Explicit model predictive control with disturbance observer for grid-connected voltage source power converters

Explicit model predictive control with disturbance observer is discussed for grid-connected voltage source power converters. Control objectives are set-point tracking of the DC-link voltage and reference tracking of the reactive power exchanged with the grid under unknown disturbances (load power). Controller and observer design are based on a linearized multi-input multi-output (MIMO) system of the DC-link dynamics with underlying current control-loops. The obstacle in DC-link voltage control is the possible non-minimum phase behavior in certain operation points which requires sufficiently large prediction horizons. Therefore, an explicit solution (control law) for the model predictive controller is derived to make a realtime implementation feasible for arbitrary prediction horizons. For the disturbance observer, it is shown that the observation (estimation) error is bounded. Simulation results illustrate control and observer performance.