An invertible dependence of the speed and time of the induction machine during no-load direct start-up

Martin P Ćalasan

doi:10.1080/00051144.2019.1689725

Abstract

In this paper, an invertible dependence of the speed and time of the induction machine during no-load direct start-up is presented. Namely, based on the parameters of the induction machine equivalent circuit as well as on the basic, well-known, equation for machine torque, the analytical expression for the induction machine time-speed dependence during direct start-up is derived. On the other hand, in order to obtain inverse i.e. speed-time dependence, the derived time-speed expression is rearranged in one nonlinear equation. As the derived nonlinear equation does not have an analytical solution, a novel iterative procedure, based on the usage of Lambert W function, is proposed for its solving. The results obtained by using the developed expressions for speed-time or time-speed curves are compared with the corresponding results obtained by using expressions known in the literature as well as with the results obtained by using a numerical time-domain computation method. Moreover, the results obtained by using the developed expressions have been compared with the corresponding experimental results to demonstrate the accuracy of the derived expressions. The Matlab code developed for solving the presented iterative procedure, as well as the Matlab code for induction machine speed-time curve determination, is also provided.

Highlights

The Induction Machine (IM) or the asynchronous machine is a widely used electric machine in industrial and household applications
The results obtained by using the developed expressions for speed-time or time-speed curves are compared with the corresponding results obtained by using expressions known in the literature as well as with the results obtained by using a numerical time-domain computation method
Other IM starting methods are based on the usage of soft starters [13,14] or on the shunting of the stator and rotor windings [6], whereas others require the usage of power electronic devices [15]

Summary

Introduction

The Induction Machine (IM) or the asynchronous machine is a widely used electric machine in industrial and household applications This machine has numerous advantages compared to other types of electrical machines – robustness, easy maintenance, easy control, a wide range of power/voltage, low cost, etc. Other IM starting methods are based on the usage of soft starters [13,14] or on the shunting of the stator and rotor windings [6], whereas others require the usage of power electronic devices [15]. The comparison of conventional motor starters and modern power electronic devices for IM starting is presented in [15].

Objectives

Results

Conclusion