无传感器无刷直流电机变频调速系统设计与实现

为了获取无传感器无刷直流电动机转子准确位置信号,采用反电势法来估算电机转子位置。针对电机起动时反电势比较小,难以通过反电势法来检测转子位置的情况,提出预定位法和变频升压相结合的电机软起动方法,设计了一套完善的速度、电流的双闭环控制无传感器无刷直流电动机调速系统。详细讨论了在去掉位置传感器的情况下无刷直流电机如何换相以及速度的提取问题,并且进行了相应的系统硬件、软件设计。实验结果验证了所设计系统的调速性能及位置检测信号的准确性。

Design and realization of variable frequency tuning velocity system of sensorless BLDCM

To acquire the accurate position-signal of the rotor of the Sensorless Brushless DC Motor,first,the Back-EMF is adopted.Second,considering that the BEMF is very 1ittle in the process of motor starting,the Back-EMF method is expired,combined with the rotor pre-setting method and the variable-frequency increase-voltage method.The soft-start method of motor is proposed in the paper.Last,the perfect double closed loops control system,with velocity and current is designed.The current commutation and motor speed withdraw problem without the position sensor is discussed in detail,and designs the corresponding hardware and software circuit is designed.The experimental results show the validity of the timing system and the veracity of the detective position-signal.