Axial Flux Stator Nested Windings for Compact High-Density Cooling
Solution Overview
Problem
Existing axial flux machines face challenges in achieving a compact size while maintaining high performance and efficient cooling, particularly in high power density applications, where surface cooling is insufficient and requires a more efficient heat transfer method.
Innovation Solution
The stator design features a plurality of axially protruding stator teeth with windings wound in a radially nested configuration, allowing for increased voltage induction and efficient cooling through the use of spacer elements to facilitate coolant flow, thereby achieving a compact axial length and high current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If surface cooling with heat dissipation to surrounding air is used, then the cooling system requires little installation space and simple structure, but it is not sufficient for high power density applications
Solution Approach 1:
The patent implements liquid cooling channels within the stator core, using hydraulic flow of coolant (water or dielectric liquid) to remove heat from the windings. The cooling channels are integrated into the stator teeth and yoke, allowing efficient heat transfer from high-power density windings without increasing axial length.
2Power
If radially nested windings are used, then voltage induction is enhanced and power density increases, but cooling efficiency deteriorates due to reduced heat dissipation surface
Solution Approach 1:
The patent employs radially nested windings where multiple winding layers are arranged concentrically around stator teeth. The inner windings are positioned closer to the stator core while outer windings surround them, maximizing space utilization and voltage induction while maintaining thermal pathways to cooling channels.
Solution Approach 2:
The patent introduces cooling channels as intermediary structures between the nested windings and the external cooling system. These channels are positioned radially outward from the windings, allowing coolant to flow close to the winding surfaces and efficiently carry away heat generated by high power density operation.
3Length of moving object
If the axial length is reduced for compact size, then the machine becomes more compact, but the available space for windings and cooling channels is reduced
Solution Approach 1:
The patent transitions from axial to radial dimension utilization by implementing cooling channels that extend radially outward from the stator core. This radial arrangement allows multiple cooling passages to be packed within the available radial space, providing sufficient cooling capacity without increasing axial length. The nested windings similarly utilize radial space rather than axial space.
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 enables a durable axial flux machine with enhanced voltage induction, efficient cooling, and high power density, ensuring effective heat transfer and reduced thermal resistance, thus maintaining performance while minimizing axial length.
Implementation Method 1
cooling with a cooling fluid is necessary... ensures optimum heat transfer
Implementation Method 2
A defined voltage is induced on each coil side of a winding in the magnetic field
Data Source
AI summary
stator of an electric axial flux machine as well as to an electric axial flux machine. The stator of the axial flux machine includes a plurality of axially protruding stator teeth, a first winding being wound about at least one stator tooth, the first winding being surrounded on at least part of its radially outer face by at least one additional winding. The stator of an axial flux machine and the axial flux machine equipped with this stator afford durable units which combine an axially compact size with high performance.