三次谐波检测无刷直流电机转子位置的研究

RESEARCH ON THE SCHEME OF SENSING ROTOR POSITION OF BLDCM BASED ON THE THIRD HARMONIC COMPONENT

论述了一种用三次谐波检测转子位置的新方法。与传统的反电动势法检测转子位置相比较,三次谐波法实现简单,可检测速度范围更宽,不需要深度滤波。文中抛弃了将三次谐波直接输入DSP A/D口的传统做法,而是将反映三次谐波相位信息的方波输入DSP的I/O口,利用DSP强大的数据处理功能,提出了用软件实现数字锁相功能和对换相时刻的准确估计,去除了传统的硬件积分方法;提出用模拟相电压代替传统的端电压作为辅助检测信号;从而简化了硬件电路,提高了转子位置估计的精度和可靠性。实际试验表明,这种方法能够准确而快速的估计转子位置,动静态特性良好,整个系统结构紧凑,可靠性高。

A novel method of sensing rotor shaft position of BLDCM (Permanent Magnet Brushless DC Motor) is presented based on the third harmonic component sensing. It is applicable to the BLDCM with trapezoidal back EMF waveform. Compared with the traditional back EMF, the third harmonic can be sensed even in a lower speed zone and only a small amount of low pass filter is needed. A digital phase locked up scheme is adopted in order to tracking on the 3rd harmonic precisely and quickly. A simulated phase voltage is sensed to help to verify the relationship between the 3rd harmonic wave and the rotor shaft position. The third harmonic sensing method is implemented in the laboratory based on a DSP 2407 control system. The experimental results shows the validity of the proposed method.