Deadbeat-direct torque and flux control for interior PM synchronous motors operating at voltage and current limits

This paper proposes a wide-speed deadbeat-direct torque and flux control (DB-DTFC) method associated with inverter voltage and current constraints of interior permanent-magnet synchronous motors (IPMSMs). The proposed approach has potential advantages controlling torque and flux linkage at voltage and current limits since integrators are not involved for torque control or flux weakening. An automatic transition between non-limited operation and six-step modulation can be achieved without modifying the control law. To support this, we provide a graphical and analytic analysis that naturally leads to a unique stator voltage vector selection on the hexagon. The proposed controller can maximize the available inverter voltage and generate higher output torque than conventional current vector controllers at high speeds. The method developed in this paper also maintains beneficial DTC features, such as fast dynamics and direct manipulation of the stator flux linkage for flux weakening.