Although three phase slip ring induction motors have excellent electrical and mechanical characteristics, lag behind three phase squirrel-cage motors, because of the maintenance costs, due to their brushes and rings.Although three phase slip ring induction motors have excellent electrical and mechanical characteristics, lag behind three phase squirrel-cage motors, because of the maintenance costs, due to their brushes and rings.The aim of this thesis is to study the possibility of developing a suitable electronic power converter, of small size, capable of being placed on the shaft of an asynchronous three phase slip ring induction motor, in order to control its speed.For the development of the electronic power converter, three topologies are initially proposed, and their effectiveness will be studied.A) Power converter with capacitor, six IGBTs and antiparallel diodes, in inverter arrangement.B) Power converter with three thyristors and antiparallel diodes.C) Power converter with three TRIACs.All three of the above arrangements will be studied as to their suitability, to be placed on the rotor’s shaft of the motor.A successful deployment of one of the three above, or another electronic power converter, could potentially lead to the elimination of the rings of the machine.This could be a significant improvement of the slip ring induction motor, as rings:

 Require frequent maintenance.

 Increase the mechanical friction.

 Increase the electrical resistance of rotor (and slip too).