Mathematical model and characteristics of dynamic modes for managing the asynchronous motors at voltage asymmetry

Abstract

The development of a comprehensive mathematical model depicting an asynchronous motor in generalised (resultant) vectors, accounting for voltage asymmetry, stands as a significant stride in this research endavour. This model serves as a powerful tool for conducting an exhaustive analysis of the motor’s characteristics in dynamic operational modes. Its unique capability lies in enabling a granular examination of the impact of both amplitude and phase asymmetry on the motor’s dynamic performance, thereby providing a nuanced understanding crucial for the effective management of asynchronous motors operating under the conditions of voltage asymmetry. In this pursuit, distinct models for an asynchronous motor are delineated separately for the direct and reverse sequence, conceptualised as two distinct machines integrated on a single shaft. Additionally, a unified model is presented, encapsulating the voltage equations along the α and β axes within the fixed coordinate system of the generalised machine. The empirical findings derived from this research present compelling insights into the behaviour of asynchronous motors in transient modes during direct starts under varying degrees of voltage asymmetry. These findings, summarised in a tabulated format, illustrate a clear correlation between the degree of voltage asymmetry and the subsequent reduction in motor performance indices. These findings not only enrich the theoretical understanding of asynchronous motor behaviour in the presence of voltage asymmetry but also lay a solid foundation for devising practical approaches to optimize their performance, further enhancing their operational efficiency and reliability.