Rotating Electric Machine Cooling with Integrated Dual-Coolant Heat Exchange
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Solution Overview
Problem
Existing rotating electric machine units do not effectively account for the differing heat generation rates between high and low heat generation circuits, leading to inefficiencies in cooling and potential overheating.
Innovation Solution
The implementation of a dual-coolant system where a first coolant is used for both high and low heat generation circuits, with a second coolant being supplied to the rotating electric machine, utilizing the excess cooling capacity of the low heat generation circuit's cooling part to efficiently cool the machine, and an in-shaft and in-rotor coolant flow path configuration to enhance heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coolant system is used to cool both high and low heat generation circuits, then the device complexity is reduced, but the cooling efficiency deteriorates due to excess cooling capacity in the low heat generation circuit
Solution Approach 1:
The cooling system is divided into two independent coolant circulation systems: a first coolant system dedicated to cooling the high heat generation circuit, and a second coolant system dedicated to cooling the low heat generation circuit. This segmentation allows each coolant to be optimized for its specific cooling load, preventing the waste of excess cooling capacity while maintaining reasonable system complexity through modular design.
2Reliability
If separate coolant systems are used for high and low heat generation circuits, then the cooling efficiency is improved, but the device complexity increases
Solution Approach 1:
The first and second coolers are integrated into a single integrated cooler assembly that houses both coolant circulation systems. The heat exchangers for both coolants are combined in one structure, allowing thermal interaction between the two coolant systems while maintaining their operational independence. This merging reduces the overall device complexity by consolidating components into a unified structure.
Solution Approach 2:
The integrated cooler serves multiple functions: it cools both the high heat generation circuit and the low heat generation circuit simultaneously, and it enables thermal energy transfer between the two coolant systems. The single integrated structure performs what would otherwise require separate cooling devices, improving efficiency while controlling complexity.
3Device complexity
If the second coolant supplier is formed integrally with the low heat generation circuit-cooling part, then the device complexity is reduced, but the heat exchange efficiency may deteriorate
Solution Approach 1:
The second coolant supplier is formed integrally with the low heat generation circuit-cooling part of the first cooler, creating a nested structure where the second coolant system is embedded within the first cooler assembly. This nesting allows the second coolant to be cooled by the first coolant through thermal conduction across shared walls, maintaining efficient heat exchange while minimizing the number of separate components.
Solution Approach 2:
The shared structural walls between the first and second coolant systems act as thermal intermediaries, enabling heat transfer from the second coolant to the first coolant. This intermediary thermal path ensures efficient heat exchange without requiring direct contact between the two coolants or additional heat exchange 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
This configuration allows for effective cooling of the rotating electric machine by utilizing the excess cooling capacity of the low heat generation circuit, preventing overheating and improving the overall cooling efficiency of the system.
Implementation Method 1
The second-coolant supplier includes a heat exchanger via which heat is exchanged between the first coolant and the second coolant
Implementation Method 2
The coolant supplier includes an in-shaft flow path which is formed in the rotating shaft along an axial direction thereof and through which the coolant flows
Data Source
AI summary
A rotating electric machine unit includes a rotating electric machine, a high heat generation circuit and a low heat generation circuit both of which are electrically connected with the rotating electric machine, a first cooler, a first-coolant supplier, a second cooler and a second-coolant supplier. The first cooler is configured to cool both the high heat generation circuit and the low heat generation circuit with a first coolant. The first-coolant supplier is configured to supply the first coolant to the first cooler. The second cooler is configured to cool the rotating electric machine with a second coolant. The second-coolant supplier is configured to supply the second coolant to the second cooler. The second-coolant supplier is formed integrally with a low heat generation circuit-cooling part of the first cooler. The second-coolant supplier includes a heat exchanger via which heat is exchanged between the first coolant and the second coolant.