Analysis of Electromagnetic Characteristics of Novel Tubular Permanent Magnet Brushless DC Linear Motor for Medical Equipment

Guiyang Xu and Jianxin Zheng


Electromagnetic property, linear motor, tubular brushless DC motor, novel structure


The cogging force and end force of the permanent magnet (PM) brushless DC linear motor are the main factors that generate magnetic drag force. The generation of magnetic drag force can lead to the occurrence of thrust fluctuations, and large thrust fluctuations can cause vibration and noise characteristics of the linear motor, hindering its development and application. Therefore, the novel tubular PM brushless DC linear motor is proposed, by adding additional magnetic guide ring at the end of the PM, the magnetic path of the motor is improved, increasing the output thrust of the motor while reducing thrust fluctuations, which can be better applied to medical machinery equipment. Firstly, the topology and basic working principle of the tubular PM brushless DC linear motor are investigated, then the electromagnetic characteristics of the PM brushless DC linear motor are analysed, such as air-gap magnetic density, flux linkage, winding current, rated output thrust, etc. Finally, the prototype and comprehensive testing platform are established, the thrust value is measured, and compared with the finite element simulation values, the rationality of the tubular PM brushless DC linear motor is verified by finite element method calculation and test.

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