Analyses of the coupling effects between passive pressure-limiting and dynamic response in a magnetically levitated direct-drive oil-free scroll compressor

Conventional oil-free scroll compressors face a fundamental limitation in achieving true oil-free operation due to their reliance on anti-rotation mechanisms and other contacting components, which introduce wear and require lubrication. This study presents a magnetically levitated direct-drive oil-free scroll compressor that eliminates these frictional sources by removing the anti-rotation mechanism altogether. While this enables a pathway to genuine oil-free operation, the resulting architecture introduces critical challenges in pressure regulation and stability under dynamic gas loads. To address these, a passive permanent magnet adaptive mechanism is introduced for axial support and overpressure protection. A high-fidelity gas force model, incorporating tangential leakage effects, is developed, correcting overestimations inherent in conventional models. Multiphysics simulations demonstrate the mechanism’s dual functionality: vibration suppression and passive pressure self-limitation, with the system re-stabilizing within 0.9 s after an exhaust blockage. Experiments confirm robust trajectory tracking from 300 to 1200 rpm under varying discharge pressures, with a maximum error of 0.09 mm. Furthermore, gas force measurements provide strong validation for the leakage-induced dynamic trends predicted by the model. This work comprehensively verifies the compressor’s dynamic performance and intrinsic safety, thereby demonstrating the viability of this approach for building robust, truly oil-free compression systems.