The Effect of Coolant Velocity for Enhancing the High-Speed Permanent Magnet Generator Efficiency

Abstract

Abstract A High-Speed Permanent Magnet (HSPM) generator was designed and developed to deliver 10 kW output power at a speed of 30000 RPM. However, achieving a compact and efficient design with lower excitation losses, magnetizing currents and rotor losses remains as a daunting challenge. At high speeds these machines produce a substantial amount of heat which makes the thermal management of these machines difficult and complicated. This paper presents the design and development of the HSPM generator. The development of an adequate cooling system (cooling jacket) is also presented and enables the control of the temperature rise of the generator. A 3D steady state model of a 10-kW electric permanent magnet machine was generated and investigated with a cooling jacket layout. The numerical simulations on the effect of coolant flowrate for enhancing the HSPM generator efficiency was performed using ANSYS Fluent. Numerical analysis was performed with two different coolant flow rates, no flow and maximum flow (3.5 m3/h) with special emphasis on the maximum motor temperature. Maximum coolant flowrate conditions showed lower temperature generation throughout the generator compared to no coolant flowrate through the cooling jackets. The lower temperatures achieved, ensure that the magnets, winding insulation, and bearings are not affected by the heat generated.