Realization of instantaneous torque control of an induction motor considering secondary flux as a parameter

Recently, many researches ain-Ling at the realization of high-performance and high-precision control of induction motors have been reported, and instantaneous torque control of an induction motor can be regarded as one of the most important topics in this field. In previous works, the authors developed a new method to realize instantaneous torque control of an induction motor with a voltage-source inverter, and demonstrated both its numerical simulations and experimental results. Unfortunately, the mathematically complicated derivation of the control method made it difficult to understand intuitively, and hindered us from analyzing the detailed characteristics of motor speed changes. In this paper, the authors propose a new method to realize instantaneous torque control of an induction motor, which differs from the concept of vector control. The proposed method is a two-degree-of-freedom control which considers the instantaneous torque command and secondary flux command as parameters. The analytical solution reported here is a particular solution of the differential state equation of an induction motor, and can be expressed as a simple explicit function of the instantaneous torque command, secondary flux command, and motor speed. The authors show the validity of the proposed method through numerical simulations and experimental results. This paper aims the realization of high-performance control of an induction motor. The authors propose a new method to realize instantaneous torque control without transient torque with a voltage-source inverter. (C) 2001 Scripta Technica.