Tommaso Caldognetto

University of Padua | UNIPD · Department of Management and Engineering

This article introduces a power controller for three-phase inverters in microgrids that can be used in three-phase three-wire and three-phase four-wire systems. The controller enables active and reactive power tracking and unbalanced current control during grid-tied operation, while also allowing seamless transitions into islanded operation. The pr...

Electronic power converters are widespread and crucial components in modern energy scenarios. Beyond mere electrical energy conversion, their electronic structure allows several functionalities to be naturally embedded in them, including energy management, diagnosis, communication, etc. The operation of the converter itself, or the system interface...

Isolated multi-port converters offer the ability to connect multiple sources and loads operating at different power and voltage levels at their ports, providing galvanic isolation and shared magnetics as benefits. Nevertheless, challenges are present in these converters, primarily due to ports coupling, a high number of modulation variables, and th...

The four-switch buck-boost (FSBB) topology is often used in combination with other isolated converters to extend the voltage range capability of the overall structure. In such applications, the duty-cycles of the two legs of the FSBB are independently controlled, and a phase-shift is typically used to shape the inductor current ripple and thus achi...

Decarbonization of major energy-consuming sectors is a top priority of the 2015 Paris Agreement and the Intergovernmental Panel on Climate Change (IPCC) climate change 2023 report. This has significantly challenged today's energy systems with the development of long-term sustainable energy production and storage. Perhaps one of the most promising s...

The article introduces an extremum seeking control (ESC) technique for determining the optimal operating points of a multi-stage converter named twin-bus buck converter (TBB) [8]. The TBB converter features several modulation parameters, such as the switching frequencies of the CLLC stage and of the TBB post-regulator, which have a notable impact o...

This paper considers a multi-carrier modulation in which the phase-shifts between the carriers are adjusted to reduce the rms current flowing into the active split dc-link capacitors of four-wire three-phase inverters when the neutral node is modulated with the third harmonic. Capacitors current reduction is beneficial in terms of volume, losses, a...

Electronic power converters are extensively applied in microgrids to interface distributed energy resources to the grid. Besides the primary active-power control, electronic converters support increasingly advanced and flexible control capabilities. While the former is typically bound to local needs (e.g., maximum power extraction from renewables),...

The integration of dc microgrids (MGs) into distribution networks offers a promising solution to address the growing demand for electric energy by facilitating the incorporation of renewable energy sources and energy storage systems. To ensure sustained and reliable operation, dc MGs are commonly linked to utility grids through interlinking convert...

Isolated multi-port converters can host loads and sources at different power and voltage levels to their ports by a single topology, giving potential merits in terms of power density and efficiency. However, the higher the number of ports, the higher the number of degrees of freedom in the modulation patterns. This high number of modulation variabl...

A flexible power electronic converter embedding a rapid control prototyping platform suitable to be applied in research test setups and teaching laboratories is proposed and described in this paper. The electronic system is composed of three subsystems, namely, i) three half-bridge power boards, ii) a dc-link capacitor bank with a half-bridge power...

In this paper the use of artificial neural networks (ANNs) for the average modeling non-linearities in dc-dc converters is explored. The aim is to analyze the effectiveness of non-linear autoregressive exogenous NARX-ANN to realize an average black-box dynamic model of dc-dc converters that includes, within the same framework, converter non-lineari...

The advent of energy communities will revolutionize the energy market. However, exploiting their full potential requires innovations in the structure and management of low-voltage grids. End users shall be aggregated within microgrids, where their physical interaction is possible and coordinated operation of power sources and energy storage systems...

This manuscript describes the operation of a droop-based controller for three-phase converters in the case of the absence of a neutral connection to the grid. The controller is capable of output power tracking and smooth transitions into the islanded operation. While independent per-phase control of the converter output power is possible if a neutr...

This paper proposes and analyzes a two-stage dc-dc isolated converter for electric vehicle charging applications, where high efficiency over a wide range of battery voltages is required. The proposed conversion circuit comprises a first two-output isolation stage with CLLC resonant structure and a second two-input buck regulator. The transformer of...

