Modular multilevel converters (MMCs) are expected to play an important role in future
high voltage direct current (HVDC) grids. Moreover, advanced MMC topologies may include various
submodule (SM) types. In this sense, the modeling of MMCs is paramount for HVDC grid studies.
Detailed models of MMCs are cumbersome for electromagnetic transient (EMT) programs due to
the high number of components and large simulation times. For this reason, simplified models that
reduce the computation times while reproducing the dynamics of the MMCs are needed. However, up
to now, the models already developed do not consider hybrid MMCs, which consist of different types
of SMs. In this paper, a procedure to simulate MMCs having different SM topologies is proposed.
First, the structure of hybrid MMCs and the modeling method is presented. Next, an enhanced
procedure to compute the number of SMs to be inserted that takes into account the different behavior
of full-bridge SMs (FB-SMs) and half-bridge submodules (HB-SMs) is proposed in order to improve
the steady-state and dynamic response of hybrid MMCs. Finally, the MMC model and its control are
validated by means of detailed PSCAD simulations for both steady-state and transients conditions
(AC and DC faults)