Research of Zero-crossing detection for Sensorless BLDC motor

摘要

The key technology of Sensorless BLDC motor control is Zero-crossing detection. Based on full research and analysis of the Back-EMF motor principle, wave and traditional detection methods, a new method of Back-EMF Zero-crossing detection is introduced. The method does not rigidly adhere to the principles of traditional back-EMF zero-crossing detection, rejected the midpoint motor, depth filter and voltage comparison circuits in the design of the traditional zero-crossing detection circuit, gets commutation points by realizing three-phase voltage real time collection, filtering and designing the effective software algorithms. The method is applied in the electric car control system. The experiment result shows that the method has some advantages which are simple zero-crossing detection circuits, software with clear structure and good real-time and so on.