Estudo de uma máquina de indução de nove fases

Abstract

Electric motors with number of phases greater than three may present advantages over conventional three-phase machines in the following applications: high power levels, once the power per phase is reduced, whether by reducing voltage or current and it is even possible to reduce the price of the converter. Applications that require high levels of reliability, because multi-phase machines can operate with one or more damaged phases. Besides that, onboard applications, like electrical and hybrid vehicles, ships and trains, have gains by using these kind of machines, because of the aforementioned high reliability and because it is possible to increase the torque by injecting harmonic currents. This work will be focused on a nine-phase induction machine. It will be shown how to model this machine for fundamental and third harmonic frequencies and how to obtain steadystate equivalent circuits with the same topology of the equivalent circuit of standard three-phase machines. In addition, it is demonstrated how the third harmonic currents can increase the torque density and how is implemented the indirect field-oriented control to always synchronize correctly the quantities of these two harmonics. Furthermore, some aspects of design of ninephase machines and the comparison of the performance of three-phase and nine-phase machines are discussed here.