| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a controlling means for direct-current brushless motors that can brake a rotor with low noise when a motor is being rotated by external force. <P>SOLUTION: A control unit for direct-current brushless motors includes: a direct-current brushless motor 1; a magnetic pole position sensor 2 that detects the magnetic pole position of the rotor of the direct-current brushless motor 1; an inverter circuit 3 in which multiple switching elements are bridge-connected in three phases and which converts direct-current voltage 4 into alternating-current voltage by opening/closing of the switching elements and supplies it to the direct-current brushless motor 1; a controlling means 5 that opens and closes the switching elements based on the output signals of the magnetic pole position sensor 2; a bus current detecting means 7; and a PWM output turn-off means 8 that turns off the PWM signals based on the output of the bus current detecting means 7. The duty of the PWM signal outputted by the controlling means 5 is finely adjusted. Thus, even when a fan is being rotated by external force, it can be braked and stopped with low noise without imposing an excessive burden on a drive circuit or the motor. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
