Method for control starting of brushless dc motor

The present invention is a brushless direct current motor as a sensor-less control on the start-up, a brush to reduce the vibration and start-up failure rate is generated at the start so as to control an over-current is not generated at the initial startup phase of the less direct-current motor it is an object. The present invention to achieve this, by switching the current applied to the stator winding depending on the rotor position according to the method of controlling the startup of the brushless DC motor, performs a phase shift to force alignment of the rotor position, and after the conversion voltage is the by detecting the counter electromotive force from the terminal voltage determined whether the period for the counter electromotive force is increased, and the integration of the terminal voltage on the back surface section of the counter electromotive force increases that voltage is applied to a large moment than the result is a predetermined value on the not applied and determine a phase transition point, a period when the current is predetermined by the large moment than the predetermined value to the change time, and the counter electromotive force is detected from the terminal voltage based on the frequency of the voltage applied to the stator windings to stabilize the back electromotive force is lowered If the interval is to switch to the sensor-less operation mode.