figure 4a~4b
AI summary
A current measuring device (1) for a conductor (7), comprising a first magnetic sensor (2) to sense a magnetic field generated by a current flowing through the conductor (7), a printed-circuit board (5), and a first non-conductive element (8). The first magnetic sensor (2) is disposed on the board (5), along to a same or a substantially parallel direction in which a current would flow through the conductor (7). The first non-conductive element (8) is configured to be disposed on a first (7a) and/or on a second side (7b) of the conductor (7) to fix the board (5) at one side (7a, 7b) of the conductor (7).