A stabilization method for DC networks with constant-power loads

Abstract

The stability of a DC power distribution system is a key design aspect. The presence of constant-power load induces negative impedance instabilities which should be considered during system design. In this paper the problem of DC power system stability is addressed and two solutions are proposed and compared. The former exploits the insertion of a suitably sized capacitor in parallel to the constant-power converter, while the latter makes use of a storage system controlled through a PI regulator. Simulation results are reported to verify the analysis

Active Damping of a DC Network with a Constant Power Load: An Adaptive Observer-based Design

“…This can be done with the connection in parallel of a suitable capacitor and the CPL. Some disadvantages of this approach are mentioned in (Carmeli et al, 2012, Section III.A). Instead of this passive approach, we propose to add a switched capacitor.…”

“…As proposed in (Carmeli et al, 2012) and (Zhang et al, 2013), we consider the addition of a controlled shunt damper between the feeder and the load, as shown in Fig. 2.…”

“…The former is based on open-loop hardware modifications, whereas the latter implies the modification of existing or added control loops, which may imply the interconnection of additional hardware. In this note we follow the ideas presented in (Carmeli et al, 2012) and (Zhang et al, 2013). In these works, a connection of a controlled power arXiv:1809.04920v1 [cs.SY] 13 Sep 2018 converter, in parallel with the CPL (shunt damper), is proposed to increase the stability margins of a smallscale DC network.…”

“…In Section 2 we give the model of a small-scale network containing a CPL, analyze its equilibria and describe the stability problem addressed in the paper. The proposed controller configuration, adopted from (Carmeli et al, 2012) and (Zhang et al, 2013), is presented in Section 3. Our main stabilization results are included in Section 4.…”

On design of a robust controller to mitigate CPL effect — A DC micro-grid application

“…Some techniques have been reported in literature to handle CPL effect and to eliminate DC bus voltage instabilities in cascaded distributed DC systems such as passive damping, active damping, load shedding and use of storage units/ultracapacitors/filters [13].…”