Stator Cooling Assembly With Radial Channels for Winding Heat
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current stator cooling systems for electric machines, particularly in electric vehicles, face challenges in effectively cooling the laminate stack and windings, leading to higher temperatures and increased copper losses, which in turn require more current to achieve the same torque.
Innovation Solution
A stator assembly with two subassemblies featuring outer and inner longitudinal cooling fluid channels, coupled by radial channels formed by a segmented annular plate, allowing cooling fluid to penetrate radially from the outside to the inside, effectively reducing winding temperatures and copper losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a stator back water jacket is used for cooling, then the cooling system is simple to implement, but the stator laminates and windings cannot be effectively cooled
Solution Approach 1:
The stator is divided into multiple segments with cooling channels distributed throughout the structure. The cooling system is segmented into outer longitudinal channels, radial channels, and inner longitudinal channels, allowing cooling fluid to access different regions of the stator for effective heat removal from laminates and windings.
Solution Approach 2:
The cooling approach transitions from a single-dimensional back water jacket to a three-dimensional cooling network. Cooling channels are arranged in multiple dimensions (outer perimeter, radial direction, inner perimeter) to provide comprehensive cooling coverage throughout the stator volume.
2Temperature
If oil cooling is used for the rotor, then rotor cooling efficiency is high, but stator cooling becomes more complicated and generally lacking
Solution Approach 1:
The cooling system uses a universal cooling fluid (oil) that serves multiple functions: cooling the rotor, cooling the stator laminates, and cooling the windings. The same cooling fluid circulates through both rotor and stator cooling channels, simplifying the overall thermal management system while providing effective cooling throughout.
Solution Approach 2:
The cooling fluid acts as an intermediary medium that transfers heat from both the rotor and stator components. The fluid circulates through cooling channels in both the rotor and stator, mediating heat removal from multiple heat-generating components without requiring separate cooling systems.
3Loss of energy
If higher current is used to compensate for increased copper losses, then the same torque can be achieved, but energy efficiency decreases
Solution Approach 1:
The cooling system converts the harmful effect of heat generation into a beneficial outcome. By effectively removing heat from the windings, the system maintains lower winding temperatures, which reduces copper losses and improves overall energy efficiency. The heat that would otherwise be wasted is now controlled and dissipated.
Solution Approach 2:
The cooling system provides thermal feedback control by continuously removing heat from the stator components. The cooling fluid absorbs heat from the laminates and windings, carries it away, and dissipates it in the heat exchanger, creating a feedback loop that maintains optimal operating temperatures and minimizes energy losses.
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 reduces winding temperatures by 15-20%, resulting in a 1% increase in cycle efficiency by lowering the current needed to achieve the same torque compared to existing technologies.
Implementation Method 1
One or more radial cooling fluid channels are coupled to the one or more outer longitudinal cooling fluid channels and are configured to deliver a cooling fluid (liquid or gas, such as oil, water, or air) to one or more inner longitudinal cooling fluid channels that also run along or adjacent to the stator laminates, along the inner perimeter of the stator subassemblies, near and/or among the stator teeth and windings
Implementation Method 2
The cooling fluid may drain from the subassembly in any convenient manner, such as from one or more of the opposed ends of the stator subassemblies, and be cooled and recycled to the process
Data Source
AI summary
A stator cooling assembly for an electric machine, including: one or more radial cooling fluid channels disposed between a first stator subassembly and a second stator subassembly disposed along a longitudinal axis, wherein the one or more radial cooling fluid channels fluidly couple one or more outer cooling fluid channels with one or more inner cooling fluid channels and deliver a cooling fluid radially between the one or more outer cooling fluid channels and the one or more inner cooling fluid channels; wherein the first stator subassembly and the second stator subassembly include or define the one or more outer cooling fluid channels adapted to contain the cooling fluid and the one or more inner cooling fluid channels adapted to contain the cooling fluid, and wherein the one or more outer cooling fluid channels are disposed circumferentially outwards of the one or more inner cooling fluid channels.