Buck-Boost Converter Control for Constant Power Loads in Aeronautical Applications

The design of control strategies for bidirectional DC/DC converters is proposed. The motivation for this paper is the increased request from aeronautic applications of innovative and "smart" controllers able to manage automatically electrical energy distribution onboard. Two different control strategies are proposed, and also a higher level, supervisory control law is presented, to switch between the two low-level strategies in a safe way, i.e., ensuring the stability of the overall control law. The first low-level controller is based on the definition of a sliding manifold on which the system state evolution is confined by means of High-Gain or Variable Structure Control, while the second low-level controller exploits an adaptive approach to define a suitable reference current. The high-level switching strategy enables the commutation from one low-level controller to the other only if the Region of Attraction of the second controller has been reached, thus ensuring stability of the commutation. The strategies are designed for the case of Constant Power Loads (CPL), that are well known causes of instability. Detailed simulation results in MATLAB/Simulink are provided, in different scenarios, showing the effectiveness of the proposed controllers.