Research for brushless motor controller using winding back-EMF to detect rotor position

As BLDCM position sensor has the shortcomings of size, cost and the manufacturing technology, in this paper, electrodes winding back EMF signal detecting the back EMF zero point is used to acquire the motor rotor signal. The BLDCM position sensor control strategies is analyzed, low-power controller has been developed by using chip ML4425, in order to improve the current volatile problem under the start-up and load disturbance situation, the speed and the current dual-closure are achieved by a simple differential circuit. And the prototype was tested, test results show that the controller has good working properties.