Permanent Magnets for High-Speed Generators

Renewable energy technology is steadily gaining importance in the energy market because of the limited nature of fossil fuels, as well as the political pressures to reduce carbon emissions. To ensure sustainable development, adequate and affordable energy should be made available to satisfy the demand of electric energy. The University of Cape Town (UCT) collaborated with the International Research Institute Stavanger, Vrije Universiteit Brussel, Faith University, and Ain Shames University to develop a scaled down prototype of an advanced power generation system with minimum carbon emission. The upscaled model would be decentralized with a target plantsizeof10 MW to serve a small industrial community with drinking water production of 1000 m3/d. UCT was tasked with the design and development of the High Speed Permanent Magnet (HSPM) Generator subsystem, in collaboration with the UCT Electrical/Mechanical Engineering Department, to be coupled to a micro-gas turbine with a blended fuel mix which includes hydrogen, biogas and biodiesel. The main specifications of the HSPM generator are a rated speed of 30000 RPM and a power output of 10 kW. However, HSPM generators produce substantial heat especially at high operating speeds and make the thermal management of these machines difficult and complicated resulting in temperature rise which leads to demagnetization, damaged insulation, bearing starvation and reduced power output and efficiency. This book presents the design and development of the HSPM generator and focuses on both the mechanical and electrical aspects for the Interior Permanent Magnet (IPM) and Surfaced-Mounted Permanent Magnet (SPM) topologies of the HSPM generator. In particular, it is the effect of coolant velocity to enhance the HSPM generator efficiency that makes it the subject of this research.