Investigation of airgap flux density and torque performance of six-phase induction motor with special phase current waveform

The airgap flux density, and torque of a double three-phase induction motor using a special phase current waveform are investigated in this paper. The special current waveform proposed by the authors comprises of field and torque current components. The aim of using the special current waveform is to realize torque and field control of the motor separately, instead of using the conventional d-q transformation. Three methods are used to verify the flux density and torque of the motor namely conventional analytical calculation, finite element calculation and practical measurements. The practical measurements include field and torque control by means of two full-bridge converters under DSP current control. The results obtained from these methods show good agreement. The results furthermore show that the field and torque of the induction motor can be controlled effectively and in a very simple way by using the special current waveform.