Implementation of the direct torque control (DTC) in current model, with current starting limiter

This paper presents the scheme of Direct Torque Control (DTC) for induction motor drives, where flux and torque of the motor are estimated by the IM current model. Its scheme requires the knowledge of speed, rotor time constant and inductive parameters of the motor. The results prove the excellent characteristics for torque response and efficiency, which confirm the validity of this control scheme. Due to the rapid response offered by the DTC, this causes a high star current inversor protections activating. To resolve this, is presents the implementation of a closed loop of current vector the optimum switching table that limits the current and put into operation to the DTC. Experimental tests demonstrate effectiveness.