Design of sensorless high speed BLDCM controller for molecular pump

The brushless direct current motor(BLDCM) of the molecular pump needs to run at high speed for a long time, which puts forward the requirements of high reliability, high speed rang and so on. The traditional sensor methods of using hall sensors for BLDCM commutation will reduce the reliability of the system and increase costs. Therefore, sensorless control methods are widely used in the field of molecular pumps. In this paper, a sensorless BLDCM control system of the molecular pump is designed, and the back-EMF zero crossing detection method is used to obtain the motor position information. Based on this method, the hardware and software of the control system are designed. Driven by the controller, the molecular pump speed can reach 90000rpm, and its steady speed fluctuation is ± 60rpm.