Previous Research Works

The complexity of the control associated with the induction machines was alleviated by the advent of vector control in the early 70's .The main difference between vector control and the existing schemes for induction machines, such as the constant volts/Hz or slip frequency control, is that the frequency and voltage or current imposed on the motor are controlled without neglecting the phase relationships.Without appropriate phase angle control, vector control degenerates into conventional slip frequency control resulting in poor dynamic characteristics.Vector control was compared with the slip frequency control and found to have a faster torque response Quick torque response is achieved even if a load is applied and the drive system reaches steady state instantaneously. A comparative study of vector control with the torque angle control and synchronous control has been performed and the advantages of vector control highlighted.Vector control is also known as decoupling control since the stator currents are decoupled into separate torque and flux producing channels. It is also known as field oriented control due to the fact that the control is based on the field orientation of stator currents.