DRIVE UNIT FOR BRUSHLESS MOTOR, METHOD FOR STARTING BRUSHLESS MOTOR, DRIVE UNIT FOR BRUSHLESS FAN MOTOR, AND METHOD FOR STARTING BRUSHLESS FAN MOTOR

摘要

PROBLEM TO BE SOLVED: To provide a drive unit for a brushless motor that makes a motor start with a simple method and in short time so as to obtain large torque when starting.SOLUTION: When a brushless motor is started, if a stopping position of a rotor is detected between a time t1 and a time t2, a start excitation pattern according to the stopping position of the rotor is input only for an initial energizing period Ts1. Then, when energization is stopped, a plurality of signals SL1, SL2, SL3, and SL4 are sequentially generated in an excitation switching timing signal, according to a rotational position of the rotor during free running. A rotor position is detected by using the second and subsequent signals SL2 to SL4 from among the signals SL1 to SL4, and control is migrated to normal energization switching control.