On the Effects of Advanced End-Winding Cooling on the Design and Performance of Electrical Machines

High performance and reliable electrical machines are often required in modern applications and an appropriate thermal management allows to fulfil such demand. Thermal management is crucial for improving performance, reducing size and preserving the insulation lifetime of electrical machines. From this prospective, a novel cooling method for machine end-windings is proposed in the present work. Its cooling action focuses on the end-windings, since they are commonly identified as the machine hot-spot. The effectiveness of the proposed cooling method is experimentally proved and the improvement, in terms of current density, for a given wire insulation thermal class, is quantified. A previously designed permanent magnet synchronous machine, implementing a traditional housing water jacket, is used as a case study. The influence of the improved current density on machine torque density is investigated, through finite element simulations, when the proposed cooling method is integrated to the existing housing water jacket.