Flux harmonic spectrum processing of direct torque controlled induction motor

The flux spectrum is greatly influenced by flux and torque controller hysteresis loops (dead bands) in direct torque control of AC motors. On the other hand, iron loss in induction motors is closely related to flux harmonics. Hence, the flux spectrum must be observed in the control process to minimize motor losses. In this paper, the relation between the magnetic-flux spectrum and electromagnetic-torque and magnetic-flux controller hysteresis loops (dead bands) as well as machine parameters is investigated. Simulation results are presented to justify the results.