Rezonans tipi evirgeçlerde dağıtılmış snubber yapılarının kullanımı ve etkilerinin araştırılması

Today, power inverters are getting more and more attraction with their conventional use in the electronics industry, as well as the latest developments in alternative energy technologies, the transition to battery-powered vehicles and their chargers, and the increasing demand for high-tech aerospace and military equipment. In this area resonant inverters are commonly used in induction heating systems and piezoelectric actuator drives. When a resonant inverter operates at its load resonant frequency then soft switching operation results in. For this reason, adding snubbers into a resonant inverter circuit may seem to be unnecessary. However, for the purpose of controlling the output power, sometimes resonant inverters are operated above or below the load resonant frequency. In this dissertation, the main resonant inverter types and snubber circuits have been investigated. Basically, techniques to reduce stray components caused by wiring assemblies of switching devices have been described. A low inductance package snubber capacitor design was introduced and its equivalent circuit model parameters were compared. Finally, a new snubber circuit consists of a transmission line only is proposed for the series type resonant inverter working above the load resonant frequency. In this case clamped inductive switching occurs. Hence, application an efficient snubbing technique would greatly increase the reliability of the inverter operation. Since a transmission line is a distributed circuit, it exhibits highly different behaviours electrically before and after a time duration determined by transmission line material properties and its dimensions. Cables with propagation times comparable switching times of the transistors to be snubbed was used in this study. These cables leaving far end open were connected across the semiconductor switches as snubber elements. These cables behaves as resistors during the turn-off process and helps to reduce electrical stress by diverting the switch current.