Stabilization and energy management in a DC network by switching between "regular"and "singularly perturbed"controllers

In this paper a switching control law, achieving both stabilization and optimal energy management in a DC network, containing a reversible load and a storage device, is proposed. When the reversible load becomes supplier, the closure of a diode en series with the main source, avoid the energy flow towards it. However, this closure disconnects the source\´s mesh containing "dynamic elements" from the network and causes a drastic change in its topology and its dynamic dimension. A control law stabilizing the "full network" may fail to stabilize the "reduced network" and vice-versa. In the proposed approach, a control law is designed for each topology and a stability preserving switching is performed between them. The switching is driven by the energy flow direction. For the conduction phase of the diode, the control law is built using Dynamic Surface Control (DSC) approach and for its blocking phase, the DSC is combined with the method of singular perturbations. Conditions guaranteeing quadratic stability of the closed loop under proposed control law are given. Simulation results illustrate the effectiveness of the proposed control law.