Power Inverter Thermal Management via Preloaded Semiconductor Mounting
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Solution Overview
Problem
Conventional power inverters for electrical machines generate significant heat, requiring intensive cooling for power semiconductors, which is often inefficient due to additional thermal conduction layers and vibration protection challenges.
Innovation Solution
The power semiconductors are directly and immediately coupled to a thermally conductive housing wall using a preloading arrangement with resilient clamps and a clamping plate, eliminating additional thermal layers and enhancing heat conduction, while also providing vibration protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power semiconductors are cooled through additional thermal layers (power circuit board and insulating foil), then the power semiconductors can be electrically isolated from the cooling plate, but thermal conduction efficiency deteriorates due to the additional thermal resistance layers
Solution Approach 1:
The invention extracts and eliminates the insulating foil layer from the thermal conduction path between the power semiconductor and the cooling plate. By removing this thermal barrier while maintaining electrical isolation through alternative means (the conductive adhesive itself providing electrical connection), the patent resolves the contradiction by taking out the harmful element that was previously necessary for electrical isolation.
Solution Approach 2:
The conductive adhesive serves multiple functions simultaneously: it provides thermal conduction (replacing both the insulating foil and adhesive layers), electrical connection (replacing the insulating foil's isolation function), and mechanical bonding. This multi-functionality resolves the contradiction by eliminating the need for separate layers for each function.
2Temperature
If power semiconductors are directly coupled to the cooling plate without additional layers, then thermal conduction is improved, but electrical isolation between the power semiconductors and the conductive cooling plate deteriorates
Solution Approach 1:
The invention changes the electrical conductivity parameter of the adhesive layer, transforming it from an electrically insulating material to an electrically conductive material. This parameter change allows the adhesive to simultaneously provide thermal conduction and electrical connection, eliminating the need for separate insulating layers and resolving the contradiction between thermal efficiency and electrical isolation.
3Temperature
If conventional cooling plates with large surface area are used to evacuate heat, then cooling capacity is improved, but the device complexity and space requirements increase
Solution Approach 1:
The invention merges the cooling plate function directly with the housing structure (housing wall or end plate). By integrating the heat sink function into the existing housing components, the patent eliminates the need for separate, large-surface-area cooling plates, thereby reducing device complexity and space requirements while maintaining adequate cooling capacity through the improved thermal contact.
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 configuration significantly improves cooling efficiency by direct thermal contact between power semiconductors and the housing wall, reducing heat conduction barriers and protecting against vibrations, leading to enhanced thermal management and reliability.
Implementation Method 1
the heat generated in the respective power semiconductor can be directly and immediately evacuated into the housing wall
Implementation Method 2
The preloading arrangement compresses the respective power semiconductor against the housing wall
Data Source
Figure 1
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AI summary
The invention relates to a power inverter (10) for an electrical machine (80). The power inverter (10) comprises a power circuit board (40) with a plurality of power semiconductors (41) and a housing (20) with a housing wall (21), which extends around a central longitudinal axis (30) of the housing (20). The power circuit board (40) is fitted in the housing (20) perpendicularly to the central longitudinal axis (30). According to the invention, the power semiconductors (41) are arranged in an edge region (43) of the power circuit board (40), and are oriented perpendicularly to the latter and in parallel with the central longitudinal axis (30). The power inverter (10) further incorporates a preloading arrangement (60) having at least one resilient clamp (63) and a clamping plate (61) in parallel with the power circuit board (40), wherein the respective resilient clamp (63) is pre-loaded between the respective power semiconductors (41) and the clamping plate (61), and compresses the respective power semiconductors (41) against an inner surface (21a) of the housing wall (21). The invention further relates to an electrical machine (80) having said power inverter (10).