Comparison of speed control performances of an induction motor using vector control and direct torque control methods

In parallel to technological advance, a new one as simplicity control of induction motors were added to its advantages such as structural and cost. Vector control of induction motors are based on control principle of DA motors. DA motors have high performance in terms of dynamic behaviour and their control is simple. Armature and excited winding currents of self-excited DA motors can be independently controlled because they are vertical to each other. There isn?t such case in induction motors. Made studies on induction motors showed that these motors could be controlled such as DA motors if three-phase variables are converted to dq-axis and dq-axis currents are controlled. Vector control methods which are done transform of axis have been developed. Thus, flux and torque of induction motors can be independently controlled. In direct moment control method, flux and torque of induction motors is controlled with selection of optimum switching in inverter. In this control method realized direct flux and torque control; hysteresis controller (comparator) is used instead of flux and torque controller used in vector control methodsIn this thesis, simulation studies are realized for speed control of an induction motor via MATLAB/Simulink software. Rotor, stator and air-gap flux methods and direct torque control method are used for speed control of induction motor. Architectures for each control methods are designed by MATLAB/Simulink and simulation results for architectures are given for same conditions. Obtained simulation results are evaluated and analyzed According to disturbance effects such as tracing different references speed, load torque and parameter variations.