This paper investigates the use of non-linear autoregressive exogenous (NARX) artificial neural networks (ANNs) to achieve black-box average dynamic models of dc-dc converters capable of capturing the main converter non-linearities. Non-linearities may include, for example, dynamic behavior variations due to changes of operating point or operating...

Voltage-controlled inverters (VCI) for distributed energy resources allow operation in grid-connected and islanded conditions. Common techniques based on P-f, Q-V droop-control use sinusoidal voltage references for the VCIs, which brings unwanted circulating harmonic currents in case of connection to grids with distorted voltage. In fact, the volta...

p>This work considers the modeling of power electronics converters by the use of artificial intelligence techniques.</p

p>This work considers the modeling of power electronics converters by the use of artificial intelligence techniques.</p

This article proposes and analyzes a two-stage isolated dc–dc converter for electric vehicle charging applications, where high efficiency over a wide range of battery voltages is required. It employs a first preregulation stage and a second half-bridge LLC stage, integrated with the first. The second stage is always operated at resonance, ensuring...

Voltage-controlled inverters (VCI) for distributed energy resources allow operation in both grid-connected and islanded conditions. Common techniques based on P -f Q-V droop-control use sinusoidal voltage references for VCI, which brings to unwanted circulating harmonic currents in case of connection to grids with distorted voltage. In fact, the vo...

Isolated multi-port converters show the merits of hosting several sources and loads with different voltage and power ratings, allowing power routing among multiple ports with high power density. However, many degrees of freedom are available for modulation, and exploiting them for optimal converter operation is challenging. This paper proposes an a...

This article presents the topology and control of a three-port energy gateway (EG) for hybrid ac/dc nanogrids. The simple hardware architecture allows connecting renewable energy generators, energy storage (ES) devices, such as ultracapacitors, and the utility grid through three different interface converters, which, altogether, define the three-po...

Local area energy networks (E-LANs) are cyber-physical systems whose physical layer is a meshed low-voltage microgrid fed by a multiplicity of sources, i.e., utilities, energy storage systems, and distributed power sources. The cyber layer includes distributed measurement, control, and communication units, located at end-user premises, as well as c...

The paper presents a multidimensional ripple correlation search technique of optimal operating points of triple active bridge (TAB) converters. Such converters present multiple modulation parameters that should be exploited to achieve high operation efficiency. On the other hand, the several degrees of freedom available make the identification of o...

This paper presents a droop-based controller for grid-tied three-phase inverters. The controller allows to regulate the inverter output power while operating grid-tied, to support the local grid voltage while operating islanded, and to seamlessly transition into this latter mode of operation. Remarkably, the use of the traditional droop control sch...

This paper presents a droop-based controller for grid-tied three-phase inverters. The controller allows to regulate the inverter output power while operating grid-tied, to support the local grid voltage while operating islanded, and to seamlessly transition into this latter mode of operation. The use of the traditional droop control scheme for per-...

Efficient management of energy resources is crucial in smart buildings. In this work, model predictive control (MPC) is used to minimize the economic costs of prosumers equipped with production units, energy storage systems, and electric vehicles. To this purpose, the predictive control manages the available energy resources by exploiting future in...

This paper proposes a multi-input multioutput (MIMO) digital control strategy for a bidirectional interleaved boost converter with coupled inductors, designed to operate as an interface between an ultra-capacitor and a high-voltage dc bus in a hybrid nano-grid. The control strategy keeps the high-voltage side dc-bus of the nano-grid stable when the...

This paper proposes a triple phase shift modulation (TPS) with an optimization technique that aims at maximizing the efficiency of the dual active bridge converter. Such a converter is often used to interface renewable or energy storage systems in smart dc power systems, where loss minimization via TPS is crucial, especially at light-load condition...

This paper describes a control methodology for electronic power converters distributed in low-voltage microgrids and its implementation criteria in general microgrid structures. In addition, a real-time simulation setup is devised, implemented, and discussed to validate the control operation in a benchmark network. Considering these key aspects, it...

