基于脉冲宽度预测的速度反馈机制研究

Research on Speed Feedback Mechanism Based on Pulse Width Prediction

针对交流调速系统中速度传感器本体故障、线路异常或信号受到电磁干扰等不确定因素影响速度反馈精度的问题,首次提出了一种基于脉冲宽度预测的速度反馈机制。首先,对速度检测环节建模,推导并创建传感器信号占空比及其失真度模型,据此预测下一时刻传感器脉冲宽度范围,可有效辨识传感器故障和信号干扰。其次,通过选择合适的故障容忍度和干扰容忍度,并将辨识结果和扩张状态观测器所得速度观测值结合,建立相应的速度反馈机制。实验结果表明,该方法能够有效解决常规速度反馈机制在受不可知因素影响后检测精度下降的问题,有利于控制系统整体鲁棒性的提高。

In order to solve the problem that speed feedback accuracy of AC speed control system is easily affected because of the speed sensor fault, line fault and the electromagnetic interference, pulse width prediction method is proposed in this paper for the first time. Speed detection model is built and sensor signal duty ratio and the function of distortion degree is derived, so as to forecast the next sensor pulse width, and thus sensor fault and signal interference is effective identification. By setting the fault tolerance and interference tolerance, the identification results and observed value obtained by the extended state observer are combined to establish the corresponding speed feedback mechanism. Simulation and experimental results show that this method can effectively prevent that the system is under attack because of the unknown factors, and robustness of the control system is increased to a great degree.