Bond Graphs in the Design of Adaptive Passivity-Based Controllers for DC/DC Power Converters

In this paper a new approach is proposed for the design of adaptive passive dynamical compensators regulating the output load voltage in pulse-width-modulation (PWM) DC/DC power converters. The approach is based on the bond graph description of the system. For the design of the passivity-based controller, a damping injection on the error dynamic bond graph is performed where dissipation is added in order to achieve asymptotic stability. Bicausality is used to determine the steady state value of the desire output variable. This controller is then modified to generate an adaptive feedback scheme. The non-minimum phase nature of the average output voltage variable is demonstrated by a graphical analysis performed directly on the average bond graph of the converter. The performance of the proposed controller of each converter is tested through computer simulations. The results obtained in the paper can be extended without any difficulty to other systems represented via bond graphs.