PhD ThesisSwitched mode DC-DC converters exhibit a variety of complex behaviours in power
electronics systems, such as sudden changes in operating region, bifurcation and
chaotic operation. These unexpected random-like behaviours lead the converter to
function outside of the normal periodic operation, increasing the potential to generate
electromagnetic interference degrading conversion efficiency and in the worst-case
scenario a loss of control leading to catastrophic failure.
The rapidly growing market for switched mode power DC-DC converters demands
more functionality at lower cost. In order to achieve this, DC-DC converters must
operate reliably at all load conditions including boundary conditions. Over the last
decade researchers have focused on these boundary conditions as well as nonlinear
phenomena in power switching converters, leading to different theoretical and
analytical approaches. However, the most interesting results are based on abstract
mathematical forms, which cannot be directly applied to the design of practical
systems for industrial applications.
In this thesis, an analytic methodology for DC-DC converters is used to fully
determine the inherent nonlinear dynamics. System stability can be indicated by the
derived Monodromy matrix which includes comprehensive information concerning
converter parameters and the control loop. This methodology can be applied in
further stability analysis, such as of the influence of parasitic parameters or the effect
of constant power load, and can furthermore be extended to interleaved operating
converters to study the interaction effect of switching operations. From this analysis,
advanced control algorithms are also developed to guarantee the satisfactory
performance of the converter, avoiding nonlinear behaviours such as fast- and slowscale
bifurcations. The numerical and analytical results validate the theoretical
analysis, and experimental results with an interleaved boost converter verify the
effectiveness of the proposed approach.Engineering and Physical Sciences
Research Council (EPSRC), China Scholarship Council (CSC), and school of
Electrical and Electronic Engineerin
