Torque closed-loop vector control of Induction Motor based on stator flux observer

Abstract

Vector control of Induction Motor (IM) is usually used in speed regulating system. However, in wind power generation system, speed regulator is not needed. On the contrary, there is only a stator current closed-loop in the traditional wind power generation system. The torque set by the turbine controller is controlled indirectly by closed-loop current control. However, the torque control accuracy is low because of the influence of the parameters. Torque closed-loop control can improve the control accuracy, but the feedback torque needs be observed. In this paper, a real-time stator flux observation method based on minimum order flux observer is proposed, based on which the stator flux and torque are calculated. The proposed stator flux observer avoids the flaws of the traditional pure integral strategy, such as saturation, phase shift, amplitude deviation, and so on. Meanwhile, the proposed stator flux observer is robust to parameters, namely, the preciseness of the observed torque is almost not affected by mutual inductance. Experiments of 130KW IM validate the performance of the proposed method.