**Research on PWM modulation mode of permanent magnet brushless DC motor**

Permanent magnet PWM modulation mode of Brushless DC motor of Fei Yuan Li Langru (voice of realgar conclusion of Huazhong University of Science and Technology, Hubei Wuhan flow fluctuation minimum, minimum torque ripple. A method of energy feedback braking is put forward to realize the energy feedback when the motor is braking.

1 brushless DC motor model 2PWM modulation on the impact of current, permanent magnet brushless DC motor in ignoring the convex pole effect, the stator three-phase winding inductance and mutual inductance is constant, independent of rotor position. At this time, GND potential, set up by the following variables: model of three-phase stator permanent magnet brushless DC motor using 120* conduction mode, each cycle consists of 6 sectors, each sector accounted for 60* of each switch element is turned on 120* in the two sectors in the continuous conduction, a total of 3 different PWM modes: half bridge, half bridge carrier carrier and carrier to the whole bridge below the trapezoidal back electromotive force and the flat top width of 120* permanent magnet brushless motor as an example, to illustrate the influence of the carrier of armature current. The EMF waveform is shown. It is assumed that the motor is changed from 1-2 sector to 2-3 sector at the same time, and the analysis of B and C two-phase conduction is carried out within this interval.