AbstractsEngineering

In this document the research related to the development of a microprocessor based field oriented controller is presented. An overview of the state-of-the-art is presented, with specific reference to all the different aspects related to the development of variable speed induction machine drives. During the development of it is necessary to use accurate system models. Such models are most useful when incorporated in a simulation program. In chapter 2 such a simulation program is described. Included in the simulation program are accurate models for the inverter and the induction machine. Effects such as resistance variation due to heating and inductance variation due to saturation are included. Modulation of the inverter output voltage wave from by the load current caused by the snubbers is also included. The development of a rotor current estimation strategy is presented in chapter 3. During the development extensive use was made of the simulation program. A new stationary reference frame current controller is also presented in chapter 3. Finally the implementation of the proposed field oriented controller is presented in chapter 4. As part of this a dual mode speed control algorithm was developed and implemented.