Structure of brushless DC motor

In order to reduce the moment of inertia, the brushless DC motor usually adopts a "slender" structure. The brushless DC motor is much smaller in weight and volume than the brushed DC motor, and the corresponding moment of inertia can be reduced by about 40%-50%. Due to the processing of permanent magnet materials, the general capacity of brushless DC motors is below 100kW.

This kind of motor has good linearity of mechanical characteristics and adjustment characteristics, wide speed regulation range, long life, easy maintenance, low noise, and there is no series of problems caused by brushes, so this kind of motor has a great role in the control system. application potential.

The stator winding of the motor is mostly made into a three-phase symmetrical star connection, which is very similar to the three-phase asynchronous motor. A magnetized permanent magnet is attached to the rotor of the motor. In order to detect the polarity of the rotor of the motor, a position sensor is installed in the motor. The driver is composed of power electronic devices and integrated circuits. Its functions are: accept the start, stop and braking signals of the motor to control the start, stop and braking of the motor; accept the position sensor signal and the forward and reverse signals to control the reverse. Change the on-off of each power tube of the bridge to generate continuous torque; accept speed commands and speed feedback signals to control and adjust the speed; provide protection and display, etc.