直流无刷电机的换相过零检测

Commutation Zero-Crossing Detection of Brushless DC Motor

控制直流无刷电机的关键在于确定过零点和换相时刻,为此提出了一种结构简单的过零检测电路。对该电路输入和输出信号的实时监测与分析表明:如果控制器采用中断方式检测过零点,则必须在过零检测电路后增加一个比较电路来过滤不规整的三角脉冲以形成标准的矩形脉冲;如果CPU采用查询方式检测过零点,则应在PWM的低电平期间进行查询,否则会出现错误结果。试验论证了通过以上两种方式可以准确获得永磁直流无刷电机过零时刻信号。

While the key of control BLDCM is confirming the zero-crossing and commutation time,so a simple structure circuit of zero-crossing detection was proposed. The real-time monitoring and analysis of the input and output signals of the circuit indicate that： if the controller uses interrupt to test zero-crossing,it must increase a comparator circuit after the zero-crossing detection circuit to filter the irregular triangular pulses to form standard rectangular pulses; if CPU uses queries to detect zero-crossing,the query should be during low level of the PWM,or will get error results. The experiment demonstrates that permanent magnet BLDCM can accurately obtain zero-crossing signals through the above two methods.