Direct torque control for dual three-phase induction motor drives

This paper discusses a direct torque control (DTC) method for dual three-phase induction motor (DTPIM) drives with multilevel hysteresis torque comparator. The DTPIM has two, three phase winding spatially shifted by 30 electrical degrees. The DTPIM fed by six phases Voltage Source Inverter (VSI) has 64 inverter switching states which provide higher possibility in selecting space voltage vectors than three phase induction machines. The machine model is based on the vector space decomposition theory. A five-level hysteresis torque comparator is used instead of conventional three-level comparator. This approach helps in tackling small and large errors separately by selecting different space voltage vectors. The advantages of discussed strategy are good transient and steady-state performance. The proposed scheme is validated by simulation.