Electro-thermal design and optimization of cryocooled electrical machines

Thermal management is a significant challenge in designing high-power-density electrical machines. Inherent resistivity losses in the electrical system limit conventional machines' achievable power density and efficiency. Cryocooled conductors and superconductors (SC) substantially reduce resistivity losses, enabling higher electrical and magnetic loading of cryocooled electrical machines, and potentially increasing the power density by a factor of ten. However, generated ac losses in these conductors must be removed in bulk, low-efficient cryogenic environments requiring a large amount of cryo-power. This is a substantial hurdle. Therefore, optimizing machine losses and designing efficient cryo-thermal management is necessary for a feasible cryocooled electrical machine. To minimize ac losses and machine weight, an electromagnetic (EM) machine design requires an electro-thermal, multiphysics optimization incorporating conductor properties, a machine thermal model, and a cryogenic cooling scheme. Reliable ac-loss estimation on an armature conductor is a crucial enabler of such an optimization. This dissertation summarizes the efforts of developing a practical electro-thermal analysis and multiphysics optimization for cryocooled electrical machines. Analytical approaches are introduced to capture the spatial and time-harmonics impacts on armature ac losses and verified with finite element analysis (FEA). An ac-loss-measurement test bench is developed to validate the proposed loss-prediction methods and calibrate the motor design analysis. Ac losses in SC samples are experimentally measured and compared against analytical models and FEA results. Examples of multiphysics optimization are presented for electric propulsion motors and wind turbine generators. Sub-scale component hardware tests, including SC armature winding and a rotating cryocooler test bench, are demonstrated for low-frequency applications. Finally, future work focuses on high-frequency tests.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Balachandran, Thanatheepan

Contributors dc:contributor

• Haran, Kiruba S
• Jin, Jianming
• Banerjee, Arijit
• Stillwell, Andrew

• Multi-physics Optimization
• Cryocooled Electrical Machine
• Superconducting Electrical Machine
• Ac Loss
• Analytical Modeling
• Electric Propulsion
• Wind Turbine

Statement dc:rights

• Copyright 2022 Thanatheepan Balachandran

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/117783

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F117783