  We investigate the effects of alternating voltage on nonequilibrium quantum
systems with localised phonon modes. Nonequilibrium Green's functions are
utilised, with electron-phonon coupling being considered with the $GD$
approximation (self-consistent Born approximation). Using a Floquet approach,
we assume periodicity of the dynamics. This approach allows us to investigate
the influence of the driven electronic component on the nonequilibrium
occupation of the vibrations. It was found that signatures of inelastic
transport gained photon-assisted peaks. A simplistic model was proposed and
found to be in good agreement with the full model in certain parameter ranges.
Moreover, it was found that driving the alternating current at resonance with
vibrational frequencies caused an increase in phonon occupation.
