A voltage source inverter is commonly used to supply a three-phase induction motor with variable frequency and variable voltage for variable speed applications. A suitable pulse width modulation technique is employed to obtain the required output voltage in the line side of the inverter. The different methods for PWM generation are broadly classified into Triangle comparison based PWM and Space Vector based PWM. Space Vector Pulse Width Modulation (SVPWM) method is an advanced, computation intensive PWM method and possibly the best among all the PWM techniques for variable frequency drive applications. The SVPWM is an alternative method for the determination of switching pulse width and their position. This method has been finding widespread application in recent years because of the easier digital realization and better dc bus utilization. 2-level inverter is the first model developed using this technique. In SVPWM methods, a revolving reference voltage vector is provided as voltage reference instead of three phase modulating waves. The magnitude and frequency of the fundamental component in the line side are controlled by the magnitude and frequency, respectively, of the reference vector. This paper describes comparison of 2-level SPWM and 2-level SVPWM inverter fed induction motor. This project also describes step by step procedure how to implement 2-level SVPWM technique for three phase inverter. All the methods are simulated and results are obtained using MATLAB/SIMULINK. Speed response and THD levels are compared. From the results it is concluded that the dynamic response is improved and THD level of input current to induction motor is reduced in case of SVPWM when compared to SPWM.

This paper presents a comparative study of speed control of a separately excited DC motor by using different type of controllers. .Conventional controllers are commonly being used to control the speed of the DC motors in various industrial applications. It's found to be simple, robust and highly effective when the load disturbance is small. But during high load or rapid variation of load, the fuzzy technique based controllers proves to be fast and reliable. Using chopper input voltage can be varied and thus speed can be varied. For better performance of the DC motor various kind of controller namely P-I, I-P, Fuzzy logic controller are used. Proportional-Integral type controller is used to eliminate the delay and provides fast control. However, the P-I controller has some disadvantages such as: sluggish response to a sudden load change, the high starting overshoots and sensitivity to controller gains. So, the relatively new Integral Proportional (I-P) controller is proposed to overcome the disadvantages of the P-I controller .After obtaining the model of separately excited DC motor, it is simulated using MATLAB (Simulink) environment. Then fuzzy logic controller has been designed and performance has been observed. Finally a comparative study is done between all the controllers.