The International Journal Of Engineering And Science (IJES) ISSN (e): 2319 – 1813 ISSN (p): 2319 – 1805 Pages || 41-51 || 2014 || International Conference on Innovations in Electrical & Electronics Engineering (ICIEEE-2014) 41 | Page GURU NANAK INSTITUTIONS HYDERABAD DESIGN AND ANALYSIS OF VARIOUS INVERTERS USING DIFFERENT PWM TECHNIQUES 1, Prof R. Kameswara Rao , 2, P. Srinivas , 3, M.V. Suresh Kumar 1, Department of Electrical and Electronics Engineering, Raghu Engineering College Email: rkameswara@gmail.com 2, Department of Electrical and Electronics Engineering, Raghu Engineering College Email: palacherlasrinu@gmail.com 3, Department of Electrical and Electronics Engineering, Raghu Engineering College Email: mvsk258@gmail.com ----------------------------------------------------ABSTRACT----------------------------------------------------- This paper presents the design and analysis of voltage source inverters (VSI) using three different pulse width modulation techniques i.e, sinusoidal pulse width modulation (SPWM), third harmonic injection pulse width modulation (THIPWM) and space vector pulse width modulation (SVPWM). In AC the quality of the sinusoidal waveform is more important than the quantity. In order to achieve that , we need to reduce the harmonic content in the output. For this purpose various pulse width modulation techniques are used. The PWM methods are simulated for various loads and the results are analyzed using FFT analysis for observing the total harmonic distortion (THD). The simulations are performed in MATLAB/SIMULINK environment. KEYWORDS : Voltage source inverter (VSI), multilevel inverter, SPWM, THIPWM, SVPWM and THD. 1. INTRODUCTION The main function of the inverter is to convert DC input voltage to a AC output voltage of the desired magnitude. The output voltage waveforms of the ideal inverters should be sinusoidal, however the waveform of the practical inverters are non sinusoidal and contains different harmonics. Square wave or quasi-square-wave voltages are acceptable only for low and medium power applications, but for high power applications low distorted sinusoidal waveforms are required. By using high speed power semi conductor devices and by using different switching techniques we can reduce the harmonic content in output voltage. Inverters are widely used in industrial applications (e.g., variable speed AC motors, induction heating, standby power supplies and uninterruptible power supplies). Inverters are broadly classified in to two types single phase inverters and three phase inverters. Each type can use controlled turn on and turn off devices. These inverters generally use pulse width modulation control signals to provide an AC output signal. II. PULSE WIDTH MODULATION TECHNIQUES Switching techniques of pulse width modulation (PWM) have been popular in the area of power electronics and drive systems. PWM is commonly used in applications like motor speed control, converters audio amplifiers etc. PWM is used to adjust voltage applied to the motor [1]. There is no single PWM method which can suite for all applications. As per the advanced technology in solid state power electronic devices and microprocessors, various pulse-width modulation (PWM) techniques have been developed for different industrial applications. For the above reasons, the PWM techniques have been the subject of intensive research since 1970s. The main objective of the PWM is to control the inverter output voltage and to reduce the harmonic content in the output voltage. The pulse width modulation (PWM) techniques are mainly used for voltage control. These techniques are most efficient and they control the drives of the switching devices. The different PWM techniques are Single pulse width modulation, Multiple pulse width modulation, Phase displacement control, Sinusoidal pulse width modulation, Harmonic Injection modulation, Space Vector pulse width modulation, Hysteresis (Delta) pulse width modulation, Selective Harmonic Elimination and Current Controlled pulse width modulation. Hysteresis controller is used for Current source inverter and all the remaining PWM techniques are used for Voltage source inverter. Sinusoidal and Space Vector PWM techniques are most widely used. They control the output voltage as well as reduce the harmonics.