Stabilization of a Distributed DC Power System by Shaping Loads Input Impedance: Feedforward Stabilization

Power electronic converters and electric motor drives have become common loads in advanced power systems. Passive LC filters are often used in these systems to reduce the DC-link ripples. These filters are poorly damped for reducing the power losses as well as the size, weight and cost of the system. This may lead to instability phenomena if the load is tightly controlled and absorbs a power exceeding a limit depending on the filter parameters. The purpose of this paper is to present an input impedance shaping method to stabilize DC-link. A matrix filter is put in cascade with load's current controllers. The filter is designed to shape properly input impedance of the load while keeping its performances. Small signal stability of the DC power system is proved using this method. Simulation and experimental results confirm the effectiveness of the proposed stabilizer.