PCB Néel-Effect Current Sensor for Low-Drift Wideband Isolation
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Solution Overview
Problem
Current current sensors face challenges such as bulkiness, high cost, limited bandwidth, thermal drift, and sensitivity to crosstalk and temperature, particularly in high-voltage and high-temperature applications, and existing Néel@ Effect sensors struggle with compactness and integration.
Innovation Solution
A current sensor design featuring a primary circuit with distinct metal tracks connected by vias on a printed circuit board, utilizing superparamagnetic cores and Néel Effect transducers to achieve low thermal drift and high bandwidth, allowing for compact and integrated measurement of DC and AC currents up to 10kA, with a focus on eliminating contact resistance and parasitic phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shunt is used for DC current measurement, then measurement precision and immunity to interfering currents are improved, but device size and power consumption increase due to heat dissipation requirements
Solution Approach 1:
The patent replaces the traditional shunt-based mechanical/electrical measurement system with a magnetic field sensing system using Néel Effect transducers. The primary circuit uses non-contact magnetic coupling through a magnetic core, eliminating the need for large physical shunts and associated heat dissipation structures, thereby reducing device volume while maintaining measurement precision.
Solution Approach 2:
The patent changes the operating parameters by using superparamagnetic material with specific magnetic properties (high permeability, low coercivity) to enhance magnetic coupling efficiency. This allows accurate current measurement through magnetic field detection rather than direct voltage measurement across a shunt, reducing the physical size required for heat dissipation.
2Volume of moving object
If Néel Effect sensor is made compact for integration, then device size is reduced, but immunity to crosstalk and external magnetic fields deteriorates
Solution Approach 1:
The patent employs asymmetric winding configurations of the Néel Effect transducers around the magnetic core, with primary and secondary windings positioned differently to optimize magnetic coupling while minimizing sensitivity to external magnetic fields and crosstalk. This asymmetric arrangement enhances the desired measurement signal while rejecting interfering fields.
Solution Approach 2:
The patent introduces a magnetic core as an intermediary element between the primary current-carrying conductor and the Néel Effect transducers. This magnetic core concentrates and guides the magnetic flux, enhancing the measurement signal while shielding the transducers from external magnetic interference and crosstalk, thus maintaining immunity even in compact configurations.
3Speed
If bandwidth is increased for AC measurement, then frequency response is improved, but thermal drift and measurement accuracy worsen
Solution Approach 1:
The patent implements a feedback mechanism where the secondary Néel Effect transducer detects the magnetic flux generated by the primary winding, and this information is fed back to compensate for thermal drift effects. The system continuously monitors and adjusts for temperature-induced changes in magnetic properties, maintaining measurement accuracy across wide bandwidths and frequency ranges.
Solution Approach 2:
The patent uses composite magnetic materials combining superparamagnetic particles with a non-magnetic matrix, providing both high permeability for wide bandwidth response and stable magnetic properties for accurate measurement. This composite structure maintains consistent magnetic characteristics across varying frequencies and temperatures, preventing thermal drift while preserving bandwidth.
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 enables precise, linear measurement of currents over a wide frequency range with reduced thermal drift and power consumption, improved integration, and enhanced immunity to crosstalk, while maintaining robustness and compactness.
Implementation Method 1
A current sensor design featuring a primary circuit with distinct metal tracks connected by vias on a printed circuit board, utilizing superparamagnetic cores and Néel Effect transducers
Implementation Method 2
utilizing superparamagnetic cores and Néel Effect transducers to achieve low thermal drift and high bandwidth
Data Source
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AI summary
The invention relates to a current sensor comprising at least one primary circuit that is intended to conduct the current to be measured, and a secondary circuit comprising at least four Néel-effect®transducers, each consisting of a coil and a superparamagnetic core. The current sensor according to the invention is designed on the basis of a printed circuit board, the primary circuit comprising at least two distinct metal tracks that are composed of one and the same metal and connected to one another by a via consisting of a rivet, of a tube or of an electrolytic deposit of the same metal.