| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve stable motor operation during forced synchronous commutation by maintaining a running state of a motor with the forced synchronous commutation for forcibly continuing commutation when a duty value of a PWM signal is small and the time required for the PWM signal to turn on is short, and by changing an inverter output voltage according to a state of an induced voltage phase to an inverter output voltage. <P>SOLUTION: The present invention comprises phase difference determination means 210 that keeps a rotor induced voltage phase to an output voltage at a predetermined phase and forced synchronous commutation control means 211 that outputs a commutation waveform preset at a predetermined frequency according to a target rotational speed of a brushless DC motor. When a PWM control duty value is smaller than a predetermined value, its operation is executed by the forced synchronous commutation and an output voltage is changed according to a changing state of a rotor phase, thus achieving stable motor operation. <P>COPYRIGHT: (C)2013,JPO&INPIT |
