Stability and robustness analysis of a DC/DC power conversion system under operating conditions uncertainties

Stability margins of the switch-mode DC/DC power conversion systems are very sensitive to variations in load and system parameters. In aerospace applications these systems can be exposed to considerable variations in temperature that can cause large changes in system parameters from their nominal values and can lead to stability problems if this issue is not properly taken into account during the design phase. In this study robust stability margins are calculated for a system that consists of a DC/DC closed loop buck converter and an input LC filter considering extreme variations in temperature. For the prototype system, the paper details a modelling approach to developing an uncertain system model which is used to assess robust stability based on the principle of Structural Singular Value. The approach is verified through simulations in MATLAB and through experimental tests.