An Effective Cooling System for High Torque Electric Motors Using Microchannels and Two-phase Coolants

Adjustable speed motor drives are an integral part of power-train in electrified vehicles. There is a growing need for an increase in torque and power density in electric propulsion motors and their accompanying power converters. In order to achieve this in motors, an effective method for cooling of stator windings is necessary. Conventional cooling systems usually suffer from long thermal time constants in transferring heat, complex arrangements for removal of heat from the windings leading to reduction of filling factor and added volume and material. To address these shortcomings, an effective cooling system for stator windings of adjustable speed ac drives is proposed. This solution uses two-phase coolant materials and an embedded set of micro-channels within the end windings for effective transfer of heat. The proposed design allows for effective usage of slot area for placement of the windings at a very high filling factor (75%) with high current density (up to 24 A/mm
²
). The integrated cooling and end-windings are separately designed and developed thereby, enabling a modular assembly for the machine. This modular design renders unparalleled simplicities for repair and recycling of the motor.