Electromagnetic modeling approaches of static electric machines

• Autor(a) principal: Carvalho, Kathleen Carolina
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10198/23554
• topic: Transformer; Finite element method; Losses; Prototype; Engenharia Industrial

The efficiency improvement of electric machines of major importance in the industrial field, considering that those devices represent a large portion of electricity consumption. Therefore, in the study of electromagnetic projects is mandatory to analyze the behavior of electric devices in rated and exceptional operation conditions. In this context, the application of the finite element method is relevant, since its high degree of discretization allows to analyze fields distribution with an accuracy not obtained by analytical approaches. When applied to complex domains, such as electric machines, that method makes it possible to verify saturation points and active losses in the device, with high accuracy. Thereby, this work proposes a computational model of a single-phase E-core transformer, assisted by the finite element method. The project is based on three approaches, in order to stablish a comparative analysis among the outputs. First of all, was analytically calculated through a reluctance mesh able to verify the magnetic flux distribution in the middle path of the transformer’s core. For this purpose, the project of the windings was necessary, based on the stablished physical characteristics and electric parameters. The second approach was the design the computational model, considered a 2D approach, to evaluate magnetic magnitudes, also calculated by the reluctance network. On the other hand, the 3D model was developed in order to evaluate the losses distribution around the whole volume of the domain. The proposed models were evaluated in a static, by reluctance mesh and the computational model, and time-varying domain, in order to analyze the losses. Finally, a physical prototype was also tested, at no-load and short-circuit tests, to provide data about the transformer losses under rating conditions. Those results were used to validate the efficiency of the computational model to predict the core and resistive losses.