The invention relates to a control device for a brushless
direct current motor sensorless based on 12-beat control and a method thereof. The device comprises a
direct current power supply, a three-phase
inverter, a brushless
direct current motor, a drive circuit of a power device of the three-phase
inverter, a
microcontroller and a rotor position detection circuit, wherein the direct current power supply is connected with the brushless direct current motor through the three-phase
inverter; after the rotor position detection circuit is connected with the brushless direct current motor for detecting, an output
signal is directly connected with an analog-to-
digital conversion input pin of the
microcontroller; and six-path output of the
microcontroller is connected to the three-phase inverter through the drive circuit of the power device of the three-phase inverter. The method detects
terminal voltage of an
inactive phase winding in a two-
pipe conducting region at PWM conducted moment by an analog-to-
digital conversion unit embedded in an XC866 singlechip, and acquires back
electromotive force zero crossing as accordance of 12-beat
phase conversion, thereby reducing the requirement of the adopted control device of the brushless direct current motor sensorless on a
peripheral circuit, and achieving the aims of not only effectively inhibiting
electromagnetic torque pulsation, but also reducing the
system cost.