Rotating Electric Machine with Integrated Power Conversion Cooling
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Solution Overview
Problem
Conventional rotating electric machines integrated with electric power conversion apparatuses require a large overall size due to cooling configurations, which is inefficient in terms of space and performance.
Innovation Solution
A rotating electric machine system with a monolithically integrated electric power conversion apparatus, featuring a casing with a first cooling flow path between the stator and the power module, and a second cooling flow path outside the stator, utilizing a direct water cooling method to reduce thermal resistance and share a water flow path, allowing for a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling tank or similar cooling configuration is used in an inverter-integrated rotating electric machine, then cooling performance is improved, but the overall size of the apparatus increases
Solution Approach 1:
The patent merges the cooling function with the structural components of the rotating electric machine by forming cooling flow paths within the stator and power conversion apparatus housing. The cooling flow paths are integrated into the existing structure rather than being separate components, allowing the housing to serve dual purposes: structural support and heat dissipation. This eliminates the need for additional cooling tanks or separate cooling systems, thereby maintaining effective cooling performance while reducing the overall apparatus size.
Solution Approach 2:
The housing structure is designed to perform multiple functions simultaneously: it provides mechanical support for the stator and power conversion apparatus, encloses the cooling flow paths, and acts as a heat dissipation structure. The first cooling flow path is formed within the housing between the stator and power conversion apparatus, while the second cooling flow path is formed outside the stator, allowing the same housing structure to facilitate cooling for multiple components without requiring separate dedicated cooling structures for each.
2Productivity
If separate mounting of rotating electric machine and electric power conversion apparatus is used, then mounting space and cooling efficiency are improved, but the number of components increases and surge prevention becomes difficult
Solution Approach 1:
The patent combines the rotating electric machine and electric power conversion apparatus into a single integrated unit with a common housing structure. The power conversion apparatus is mounted on the housing, and the stator is positioned such that cooling flow paths are formed between them and outside the stator. This integration reduces the number of separate components and simplifies the system configuration while maintaining effective cooling through the integrated flow paths.
Solution Approach 2:
While integrating the components, the patent segments the cooling system into distinct first and second cooling flow paths: one between the stator and power conversion apparatus, and another outside the stator. This segmentation allows each component to be cooled effectively through dedicated flow paths within the integrated structure, managing thermal complexity without requiring separate physical mounting of components.
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 direct water cooling method reduces thermal resistance and area requirements, enabling a smaller-sized electric power conversion apparatus while maintaining performance, with improved cooling efficiency and torque per volume compared to indirect cooling methods.
Implementation Method 1
a first cooling flow path arranged in a portion of the casing between the stator and the electric power conversion apparatus, via which cooling medium is caused to flow so as to cool the stator and the electric power conversion apparatus
Implementation Method 2
the power module comprises a heat radiation fin; and the heat radiation fin is arranged to protrude toward a cooling medium side via an opening formed between the power module and the first cooling flow path
Implementation Method 3
a second cooling flow path arranged in a portion of the casing outside of the stator to extend along a direction of rotation of the rotating electric machine, via which the cooling medium flows; and the second cooling flow path communicates with the first cooling flow path such that the cooling medium cools the stator after cooling the electric power conversion apparatus
Data Source
AI summary
A rotating electric machine system includes: a rotating electric machine including a stator and a rotor arranged with a gap to the stator; a casing configured to hold the stator; an electric power conversion apparatus held by the casing, and configured to drive the rotating electric machine; and a first cooling flow path arranged in a portion of the casing between the stator and the electric power conversion apparatus, via which cooling medium is caused to flow so as to cool the stator and the electric power conversion apparatus. And; the electric power conversion apparatus comprises a power module configured to include a power semiconductor element therein; the power module comprises a heat radiation fin; and the heat radiation fin is arranged to protrude toward a cooling medium side via an opening formed between the power module and the first cooling flow path.