Magnetic bearing device and fluid mechanical system

A magnetic bearing device, comprising:

• a magnetic bearing including a plurality of electromagnets and configured to support a target member in a contactless manner using composite electromagnetic force of the plurality of electromagnets;
• a position sensor configured to output a detection signal having a signal level according to a position of the target member in a predetermined position detection direction;
• a controller having a first mode and a second mode and configured to acquire a reference value that correlates with a change in an input-output characteristic of the position sensor following a change in an ambient temperature of the position sensor;
• and
• a touchdown bearing configured to come into contact with the target member moving toward the magnetic bearing in a space between the plurality of electromagnets, thereby avoiding contact between the target member and the magnetic bearing, wherein
• the controller performs
• in the first mode, a movement control operation for controlling the composite electromagnetic force of the plurality of electromagnets such that the target member moves within a predetermined moving range in the predetermined position detection direction, and an information acquisition operation for acquiring temperature drift correlation information indicative of a correlation between the reference value and the input-output characteristic of the position sensor, based on the reference value and the input-output characteristic of the position sensor in the movement control operation, and
• in the second mode, a magnetic levitation control operation for controlling the composite electromagnetic force of the plurality of electromagnets in accordance with the signal level of the detection signal from the position sensor, and a temperature compensation operation for compensating the input-output characteristic of the position sensor in the magnetic levitation control operation, based on the temperature drift correlation information and the reference value in the magnetic levitation control operation, and
• the controller performs the movement control operation in the first mode such that the target member moves from one end to another end of a movable range in the position detection direction restricted by the touchdown bearing.