Current Sensor Conductor-Plate Layout for High-Frequency Stability
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Solution Overview
Problem
Existing current sensors face challenges in maintaining sensitivity and reliability due to variations in eddy currents and skin effects, particularly when high-frequency currents are measured, and alignment issues during assembly can affect performance.
Innovation Solution
The current sensor design incorporates a lead frame and a conductor plate that partially overlaps the current conductor, with magnetoelectric conversion elements sealed within a sealing portion, and a slit portion to stabilize their position, reducing eddy current effects and enhancing sensitivity by minimizing skin effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal plate or semiconductor substrate is used as support member, then mechanical strength is improved, but eddy current effects increase causing sensitivity variation
Solution Approach 1:
The patent extracts the harmful eddy current path by introducing a non-conductive resin layer between the metal plate and the magnetoelectric conversion element. This separates the mechanical support function (performed by the metal plate) from the eddy current generation path, allowing the metal plate to provide strength without causing sensitivity variation through eddy currents.
Solution Approach 2:
The resin layer acts as an intermediary between the metal plate and the magnetoelectric conversion element. It provides electrical insulation to prevent eddy currents while maintaining mechanical support through the metal plate structure, thus resolving the contradiction between strength and sensitivity stability.
2Measurement precision
If current conductor is positioned close to magnetoelectric conversion element, then measurement sensitivity is improved, but skin effects and eddy currents increase
Solution Approach 1:
The resin layer serves as an intermediary that allows the current conductor to be positioned close to the magnetoelectric conversion element for high sensitivity while preventing direct eddy current paths. The resin provides electrical insulation that blocks eddy currents despite the close proximity of conductive elements.
Solution Approach 2:
The patent applies different material properties to different regions: the resin layer provides electrical insulation and eddy current blocking in the critical region between conductors, while the metal plate provides mechanical strength. This localized application of insulating properties allows close positioning without harmful eddy current effects.
3Measurement precision
If alignment between current conductor and magnetoelectric conversion element is critical, then measurement accuracy is improved, but assembly difficulty increases
Solution Approach 1:
The resin layer is pre-formed with recess portions that preliminarily position and constrain the magnetoelectric conversion element and current conductor in the correct relative positions. This preliminary structuring eliminates the need for complex post-assembly alignment procedures while ensuring accurate positioning is achieved.
Solution Approach 2:
The resin layer's recess portions automatically guide and constrain the components during assembly, allowing the structure to self-align the current conductor and magnetoelectric conversion element without requiring external alignment tools or complex procedures. The geometry of the recess portions provides inherent positioning.
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 design stabilizes the position of magnetoelectric conversion elements, reduces sensitivity variations, and enhances sensitivity and reliability by minimizing eddy currents and skin effects, allowing for accurate high-frequency current measurements.
Implementation Method 1
a magnetoelectric conversion element that converts a magnetic field into an electric signal
Implementation Method 2
a current conductor through which a measurement current measured by the at least one magnetoelectric conversion unit flows
Data Source
AI summary
A current sensor may include: at least one magnetoelectric conversion unit; a current conductor through which a measurement current measured by the magnetoelectric conversion unit flows; and a conductor plate which at least partially overlaps the current conductor in plan view. A main body portion of the current conductor includes a first portion. A thickness of the conductor plate, magnetic permeabilities of the conductor plate and the current conductor, electrical conductivities of the conductor plate and the current conductor, a shortest distance between a magnetic sensing surface and the current conductor, a maximum width of the first portion, a shorter distance of a distance between the conductor plate and the current conductor and a distance between the conductor plate and the magnetic sensing surface of the magnetoelectric conversion unit, and a narrowest width in a portion, which crosses the magnetoelectric conversion unit, of the conductor plate satisfy a condition.