Metal-Base Coil Structure for Heat Dissipation in Power Converters
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Solution Overview
Problem
The challenge is to enhance heat dissipation in coil devices to manage increased Joule heat and skin effect-induced resistance, which hinders miniaturization of power conversion devices.
Innovation Solution
A coil device with a core and first winding part, where a metal base substrate with an insulating layer is used, allowing heat generated in the winding part to be dissipated to a cooling body through the substrate, effectively improving heat dissipation by utilizing the insulating layer and metal base body for both inner and outer region heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the frequency of AC voltage is increased to miniaturize the coil device, then the core size and number of windings are reduced, but the electric resistance value increases due to skin effect and Joule heat increases
Solution Approach 1:
The coil device is divided into inner region (inside core) and outer region (outside core), with separate heat dissipation paths for each region. The first winding part is disposed in the inner region while the second winding part is disposed in the outer region, allowing independent thermal management for each segment.
Solution Approach 2:
A heat dissipation member is introduced as an intermediary component between the coil windings and the external environment. This member has high thermal conductivity to efficiently transfer heat from the coil windings, particularly from the inner region windings that are thermally isolated from the external environment.
2Volume of moving object
If wiring with small sectional area is used to miniaturize the coil device, then the device size is reduced, but Joule heat generated in the coil device increases
Solution Approach 1:
Heat dissipation is enhanced by utilizing the radial dimension through the core structure. The first winding part disposed inside the core can dissipate heat radially outward through the core material, providing an additional thermal pathway perpendicular to the conventional axial heat flow direction.
Solution Approach 2:
The core material serves as a thermal intermediary between the first winding part (inner region) and the heat dissipation member. The core's thermal conductivity enables efficient heat transfer from the internally disposed windings to the external cooling structure.
3Productivity
If high frequency AC voltage is applied to miniaturize the coil device, then switching frequency increases, but electric resistance value monotonously increases due to skin effect
Solution Approach 1:
Different winding parts are positioned in different thermal environments with distinct heat dissipation characteristics. The first winding part in the inner region utilizes radial heat dissipation through the core, while the second winding part in the outer region utilizes axial heat dissipation to external cooling structures, allowing each to operate optimally in its local thermal zone.
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 solution improves heat dissipation in the coil device, allowing for effective management of heat generated in both inner and outer regions, contributing to the miniaturization of the coil device and the power conversion device.
Implementation Method 1
heat generated in a portion of the first winding part located in the outer region of the core is dissipated to the cooling body via the insulating layer and the metal base body. Heat generated in a portion of the first winding part located in the inner region of the core is also dissipated to the cooling body via the insulating layer and the metal base body.
Implementation Method 2
when an alternating current flows, the current flows only near the surface of the wiring due to the skin effect, and thus, the electric resistance value of the coil device increases.
Implementation Method 3
The core has a function of forming a magnetic path that is a path of lines of magnetic force generated by a current flowing through the coil.
Data Source
AI summary
A coil device includes a core having a loop-shaped magnetic path and a first winding part. The first winding part is wound around the core so as to pass through an inner region of the core surrounded by the core. In the inner region of the core and an outer region of the core, a metal base substrate in which a coil pattern is formed with an insulating layer interposed on a metal base body is disposed. A cooling body is thermally bonded to a side of the metal base body opposite to a side where the insulating layer and the coil pattern are formed. The first winding part includes the coil pattern.