感应电动机定子磁场定向直接转矩控制中定子电阻自适应估计方法

ADAPATIVE ESTIMATE METHOD OF STATOR RESISTANCE IN STATOR FLUX ORIENTED DIRECT TORQUE CONTROL SYSTEM FOR INDUCTION MOTOR

定子磁链定向的直接转矩控制技术逐渐被广泛应用于高性能异步电动机调速系统。而在低速运行阶段,由于定子电阻参数的变化,传统的磁场定向控制性能往往很差。基于此,利用波波夫超稳定理论提出了基于定子电流的参考模型自适应系统,通过定子电流反馈构成了对电动机参数进行闭环估计,不仅考虑了定子电阻与电动机转速变化参数,而且还考虑了电动机的转子电阻变化参数,进而加速了估计过程的收敛速度,提高了定子电阻及转速估计的精度。在此基础上,提出定子电阻整定的定子磁链估计方法,并建立一个定子磁场定向直接转矩控制的仿真系统。仿真结果进一步验证了其有效性。

The stator flux oriented direct torque control technique is becoming widely used in high performance motion control of induction motors. However, the conventional stator-flux-oriented control schemes have the disadvantage of poor performance in the low-speed operating range, due to the stator resistance variables and uncertainties. A stator current based model reference adaptive system （MRAS）, using Popov＇s super-stability theory, is presented to estimate motor parameters, which constitutes a closed-loop system by the stator current feedback. The scheme considers not only stator resistance and speed, but also rotor resistance. Therefore, the convergence speed of estimating process is quickened, and the estimate precision is improved. On the basis of the scheme, a stator flux estimate technique based on stator resistance compensation is also presented, and the simulation system of the direct torque control project is established. The simulation results verify the validity of the proposed scheme.