| 摘要 |
PROBLEM TO BE SOLVED: To provide a noise suppression method of a DC brushless motor by which the vibrations and noises at the time of motor driving can be suppressed. SOLUTION: A DC power supply 1 is connected to a stator 4 of a 3-phase DC brushless motor through a power supplying means consisting of semiconductor switching devices which are connected into a 3-phase bridge formation. A control circuit 5 calls and controls the transistors of which the power supplying means consists in a predetermined order, a rotor position detecting means 6 detects the rotation position of the permanent magnet rotor 2 of the brushless motor, and the control circuit 5 sets a timing when currents are applied to stator windings to control the current application to the stator windings. When a motor driving frequency is less than Hz1, the motor is driven by currents with the mutual phase angles of 120 deg.. When the motor driving frequency is not less than Hz1 and less than Hz2, the motor is driven by currents with the mutual phase angles of not less than 120 deg.. When the motor driving frequency is not less than Hz2, the motor is driven by currents with phase angles of 120 deg., With this constitution, the resonance with motor vibrations and the resonance with motor noises can be avoided. |
