BIFURCATION ANALYSIS OF DC-DC CONVERTERS BY USING NON-LINEAR METHODOLOGIES

Abstract

Power electronic systems display a variety of complex behaviors in Switched mode DC-DC converters for example rapid adjustments, in the operation, and bifurcation followed by chaotic performance. This unanticipated behavior leads the power electronic converter to action outside the operating regime and oftenly attributed to random external influences, which may causes sensor failure, Electromagnetic interference, reduction of converters efficiency and in the worst situation, a state of loss of control leads to a converter failure. The swiftly growing DC-DC power conversion market wants more cheap operations. To attain this objective, power electronic converters must work reliability in all loading circumstances including border conditions. For the past ten years, these boundary conditions have gotten a lot of attention from scientists. These boundary conditions in power electronic converters, result in various analytical and theoretical approaches. The most intriguing results, on the other hand, are built on mathematical structures that are abstracted, which is it can’t be used straightly in the development of effective industrial application systems. In the thesis, the discrete time analysis method of DC-DC Flyback converters and cuk converters are used to determine the full dynamics of non-linear behavior. The stability of the system can be demonstrated by deriving a state space and discrete iterative mapping which includes complete information about the closed loop control and DC converter parameter. Discrete iterative mapping could be used for additional analysis of stability, under the effects of nonlinear loads, parasitic parameters, and could also be extended to different functional converters. After analyzing the results, some modern control algorithms may develop to ensure the adequate functionality of the converter and to avoid complex behaviors like as rapid and slow-scale bifurcations. The flyback converter and cuk converter are theoretically derived and analyzed experimentally for doublet and chaotic bifurcations.