| The system of electric power generation, transmission and distribution is three-phase since on the beginning of the last century. So lots of electric machine adjustable speed drives are made up of three-phase electric machine and three-phase converter. But the present three-phase electric machine status has already received the certain challenge. One is in the situation which required high power rating and lower per phase voltage. The other is in the situation which required high reliability. In addition to high power handling capability, the multiphase winding structure provides a multiphase machine with capabilities of starting and running even with one or more of its stator excitation sets failed. Therefore, research on multiphase electric machine adjustable speed drive receives day by day the wide spread attention.Multiphase induction machine has many advantages over conventional three-phase, such as capability to start and continue running even with one or more of its many stator phases open or short circuited, reduced torque pulsation, reduced rotor copper loss leading to improved overall performance, increased power rating without increase in per phase voltage. It suits applied to naval vessel propulsion system and so on.In this paper, based on the traditional three-phase induction machine adjustable speed drive, the multiphase induction machine adjustable speed drive is mainly researched. A comprehensive research is made on the multiphase induction machine. The following items are included:1. Summarize the research on multiphase induction machine adjustable speed drive, introduce its characteristic and the domestic and foreign research situation.2. The winding connection way and harmonic analysis of multiphase induction machine is studied, the superiority of multiphase induction machine in reduced harmonic content compared with three-phase induction machine is proved in theory, mathematical model of multiphase induction machine is brought forward at the same time.3. Based on the electromagnetism design program of three-phase induction machine, the electromagnetism design program of multiphase induction machine is firstly derived. And the electromagnetism design software is developed by using Visual C++.4. The multiphase induction machine's transient electromagnetic field has been analyzed in detail by the Maxwell 2D. The result of analysis compared with the calculative result by VC program confirmed the validity of multiphase induction machine which is designed in this paper. |
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