Effects of various modulation techniques on harmonic distortion

Nonlinear elements in power systems are caused a serious harmonic distortion at transmission and distribution systems, and affected quality of supplying energy to consumer in negative form. Even if source voltage is sinusoidal, its output will include harmonic components due to loads which produce harmonic. Other loads connected to bus are affected from this situation. Each of induction motors is a harmonic source due to semiconductor switching power elements. As harmonics which are produced by inverter are unavoidable, optimization of these is preferred. With this purpose, as they are preferred quicker of used semiconductor power switching elements and less switching loss of its, PWM (Pulse Width Modulation) techniques which are used inverters have developed. In this study, dsPIC2010 micro controller which is one of the DSP (Digital Signal Processor) controllers was used. Sinus PWM (SPWM), square wave PWM (KDPWM), carrier base space vector PWM (TTSVPWM) and space vector PWM (SVPWM) techniques are carried out with this DSP controller. In this thesis study, currents at output of inverter for various PWM techniques are analyzed with software which is developed with micro controller. Technique which has minimum harmonic was determined by measuring harmonics of these currents and comparing of techniques was done according to each other.