Inductive Displacement Sensors Based on the Integrated Demodulation Chip

As an important component of a high-speed active magnetic bearing (AMB) system, a non-contact displacement sensor has important impacts on the overall performance of the system. A traditional inductive displacement sensor signal demodulation circuit which is composed of discrete components, has a high cost and a large space occupation. In order to develop a low-cost, high-integrated demodulation design of an inductive displacement sensor, this paper took the integrated synchronous demodulation chip as the core, performed tasks including the hardware design and manufacturing, software development and circuit debugging, built a test platform of the inductive displacement sensor and finished evaluation experiments for the integrated synchronous demodulation design. The experimental results shown that the linearity between the synchronous demodulation chip output signal and rotor displacement was 2.187%, the sensitivity was 2.9185 V/mm, the minimum resolution was up to 1 μm, and it could meet the displacement detection requirements of general AMB systems.