Miniaturization Research Of Linear Variable Differential Transformer For Cryocooler

Linear variable differential transformers(LVDT) have many advantages, so they are widely applied to measure piston’s displacement in cryocooler system. Nowadays, as the requirements of cryocooler’s size and control system are higher and higher, it is more important to develop the LVDT with small size and high precision for different cryocoolers. Computer Aided Design(CAD)has been a mature technology, and the finite element simulation software has been used in the design stage of various industries. The purpose of our study was to research the influence factors of LVDT’s performance, and apply the simulation results to optimize and design LVDT, and rapidly work out the proper LVDT for different requirements, at last, realize the miniaturization of LVDT.In this paper, we firstly analyzed the working principle of LVDT using the equivalent circuit, from the aspects of circuit, the relationship between the induced voltage and excitation was given out. Base on the acknowledge of electromagnetics, Ampere circuital theorem was applied to analyze the magnetic-filed distribution and magnetic paths of the LVDT, and we worked out the mathematical expression of the output voltage of LVDT, the expression gives out the relationships between the induced voltage and electrical and structural parameters.The design theory and characteristics of LVDT was discussed. Electromagnetic finite element simulation software was used in this study, the procedures of building the model and simulation analysis were introduced, the magnetic-filed distribution and induced voltage curve were presented, the simulation results verified the theoretical analysis. Static characteristic experiments and relevant simulations were carried out for the three-section LVDT.As the simulation model was parameterized, the parameters influence on the LVDT’s performance was analyzed. The simulation model was applied to optimize the initial design parameters, two-section LVDT was designed. Experiments was carried out with the prototypes, the reason of the deviation between simulation and experiment was analyzed. According to the experiment results, the parameters were optimized again, the bobbin structure was also improved.Deviation was existed between experiment results and simulation results, and the deviation was mainly caused by shortage of manufacture technology. Taking many factors into consideration, to some extent, the simulation results can reflect the characteristics of the real product. The results of the study have proved the feasibility of simulation aided design. The model and method of the simulation can be applied into the studies and design of the LVDT. The results of the study are full of guiding significance to the optimization and design of LVDT.