Power Converter Thermal Management via Integrated Substrate Cooling
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Solution Overview
Problem
Conventional power conversion devices face challenges in effectively dissipating heat generated at coil patterns on substrates, leading to increased size and thermal resistance issues, particularly in high-power applications like on-vehicle chargers, and require separate housings for ferrite cores which introduce additional thermal resistance.
Innovation Solution
A power conversion device with a single-sheet substrate and integrated heat dissipation portions, including coil cooling, element cooling, and core cooling, which directly transfers heat from transformer coils and switching elements to a metallic heat dissipation member, reducing thermal resistance and eliminating the need for separate housings and high-thermal-resistance adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat dissipation member is merely in contact with the core, then the device structure is simple, but heat generated at the circuit substrates is not effectively transferred to the heat dissipation member
Solution Approach 1:
The patent combines the heat dissipation member with the circuit substrates by forming recesses in the heat dissipation member that receive and contact the coil patterns directly. This merging of functions allows heat to be transferred more effectively from the coil patterns to the heat dissipation member without requiring separate complex cooling structures.
Solution Approach 2:
The patent introduces a vertical dimension to heat transfer by creating recesses in the heat dissipation member that extend downward to contact the coil patterns. This dimensional change allows heat to be extracted from the coil patterns through direct contact in the vertical direction, improving thermal efficiency without increasing horizontal footprint.
2Reliability
If separate housings are provided for ferrite cores, then the core is protected, but additional thermal resistance is introduced
Solution Approach 1:
The patent merges the core holding function with the heat dissipation function by integrating the ferrite core directly into the heat dissipation member structure. The core is positioned to contact the heat dissipation member directly, eliminating the need for separate protective housings that would act as thermal barriers.
Solution Approach 2:
The patent extracts the protective housing function from the thermal management system, removing the unnecessary intermediate layer between the core and heat dissipation member. By taking out the separate housing, the design achieves both core protection (through direct contact with the heat dissipation member) and reduced thermal resistance.
3Reliability
If multiple laminated substrates are used for primary and secondary windings, then electrical isolation is achieved, but device height increases
Solution Approach 1:
The patent transitions from vertical stacking (laminated substrates increasing height) to horizontal integration (coil patterns on the same substrate). By arranging primary and secondary windings as patterns on a single substrate plane with the core penetrating through, the design achieves electrical isolation through the core structure rather than through multiple substrate layers, thereby reducing device height.
4Power
If high-power applications are implemented, then power conversion capability increases, but heat dissipation becomes more difficult
Solution Approach 1:
The patent performs preliminary heat extraction by designing the heat dissipation member with recesses that contact the coil patterns before the heat accumulates to problematic levels. This preliminary action of heat transfer from the high-power coil patterns to the heat dissipation member enables the system to handle higher power applications without excessive temperature rise.
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 effective heat dissipation, reduces the device's height, and improves thermal efficiency, making it thinner and more suitable for high-power applications without the need for additional housings or high-thermal-resistance materials.
Implementation Method 1
a metallic heat dissipation member, which cools the coil patterns and switching elements through contact with a lower surface of the substrate
Implementation Method 2
Heat generated from the transformer is transmitted to the metal frame and the bottom portion of the case and is then radiated
Implementation Method 3
a core is provided which penetrates the first circuit substrate and the second circuit substrate such that both of the primary winding and the secondary winding are wound around the core
Data Source
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AI summary
A power conversion device (100) includes: a main body (10) including a substrate (6) to which a power conversion unit (2, 4) and a coil (31) are provided; and a first heat dissipation portion (11) which holds the substrate (6) and dissipates heat of the substrate (6), wherein the substrate (6) is formed by one sheet, the coil (31) is formed integrally with the substrate (6), the first heat dissipation portion (11) is fixed to a substrate first surface (6X) of the substrate (6), a heat dissipation second surface (11Y) of the first heat dissipation portion (11) has a coil cooling portion (11A) opposed to and abutting on a part where the coil (31) is formed, of the substrate (6), and a heat dissipation first surface (11X) of the first heat dissipation portion (11) is formed to be an outermost peripheral surface on the first direction side (Y1) of the power conversion device (100).