A Novel Concept for Multimachine Drive System with Single Inverter Supply

The interest in multiphase machines for high performance applications has been growing in recent years due to their potential advantages over three-phase machines. One of the possibilities of taking advantage of the additional degrees of freedom that exist in multiphase machines is the series connection of several multiphase machines, with the supply coming from a single multiphase inverter. This paper discusses the possibility of connecting in series the stator windings of a six-phase and three-phase induction machines in an appropriate manner. This enables full decoupling of the dynamics of the two machines by means of vector control. Mathematical derivations and simulation proof of independent vector control, achievable with this system, are provided for the series connection of six-phase induction machine and a three-phase induction machine. The existence of the independent control of the machines is fully verified both in torque and speed mode using indirect rotor-flux oriented control principles.