Robust Output Set-Point Tracking for a Power Flow Controller via Forwarding Design

Abstract

This paper tackles the problem of robust output set-point tracking for a power flow controller (PFC) for meshed DC micro-grids. The PFC is a power electronics device used to control the power (or current) flow in the lines of the grid and act as a DC circuit breaker. The state-space model of this system is bilinear with uncertain dynamics and a polynomial output. In the proposed design, the plant is first extend with an integral action on the tracking error. The cascade model composed by the plant and the integrator is then stabilised by means of a state-feedback law, with a forwarding approach. If the plant parameters are sufficiently close to their nominal value, robust regulation is then achieved. Simulations are given to validate the results.

Robust nonlinear control of a power flow controller for meshed DC grids

“…This article continues a series of studies on the regulation of an m-terminal low voltage DC PFC drawn in Fig. 2 ( Simon et al, 2021b;Lin-Shi et al, 2021;Simon et al, 2021a). As explained in (Simon et al, 2021b), the system formed by the PFC and the microgrid can be modelled using a bilinear state-space model with uncertain parameters and a second-order polynomial output.…”

“…It requires 2m + 1 measurements. (Simon et al, 2021a) This paper is the authors' first control law for a threeterminal PFC. In this paper, the model ( 2) is offered.…”

“…The Forwarding method (Astolfi and Praly, 2017;Zitte et al, 2020), can be applied to nonlinear systems with nonlinear outputs with some local robustness properties. It has been applied to the PFC problem in (Simon et al, 2021a), yielding interesting results. The main concern of our paper is to improve the theoretical results of (Simon et al, 2021a) through a new control method designed specifically for the PFC problem.…”

“…It has been applied to the PFC problem in (Simon et al, 2021a), yielding interesting results. The main concern of our paper is to improve the theoretical results of (Simon et al, 2021a) through a new control method designed specifically for the PFC problem. First, in (Simon et al, 2021b,a), the proofs of stability are given for a nominal vector of parameters and nominal references.…”

“…First, in (Simon et al, 2021b,a), the proofs of stability are given for a nominal vector of parameters and nominal references. Although it is proven in (Simon et al, 2021a) that sufficiently small disturbances of those parameters or references would not destabilise the system, it is unclear whether or not these control laws would be suitable for the high uncertainty of a microgrid. In (Lin-Shi et al, 2021), the uncertainty of the grid is not taken into account directly, and strong hypotheses are taken to simplify the design.…”