  We present a full review of PID passivity-based controllers (PBC) applied to
power electronic converters, discussing limitations, unprecedented merits and
potential improvements in terms of large-signal stability, robustness and
performance. We provide four main contributions. First, we prove that, under
perfect knowledge of the parameters, the controller ensures global exponential
stability of the closed-loop system. Second, we analyze its robustness
properties for a specific class of power converters, by establishing precise
stability margins. Third, we propose a modification of the controller by
introducing a leakage, in order to overcome some of the intrinsic performance
and robustness limitations. Interestingly, such controller can be interpreted
at steady-state as a droop between the input and the passive output. Fourth, we
robustify the design against saturation of the control input via an appropriate
monotone transformation of the controller. The obtained results are thoroughly
discussed and validated by simulations on two relevant power applications: a
dc/dc boost converter and an HVDC grid-connected voltage source converter.
