{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/108422"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/108422","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Nonlinear electromagnetic-thermal modeling using time domain finite element method in the machinery design","abstract":"In this thesis, an electromagnetic-thermal co-simulation algorithm is developed for the three-dimensional modeling of electric machines. To couple electromagnetic (EM) and heat transfer processes, the time-domain finite element method is employed for its capability of modeling complex geometries. Losses generated from EM fields lead to temperature increase, while the temperature change, in turn, modifies material properties and thus affects EM field distribution. An efficient and accurate EM-thermal scheme is proposed to fully couple these two phenomena. Nonlinear magnetic problems arising from ferromagnetic materials are considered and solved by applying the Newton-Raphson method. For soft ferromagnetic materials, B-H curves are used to describe the permeability, and polynomial fitting is used to construct smooth curves from experimental data. To include the hysteresis phenomenon in hard ferromagnetic materials, the Jiles-Atherton (J-A) model is introduced to characterize the nonlinear property in which an ordinary differential equation (ODE) relates the magnetic flux density with its corresponding magnetic field. The classic Runge-Kutta method is adopted to accurately solve the ODE in the J-A model. EM and thermal variations have different timescales and the heat transfer process is far slower than electromagnetic variations. To enhance the simulation efficiency, different time-step sizes are applied. After each thermal time step, the material properties are first updated based on the temperature distribution and the EM problem is solved for several periods. When marching into the next thermal time step, the heat source is extrapolated from the EM losses to obtain the updated values, and the thermal system is solved again until a steady state is reached. Various numerical examples are presented to validate the implementation and demonstrate the accuracy, efficiency, and applications of the proposed numerical algorithms.","abstract_html":"In this thesis, an electromagnetic-thermal co-simulation algorithm is developed for the three-dimensional modeling of electric machines. To couple electromagnetic (EM) and heat transfer processes, the time-domain finite element method is employed for its capability of modeling complex geometries. Losses generated from EM fields lead to temperature increase, while the temperature change, in turn, modifies material properties and thus affects EM field distribution. An efficient and accurate EM-thermal scheme is proposed to fully couple these two phenomena. Nonlinear magnetic problems arising from ferromagnetic materials are considered and solved by applying the Newton-Raphson method. For soft ferromagnetic materials, B-H curves are used to describe the permeability, and polynomial fitting is used to construct smooth curves from experimental data. To include the hysteresis phenomenon in hard ferromagnetic materials, the Jiles-Atherton (J-A) model is introduced to characterize the nonlinear property in which an ordinary differential equation (ODE) relates the magnetic flux density with its corresponding magnetic field. The classic Runge-Kutta method is adopted to accurately solve the ODE in the J-A model. EM and thermal variations have different timescales and the heat transfer process is far slower than electromagnetic variations. To enhance the simulation efficiency, different time-step sizes are applied. After each thermal time step, the material properties are first updated based on the temperature distribution and the EM problem is solved for several periods. When marching into the next thermal time step, the heat source is extrapolated from the EM losses to obtain the updated values, and the thermal system is solved again until a steady state is reached. Various numerical examples are presented to validate the implementation and demonstrate the accuracy, efficiency, and applications of the proposed numerical algorithms.","abstract_has_math":false,"creators":["Li, Hongliang"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical and Computer Engineering","degree_department":null,"school":null,"contributors":["Jin, Jianming"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-10-07T20:59:22Z","date_published":"2020-10-07T20:59:22Z","updated_at":"2026-07-22T22:24:48Z","subjects":["Nonlinear magnetic problem","Hysteresis loop","Ferromagnetic materials","Electromagnetic-thermal modeling","Machinery design","Finite element method"],"languages":["en"],"rights":["Copyright 2020 Hongliang Li"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/108422","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Jin, Jianming"]},{"key":"dc:creator","label":"Author","values":["Li, Hongliang"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-10-07T20:59:22Z","2020-06-04","2020-08"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical and Computer Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Nonlinear magnetic problem","Hysteresis loop","Ferromagnetic materials","Electromagnetic-thermal modeling","Machinery design","Finite element method"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2020 Hongliang Li"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/108422"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this thesis, an electromagnetic-thermal co-simulation algorithm is developed for the three-dimensional modeling of electric machines. To couple electromagnetic (EM) and heat transfer processes, the time-domain finite element method is employed for its capability of modeling complex geometries. Losses