Review of methods for energy-efficiency improvement in induction machine

Abstract

Purpose. To present a comprehensive analysis of domestic and foreign experience regarding the existing optimization techniques in the problems of the power losses minimization in electromechanical systems with an induction machine for reduction of the total electricity consumed from the grid. Methodology. A detailed study of the developments in the field of efficiency optimization of three-phase induction machines through optimal control and design techniques has been done. Special attention is given to vector-controlled systems. Sustainable development of a few trends was traced in this domain. The reference value of the field-generating current is an additional degree of freedom in the mathematical model of the investigated system. It influences the magnetic flux linkage dynamics and mechanical torque equations. Hence, the implemented model allows for a comparative analysis of different approaches to ensure minimum energy consumption with an adequate intensity of transients. Findings. Among numerous control techniques, simple state control, loss model-based control and search control efficiency optimization algorithms have been highlighted. The simulation example on efficiency optimization of an asynchronous machine was performed in the framework of an indirect field-oriented control system considering the stepped trajectory of load torque, which is possible as a result of mechanical perturbation or when the motor performs complex speed profiles or counteracts shock loads. Originality. The rigorous review indicates that existing optimization algorithms in conventional still can be used for induction motor drive applications. However, some existing problems in achieving the best control were not summarized. Accordingly, for the first time, this review provides suggestions for the future research and development of dynamic energy-efficient control in induction motors. Practical value. The three-phase induction motor drives are a nonlinear system that is tough to describe precisely theoretically due to their sudden changes in conditions of operation mode and parameter variation. Thus, advanced algorithms are needed to enhance their performance in addition to effective hardware solutions. The suggested alternative solution will hopefully lead to increased efforts toward the development of advanced control systems for future applications.