Thermofluidic analysis of interior permanent magnet synchronous motors with internal air circulation by protrusion-shaped flow inducers for effective thermal management

Abstract

A three-dimensional thermofluidic model was developed for simulating fluid flow and heat transfer in interior permanent magnet synchronous motors (IPMSMs) with internal air circulation for effective thermal management. Protrusion-shaped flow inducers were introduced to facilitate the internal air circulation through rotor ventilation holes, increasing convection and preventing temperature rises in primary motor components. The numerical model agreed well with the experimental data. Subsequently, various geometrical design variables of the protrusion were selected to determine the thermofluidic characteristics of the electric motor associated with local temperature distributions for critical motor components. The protrusion increased the mass flow into the ventilation holes; accordingly, the maximal rotor temperature was inversely proportional to the protrusion design. Additionally, a thin airgap between the stator and rotor affected the radial heat transfer rate by forming additional thermal resistance layers. This flow was modeled using the Taylor-Couette paradigm, with the relative error under 1 %.