中文摘要：

无位置传感器无刷直流电动机的过零检测是该类型电机控制的关键技术。在充分研究与分析该类电机的反电动势原理、波形及传统检测方法的基础上，提出了一种反电动势过零检测新方法。该方法不拘泥于传统反电动势过零检测原理，摈弃了传统过零检测电路设计中的电机中点、深度滤波及电压比较等电路，利用DSC实现三相端电压动态实时采集、滤波，并设计有效的软件算法，得到换相点。实际应用结果表明，该过零检测电路具有实现简洁、软件结构清晰及实时性好等优点。

英文摘要：

The key technology of sensorless brushless DC motor control is zero-crossing detection. Based on full re- search and analysis of the back-EMF motor principle, wave and traditional detection methods, a new method of back-EMF zero-crossing detection was introduced. The method did not rigidly adhere to the principles of traditional back-EMF zero- crossing detection, and the motor midpoint, depth filter and voltage comparison circuits in the design of the traditional zero- crossing detection circuit were rejected. The commutation points were received by realizing three-phase voltage real time collection,filtering and designing the effective software algorithms. The method was applied in the electric car control sys- tem. 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.