  In this contribution we present an intrinsic description of time-variant Port
Hamiltonian systems as they appear in modeling and control theory. This
formulation is based on the splitting of the state bundle and the use of
appropriate covariant derivatives, which guarantees that the structure of the
equations is invariant with respect to time-variant coordinate transformations.
In particular, we will interpret our covariant system representation in the
context of control theoretic problems. Typical examples are time-variant error
systems related to trajectory tracking problems which allow for a Hamiltonian
formulation. Furthermore we will analyze the concept of collocation and the
balancing/interaction of power flows in an intrinsic fashion.
