Design optimization of an eddy current sensor using the finite-elements method

摘要

In the future increasingly more sensors will be used for the control of engines. To that purpose positions, velocities or accelerations of moving components will have to be monitored in very harsh environments. In our work an electromagnetic sensor based on the eddy current principle has been designed. Most of the simulations of the physical behavior were performed using the finite-elements program ANSYS. In a first step the sensor's geometry and its mounting position were adapted to the shape and motion of the component. To that purpose, a modal analysis of the part was performed. In a next step the sensor's function was evaluated and the sensitivity to be expected was computed. Furthermore the functional optimization yielded the optimum electrical parameters for the subsequent circuit design. In addition to these optimizations the finite elements software was also used for an improvement of the assembly and packaging technology. The most critical issue was the reliability under high temperature operating conditions. With the corresponding simulations different assembly solutions and packaging materials are evaluated. These include ceramic technologies (low temperature cofired ceramic) in comparison to conventional coil designs. On the specific example the paper outlines the prospects and requirements of hardware design for microsystems by consistent application of simulation techniques.