Power Inverter Cooling Channel Geometry for Heat Distribution
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Solution Overview
Problem
Power inverter devices experience significant heat distribution imbalance due to liquid cooling, where the outlet-side semiconductor switching elements are less cooled than the inlet-side elements, leading to inefficient heat transfer.
Innovation Solution
The cooling channel geometry is modified by varying the mean cross-sectional area along its length, with sections having different areas to increase heat transfer from the outlet-side elements, and incorporating features like step-shaped connections and projections to enhance heat dissipation, thereby balancing heat distribution and increasing cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a liquid cooling system with a cooling channel is used to cool semiconductor switching element arrangements, then heat dissipation is improved, but the heat distribution among the semiconductor switching element arrangements becomes highly unbalanced along the mounting direction
Solution Approach 1:
The cooling channel is designed with varying cross-sectional areas along its length, creating different cooling characteristics for different sections. Specifically, the cross-sectional area decreases in the direction of coolant flow, providing stronger cooling capacity to outlet-side semiconductor switching element arrangements that previously received insufficient cooling. This local variation in cooling channel geometry addresses the unbalanced heat distribution by tailoring the cooling intensity to the specific thermal needs of each section.
Solution Approach 2:
The patent changes the geometric parameters of the cooling channel, specifically the cross-sectional area, to optimize heat transfer. By reducing the cross-sectional area along the flow direction, the coolant velocity increases and thermal boundary layers are reduced, enhancing heat transfer coefficients. This parameter change transforms the uniform cooling channel into a non-uniform one that actively compensates for the heat distribution imbalance among semiconductor switching element arrangements.
2Temperature
If the cooling channel cross-sectional area is reduced to increase heat transfer from outlet-side elements, then cooling efficiency is improved, but pressure drop constraints may be violated
Solution Approach 1:
The cooling channel geometry is locally optimized by implementing gradual transitions rather than abrupt changes in cross-sectional area. Connection sections with stepped or sloped bottom sides create controlled geometric transitions that induce turbulence for enhanced heat transfer while minimizing sudden pressure losses. This local quality variation in the channel geometry allows the system to achieve improved cooling efficiency without violating pressure drop constraints.
Solution Approach 2:
The cooling channel design incorporates dynamic flow characteristics by creating controlled turbulence through geometric transitions. The stepped or sloped connection sections between main sections dynamically alter the flow regime, inducing turbulence that enhances heat transfer coefficients. This dynamic approach allows the system to maintain effective cooling while managing pressure drop through controlled flow regime transitions rather than simple geometric scaling.
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 results in more balanced heat transfer and improved cooling efficiency by increasing heat dissipation at the outlet-side elements, reducing thermal boundary layers, and inducing turbulence, leading to enhanced overall cooling performance.
Implementation Method 1
a coolant flows from an inlet channel through a cooling channel into an outlet channel
Implementation Method 2
inducing turbulence, leading to enhanced overall cooling performance
Implementation Method 3
reducing thermal boundary layers
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
Power inverter device (2), comprising a plurality of semiconductor switching element arrangements (7, 8, 9) each configured to provide an output phase current of the power inverter device (2), and a cooling device (15), on which the semiconductor switching element arrangements (7, 8, 9) are mounted in a row extending along a mounting direction (18), the cooling device (15) comprising - a cooling channel (19) being configured so as to allow a coolant to flow along the mounting direction (18), - an inlet channel (20) that is connected to a first end of the cooling channel (19), and - an outlet channel (21) that is connected to a second end of the cooling channel (19), wherein the cooling channel (19) has - a first main section (22) extending from one end of the cooling channel (19) underneath a first semiconductor switching element arrangement (7) along the mounting direction (18) and having a mean cross-sectional area with respect to a plane being perpendicular to the mounting direction (18), and - a second main (23) section extending from the other end of the cooling channel (19) underneath a second semiconductor switching element arrangement (8) along the mounting direction (18) and having a mean cross-sectional area with respect to a plane being perpendicular to the mounting direction (18) that is smaller than the mean cross-sectional area of the first main section (22).