Instantaneous space vector model for direct flux and torque control of an inverter controlled induction motor

Based on the instantaneous space vector variables of the induction motor and control vector models, this paper presents a digital simulation of the direct stator flux and torque instantaneous space vector controllers of a VSI-fed-induction-motor. The voltage-source inverter commutation strategy is based on the control actions of one stator flux hysteresis controller and one electromagnetic torque hysteresis controller. A switching table is derived from these controllers, that select the optimum inverter output voltage vectors, to obtain a rapid torque response. The instantaneous value of the stator flux space vector, and the region in the αβ domain, to which this instantaneous flux vector belongs, together with the instantaneous value of the electromagnetic torque are directly computed from the output vector voltages and currents of the VSI feeding the induction motor. These stator flux and electromagnetic torque instantaneous values are professed in their respective hysteresis controller to logically determine the switching pulses to the voltage source inverter