Reducing switching losses of resonant inverter

Abstract

This thesis report is submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Electrical and Electronic Engineering, 2015.Inverter is used in different purposes of lives. Inverters are required in a variety of applications including electronic ballasts for gas discharge lamps, induction heating and electrosurgical generators. These applications usually require a sinusoid of tens or hundreds of kHz having moderate or low harmonic distortion. Induction heater is another field where inverter is needed. It is one of the popular techniques of producing high temperature. Since the inverter has been invented long ago now different types of topologies came to light. Resonant inverter is one of them. Voltage and current source inverter was invented before resonant inverter, but resonant inverter has brought something new in engineering society. Now here is a point why resonant inverter is more important than voltage and current source inverter especially for those applications where output power control is needed. A very common term in electrical field is switching loss. In normal inverter circuits when the switches swap their positions they consume some powers, as they conduct their activities when both current and voltage are nonzero. As a result of imperfect switching causes power loss which is strongly unexpected. Moreover with the increase of switching frequencies power loss increases. As expected smaller size filter components needed higher frequencies. So the invented solution for avoiding the power loss is using a new type of inverter which is known as resonant inverter. The most significant part of resonant inverter is, here switching takes place when voltage and current are zero which is known as ‗soft switching‘. Since switching takes place in zero voltage and current stage there is no possibility of power loss in resonant inverter