| 摘要 |
PROBLEM TO BE SOLVED: To prevent a power supply device and a DC motor from being damaged by preventing overcurrent, when changing the speed command of the DC motor in which a blower is used as a load. SOLUTION: The feedback system of current detection is constituted of a power control part 2 for controlling current which is supplied to a DC motor 3, a current detector for detecting current flowing to the DC motor, and a first error amplifier 7 for amplifying the error between a current detection signal and a command signal for commanding the current which flows to the DC motor 3. Also, the feedback system of speed detection is constituted of a speed detector 11 for detecting the speed of the feedback system for detecting a current in the above and the speed to the DC motor 3 and a second error amplifier 14 for amplifying the error between a speed detection signal and a speed command signal for instructing the speed of the DC motor 3. Furthermore, current limiter 20 that is limited by a current that uses the speed detection signal as input and is limited by the current that is larger than that of the speed command signal, an OR circuit 16 that selects the output signal of the second error amplifier 14, and the output signal of the current limiter and obtains the current command signal are provided. |
