Drive voltage from outside it is based on the timing in the turning lead angle which is configurated beforehand according to the rotor

摘要

PROBLEM TO BE SOLVED: To provide a commutation control method for brushless direct-current motors, wherein the characteristics such as efficiency of a motor can be improved substantially, without changing the characteristics of the torque/rotational speed from optimal operating points.;SOLUTION: The control method comprises first to third stages. In a first stage, a first drive voltage is externally supplied with the timing of a preset first commutation angle of lead, to drive and bring the motor into a first drive state (S1), and a first rotational speed is detected (S2). In a second stage, the timing of supply of the first driving voltage is changed to that of a preset second commutation angle of lead, to change the first driving state into a second driving state (S3), and a second rotational speed is detected (S4). Then first and second rotational speeds are compared with each other (S5) (S7). If the result of comparison shows that the first and second rotational speeds are different, in a third stage, the first driving voltage is changed to a second drive voltage so that the second rotational speed coincides with the first rotational speed (S6) (S8).;COPYRIGHT: (C)2005,JPO&NCIPI