  Lagrangian modelling can be used to derive mathematical models for complex
power electronic converters. This approach uses scalar quantities (kinetic and
potential energy) to derive models, which is simpler than using (vector-based)
force balance equations. It employs generalized coordinates, making it easier
to deal with complex systems with constraints. This systematic approach results
in equations that can be expressed in state-space form, which allows for the
simplification of the simulation and design process and the use of many
standard software packages for system analysis and simulation. In this work,
contributions are made regarding the procedure to be followed for the
Lagrangian modelling of power converters and the incorporation of constraints
within the Lagrangian framework. Furthermore, for the first time, Lagrangian
modelling is extended to non-ideal, high-fidelity descriptions of standard
power electronic circuits.
