| 摘要 |
PURPOSE: A method for judging overload of a brushless DC motor and a method for driving the brushless DC motor are provided to properly correspond to a BLDC overload operation mode by detecting a free wheeling time through a control part without using an additional load sensing device. CONSTITUTION: VEv, UEu and WEw are applied to each terminal. A control part detects a back electromotive force and a free wheeling time with respect to a free wheeling current generated from the phase(S41). It is judged if the free wheeling time is passed through the control part(S42). In the affirmative, an overload correspondence operation mode is operated(S44). In the negative, a normal operation mode is operated(S43). If the overload operation mode is continued, the free wheeling time is detected once again(S45). It is judged if the first predetermined time(t2) and the second predetermined time(t2) of the free wheeling time are passed(S46,S47). If the first and second predetermined times are passed, a motor is stopped instantly(S48).
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