generated from EM fields lead to temperature increase, while the temperature change, in turn, modifies material properties and thus affects EM field distribution. An efficient and accurate EM-thermal scheme is proposed to fully couple these two phenomena. Nonlinear magnetic problems arising from ferromagnetic materials are considered and solved by applying the Newton-Raphson method. For soft ferromagnetic materials, B-H curves are used to describe the permeability, and polynomial fitting is used to construct smooth curves from experimental data. To include the hysteresis phenomenon in hard ferromagnetic materials, the Jiles-Atherton (J-A) model is introduced to characterize the nonlinear property in which an ordinary differential equation (ODE) relates the magnetic flux density with its corresponding magnetic field. The classic Runge-Kutta method is adopted to accurately solve the ODE in the J-A model. EM and thermal variations have different timescales and the heat transfer process is far slower than electromagnetic variations. To enhance the simulation efficiency, different time-step sizes are applied. After each thermal time step, the material properties are first updated based on the temperature distribution and the EM problem is solved for several periods. When marching into the next thermal time step, the heat source is extrapolated from the EM losses to obtain the updated values, and the thermal system is solved again until a steady state is reached. Various numerical examples are presented to validate the implementation and demonstrate the accuracy, efficiency, and applications of the proposed numerical algorithms.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2020-10-02 without embargo terms","The student, Hongliang Li, accepted the attached license on 2020-06-02 at 14:33.","The student, Hongliang Li, submitted this Thesis for approval on 2020-06-02 at 14:47.","This Thesis was approved for publication on 2020-06-04 at 15:17.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15430 on 2020-10-02 at 15:10:14","Made available in DSpace on 2020-10-07T20:59:22Z (GMT). No. of bitstreams: 2 LI-THESIS-2020.pdf: 1426293 bytes, checksum: 3586bea45e35fa0bcb09bca4b0ad39d6 (MD5) LICENSE.txt: 4209 bytes, checksum: 455a55bd300a930dca7f4b4d56b26322 (MD5) Previous issue date: 2020-06-04"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Nonlinear electromagnetic-thermal modeling using time domain finite element method in the machinery design"]}]}],"canonical_facts":{"dc:contributor":["Jin, Jianming"],"dc:creator":["Li, Hongliang"],"dc:date":["2020-10-07T20:59:22Z","2020-06-04","2020-08"],"dc:description":["In this thesis, an electromagnetic-thermal co-simulation algorithm is developed for the three-dimensional modeling of electric machines. To couple electromagnetic (EM) and heat transfer processes, the time-domain finite element method is employed for its capability of modeling complex geometries. Losses generated from EM fields lead to temperature increase, while the temperature change, in turn, modifies material properties and thus affects EM field distribution. An efficient and accurate EM-thermal scheme is proposed to fully couple these two phenomena. Nonlinear magnetic problems arising from ferromagnetic materials are considered and solved by applying the Newton-Raphson method. For soft ferromagnetic materials, B-H curves are used to describe the permeability, and polynomial fitting is used to construct smooth curves from experimental data. To include the hysteresis phenomenon in hard ferromagnetic materials, the Jiles-Atherton (J-A) model is introduced to characterize the nonlinear property in which an ordinary differential equation (ODE) relates the magnetic flux density with its corresponding magnetic field. The classic Runge-Kutta method is adopted to accurately solve the ODE in the J-A model. EM and thermal variations have different timescales and the heat transfer process is far slower than electromagnetic variations. To enhance the simulation efficiency, different time-step sizes are applied. After each thermal time step, the material properties are first updated based on the temperature distribution and the EM problem is solved for several periods. When marching into the next thermal time step, the heat source is extrapolated from the EM losses to obtain the updated values, and the thermal system is solved again until a steady state is reached. Various numerical examples are presented to validate the implementation and demonstrate the accuracy, efficiency, and applications of the proposed numerical algorithms.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2020-10-02 without embargo terms","The student, Hongliang Li, accepted the attached license on 2020-06-02 at 14:33.","The student, Hongliang Li, submitted this Thesis for approval on 2020-06-02 at 14:47.","This Thesis was approved for publication on 2020-06-04 at 15:17.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15430 on 2020-10-02 at 15:10:14","Made available in DSpace on 2020-10-07T20:59:22Z (GMT). No. of bitstreams: 2 LI-THESIS-2020.pdf: 1426293 bytes, checksum: 3586bea45e35fa0bcb09bca4b0ad39d6 (MD5) LICENSE.txt: 4209 bytes, checksum: 455a55bd300a930dca7f4b4d56b26322 (MD5) Previous issue date: 2020-06-04"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/108422"],"dc:language":["en"],"dc:rights":["Copyright 2020 Hongliang Li"],"dc:subject":["Nonlinear magnetic problem","Hysteresis loop","Ferromagnetic materials","Electromagnetic-thermal modeling","Machinery design","Finite element method"],"dc:title":["Nonlinear electromagnetic-thermal modeling using time domain finite element method in the machinery design"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Electrical and Computer Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:48Z"}