DTC of an IPM-BLAC motor with a bus-clamping bang-bang controlled VSI in the armature

Abstract

This paper investigates the performance of a novel direct torque control (DTC) strategy dedicated to interior permanent magnet (IPM) brushless AC (BLAC) motor drives. The proposed strategy is based on a dual control approaches, consisting in: (i) a conventional DTC strategy where the control laws are inspired from the earlier Takahashi DTC strategy implemented in induction motor drives, and (ii) the bus-clamping (BC) strategy recently-introduced for the control of voltage source inverters, yielding the so-called “bus-clamping DTC” (BC-DTC). It consists in the synthesis of two vector selection tables depending on the rotation direction, in such a way to clamp each motor phase during 60°-interval in every half cycle of the reference stator flux vector. A simulationbased comparative study between the performance of the introduced BC-DTC and the conventional one, considering appropriate criteria, has highlighted the superiority of the proposed strategy which exhibits lower inverter switching losses, reduced harmonic distortion of the motor phase currents and damped torque ripple in a wide speed range.