Rotor Cooling Channels for Higher-Power Electric Machines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric machines in motor vehicles face limitations in cooling efficiency due to thermal resistance between the rotor and stator, which restricts power output, especially in high-power vehicles.
Innovation Solution
The electric machine design incorporates a rotor with groove-like recesses containing electrically conductive conductors and a displacement body, featuring cooling channels that extend along the rotor shaft, allowing direct fluid cooling of the rotor for enhanced heat removal and improved power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If stator cooling with coolant channels is used, then cooling effectiveness is improved, but device complexity and sealing requirements increase
Solution Approach 1:
The invention extracts the cooling function from the stator and transfers it to the rotor by providing coolant channels directly in the rotor core. This separates the cooling system from the stator sealing requirements, reducing overall device complexity while maintaining effective cooling.
Solution Approach 2:
The rotor acts as an intermediary component that receives coolant from the stator region and distributes it to the rotor windings. This mediator approach allows cooling without direct coolant contact with stator live parts, simplifying sealing requirements.
2Temperature
If heat conduction across the rotor-stator gap is used, then cooling is achieved, but heat transfer is limited by thermal resistance
Solution Approach 1:
The invention uses fluid convection through coolant channels in the rotor to replace thermal conduction across the air gap. The coolant directly contacts the rotor windings and conducts heat away efficiently, eliminating the thermal resistance bottleneck of the rotor-stator gap.
Solution Approach 2:
The invention changes the heat transfer parameter from thermal conduction (through air gap) to forced convection (through coolant). This parameter change dramatically improves heat transfer efficiency by replacing the high thermal resistance air gap with a liquid coolant pathway.
3Temperature
If rotor cooling is added to conventional stator cooling, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The invention merges the rotor cooling function with the existing stator cooling system by using the rotor as both a magnetic component and a coolant distribution medium. The coolant channels are integrated into the rotor structure itself, combining multiple functions in one component rather than adding separate cooling systems.
Solution Approach 2:
The rotor serves multiple functions: it generates magnetic fields through its windings and simultaneously acts as a heat exchanger with integrated coolant channels. This multi-functionality eliminates the need for separate cooling systems, reducing overall device complexity while improving cooling effectiveness.
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 design achieves increased continuous power and more homogeneous component temperatures, simplifying the operating strategy and reducing design risks while maintaining durability and cost-effectiveness.
Implementation Method 1
at least one cooling channel, which extends in a longitudinal direction of the rotor shaft, is arranged in at least one groove-like recess
Implementation Method 2
electrically conductive conductors of a rotor winding are provided in the groove-like recesses
Implementation Method 3
a displacement body for arranging the conductors in the groove-like recess are provided in the groove-like recesses
Data Source
AI summary
An electrical machine, as a prime mover of an electrically driven motor vehicle, including a rotor and a stator, wherein the stator surrounds a substantially cylindrical space area, in which the rotor is rotatably arranged, the rotor includes a rotor shaft, on which a rotor core is arranged, the rotor core including groove-like recesses which extend toward the rotor shaft, electrically conductive conductors of a rotor winding and a displacement body for arranging the conductors in the groove-like recess are provided in the groove-like recesses, and at least one cooling channel, which extends in a longitudinal direction of the rotor shaft, is arranged in at least one groove-like recess.