| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a brushless motor having a smooth rotation and a low noise by reducing a calculating error of a rotational speed generated cur to an unevenness in mounting position of each Hall sensor. <P>SOLUTION: A method for calculating the rotational speed of the brushless motor comprises the steps of disposing a permanent magnet rotor at a stator having three-phase windings, generating a PWM signal in a PWM control circuit having a microcomputer M based on Hall sensor signals (Hu, Hv, Hw) by three Hall sensors, controlling an inverter according to the PWM signal, rotatably driving the motor, and calculating the rotational speed of the rotor by the microcomputer M based on a time interval of half a period or one period of the interval between the rise or fall edges of the pulse-like position sensor signal to be detected by each Hall sensor. <P>COPYRIGHT: (C)2003,JPO |
