| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive device for a vacuum pump, capable of reducing a harmonic component of motor current. <P>SOLUTION: The motor drive device for a turbo molecular pump that performs exhaust by rotatingly driving a rotor part formed with a rotating blade and a screw rotor as an exhaust function part by a motor includes: an inverter 43 that drives the motor; a DC-DC converter 41 as a DC voltage source having a different plural setting voltages for an inverter input voltage of the inverter 43; and a motor control circuit 44 as voltage switching means that switches a setting voltage of the DC-DC converter 41 according to motor load information. The motor control circuit 44 is configured to PWM control the inverter 43 by setting a duty ratio of a PWM signal so that the rotational speed of the motor is maintained at a predetermined target rotational speed. <P>COPYRIGHT: (C)2012,JPO&INPIT |
