DIRECT TORQUE CONTROL OF A SIX PHASE INDUCTION MOTOR DRIVE

Six-phase induction motor IM has advantages over three phase3-φ IM like lower harmonics, lower losses, improved reliability, higher torque per ampere, and higher power rating drive. However the control of such motors is more complex than that of the 3-φ motors. The principles of direct torque control DTC , which is a wellknown control method for 3-φmotors, can be utilized to overcome this complexity. This paper introduces the application of the DTC principles to 6-φ IMs drives. The whole 6-φ IM drive system is modeled and simulated in the stationary reference frame However, it is noted from circuit analysis and Matlab stimulations that the use of the conventional 6-φ inverter gives poor performance drive. This is due to the fact that with the conventional inverter only six switching states can give balanced output voltages instead of 64 switching states. This results in lower capability of control, less utilization of the DC supply, and more harmonic distortion as well. However to avoid this demerits, the authors, after various trials, have inferred that the use of a dual 3-φ inverter is the solution to be adapted. Simulation results of a DTC 6-φ IM drive show improved performance over the results of the field orientation trials in the literature.