Review of Multiphase Machines for Integrated Motor Drives

In applications such as electric vehicles, numerous long AC cables with electromagnetic pollution must be carefully implemented. If an Integrated Motor Drive (IMD) is used, this cable problem is not induced even with a high number of connections between the inverter and the motor. It is one of the advantages of IMDs, making the number of phases in IMDs higher than three popular. In general, an electric machine with more than three connections to the inverter or with more than two independent currents is called a multiphase machine (MM). MMs not only provide fault tolerance but also low power converter per phase ratings for low-voltage IMDs. Popular MMs can be classified into two main categories, including multiple 3-phase-star and regular symmetrical MMs. The former is attractive since it appears as an adaptation of previous studies of classical three-phase machines, but some traps can be encountered. The latter deserves in-depth study because of its more interesting characteristics with a comparable number of inverter legs. In this paper, a review of different existing and possible configurations of MMs for IMDs is proposed. The advantages and drawbacks of different solutions will be discussed.