| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotor starting method of a brushless DC motor capable of stably starting a rotor from a stopped state to a desired rotation speed range without using a sensor, and a system.SOLUTION: A predetermined pulse train P(k) is applied between coils of a stator 1a, and phase current values flowing between the coils are successively fetched. A maximum phase current value (Ip) with which a phase current value becomes maximum among fetched phase currents, a reference phase current value (Ir) in the case where a specific number of pulses are applied, and a final phase current value (Ie) in the case where a final pulse is applied, are calculated, respectively. Next, a post peak time (Tpp) is calculated that is a time width from a time T(k)_p relating to the maximum phase current value (Ip) to a time T(k)_e relating to the final pulse. Next, on the basis of the post peak time (Tpp), a pulse train application time (&Dgr;T(k)), the maximum phase current value (Ip), the reference phase current value (Ir) and the final phase current value (Ie), it is decided whether excitation switch timing between stator coils relative to rotation of a rotor 1b is suitable.SELECTED DRAWING: Figure 4 |
