Design and optimisation of tubular linear motor (TLM) for oxygen concentrator device

Abstract

Patients with chronic respiratory conditions such as Chronic Obstructive Pulmonary Disease (COPD) receive long- term oxygen therapy (USOT) to sustain their lives [1],[2]. With the development of oxygen concentrator (OC) devices that can produce the concentrated oxygen required for USOT, COPD patients are required to use these devices for more than 12 hours daily depending on the prescription [3],[4]. OC are medical devices that separate oxygen from the atmosphere using physical means to produce concentrated gas for medical purposes [5],[6]. The use of conventional motors based on the permanent magnetic rotary motor operating principle in OC devices increases the mass of the device and the operating noise disturbs the patients [3],[4],[7]. In this study, with the advances in magnet material, a tubular linear motor (TLM) structure with a strong, fixed coil moving permanent magnet, which is stronger than the linear motor used in many fields such as medical electronics, nanotechnology, defence industry, maglev trains, is designed and proposed for use in OK devices. It is difficult to optimise the TLM due to multiple design parameters and each parameter has a non- linear relationship with the static electromagnetic force. In this study, the thrust of the TLM is optimised by the finite element method (FEM) using the magnetic magnetostatic and transient solvers in Ansys Maxwell3D. Optimisation method based on FEM 3D model was used to optimise the design parameters. Comparing the pre- and post-optimisation of the TLM designed for use in the OC device, the thrust force was increased from 567.91 fN to 5.82 nN at the same working stroke distance.