DESIGN AND ANALYSIS OF HYSTERESIS CURRENT CONTROL AND SVPWM ON FUZZY LOGIC BASED VECTOR CONTROLLED INDUCTION MOTOR DRIVE

Abstract

The induction machine is an important class of electric machines which finds wide applicability as motor in industry and in its single-phase form in several domestic applications. More than 85% of industrial motors in use today are in fact induction motors. In many applications it is required to adjust the speed of Induction Motor (IM) according to load variation. Because of its highly nonlinear dynamic structure with strong dynamic interactions, it requires more complex control schemes than DC machines. The indirect vector control of IM is a control similar to fully compensated DC machine as vector control reduces the coupling effect which is responsible for sluggish response. Traditionally for speed controlling purpose PI controllers are used but it‘s hard to tune PI every time with change in parameters. To avoid the effect of parameter variation, fuzzy logic controllers are used. The induction motor is fed from voltage source inverter and to control the output voltage of the inverter different modulation techniques are implemented. This dissertation presents the performance comparison of Hysteresis Current Control and Space vector pulse width modulation (SVPWM) for generation of pulse width modulation (PWM) signals for voltage source inverter in vector controlled Induction Motor Drive. The dynamic performance of the drive for its speed regulation mode is described using both PWM techniques. Fuzzy Logic Control (FLC) is used for speed controller in both cases. The dynamic performance and ripple content is analyzed using FLC based SVPWM and HCC IM drive and compared at different operating conditions such as change in load torque and speed reversal. A MATLAB /SIMULINK model of FLC based vector controlled IM drive is simulated using hysteresis current controller and SVPWM for PWM signal generation and dynamic performance of these two techniques are compared.