Analysis of an induction motor fed from a six step voltage source inverter

The three-phase squirrel-cage induction motor fed from a six-step voltage-source inverter is analyzed. Particular attention is paid to the influence of the nonsinusoidal voltage source on the steady and dynamic performance of the machine. It is shown that, while the stator quantities such as currents and flux linkages respond to the switching of the voltage by the inverter producing hexagonal vectors in the d -q stationary reference frame, the rotor variables are almost circular. The presence of the sixth harmonic torque is confirmed both by simulation and the fast Fourier transform of the electromagnetic torque