CSI drive induction motor by vector approximation

The authors present a new method to decrease torque ripple for a current source inverter (CSI) drive induction motor system using a detailed on-line simulation of a rotor magnetizing circuit. This method also computes an optimal stator current that cannot be realized by the CSI but will be approximated by the realizable stator current vectors. The approximation, that is, the composition of space vectors, is done by the concept of time average. It is also proved that the observer theory assures a rapid convergence of the simulated value of the rotor magnetizing current to the real one. Experimental results are shown. One of the problems with this idea is that it takes considerable computational time for on-line simulation (about 4 ms). Although a higher speed computer will solve this problem, the experiments are done for relatively low speeds