Cryocooled Litz Armature Windings for High-Current Electric Machines
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Solution Overview
Problem
Existing technologies have not provided sufficient power density and efficiency for electric machines to be viable as primary propulsion systems in commercial aircraft, particularly due to limitations in current density and electrical losses in conventional electric machines.
Innovation Solution
The use of a magnetic core stator and cryogen source to maintain armature arrangements at low temperatures, combined with Litz wires and high-purity materials, to achieve a synergistic effect, enabling efficient power transmission and reduced electrical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrogen systems are used for aircraft propulsion, then environmental impact is reduced, but power output is insufficient for commercial aircraft
Solution Approach 1:
The patent applies parameter changes by operating the electric machine at cryogenic temperatures (below 77K) to achieve hyperconductive state in the armature windings. This temperature parameter change enables extremely high current densities (greater than 25 A/mm²) that were not achievable at conventional temperatures, thereby providing the necessary power output for commercial aircraft while maintaining the environmental benefits of electric propulsion.
2Power
If standard electric machines are used, then power output is sufficient, but electrical losses are high and efficiency is low
Solution Approach 1:
The patent fundamentally changes the temperature parameter of the armature windings to cryogenic levels, transforming the electrical conductivity parameter from conventional to hyperconductive state. This parameter change reduces electrical resistance and associated I²R losses, enabling the machine to deliver high power output with minimal energy loss, achieving efficiencies unattainable by standard electric machines.
3Power
If current density is increased in armature windings, then power output increases, but electrical losses and heating increase
Solution Approach 1:
The patent resolves this contradiction by changing the temperature parameter to cryogenic levels, which fundamentally alters the relationship between current density and electrical losses. At temperatures below 77K, the armature windings enter a hyperconductive state where extremely high current densities (greater than 25 A/mm²) can be sustained with minimal resistive losses, breaking the conventional trade-off between power output and energy loss.
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
The solution achieves a current density of over 25 A/mm², significantly reducing electrical losses and enabling efficient power output, making electric machines viable for aircraft propulsion.
Implementation Method 1
a low temperature source arranged to provide a low temperature to the armature arrangement
Implementation Method 2
The use of the magnetic core stator and the cryogen source to provide cryogen to the armature arrangement provides a highly effective and highly efficient electromagnetic arrangement that allows a significantly higher current density to be handled by the armature than has previously been used
Implementation Method 3
The electric machine disclosed herein provides a far greater current density than is presently provided by standard electric machines. The use of the magnetic core stator and the cryogen source to provide cryogen to the armature arrangement provides a highly effective and highly efficient electromagnetic arrangement
Implementation Method 4
the armature arrangement comprises a plurality of Litz wires, wherein during operation the armature arrangement provides a current density of more than 25 A/mm²
Data Source
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AI summary
The present invention relates to an electric machine comprising: a stator comprising a magnetic core; a rotor; an armature arrangement; and, a cryogen source arranged to provide a cryogen to the armature arrangement, wherein the armature arrangement comprises a plurality of Litz wires, wherein during operation the armature arrangement provides a current density of more than 25 A/mm2.