Pole-placement based nonlinear state-feedback control of the DC-link voltage in grid-connected voltage source power converters: A preliminary study

We discuss pole-placement based nonlinear state-feedback control of the DC-link voltage in grid-connected voltage source power converters. For controller design we use a linearized system model, compute the feedback gains via pole placement and present an analytical expression for the gains in dependence of the actual operating point. The linearized model also allows to illustrate the non-minimum phase behavior of the DC-link dynamics for certain operation points. By online adjustment of the feedback gains, we achieve a stable closed-loop system behavior for different operation points (e.g. different reference set-points and load steps). Simulation results illustrate the control performance of a proportional state-feedback controller, a state-feedback controller with integral action and a proportional-integral state-feedback controller.