CHAOTIC DYNAMICS OF VOLTAGE-MODE CONTROLLED BUCK CONVERTER WITH PERIODIC INTERFERENCE SIGNALS

Abstract

The undesirable intermittency in periodically driven nonlinear systems such as switching power converters is a more common problem in power electronic circuit design. Such operations are usually avoided by modifying the circuit parameters which necessitates a proper understanding of the effects of various spurious signals. In the present work, the effect of different types of periodic interference signals like sinusoidal, triangular and saw-tooth waveforms have been considered and the influence of these signals in the input, control and reference voltages of the buck converter has been investigated. It is found that the presence of sinusoidal or triangular interference signal whose frequency is comparable with the switching frequency of the converter or its rational multiples manifests as symmetrical period-doubling bifurcation in intermittent periods. However, the presence of either sinusoidal or triangular interference signal having irrational frequency ratios with the switching frequency of the converter leads to quasi-periodic route to chaos. Also it is observed that the influence of saw-tooth interference signal results in intermittent chaos in the dynamics of the system. Further, the effect of simultaneous presence of more than one interference signal has been considered. The dynamics of this converter system has been mathematically described and analyzed with a simple discrete map. The ordered and the chaotic dynamics of this system have been investigated with suitable analytical, numerical and experimental means.