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Michele Tucci

Publications and source records attributed to Michele Tucci.

27 records · Page 2Linked to original sources
arXiv2017

Hierarchical Plug-and-Play Voltage/Current Controller of DC Microgrid Clusters with Grid-Forming/Feeding Converters: Line-independent Primary Stabilization and Leader-based Distributed Secondary Regulation

Considering the structure of dc Microgrids (MGs) composed of grid-forming/feeding converters, a hierarchical Plug-and-Play (PnP) voltage/current control architecture for MG clusters is proposed. In the primary level, a PnP voltage/current controller is proposed to achieve simultaneous voltage support and current feeding function according to local references. In addition, stabilizing controller is characterized by explicit inequalities which are only related to local parameters of a MG. In the secondary level, for the system with interconnection of MGs, a leader-based voltage/current distributed controller is proposed to achieve both voltage and current regulation without specifying the individual setpoints for each MG. The proposed controller requires a communication network and each controller exchanges information with its communication neighbors only. With the proposed controller, each MG can plug-in/out of the system seamlessly, irrespectively of the power line parameters and models of other MGs . The proof of the MG cluster closed-loop stability exploits structured Lyapunov functions, the LaSalle invariance theorem and properties of graph Laplacians. Theoretical results are validated by hardware-in-loop (HiL) tests.

math.OC↗
arXiv2017

Voltage stabilization in DC microgrids: an approach based on line-independent plug-and-play controllers

We consider the problem of stabilizing voltages in DC microGrids (mGs) given by the interconnection of Distributed Generation Units (DGUs), power lines and loads. We propose a decentralized control architecture where the primary controller of each DGU can be designed in a Plug-and-Play (PnP) fashion, allowing the seamless addition of new DGUs. Differently from several other approaches to primary control, local design is independent of the parameters of power lines. Moreover, differently from the PnP control scheme in [1], the plug-in of a DGU does not require to update controllers of neighboring DGUs. Local control design is cast into a Linear Matrix Inequality (LMI) problem that, if unfeasible, allows one to deny plug-in requests that might be dangerous for mG stability. The proof of closed-loop stability of voltages exploits structured Lyapunov functions, the LaSalle invariance theorem and properties of graph Laplacians. Theoretical results are backed up by simulations in PSCAD.

eess.SY↗
arXiv2017

Plug-and-play and coordinated control for bus-connected AC islanded microgrids

This paper presents a distributed control architecture for voltage and frequency stabilization in AC islanded microgrids. In the primary control layer, each generation unit is equipped with a local controller acting on the corresponding voltage-source converter. Following the plug-and-play design approach previously proposed by some of the authors, whenever the addition/removal of a distributed generation unit is required, feasibility of the operation is automatically checked by designing local controllers through convex optimization. The update of the voltage-control layer, when units plug -in/-out, is therefore automatized and stability of the microgrid is always preserved. Moreover, local control design is based only on the knowledge of parameters of power lines and it does not require to store a global microgrid model. In this work, we focus on bus-connected microgrid topologies and enhance the primary plug-and-play layer with local virtual impedance loops and secondary coordinated controllers ensuring bus voltage tracking and reactive power sharing. In particular, the secondary control architecture is distributed, hence mirroring the modularity of the primary control layer. We validate primary and secondary controllers by performing experiments with balanced, unbalanced and nonlinear loads, on a setup composed of three bus-connected distributed generation units. Most importantly, the stability of the microgrid after the addition/removal of distributed generation units is assessed. Overall, the experimental results show the feasibility of the proposed modular control design framework, where generation units can be added/removed on the fly, thus enabling the deployment of virtual power plants that can be resized over time.

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arXiv2016

Kron reduction methods for plug-and-play control of ac islanded microgrids with arbitrary topology

In this paper, we provide an extension of the scalable algorithm proposed in (Riverso et al., 2015) for the design of Plug-and-Play (PnP) controllers for AC Islanded microGrids (ImGs). The method in (Riverso et al., 2015) assumes DGUs are arranged in a load-connected topology, i.e. loads can appear only at the output terminals of inverters. For handling totally general interconnections of DGUs and loads, we describe an approach based on Kron Reduction (KR), a network reduction method giving an equivalent load-connected model of the original ImG. However, existing KR approaches can fail in preserving the structure of transfer functions representing transmission lines. To avoid this drawback, we introduce an approximate KR algorithm, still capable to represent exactly the asymptotic periodic behavior of electric signals even if they are unbalanced. Our results are backed up with simulations illustrating features of the new KR approach as well as its use for designing PnP controllers in a 21-bus ImG derived from an IEEE test feeder.

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arXiv2015

A decentralized scalable approach to voltage control of DC islanded microgrids

We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed by several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates to a reference value the voltage of the Point of Common Coupling (PCC) of the corresponding DGU. Notably, off-line control design is conducted in a Plug-and-Play (PnP) fashion meaning that (i) the possibility of adding/removing a DGU without spoiling stability of the overall ImG is checked through an optimization problem; (ii) when a DGU is plugged in or out at most neighbouring DGUs have to update their controllers and (iii) the synthesis of a local controller uses only information on the corresponding DGU and lines connected to it. This guarantee total scalability of control synthesis as the ImG size grows or DGU gets replaced. Yes, under mild approximations of line dynamics, we formally guarantee stability of the overall closed-loop ImG. The performance of the proposed controllers is analyzed simulating different scenarios in PSCAD.

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arXiv2006

Evolutionary Socioeconomics: a Schumpeterian Computer Simulation

The following note contains a computer simulation concerning the struggle between two companies: the first one is "the biggest zaibatsu of all", while the second one is "small, fast, ruthless". The model is based on a neo-Schumpeterian framework operating in a Darwinian evolutionary environment. After running the program a large number of times, two characteristics stand out: -- There is always a winner which takes it all, while the loser disappears. -- The key to success is the ability to employ efficiently the technological innovations. The topic of the present paper is strictly related with the content of the following notes: Michele Tucci, Evolution and Gravitation: a Computer Simulation of a Non-Walrasian Equilibrium Model; Michele Tucci, Oligopolistic Competition in an Evolutionary Environment: a Computer Simulation. The texts can be downloaded respectively at the following addresses: http://arxiv.org/abs/cs.CY/0209017 http://arxiv.org/abs/cs.CY/0501037 These references include some preliminary considerations regarding the comparison between the evolutionary and the gravitational paradigms and the evaluation of approaches belonging to rival schools of economic thought.

cs.GT↗
arXiv2005

Oligopolistic Competition in an Evolutionary Environment: a Computer Simulation

The following notes contain a computer simulation concerning effective competition in an evolutionary environment. The scope is to underline the existence of a side effect pertaining to the competitive processes: the tendency toward an excess of supply by producers which operate in a strongly competitive situation. A set of four oligopolistic firms will be employed in the formal reconstruction. The simulation will operate following the Edmond Malinvaud "short side" approach, as far as the price adjustment is concerned, and the sequential Hicksian "weeks" structure with regard of the temporal characterization. The content of the present paper ought to be considered as a development of the writing: Michele Tucci, Evolution and Gravitation: a Computer Simulation of a Non-Walrasian Equilibrium Model, published with the E-print Archives at arXiv.com (section: Computer Science, registration number: cs.CY/0209017). In such a paper there can be found some preliminary considerations regarding the comparison between the evolutionary and the gravitational paradigms and the evaluation of approaches belonging to rival schools of economic thought.

cs.CY↗