  A new strategy is proposed to control interior permanent magnet generators in
dc microgrids interfaced through an active rectifier. The controller design is
based on the decomposition of the system dynamics into slow and fast modes
using singular perturbation theory. An inner current controller is developed
based on output regulation techniques and an outer voltage controller is
proposed using Nonlinear Model Predictive Control (NMPC). The NMPC regulates
the dc bus voltage and minimizes the ac side losses. Simulation results are
then presented based on realistic conditions for aircraft power systems.
