This paper deals with the problem of trajectory tracking of a class of power converters. To analyze the stability of these systems we consider the bilinear structure they admit. First, we propose the theoretical framework for which it is possible to ensure global tracking of trajectories. To do so, a construction of an output signal respect to which the incremental model becomes passive is carried out. This leads to a simple linear PI controller for the plant. Then, we apply this result in a realistic simulation for two well-known converters systems: the boost and the modular multilevel converter (MMC).