Research on temperature compensation of displacement sensors integrated with phase change materials

Abstract Linear variable differential transformers (LVDTs) serve as essential displacement transducers in high-precision nano-metrology, due to their intrinsic high accuracy and excellent linearity, leading to their widespread adoption in precision measurement systems. However, the temperature sensitivity of coil resistance and the thermal expansion of mechanical structures induced by environmental temperature variations can lead to nonlinear thermal drift, thereby affecting long-term measurement stability. To address this issue, this work proposes an embedded dual-layer phase change material (PCM) thermal regulation structure inspired by thermal management strategies in miniature electronic devices, and integrates it into the coil bobbin. By employing a cascaded PCM configuration with different melting points, sequential latent-heat absorption is achieved, thereby extending the effective thermal regulation window and enabling spatially graded thermal stabilization. Microencapsulated paraffin is further adopted to ensure material compatibility and to prevent leakage. COMSOL Multiphysics simulations show that the proposed structure reduces the coil temperature rise by 16.8 ∘ C under representative thermal load conditions, and decreases the simulated temperature drift rate from 0.3927 %FS/ ∘ C to 0.1544 %FS/ ∘ C, corresponding to an improvement of approximately 60.7%. Temperature-controlled experimental verification shows consistent results, with the coil temperature rise reduced by about 36.6% and the drift rate reduced from 0.81 %FS/ ∘ C to 0.39 %FS/ ∘ C. These results indicate that the cascaded PCM thermal regulation structure can continuously suppress temperature-induced measurement deviations without requiring additional compensation circuitry or software algorithms, providing a passive and easily integrable approach for enhancing the thermal stability and measurement reliability of LVDTs under sustained thermal loads.