| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress the influence of noise on execution of the positional detection of a rotor while enabling the positional detection of the rotor regardless of a pulse width modulation signal, relating to the drive unit for a brushless motor. <P>SOLUTION: The drive unit for a brushless motor, which localizes the rotor position, based on an induced voltage generated in each phase of stator coil, detects the terminal voltage of each phase of stator coil, and compares the detected terminal voltage with reference voltage so as to determine whether a state that the terminal voltage is not less than the reference voltage continues for a specified time or not. Then, in case that it determines that the state has continued for a specified time, it detects the neutral point of the induced voltage that becomes the reference to localize the rotor position, thereby localizing the rotor position. Moreover, it changes the specified time, according to the duty ratio of a pulse width modulation signal for controlling the current application to each phase of stator coil. <P>COPYRIGHT: (C)2010,JPO&INPIT |
