Nonlinear analysis and control of dc-dc converters

It is well known that switching dc-dc converters show a wide range of nonlinear behaviours including bifurcation, sub-haraionics and chaos when they operate outside their design specifications. These nonlinear patterns force the converter to change its normal periodic behaviour to a random-like behaviour; a situation that must be avoided. In this thesis, the nonlinear dynamics of switching dc-dc converters are investigated. It is shown for the first time that the concept of the monodromy matrix (i.e. the state transition matrix for one switching cycle, including the state transition matrices during the switching slants) can be successfully applied to determine the stability of switching dc-dc power converters.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Control of period doubling bifurcations in DC-DC converters

The dc to dc buck converter operating with a voltage controller is a nonlinear, nonsmooth system that presents different circuit topologies within the same switching cycle. In this paper, we propose two new bifurcation or chaos control strategies based on the use of the saltation matrix and the location of the floquet multipliers to stabilize the period-1 orbit of the circuit regardless of the input voltage of the converter. The new methods are analytically and numerically validated and their sensitivity to parameter variations is assessed