中文摘要：

针对定子磁链U—J观测模型在电机低速运行时失效的问题，在感应电机定子磁场定向控制基础上，用一种阈值可变的改进型积分器算法进行定子磁链观测，并对转速进行估算，构成无速度传感器的速度闭环控制。在自行设计构建的dSPACE试验平台上，对所提方案进行了低速空载及负载条件下的实验研究。实验结果表明转速估算值与实际值相一致，系统具有优良的动、静态控制效果。

英文摘要：

Aiming at the problem of a conventional U -I model at low speed running, a new improved integrator algorithm with alterable threshold for stator flux observer based on the stator flux-oriented control of induction motor was investigated. In addition, a method to estimate exactly speed and form sensorless speed closed-loop control was proposed. The proposed method was verified by experiment at low speed with no and full load on a dSPACE test platform. The experimental results show the estimated speed is true of exactly speed, and good behavior of the drive in both transient and steady state operating conditions.