基于形态学滤波的反电动势过零检测算法

Zero⁃crossing detection algorithm of Back⁃EMF based on morphological filtering

为了解决传统的反电动势过零点检测算法存在滤波延时以及相位补偿误差的缺点,将形态学滤波应用于二维信号,设计了固定延时的数字滤波器,使滤波延时不再随转速变化,且不需要额外的采样电路;同时采用数字锁相环算法跟踪换相位置,实现换向位置的闭环调节,提高了换向精度.根据以上方法,搭建了仿真模型,设计开发了无刷直流电机控制器.仿真和实验结果表明,这种新型反电动势检测算法可以有效提高无刷直流电机的转子位置检测精度,并使转速波动的控制精度达到万分之一水平.

In order to overcome the shortcomings of the traditional Back Electromotive Force(BEMF)Detection Algorithm,such as filtering delay and error of phase compensation,the morphological filtering is applied to two⁃dimensional signal to design a digital filter with fixed delay,which makes the filtering delay not to change with the speed and no additional sampling circuit is needed.At the same time,the digital phase⁃locked loop algorithm is used to improve the delay algorithm of back EMF zero crossing.According to the above methods,a simulation model is built and a controller of brushless DC motor is designed.The simulation and experimental results show that this new BEMF detection algorithm can improve the rotor position detection accuracy of brushless DC motors effectively,and make the control accuracy of speed fluctuations reach the level of one ten thousandth.