Rotor Flux Controller for Induction Machines Considering Main Inductance Saturation

This paper discusses the problem of controlling electromechanical systems with maximum performance while maintaining accuracy and minimum power consumption. The objective of the study is to develop a law for regulating the coordinates of an electromechanical system, taking into account an energy-efficient algorithm for transferring the system from one operation point to another. An essential feature of the proposed solution is the possibility of applying the approach in modern high-speed electromechanical systems operating mainly in transient modes, without providing additional requirements for the digital part. The objective is achieved through the use of the law of the rotor flux generation augmented with adaptive low-pass filtering of the flux reference at each sampling step. The proposed method is investigated in both steady-state and dynamic modes of operation using laboratory experiments with a 370-W induction machine. With appropriate control of the change rate of the magnetic flux, the losses during the full operating cycle with changes in the torque can be significantly reduced compared to the conventional approach. The varying load is typical for the electromechanical systems with a variable moment of inertia and requirements for the positioning accuracy. The most critical result of the study is the reduction of the minimum possible cycle time, at which the expediency of using loss-minimizing control methods remains actual. The significance of the results obtained is in the reduction of losses while maintaining the required torque, contributing to the more efficient operation of this machine type.