Thermal and Mechanical Design and Manufacturing of Electrically Excited Synchronous Machine for High-Speed applications

Abstract

Abstract This thesis delves into the operational dynamics of Electrically Excited Synchronous Machines (EESMs), which are increasingly favored in high-speed applications due to their controllable rotor flux characteristics. However, high-speed operation introduces significant challenges, including the cooling of the rotor and end windings, as well as ensuring the mechanical integrity of joints under substantial centrifugal forces. This study aims to thoroughly investigate various losses inherent in EESMs, namely copper losses, iron losses, and mechanical losses, alongside the design and optimization of a cooling circuit specifically for the end winding. A comprehensive analysis employing Computational Fluid Dynamics (CFD) simulations was undertaken to evaluate different duct designs for cooling efficiency. These simulations varied flow rates to determine the most effective duct design based on key parameters such as outlet velocity, flow rate, and the pressure head required for coolant pumping. Among the designs evaluated, an elliptical-shaped duct emerged as the most efficient, offering optimal cooling by balancing the flow rate and minimizing resistance, thereby enhancing the overall performance and reliability of EESMs in high-speed applications. This research not only contributes to the advancement of EESM technology but also provides a framework for future exploration in the optimization of cooling systems within high-speed electric machinery.