Hall position sensor is one of the three major parts of the BLDC motor system, and it is also the main symbol different from the brushed DC motors. Its function is to detect the position of the main rotor in the process of motion. The position signals of rotor magnet poles are converted into electrical signals to provide correct commutation information for logic switching circuits to control their turn-on and cut-off. With the change of rotor position, the current in the armature winding of the motor is reversed in order to form a step-by-step rotating magnetic field in the air gap, which drives the permanent magnet rotor to rotate continuously.

When motor problems occur, we should check and solve them in time. The premise is that we have a certain understanding of the problems that may arise in the motor. The following ATO mainly introduces the method of noise treatment for brushless DC gear motor.

The basic model of BLDC motor drive circuit is shown in figure below. The energizing state of motor three-phase winding can be controlled by switching tube Q0~Q5. The switching tube can be IGBT or power MOS tube. Among them, the switch tube located at the top that is connected to the positive end of the power supply is called "upper bridge", and the switch tube located at the bottom that is connected to the negative end of the power supply is called "lower bridge".