| 摘要 |
PURPOSE:To prevent an inverter power converter from damaging and the perma nent magnet of a rotor from demagnetizing by setting the maximum value of a rotating speed change rate per unit time of the rotor, comparing the change rate of the actual rotating speed with the set value, and stopping in emergency a motor in case of its malfunction. CONSTITUTION:A position detection signal discriminator 10 inputs the real rotating speed N of a rotor 5a from a microcomputer (muc) 7, further inputs position detection signals (a), (b), (c) from a counterelectromotive force position detector 6, determines whether the detection of the maximum change rate (dN/ dt)max of the rotating speed per unit time of the rotor having a minimum inertial moment, set therein from the detector 6 is according to an erroneous detection due to a noise or the like or not, and outputs an emergency stop command to the muc 7 as an erroneous detection determination signal E. The muc 7 stops a base driver 9 and an inverter 4 with the command. Thus, it can prevent Tr1-Tr6 from damaging and the rotor 5a from demagnetizing. |
