| 摘要 |
Disclosed is a magnetic bearing system for use in a vacuum pump including a rotor provided with a rotary blade. The magnetic bearing system comprises a rotary shaft rotationally holding the rotor, a motor for rotationally driving the rotary shaft, a magnetic levitation section for supporting the rotor relative to a stator through the rotary shaft in a non-contact manner, a rotation detection section for detecting a magnetic pole position of the motor, a rotor-temperature detection section for detecting a temperature of the rotor, a carrier-wave generation section for supplying a common carrier wave to each of a plurality of sensors provided in the magnetic levitation section, the rotation detection section and the rotor-temperature detection section, and an A/D conversion section for sampling a sensor signal output from each of the sensors, in synchronization with the carrier wave. Each of the sensors provided in the magnetic levitation section, the rotation detection section and the rotor-temperature detection section is operable to fix a relative phase relationship between respective AM modulated waves. i.e., sensor signals output from the sensors by receiving the carrier wave generated by the carrier-wave generation section
|
