| 摘要 |
PROBLEM TO BE SOLVED: To shorten the initial arriving time in the initial stage of the frequency locking process by controlling velocity vibration (frequency vibration) in a motor speed controller using in common the PLL control and FG servo. SOLUTION: In a motor speed controller, a control signal correction circuit 10 generates a correction phase control signal APC' by monitoring transition of voltages of a frequency control signal AFC and phase control signal APC. Upon start of motor operation, a locking process detecting circuit 11 detects it, a movable contact of an analog switch 17 is switched to fix a correction phase control signal APC' to a target voltage value ϕVS (=VCC/2). Therefore, even when a phase difference is circulated, the phase difference control signal of the resultant sawtooth wave is not applied to a mixing circuit 7 but since the fixed target voltage value ϕVS is applied thereto, vibration of frequency (velocity) can be controlled and the time required for arriving at the target frequency (initial arriving time) can be shortened in the frequency locking process. |
