Abstract
This dissertation presents the comprehensive development and multiphysics analysis of a tubular permanent magnet linear generator (TPMLG) specifically engineered for compressed air energy storage (CAES) applications. The primary objective was to determine whether a parametrically tuneable TPMLG could deliver the requisite force (12 kN average), voltage and power under the reciprocating motion characteristic of a three-stage CAES system. Current literature lacks comprehensive multiphysics analyses of Tubular Permanent Magnet Linear Generators (TPMLGs) specifically optimized for the high-force requirements of small-scale Compressed Air Energy Storage systems. This study addresses this gap by presenting validated simulations that demonstrate a peak thrust of 15–21 kN, balanced three‑phase currents of ±40–45 A, and EMF peaks of approximately 10–11 kV.
A full digital workflow was established, integrating 3D geometry creation in SolidWorks with high-fidelity finite element analysis in JMAG Designer for quasi-static and transient electromagnetic studies, complemented by CST Studio Suite for rapid 3D variant exploration. A MATLAB/Simulink co-simulation interface was developed to drive stroke-controlled motion and capture dynamic performance metrics, including phase currents, induced voltages, magnetic field quantities and thrust forces.
The baseline machine employs high-energy NdFeB N48 magnets in an axial arrangement and laminated electrical steel, operating with a dual-chamber motion law (±30 mm, 60 mm total stroke) and three-phase windings. Parametric studies investigated the influence of magnet thickness and spacing, tooth and yoke dimensions and air-gap quality. Simulation results consistently demonstrated balanced three-phase currents (≈ ±40-45 A), induced phase voltages in the kilovolt range commensurate with the selected turns and operational frequency, and thrust forces peaking between 15-21 kN, correlating with maximum translator velocity. Magnetic field solutions revealed flux density concentrated in stator teeth and the air gap, with local peaks consistent with material saturation limits, while current density and surface force distributions confirmed the expected electromagnetic coupling.
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The study conclusively demonstrates that a TPMLG, sized and optimised via the presented workflow, is capable of meeting the demanding electromechanical requirements of a CAES system. The dissertation contributes a traceable modelling framework, validated simulation outcomes and practical design guidance. Key recommendations are offered for critical areas such as magnet and tooth sizing, air-gap control, thermal management and the implementation of controller-in-the-loop testing, thereby de-risking future TPMLG prototyping and integration for advanced energy storage solutions.