| 摘要 |
PURPOSE:To prevent transient vibration or sustaining vibration by employing a CPU for operating speed data and position data of the rotor of synchronous motor, a value obtained through A/D conversion of the input current to the motor, and a speed command signal. CONSTITUTION:A CPU 15 rotates a synchronous motor M1 through an inverter 13 based on a speed command fed from a host CPU 9. Two-phase square wave signals A, B of an incremental rotary encoder 2 coupled with the M1 are fed to a counter circuit 3 in order to obtain the speed of the rotor of the M1. An absolute rotary converter 4 determines the position of the rotor of the M1 based on the three-phase outputs. If the difference between the maximum positive and negative values of sine wave currents detected through CTs 5, 6 increases when a speed feedback value fed from the counter circuit 3 matches with the natural vibration frequency band of a mechanism system coupled with the M1, the CPU 15 makes a decision that vibration occurred and then decreases the speed command value. Consequently, transient vibration or sustaining vibration is prevented. |
