Dual-Circuit Electric Motor Cooling for Higher Power Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric motors, such as those in cycloidal propulsion units, face challenges in achieving sufficient cooling, which limits power output and requires increased motor size unless efficient cooling is implemented.
Innovation Solution
A dual cooling method is employed, where a cooling fluid circulates through the stator and a cooling gas flow is directed along the rotor, entering through an inlet, passing through a heat exchanger, and exiting via an outlet, ensuring efficient heat dissipation without enlarging the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cooling is improved to increase power output, then power availability increases, but motor size must be increased to accommodate cooling components
Solution Approach 1:
The cooling system is segmented into two independent subsystems: a liquid cooling circuit for the stator and a gas cooling circuit for the rotor. This segmentation allows each subsystem to be optimized independently and integrated into the motor structure without requiring a single large cooling system, thus increasing power output while minimizing overall motor size increase.
Solution Approach 2:
The cooling components are nested within the motor structure. The liquid cooling channels are integrated into the stator core, and the gas cooling passages are incorporated into the rotor assembly. This nesting approach embeds cooling functionality within existing motor components rather than adding external cooling systems, thereby increasing cooling efficiency without proportionally increasing motor volume.
2Power
If cooling efficiency is increased to avoid temperature rise, then power loading increases, but cooling system complexity increases
Solution Approach 1:
The system employs liquid hydraulics for stator cooling and gas pneumatics for rotor cooling. The liquid cooling circuit uses a pump, heat exchanger, and circulation system integrated with the stator. The gas cooling circuit uses a fan or blower directing airflow through rotor passages. These pneumatic and hydraulic systems provide efficient heat removal with relatively simple component integration, enabling high power loading without excessive cooling system complexity.
Solution Approach 2:
The cooling system is designed to serve multiple functions: the liquid cooling circuit cools the stator windings and core, while the gas cooling circuit cools the rotor magnets and windings. Additionally, the gas cooling system can serve dual purposes by providing both cooling and potential lubrication for rotor bearings. This multi-functionality reduces the need for separate specialized cooling systems for each component, thereby increasing power loading capability while controlling overall system complexity.
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 approach allows for increased power output without enlarging the motor, effectively managing temperature and maintaining component integrity through efficient cooling of the stator, rotor, and other critical components.
Implementation Method 1
circulating a cooling fluid to the stator
Implementation Method 2
circulating a cooling fluid
Implementation Method 3
cooling other components of the electric motor with a cooling gas flow, which from an inlet enters the electric motor and flows along a rotor before exiting the electric motor via an outlet
Data Source
Figure 1~3
Figure 4~5
Figure 6~8
AI summary
This invention relates to an apparatus and to a method for cooling an electric motor. To obtain simple and sufficient cooling the electric motor is provided with a dual cooling system including a cooling space (11) provided to the stator (2) for receiving and passing on a cooling fluid which cools the stator, and an inlet (12) and an outlet (13) provided to the electric motor for receiving and passing on a cooling gas flow which cools at least the rotor (4) before exiting the electric motor.