High Performance Control of AC Drives with Matlab / Simulink Models

7.2 Advantages and Applications of Multi-Phase Drives

Multi-phase drives offer some distinct advantages over their three-phase drive counterparts. The major advantages of using a multi-phase machine instead of a three-phase machine are described in [17–42]:

• higher torque density [22–26];
• reduced torque pulsations [1, 27];
• greater fault tolerance [27–38];
• reduction in the required rating per inverter leg (and therefore simpler and more reliable power conditioning equipment) [39, 40]; and
• better noise characteristics, higher phase, number yield smoother torque due to the simultaneous increase of the frequency of the torque pulsation, and reduction of the torque ripple magnitude [41, 42].

Multi-phase drives are still unsuitable for general purpose drives application and thus their application areas are restricted to some critical domains such as ship propulsion, more-electric aircraft, hybrid electric vehicles, electric traction, and battery-powered electric vehicles [43–48]. The reasons behind this are primarily two-fold. In high power applications (i.e. ship propulsion), the use of multi-phase drives enables reduction of the required power rating per inverter leg (phase). This is a major advantage over the converter end side, as lower switch ratings can handle reduced per-phase power. In high power applications, series and/or parallel combinations of power electronics switches are required to process large amounts of power. The series/parallel combination of switches poses the ...