Current Sensor Protruding Substrate for High-Current Accuracy
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Solution Overview
Problem
Current sensors used in electric vehicles face challenges with increased heat generation due to high currents, leading to temperature rises that affect measurement accuracy and component lifespan, and existing designs either increase size or manufacturing costs or fail to manage heat effectively.
Innovation Solution
A current sensor design with a busbar, magnetic detection unit, casing, and first magnetic shield, where a substrate with a protruding portion dissipates heat and is protected by a spacer and guard configuration, reducing temperature rise and improving measurement accuracy while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat radiating uneven portion is provided in the insulating material part of the casing, then heat dissipation is improved, but the size of the product and manufacturing cost increase
Solution Approach 1:
The substrate is divided into a heat radiating portion and a non-heat radiating portion, allowing selective heat dissipation only where needed (near the busbar) while maintaining simplicity in other areas. This segmented approach improves heat dissipation efficiency without requiring complex structures throughout the entire device.
Solution Approach 2:
The substrate is designed with different thermal properties in different regions: the heat radiating portion has high thermal conductivity and large surface area for heat dissipation, while the non-heat radiating portion maintains standard properties. This local differentiation optimizes heat management without increasing overall device complexity or cost.
2Volume of moving object
If the magnetic detection unit is provided inside a cover with a shield, then the size is reduced, but the temperature in the storage space may increase beyond the heat-resistant temperature of the magnetic detection unit
Solution Approach 1:
The substrate acts as an intermediary heat transfer medium between the busbar and the magnetic detection unit. The heat radiating portion of the substrate conducts heat away from the magnetic detection unit's storage space, preventing temperature buildup while maintaining the compact enclosed structure.
Solution Approach 2:
Heat dissipation is achieved by extending the substrate in the width direction (perpendicular to the heat flow direction from the busbar), creating a heat radiating surface that is spatially separated from the magnetic detection unit. This dimensional approach allows effective heat dissipation within the compact device volume without requiring additional external heat sinks.
3Temperature
If the substrate has a protruding portion for heat dissipation, then heat dissipation is improved, but the device complexity increases
Solution Approach 1:
The substrate simultaneously serves multiple functions: it provides mechanical support for the magnetic detection unit, acts as a heat radiating fin, and serves as a mounting structure. By making the substrate itself multi-functional rather than adding separate components, heat dissipation is improved without increasing device complexity.
Solution Approach 2:
The heat radiating structure is merged with the substrate rather than being a separate component. The protruding portion of the substrate integrates the heat dissipation function into the existing structural element, eliminating the need for additional heat sinks or cooling components and thereby maintaining structural simplicity.
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 effectively dissipates heat from the busbar, protects the magnetic detection unit, and maintains measurement accuracy even with high currents, while minimizing size and manufacturing complexity.
Implementation Method 1
The substrate can dissipate the heat generated from the busbar due to the current to be measured from its protruding portion to the outside.
Implementation Method 2
The substrate having the magnetic detection unit on a surface of the substrate on one side in a first direction where three directions perpendicular to one another are defined as the first direction, a second direction, and a third direction
Implementation Method 3
a first magnetic shield configured to reduce disturbance magnetic field noise applied to the magnetic detection unit
Implementation Method 4
a magnetic detection unit configured to detect a magnetic field generated when the current to be measured flows through the busbar
Data Source
AI summary
A current sensor includes a busbar through which a measured current flows, a magnetic detector that detect a magnetic field generated by the measured current, a casing that holds the busbar, a first magnetic shield that reduces disturbance magnetic field noise applied to the magnetic detector, a substrate having the magnetic detector on its surface on one side in a first direction perpendicular to second and third directions perpendicular to each other, where the busbar, magnetic detector, substrate, and first magnetic shield are disposed in this order from the one side in the first direction, and a spacer portion provided between the casing and substrate to separate the busbar from the magnetic detector in the first direction. The substrate has a protruding portion protruding from a position where the substrate is held by the spacer portion in at least one of protruding directions that are the second and third direction.