| 摘要 |
PROBLEM TO BE SOLVED: To stabilize operation for stable start and rapid acceleration/ deceleration for coping with disturbance by providing a rapid change prevention means by suppressing the change rate of the output of a signal selection means to a specific value or less as the duty of PWM. SOLUTION: For example, phase comparison 30 compares the phases of a position detection signal and a synchronization signal 23 and outputs the phase difference between them. At this time, the phase of the synchronization signal is constantly delayed from the position signal, and a phase controller 31 reduces the command value of the output, namely duty, so that the phase delay is equal to or less than a specific value. Rapid change prevention 32 transmits an input signal to output by suppressing the change rate to a specific value or less. When the phase controller 31 lowers the command value of the duty, the armature current of a motor 10 decreases. Since the amount of decrease in a torque due to the decrease in current is compensated for, the phase difference decreases. Operation switching 24 detects that the phase difference is equal to or less than a certain amount, outputs a switching signal to sensorless drive, and switches from synchronization operation to sensorless drive. |
