Abstract:
The continued and envisioned large-scale integration of renewable energy sources as a
reaction to rising global temperatures and climate change will need a readily available DC grid to
increase commissioning and operating efficiency. The effective operation of these grids is predicated
on the correct control of its main control points. A plethora of DC-DC converters that find use in
DC microgrids act as the main control points. DC-DC converters are non-linear and can operate
in different modes with completely unique characteristics. To utilise classical control techniques,
laborious equivalent linear models are derived for DC-DC converters using averaging modelling
schemes. The application and limitations of these modelling techniques are well captured in the
available literature. The most common limitation of the available modelling schemes is that more
focus is dedicated to converter attributes like order, functionality and operating mode, even when
optimal power flow and voltage regulation within the DC network are of more interest. Structurebased modelling techniques like the use of basic building blocks nullify converter attributes in the
modelling process which translates to modelling efficiency. In light of the merits seen with the use of
basic building blocks when modelling converters in CCM, the current study extends these merits
to converters operation in DCM. Similar to modelling converters in CCM, modelling techniques
that are available in the literature continue to consider converter attributes in the modelling process
for DCM operation. Moreover, the two modes of operation are treated as unique entities and often
modelled in a non-unified manner, which compromise modelling efficiency since the same converter
can operate in a different state solely based on loading. The aim is to increase modelling efficiency
but also nullify operating mode in the modelling process. The same basic building blocks are now
modelled as two-port networks for DCM operation and adopted based on the exact configuration
of a specified converter to compute its steady-state and dynamic models. All the advantages seen
when modelling converters in CCM using basic building blocks are retained and augmented when
considering DCM operation. Thus, any converter with well-defined basic building blocks can be
easily modelled solely based on the connection of constituent basic building blocks.
