Novel method of pre-determining induction machine parameters and energetic efficiency

Abstract

The efficiency concept becomes present at all levels of electric motors design, manufacturing and repairing activity. New legislations including Energy Independence Security Act and similar will effectively impose a new design constraint: efficiency of induction machines (IM). Various motor management programs promoted by the utilities, new standards will also closely monitor efficiency of the repaired motors. Proposed method covers the need of a rapid and effective evaluation of energetic efficiencies of new (including preliminary designs or prototypes) and/or rewound IM. Based on the d-q orthogonal Park model, differential equations modeling IM parameters are written. An original mathematical approach is used to determine the existence domain of the machine parameters, with direct estimation of energy efficiency domain as a function of IM parameters. The work presented in this paper has been done without considering non-sinusoidal power supply conditions and magnetic saturation. These topics, in the context of efficiency estimation, will make the subject of future published research. Proposed algorithm (MEMPE) was validated during pre-design process of dedicated IM for special applications. It was also used to pre-determine the new values of parameters of the rewound IM. Practical implications of this work are described with all their benefits for customers, utility programs, IM designers and service centers implementing new methodology for efficient repairs/rewinds of IM. This paper is a step into laborious work in finding analytical expressions that would allow efficiency estimation by non intrusive site measurements, without any need of performing costly dynamometer tests.