Microgrids are increasingly recognized as a key technology for the integration of distributed energy resources into power network, allowing local clusters load and to operate autonomously. However, microgrid operation brings new challenges, especially in islanded frequency voltage control no longer provided by large rotating machines. Instead, converters must coordinate regulate ensure stability. We consider problem designing controllers achieve these objectives. Using passivity theory...

We consider the problem of ensuring stability in a DC microgrid by means decentralized conditions. Such conditions are derived which formulated as input–output properties locally defined subsystems. These follow from various decompositions and corresponding resulting representations. It is shown that these can be combined together appropriate homotopy arguments, thus reducing conservatism relative to more conventional approaches often rely on passivation bus dynamics. Examples presented...

In this paper, the problem of robust performance analysis interconnected uncertain systems with hierarchical structure is investigated. The computational load associated such problems does not allow a direct application robustness usual tools. To overcome difficulty, we exploit and propose an algorithm to perform using integral quadratic constraint "propagation" along structure. This allows us establish tradeoff between computation time required conservatism obtained results. Furthermore, it...

Grid-forming inverter-based autonomous microgrids present new operational challenges as the stabilizing rotational inertia of synchronous machines is absent. The design efficient control policies for grid-forming inverters is, however, a nontrivial problem where multiple performance objectives need to be satisfied, including voltage/frequency regulation, current limiting capabilities, and active power sharing scalable operation. We propose, in this article, novel architecture frequency...

We consider the problem of synchronization coupled oscillators in an advanced Kuramoto model that includes coupling conductances, and is characterized by nonhomogeneous weights noncomplete graphs. Lyapunov analysis once such conductances aforementioned properties are included becomes nontrivial more conventional energy-like functions not applicable or conservative. Small-signal has been performed for models, but due to fact we have convergence a manifold, stability via linearization on its...

Control and fault compensation in wind turbines represents a challenge due to the stochastic nature of driving force power generation these systems, their inherent nonlinearity high coupling between control inputs. In this paper, robust nonlinear predictive is considered order satisfy objectives full load regime. Model allows taking into account constraints on inputs outputs as well model nonlinearity. Robust MPC parameter uncertainties, that are supposed work be pitch angle actuator fault....

This paper presents an averaged model and nonlinear observer for on/off pneumatic actuator. The actuator is composed of two chambers four solenoid valves. proposed has the advantage using only one continuous input instead binary inputs. Based on this new model, a sliding mode designed piston position pressure measurements in order to estimate velocity other chamber. observation errors converge towards zero finite time performance validated closed loop experimental benchmark.

Cooperative Adaptive Cruise Control with a variable time headway is considered in this paper. The two main objectives are the convergence of spacing errors towards zero and attenuation any disturbance propagating along platoon. To ensure those for headway, H∞ - Linear Parameter Varying approach used. efficiency designed controller illustrated through frequency domain analysis simulations.

This paper investigates the performance analysis of uncertain large scale systems. Due to their complexity, usual robustness methods based on e.g: μ or Integral Quadratic Constraints (IQC) cannot be practically applied. In order address this problem, in [1], we propose represent a system as an interconnection sub-systems and perform hierarchical by propagating IQC characterization each sub-system through interconnection. For given computational time, conservatism dramatically depends class...

Time domain specifications such as overshoot, rise time and tracking behaviour can be extracted from an amplitude frequency response. For uncertain systems we use for this upper bound on the maximum There are tools which compute each in a grid. Computing computational expensive when studying large scale system hence it is interesting to have low dense However, case, example occur that peak of response occurs at not A consequence overshoot will determined well system. In paper present method...

We consider the problem of stability analysis an inverter-based microgrid where higher order models are used for inverter and line dynamics. Decentralized conditions derived through which network can be deduced, with these formulated as input/output on locally defined subsystems. The allow to exploit natural passivity properties lines when represented in a common reference frame, but reduce conservatism by additionally taking into account coupling neighbouring buses. Examples given...

We consider the problem of ensuring stability in a DC microgrid by means decentralized conditions. Such conditions are derived which formulated as input-output properties locally defined subsystems. These follow from various decompositions and corresponding resulting representations. It is shown that these can be combined together appropriate homotopy arguments, thus reducing conservatism relative to more conventional approaches often rely on passivation bus dynamics. Examples presented...

Abstract This paper presents a state-averaged model and the design of nonlinear observers for an on/off pneumatic actuator. The actuator is composed two chambers four solenoid valves. elaborated has advantage using only one continuous input instead binary inputs. Based on this new model, high-gain observer sliding-mode are designed position pressure measurements in chambers. Finally, their closed-loop performance verified compared experimental benchmark.

Grid-forming inverters-based autonomous microgrids present new operational challenges as the stabilizing rotational inertia of synchronous machines is absent. We propose in paper a control architecture for frequency and voltage with good scalability properties. At slower timescales it allows to incorporate distributed secondary policy which we provide stability result line conductances taken into account. faster timescale this satisfies passivity property wide range parameters. The...

This paper investigates the uncertain power flow analysis in distribution networks within context of renewable resources integration such as wind and solar power. The aims to bound worst-case voltage magnitude any node network for a given generation scenario. major difficulty this problem is non-linear aspect equations. proposed approach does not require linearization these equations formulates an optimization with polynomial constraints. A new tool investigate feasibility problems presented...

This paper is concerned with convergence analysis for the mirror descent (MD) method, a well-known algorithm in convex optimization. An framework via integral quadratic constraints (IQCs) constructed to analyze rate of MD method strongly objective functions both continuous-time and discrete-time. We formulate problem finding rates algorithms into feasibility problems linear matrix inequalities (LMIs) schemes. In particular, continuoustime, we show that Bregman divergence function, which...

This paper presents a comprehensive convergence analysis for the mirror descent (MD) method, widely used algorithm in convex optimization. The key feature of this is that it provides generalization classical gradient-based methods via use generalized distance-like functions, which are formulated using Bregman divergence. Establishing rate bounds general non-trivial problem due to lack monotonicity properties composite nonlinearities involved. In paper, we show divergence from optimal...