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

Abstract

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.

Simulink Model of Parallel Resonant Inverter with DSP Based PLL Controller

“…In (10) it is assumed that the load voltage is nearly sinusoidal. Equation (9) can be discretized as follows:…”

“…Among them current source topology has short circuit protection capability, and power switches can be driven with a simple gate drive circuit. Current source parallel resonant topology is used in many applications such as induction heaters [1]- [5], inverters [6]- [10], dc-dc converters [11]- [13], electronic ballasts [14], battery chargers [15] etc.…”

Self-Oscillated Induction Heater for Absorption Cooler

“…Since self oscillating circuits have the advantages of simplicity, reliability and low cost [1], [2] they are used in high frequency applications such as electronic ballasts [3]- [5], dc-dc converters [6] and induction heating systems [7]- [9].…”