Starting Torque: When the motor starts, the torque equation of a DC motor shows that starting torque, also known as standstill torque, is maximum because slip equals one. Maximum Torque Condition: Maximum torque is achieved when slip equals the ratio of rotor resistance to rotor reactance, highl...
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Based on the bounded constraints on both current and voltage, the optimal flux values which maximize the torque are obtained by solving first-order differential equation of the rotor flux. This leads naturally to three regions of operation in which the induction machine is at either the current ...
The expression for the electromagnetic torque,T, is obtained by applying the principle of virtual displacement [1]. T=p(aψ′qri′dr−1aψ′dri′qr) The mechanical equation is Jdωmdt=T−TL−Bmωm, whereωmis the rotor angular velocity. ...
2.2.2 Induction machine (IM) IM can be considered as the best alternative in high power applications. As they have rough construction, low cost, high torque, high robustness, and high reliability [64]. The key problem with IM is speed limitation [44] and [64]. In order to overcome this...
In this paper, a direct torque control (DTC) method of an induction machine is proposed which enables the minimum torque ripple control, while maintaining constant switching frequency. Some drawbacks of the conventional DTC are the relatively large torque ripple in a low speed range and the variat...
equation containing a relationship between the stator and rotor flux time derivatives. This way, the flux conservation law is met. We take the expressions of these derivatives from the space phasor model of each machine, and find the only unknown, ( ) + =0 t s V , as the values of...
(33.54) and (33.55) into the torque equation of Eq. (33.41), (33.56)T=3P2LmLr(λdriqs−λqrids)=3P2LmLrλˆriqs It is clear from Eq. (33.53) that the rotor flux λˆdr is determined by ids, subject to a time delay Tr which is the rotor time constant (Lr/Rr). The ...
The torque-speed relationship as a general equation for torque as a function of slip is derived from the induction motor equivalent circuit. The induced torque is (7.5)τind=3VTHRTH+R2s2+XTH+X222R2sωsync where VTH, RTH, and XTH are the Thevenin equivalents of voltage, resistance, and reac...
Generally in induction motor related operations, squirrel cage induction motors are widely used. The starting torque equation of an induction motor is given byWhere, R2 and X2 are the rotor resistance and inductive reactance at starting respectively, E2