A new torque control method for induction motor drives

The conventional vector control method involves coordinate transformations and hence requires real time computations which involves time consuming complex calculations. On the other hand, it is shown in this paper that in drive systems involving periodic load change cycles the fast torque response can be achieved by giving a phase lead to the input voltage whenever the load changes. In addition, a fixed amount of short term voltage boost can also be given for further improving the torque response. This principle is simulated on an induction machine and the results show a marked improvement in the response time. Experiments were conducted based on this principle and the results show that this method improves the transient response. Thus, by pre-calculating the phase angle correction required, this method could be effectively used where the load changes undergo cyclic fixed changes.