1. Position sensor circuit

　　From the working principle of the brushless DC motor, the rotor position information relative to the stator winding is required. The position sensor circuit provides excitation for the position sensor, such as providing low-voltage stabilized DC power supply for photoelectric sensors and Hall sensors, high-frequency AC excitation power supply for electromagnetic sensors, etc., and accepts, amplifies, and reshapes the output signal of the position sensor , Get the rectangular wave signal and send it to the control circuit. For the position sensorless control method, it is still necessary to obtain certain information from the motor, and obtain the rotor position information by specific circuits and software calculations.

　　2. Commutation signal processing circuit

　　This circuit performs logic processing and comprehensive calculation on the position sensor signal and the control signal, and obtains the logic signal of the conduction sequence and the appropriate conduction angle of each phase winding, and provides it to the power switch circuit.

　　This article is taken from ------"Permanent Magnet Brushless DC Motor Technology"