This paper investigates the design of an Eddy Current Sensor (ECS) for position measurement of a moving conductive target located behind a fixed conductive shielding surface. Such a sensor can e.g. be used in completely sealed actuators with magnetically levitated rotor or mover for high purity applications. Starting from the analysis of the sensor’s operating principle, the design of the excitation coil, the achievable sensitivity and bandwidth as well as the temperature stability of the sensor are investigated. Subsequently, a suitable sensor interface, consisting of the driving and signal conditioning electronics, is selected. With this it is possible to distinguish between position and temperature variations, for which the optimal operational frequencies are identified. The results are finally verified with measurements on a hardware sensor prototype, showing that the ECS can achieve a sensitivity of 1 mV/µm, a position resolution of 1 µm, with a measurement bandwidth of 30 kHz and can hence be used to capture the mover’s position in an active magnetic bearing feedback control structure.

中文翻译：

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具有温度漂移校正的基于高动态涡流的密封磁力轴承位置测量 - “透视导电壁”

本文研究了涡流传感器 (ECS) 的设计，用于对位于固定导电屏蔽表面后面的移动导电目标进行位置测量。这种传感器可以例如用在具有磁悬浮转子或动子的完全密封的致动器中，以用于高纯度应用。从传感器工作原理分析入手，研究了励磁线圈的设计、可实现的灵敏度和带宽以及传感器的温度稳定性。随后，选择合适的传感器接口，包括驱动和信号调节电子设备。这样就可以区分位置和温度变化，从而确定最佳操作频率。