Enhanced switching characteristics of DC-DC boost converter systems

Abstract

In this paper, improvement of the switching characteristics of DC-DC boost converters based on power bipolar junction transistor (BJT) against excessive rise rates of voltage (dv/dt) or current (di/dt) was investigated. Here, it was proven that, in the normal operation of the boost converter (for free running devices), signal voltage across the switch resonates at parasitic ringing frequency of 1.14 MHz during turn-off. Also, ringing signal frequency of 89.0 kHz superimposed the output current waveform was noticed during turn-on mode of operation. Thus, the paper was devoted in the design, analysis and applications of dissipative voltage and current – snubber circuits, as a trial to improve such systems. From which, it is shown that the snubber circuits successfully improve the noticed problems, where for the first case (dv/dt), the ringing frequency was decreased down to 0.20 MHz, while for the second case (di/dt), the ringing frequency was completely damped.

Keywords: DC-DC boost converter, dissipative voltage and current – snubber circuits.