Dual-Channel Current Sensor Assembly for Better Low-Current Linearity
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Solution Overview
Problem
Existing current sensors face limitations in shaping magnetic cores, leading to issues with saturation point and linearity, and ultrasonic welding damages electronic components during assembly, resulting in low manufacturing efficiency.
Innovation Solution
A dual-channel current sensor design featuring cylindrical cores with flat zones and separate insertion points for a printed circuit board assembly (PCBA) and magnetic cores, allowing for stamped or wound cores, and orthogonal sensing channels to improve linearity and accuracy, while avoiding component damage during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a wound core is used, then the magnetic core can be shaped, but the saturation point and linearity are limited
Solution Approach 1:
The patent divides the single magnetic core into two separate magnetic cores (first and second magnetic cores) with different cross-sectional areas. This segmentation allows each core to be optimized for different current ranges, improving overall measurement linearity while maintaining shaping flexibility. The two cores work together to extend the measurable current range with better linearity characteristics.
Solution Approach 2:
The patent applies different cross-sectional areas to different magnetic cores to create local quality variations. The first magnetic core has a larger cross-sectional area for measuring higher currents, while the second magnetic core has a smaller cross-sectional area for measuring lower currents. This local differentiation optimizes the saturation point and linearity for each specific measurement range.
2Adaptability or versatility
If two cores are replaced in respective hollow rings with a PCBA, then the magnetic core flexibility is improved, but the electronic components are destroyed during ultrasonic welding
Solution Approach 1:
The patent performs preliminary assembly by placing the PCBA into the housing and securing it with the end cap before inserting the magnetic cores. This sequence ensures that the PCBA and its electronic components are already positioned and protected before any welding operations occur on the magnetic cores, preventing damage to sensitive electronics during the welding process.
Solution Approach 2:
The housing and end cap serve as intermediary structures that separate and isolate the PCBA from the welding process. The end cap is welded to the housing to secure the PCBA, creating a protective barrier that prevents ultrasonic welding energy from reaching and damaging the electronic components while still allowing the magnetic cores to be properly positioned and welded.
3Ease of manufacture
If two-sided welding for cores is performed, then the assembly is completed, but the manufacturing efficiency is low
Solution Approach 1:
The patent combines multiple assembly operations into a single integrated process. The magnetic cores are inserted through the housing in a sequence that allows both cores to be positioned and secured in one continuous operation, eliminating the need for separate two-sided welding steps. This merging of operations maintains complete assembly while significantly improving manufacturing efficiency.
Solution Approach 2:
The patent inverts the traditional assembly sequence by inserting and welding the magnetic cores from one side of the housing rather than requiring two-sided access. The first magnetic core is inserted and welded, followed by the second magnetic core, both from the same side. This inverted approach maintains proper assembly while enabling more efficient single-sided manufacturing operations.
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 design provides high accuracy and flexibility in current measurement, especially for low current ranges, enhancing Amp-hr integration and reducing manufacturing inefficiencies.
Implementation Method 1
A Hall effect current sensor consists of an open-loop magnetic core and a Hall sensor, which is a magneto sensitive semiconductor device. When current passes through the conductor, a magnetic field is produced on the core. When the Hall sensor is exposed to the magnetic field from the core, a small Hall voltage is produced.
Data Source
AI summary
A dual-channel current sensor includes a housing, a core, and a printed circuit board assembly (PCBA). The housing has a cylindrical cavity and an end portion, where the cylindrical cavity is open at a first end. The core is cylindrical in shape with flattened top and bottom surfaces and has a flat zone on an interior surface, a gap perpendicular and opposite the flat zone, a first portion adjacent one side of the gap, and a second portion adjacent the other, opposite side of the gap. The core is inserted into first end of the cylindrical cavity. The PCBA, which is inserted into the end portion of the housing, has a sensor disposed in the gap.