| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent noises generated when the rotational direction of a motor driven through an H-bridge circuit is switched from occurring without making the control of a switching element more complicated. <P>SOLUTION: As shown in Figure (A), the fourth switching element 45d of the H-bridge circuit 41 is PWM-controlled, and the first switching element 45a is ON-controlled to drive the motor M in one direction. In a transition stage after the switching of the rotational direction of the motor M is indicated, as shown in Figure (C), the second switching element 45b located in a circuit in which the regeneration current of the motor M flows is PWM-controlled by setting a duty initial vale in response to the rotational number of the motor M, and the other third switching element 45a is ON-controlled to drive the motor M in the other direction. Thus, the regeneration current generated by the motor M which tries to rotate in the old direction by inertia when the rotational direction is switched is canceled by the duty initial value, and the switching of the rotational direction of the motor M is smoothly performed, and the generation of noises can be prevented from occurring. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
