Browsing by Author "Mendes, Gabriel Dias"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Advances in the control schemes for MR actuatorsPublication . Mendes, Gabriel Dias; Goldasz, Januszvices. In the essence, the hardware incorporates a valve being a solenoid with a flow channel. Supplying the current to the solenoid’s coil induces the magnetic field in the channel. As a results, the fluid transitions from a near-Newtonian one to a pseudo-solid. In the paper we show that significant improvements in the MR actuator dynamics can be achieved by exploring flux feedback control systems rather than current feedback ones. The flux-based approach would improve the system’s response time and its bandwidth as well as minimize the contribution of the eddy currents. Thus, numerical simulations have been carried out to test the original hypothesis. The obtained data (from co-simulations) prove that the proposed approach delivers good results although further research is required on further optimizing the controller’s gains and prior to building a real prototype.
- Analytical and numerical thermal modelling of a low power transformerPublication . Mendes, Gabriel Dias; Ferreira, Ângela P.; Miotto, EdneiIn past decades, thermal modelling of electric machines was overlooked and based on empirical experience. Due to modern requirements, using novel materials and innovative configurations, the thermal model became a crucial component in the modern design process. The thermal modelling can be performed by analytical methods, as the thermal resistance network (TRN) or by numeric methods as the finite element analysis (FEA). This work presents a methodological approach to thermal modelling, addressing both approaches and applying them to a study case of a low power shell-type single-phase transformer. The results from both approaches are compared with experimental results, achieving relative errors of 5.70% and 21.24% on the determination of windings' temperature, for the FEA and TRN model respectively, which helps define model improvements.
- Coupled electromagnetic and thermal analysis of electric machinesPublication . Mendes, Gabriel Dias; Miotto, Ednei LuizThe actual trend of the design process of electric machines is oriented to specific requirements of the application and is no longer based in a standard structure. From this point of view, the design procedure of electric machines became a multidisciplinary process, involving electromagnetic, thermal, and mechanical modelling in a highly iterative process between the different physics fields. This dissertation deals with the design process of electric machines, proposing a coupling methodology for the electromagnetic and thermal models which are interrelated. The electromagnetic model establishes the main losses in electric machines: iron and resistive losses. These losses are, in turn, the main heat sources, responsible for heating and temperature distribution, i.e., the object of the thermal analysis, which affects recursively the losses, due to parameter’ dependency on temperature. Also, the machine temperature is crucial to maintain the lifetime of the machine. So, the coupled analysis is mandatory to achieve the nowadays requirements of higher energy efficiency and power density and cost reduction. Also, the coupled analysis enables optimization without the need to build several prototypes, making this process more time and cost-efficiency. Despite the temperature importance in electric machines, the thermal model was overlooked over the years. However, it has been receiving more attention in the past years. In this work, the thermal modelling process is handled analytically and numerically through finite element analysis (FEA), which is also used to obtain the electromagnetic model. The modelling processes detailed during this work are applied into a case study of a single-phase transformer with the rated power of 1 kW. The numerical models were developed in the Ansys software suite, being the electromagnetic model developed in Ansys Maxwell while the thermal model has developed in Ansys Mechanical. At last, the coupling between the electromagnetic and thermal models was accomplished in Ansys Workbench. The results obtained from the models are compared and validated with the experimental measurements of the losses and temperatures.
- Coupled electromagnetic and thermal analysis of electric machinesPublication . Mendes, Gabriel Dias; Ferreira, Ângela P.; Miotto, EdneiThis paper deals with the design process of electric machines, proposing a design flowchart which couples the electromagnetic and thermal models of the machine, assisted by finite element techniques. The optimization of an electrical machine, in terms of the energy efficiency and cost reduction requirements, benefits from the coupling design of the electromagnetic and thermal models. It allows the maximization of the current density and, consequently, the torque/power density within thermal limits of the active materials. The proposed coupled electromagneticthermal analysis is demonstrated using a single-phase transformer of 1 kVA. Finite element analysis is carried out via ANSYS Workbench, using Maxwell 3D for the electromagnetic design, with resistive and iron losses directly coupled to a steady-state thermal simulation, in order to determine the temperature rise which, in turn, returns to electromagnetic model for material properties update.
- Extending the multiphysics modelling of electric machines in a digital twin conceptPublication . Mendes, Gabriel Dias; Ferreira, Ângela P.The digital twin is a trending technology that has been applied to different fields. In this work, the use of the digital twin of electric machines in a life cycle perspective is investigated. It presents a literature review of the main concepts and applications of the digital twin in the field. In addition, it discusses the methodological approach to obtain the digital twin of a static electric machine by using its multiphysics model in a reduced order model, to improve the maintenance scheme and estimate the lifetime of its insulation system based on the machine’s temperature profile.