Thermal Analysis and Experimental Validation of a 30 kW 60000 r/min High-Speed Permanent Magnet Motor With Magnetic Bearings

Baotian Dong,Bangcheng Han,Kun Wang,Shiqiang Zheng

doi:10.1109/access.2019.2927464

Abstract

Thermal analysis calculation is an indispensable checking process in the design of the high-speed permanent magnet synchronous machine (HSPMSM) with the active magnetic bearings, due to its high loss density and non-contact support mode. The finite element method (FEM) is applied for visual global temperature distribution. Because the thermal analysis is a complex problem reflected the interaction among the electromagnetic field, temperature field, and fluid field, so it cannot be solved independently, and a multi-physical field simulation based on magneto-thermal-fluid coupled iterative solution is proposed. An electromagnetism (EM) model is established to solve electromagnetic loss and the computational fluid dynamics (CFD) software is used to simulate convective condition, both the results are applied to the thermal analysis of motor. The data interaction is bidirectional and transfers in the form of a field, and the interaction during the EM model, the CFD model, and thermal analysis is fully considered to guarantee high accuracy. Finally, two prototypes of 30-kW 60000 r/min magnetically suspended HSPMSMs have been developed. The experimental results of back-to-back towing test validate the accuracy of the proposed multi-physical field simulation.

Highlights

High-speed permanent magnet synchronous machines (HSPMSMs) have attracted much attention due to their compact size for direct-drive applications
High speed and high frequency will lead to high wind friction loss and high eddy current loss on the rotor, and the rotor is supported by active magnetic bearings (AMBs) with non-contact, hard to dissipate heat through heat conduction [7], [8]
Where nx, ny and nz are normal vectors, h is the convection heat transfer coefficient (CHTC) on the interface, Tw is the temperature on the solid side, and Tf is the temperature of the fluid

Summary

INTRODUCTION

High-speed permanent magnet synchronous machines (HSPMSMs) have attracted much attention due to their compact size for direct-drive applications. Accurate simulation method of the temperature field is related to the accurate electromagnetic loss estimation and cooling medium characteristic analysis. B. Dong et al.: Thermal Analysis and Experimental Validation of a 30 kW 60000 r/min High-Speed Permanent Magnet Motor. The electromagnetic loss and convection heat transfer coefficient (CHTC) are obtained by simplified mathematical models with empirical formulas and are assigned to these nodes as uniform values [10], [11]. Most CFD software has integrated the thermal solver and realizes the fluid-solid coupling technique to solve the temperature field of motor. In which the CHTC is not as a uniform value, but a data field to be submitted to the thermal calculation, the interaction between fluid temperature and motor temperature is considered [23]–[25]. The experimental data are compared with simulation results to verify the correctness of the proposed method

METHODOLOGY

EXPERIMENTAL VALIDATION

Findings

CONCLUSIONS