廖曉文1， 劉  美1， 曾  光2， 田志波1
（1. 廣東石油化工學院自動化系，廣東 茂名 525000； 2. 廣州東芝白云菱機電力電子有限公司，廣東 廣州 510460）
摘  要：針對混合式步進電機開環控制容易出現丟步的問題，利用冪次函數代替開關函數，設計基于改進滑模觀測器的丟步檢測算法。證明該觀測器在較大電流觀測偏差時是一變增益的滑模觀測器，在較小電流觀測偏差時具備低通濾波功能，可消除抖振現象。同時，通過觀測反電動勢得到電角度，并利用冪次函數設置較大的邊界層厚度，將電角度收斂到π/2整數倍的區域，可直接根據觀測結果判定電機有無丟步。實驗結果驗證了該方法在低細分、寬調速范圍的有效性。
關鍵詞：滑模觀測器；冪次函數；混合式步進；丟步檢測
中圖分類號：TM383.6；TM930.12；TP277；TP391.97    文獻標志碼：A     文章編號：1674-5124（2013）03-0088-04
Lost steps detection based on sliding-mode observer for hybrid stepper motors
LIAO Xiao-wen1， LIU Mei1， ZENG Guang2， TIAN Zhi-bo1
（1. Automation Department，Guangdong Institute of Petrol-Chemical Technology，Maoming 525000，China；
2. Guangzhou Toshiba Baiyun Ryoki Power Electronics Co.，Ltd.，Guangzhou 510460，China）
Abstract: As the lost steps problem exists in hybrid stepper motors in their open loop control mode， the lost steps detection was designed by replacing the switching function with power function and based on improved sliding-mode observer. It was proven that the improved observer is a variable gain sliding-mode observer when the current observation errors are large. When the current observation errors are smaller， the improved observer has a low-pass filtering feature and the chattering phenomenon can be eliminated. The estimated back EMF is used to obtain electrical angle and the larger boundary layer thickness is set by power function. Thus， the electrical angle can be convergence to integer multiple area of π/2. So any lost steps can be obtained from observations directly. The experimental results verify the validity of the method in the low subdivision and wide speed range.
Key words: sliding-mode observer； power function； hybrid stepper； lost steps detection