  We show that the dynamics of a driven quantum system weakly coupled to a
finite reservoir can be approximated by a sequence of Landau-Zener transitions
if the level spacing of the reservoir is large enough. This approximation can
be formulated as a repeated interaction dynamics and leads to a quantum master
equation for the driven system which is of Lindblad form. The approach is
validated by comparison with the numerically exact full system dynamics. To
emphasize the role of coherence in the master equation, we propose a
model-system which shows that in its presence, work can be extracted from a
thermal reservoir while if the coherences vanish no work can be extracted.
