Multiphysics Design of a V-Shape IPM Motor

Abstract

In this paper a multi-physics model is proposed for a multi-V-shape Interior Permanent Magnet (IPM) motor with concentrated winding. This work develops a non-linear magnetic model that computes the flux density in the motor. The analytical model includes several novel aspects: it takes into account the local saturation near the iron bridges, it proposes a method for modeling the concentrated tooth winding, it calculates the slot tangential leakage flux and includes it in the flux linkage calculation. The magnetic model is coupled with an electrical model that computes the power factor and the voltage at the motor terminals. A loss model is developed in order to calculate the copper and the iron losses. They are used as inputs to a nodal thermal model that introduces a thermal circuit for concentrated end-winding and computes the temperature of the motor. A mechanical model is developed. It evaluates the mechanical constraints encountered by the structure. The models are verified using finite element computations and numerical calculations performed with dedicated software. Besides, the coupled analytical model is experimentally validated using a prototype motor. Finally, two multi-physics bi-objective optimizations are carried out in order to design the motor for high torque and low speed application.

Axial Ferrite-Magnet-Assisted Synchronous Reluctance Motor

“…Then, a 2D saturated analytical modeling of the axial flux machine is proposed in order to compute the flux density in the different parts of the motor. The modeling method was presented in [6] and validated experimentally. It relies on Maxwell equations.…”

“…The mmf level of each tooth is given by the total current of the tooth coil. A linear variation of the mmf is considered in the slots [6]. The general scheme of the model that links the stator and the rotor, is given in Fig.…”

“…8) is determined by applying the flux conservation law to the tooth with a discretization of 1°elec. Under each tooth the flux density (B stag 0 ) is given by (6). The flux linkage density from both sides of the slots around the tooth B st ag−slot is given by (7)…”

“…This configuration is known as the Permanent Magnet Assisted Synchronous Reluctance Motor [3] - [5]. In previous work [6], we proposed to study an 18 slots and 16 poles radial flux motor with two V-shape barriers per pole filled with ferrite magnets with non-overlapping concentrated winding. A developed multiphysics model considering the electromagnetic, thermal and mechanical coupling was proposed and experimentally validated.…”

“…Secondly, an electromagnetic analytical model of the 2D linearized AFM is detailed. It is based on an earlier developed model for the radial flux machine [6]. The model takes into consideration the saturation in the rotor and the stator parts, the leakage flux in the slots and the local saturation in the areas next to the iron ribs.…”