In the brushless DC motor control system, the commutation of the motor is determined by the position of the rotor, so a rotor position sensor must be used to detect the rotor position in real time. There are many rotor position sensors that are actually available. Permanent magnet synchronous motors driven by sine waves generally use rotary transformers and photoelectric pulse encoders as position detectors, which require continuous detection of the rotor position, requiring high resolution and high cost. In the rectangular wave driven brushless DC motor, only discrete rotor position information is needed, that is, a limited number of commutation point moments. For example, in the commonly used three-phase six-state working mode, only six commutation points need to be determined for a pair of poles. Just click on the moment. Therefore, a simple position detector can be used. The resolution requirement for detecting the rotor position is much lower, so the cost is also lower.

Working principle of brushless DC motor rotor position sensor

The position sensor is one of the components of the brushless DC motor system. Its function is to detect the relative position of the main rotor to the stator winding during movement, convert the position signal of the permanent magnet rotor magnetic field into an electrical signal, and provide the correct signal for the logic switch circuit. Commutation information is used to control their on and off, so that the current in the motor armature winding commutates in sequence as the rotor position changes, forming a step-by-step rotating magnetic field in the air gap to drive the permanent magnet rotor continuously rotate.

The above is all the characteristics and working principles of the brushless DC motor rotor position sensor. Xinda Motor focuses on the global industrial automation field and is committed to high-performance, high-quality brushless DC motors, the R&D and production of stepper motors and supporting drive controllers, and is a leading high-tech enterprise in China providing motion control technology solutions.