  As the share of Converter-Interfaced Distributed Energy Resources (CIDERs) in
power distribution systems increases, hybrid AC/DC distribution systems are
drawing more interest. Indeed, CIDERs usually rely on DC power and hybrid AC/DC
grids with few Network-Interfacing Converters (NICs) are a promising solution
to decrease installation costs and conversion losses compared to a pure AC
grid. However, interactions between the AC and DC subsystem of a hybrid AC/DC
grid can lead to undesirable amplification and propagation of harmonics. The
authors of this paper have recently proposed a Harmonic Power-Flow (HPF) method
that accurately represents the AC power flows including the coupling between
different harmonics. The HPF framework is formulated through the mismatch
equations of the nodal equations between the grid and the resource models and
solved by a Newton Raphson algorithm. This paper updates the HPF method to
model hybrid AC/DC grids interconnected through NICs. To this end, the model of
the NICs and the resulting coupling between the AC and DC subsystems is
included in the mismatch equations and the Jacobian matrix of the algorithm.
The updated HPF method is applied to a typical hybrid AC/DC grid, and its
accuracy is validated through detailed time-domain simulations with Simulink.
