Non-invasive rotor temperature detection of magnetically levitated turbo molecular pump based on high-frequency inductance

The rotor temperature has a significant effect on the reliable operation of the magnetically levitated turbo molecular pump (MLTMP). Therefore, it is crucial to monitor the rotor temperature during the operation of the MLTMP to prevent irreversible demagnetization of the permanent magnet and improve production efficiency. However, direct measurement of rotor temperature is a challenge due to the complexity of installing a temperature sensor on the high speed spindle. This paper presents a non-intrusive method for detecting rotor temperature based on high-frequency(HF) inductance estimation. On this basis, a novel method is proposed that injects a HF rotating voltage into the stationary coordinate frame and introduces synchronous demodulation to achieve accurate estimation of the HF inductance. Finally, the experimental results conducted on the MLTMP test bench indicate that the proposed method can effectively detect the rotor temperature, and the temperature error is within 3 ^∘C.