Selim Öncü

A simplified procedure for the optimal design of induction cooking appliances

By using the phase plane approach, a single switch resonant inverter (SSRI) for home cooking application is analysed in detail to provide a more straightforward and easy-to-use design tool. A new set of characteristic curves and design procedures are presented. The key results are presented in the form of normalized design graphs, so that a designer can use them without lengthy and complex calculations. These design graphs will make it faster and easier for a SSRI design engineer to obtain various design parameters. A simple design procedure is given and a design example for 125 W, 62.5 kHz induction cooker is presented for illustrative purposes. Computer simulations are also presented and compared with results measured on the operational prototype.

Switching-Mode BJT Driver for Self-Oscillated Push-Pull Inverters

Self oscillating current fed push pull resonant inverters can be controlled without using special drivers. Dc current flows through the choke coil and the power switches, although the driving signals of the power switches are sinusoidal. When the base current is near zero, the transistors cannot be operated in switching mode. Hence higher switching power losses and instantaneous peak power during off transitions are observed. In this study, an alternative design has been proposed to overcome this problem. A prototype circuit has been built which provides dc bias current to the base of the transistors. Experimental results are compared with theoretical calculations to demonstrate the validity of the design. The proposed design decreases the peak and average power losses by about 8 times, when compared to conventional designs.

TEK ANAHTARLI İNVERTERDE BAZI KONTROL PALSLERİNİN SİLİNMESİYLE GÜÇ KONTROLÜ

Basit, ucuz ve yuksek verimli olmasi sebebiyle tek anahtarli yari iletken guc donusturuculer bircok guc elektronigi uygulamasinda kullanilmaktadir. Bu calismada mutfak tipi bir induksiyon isitici, gerilim beslemeli sifir gerilim anahtarlamali tek anahtarli seri rezonans inverter (SRI) devre kullanilarak gerceklestirilmistir. Isiticida yari iletken anahtarin iletimde kalma suresinin degistirilmesiyle cikis gucunun kontrolune alternatif olarak, surme sinyalindeki kontrol palslerinden bazilarinin silinmesi yontemiyle cikis gucu kontrolu saglanmistir. Boylece daha genis aralikta guc kontrolu gerceklestirilmistir. Sistemin 62.5kHz anahtarlama frekansinda farkli kontrol sinyalleri icin deneysel calisma sonuclari alinarak elektronik simulasyon sonuclari ile karsilastirilmistir