Impact of Winding Parameters on Torque Level under Harmonic Injection in Multiphase Induction Machine

Abstract

Multiphase induction machines have the advantage of producing torque under different current harmonics. Theoretically, with some simplifications, the maximum produced torque can be considered proportional to the harmonic winding factor related to the injected current harmonic. However previous work has shown that this theoretical proportionality between the maximum developed torque and harmonic winding factors is not obtained in the case of a five-phase induction machine with eight-poles and fractional-slot tooth concentrated winding. This paper aims to investigate the effect of winding parameters, especially phase number, fundamental polarity and stator slots number, on the torque production in multiphase induction machine under harmonics injection. A comparative study is done between four five-phase winding configurations, with the same geometry and copper volume, under both first and third harmonic injection. Finally, a special 15-phase winding presenting better consistency between maximum developed torque and harmonic winding factors is proposed.