| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic bearing device that can obtain magnetic levitation information with almost no influence of spike noise.SOLUTION: A magnetic bearing device comprises: a plurality of excitation amplifiers for supplying an electromagnet current with a sensor carrier signal superposed thereon to each of the magnet bearing electromagnets; and a control unit for acquiring magnetic levitation information by AD sampling of a sum signal formed by adding current detection signals from a plurality of current sensors and a pair of current detection signals relating to a pair of magnet bearing electromagnets, and for performing PWM control of the excitation amplifiers based on the magnetic levitation information. The device performs PWM control so that a length of on-duty section Ton of the PWM carrier signal always gets longer than a predetermined time width Td. Accordingly, the magnetic levitation information with almost no influence of spike noise can be acquired by performing the AD sampling after the predetermined time Td elapses from the initiation timing of the on-duty section Ton. |
