Wide Operational Speed Range of Five-Phase Permanent Magnet Machines by Using Different Stator Winding Configurations

The winding changeover technique is an effective method for extending the operational speed range of permanent magnet synchronous machines (PMSMs). Unlike three-phase machines which could be wound in wye or delta connections, there are three possible connections, i.e., star, pentagon, and pentacle for five-phase electric machines. In this work, the effects of these three winding connections on a five-phase PMSM performance are studied. First, based on the mathematical model and finite-element analysis, the effects of different stator winding connections on torque-speed and efficiency characteristics are investigated. Then, the complete electric machine drive system including the winding changeover mechanism is simulated to present its dynamic performance. Finally, experimental results are provided to show the transient and steady-state operation of a five-phase PMSM with star, pentagon, and pentacle winding connections.