Symmetrical/Asymmetrical Winding Reconfiguration in Multiphase Machines

This paper investigates multiphase drives in which winding configuration (symmetrical or asymmetrical) can be easily obtained by only rearranging voltage source inverter (VSI) power supply cables at the machine's terminal box. The type of the machines where this is possible is identified and the examples of reconfiguration are given and explained. Following from the examples (for nine- and fifteen-phase cases), a general reconfiguration algorithm is introduced. As shown, changing asymmetrical to symmetrical winding configuration (and vice versa) means that just another mimic diagram needs to be placed over the existing one on the machine's terminal box. Possible reconfigurations of a six-phase machine, which do not follow the same pattern, are also addressed. Differences caused by different winding configuration are identified and experimentally confirmed using a nine-phase surface mounted permanent magnet synchronous machine (PMSM) and a nine-phase induction machine (IM).