Port-Hamiltonian modelling of Modular Multilevel Converters with fixed equilibrium point

The paper presents the derivation of a port-Hamiltonian model of an averaged Modular Multilevel Converter (MMC) that reaches a fixed equilibrium point solution. This MMC model can not be expressed in a straightforward way in a port-Hamiltonian framework due to the lack of skew-symmetry of its interconnection matrices. This work proposes a change of variable and a new per unit notation to overcome this limitation, obtaining a port-Hamiltonian model of the MMC with static equilibrium, useful for control design purposes.