The diffusion of distributed energy resources in distribution networks requires new approaches to exploit the users’ capabilities of providing ancillary services. Of particular interest will be the coordination of microgrids operating as an aggregate of demand and supply units. This work reports a model predictive control (MPC) application in micro...

div> Grid-tied inverters are widely used for inter- facing renewable energy sources or storage devices to low-voltage electrical power distribution systems. Lately, a number of different control techniques have been pro- posed to address the emerging requirements of the smart power system scenario, in terms of both functionalities and performance....

div> Grid-tied inverters are widely used for inter- facing renewable energy sources or storage devices to low-voltage electrical power distribution systems. Lately, a number of different control techniques have been pro- posed to address the emerging requirements of the smart power system scenario, in terms of both functionalities and performance....

Grid-tied inverters are widely used for interfacing renewable energy sources or storage devices to low-voltage electrical power distribution systems. Lately, a number of different control techniques have been proposed to address the emerging requirements of the smart power system scenario, in terms of both functionalities and performance. This pape...

Pervasive proliferation of non-linear and time-varying loads and distributed generation make the power system operate under conditions that are substantially different from traditional sinusoidal ones. This calls for advanced compensation equipment and coordinated operation to improve power quality and efficient use of distributed resources. Power...

This work presents the application of model predic-tive control (MPC) for the energy management of smart buildings in microgrids. It is shown that by means of the described MPC formulation the power exchange at the point of connection of the building can be made close to a given power reference, typically available in microgrid contexts, and, there...

This paper proposes a power control loop strategy for Voltage-Source Inverters (VSIs), based on the use of abc frame PI controllers. Its physical behaviour and mathematical model are presented in detail and the inverter output impedance is derived to analyze the obtained disturbance rejection performance. The results show that the proposed scheme i...

This paper proposes an approach to obtain harmonic compensation and power control by exploiting the electronic power converters deployed in low-voltage microgrids. By the proposed approach, distributed harmonic current compensation is achieved without interfering with the converter's power exchange involved in interfacing the local energy resources...

The European directive "Clean Energy for All Europeans" depicts for 2030 a new scenario for low-voltage distribution grids, where each end-user will have the right to trade energy and offer demand-response in the electrical market either individually or in aggregation with others. This creates a new perspective for renewable energy sources (RES) an...

This paper proposes a technique to control distributed energy resources in low-voltage microgrids aiming at (i) allowing power flow control at the point of connection with the upstream grid, (ii) keeping voltage profiles within the operational limits. The first feature is crucial in smart low-voltage power systems. In fact, it enables both demand-r...

Droop-controlled distributed energy resource converters in dc microgrids usually show low output impedances. When coupled with ac systems, second-order harmonics typically appear on the dc-bus voltage, causing significant harmonic currents at the converters resource side. This paper shows how to reduce such undesired currents by means of notch filt...

AC microgrid is an attractive way to energize local loads due to remotely located renewable generation. The AC microgrid can conceptually comprise several grid-forming and grid-following power converters, renewable energy sources, energy storage and local loads. To study the microgrid dynamics, power-hardware-in-the-loop (PHIL)-based test setups ar...

This paper proposes the third generation of the Power-Based Control, that is, an approach to effectively coordinate the operation of single-and three-phase inverter-interfaced distributed energy resources that can be arbitrarily connected among the phases of three-phase four-wire low-voltage microgrids. The aim of the approach is to precisely regul...

An on-line approach to evaluate and monitor the stability margins of dc microgrid power converters is presented in this paper. The discussed online stability monitoring technique (MT) is based on the Middlebrook's loop-gain measurement technique, adapted to the digitally controlled power converters. In this approach, a perturbation is injected into...

This paper presents a multifunctional control system for interlinking converters interfacing microgrids and AC mains. Applicable standards pose power quality and grid support function requirements for converters that interface energy resources of DC nature with the AC utility grid. At the same time, the forthcoming smart grid scenario calls for add...

This paper proposes a local power-based droop controller for distributed energy resource converters in dc microgrids that are connected to upstream grids by grid-interface converters. During normal operation, the grid-interface converter imposes the microgrid bus voltage and the proposed controller allows power flow regulation at distributed energy...

The paper analyzes a large-bandwidth, triple-loop controller designed for single-phase, grid-tied, voltage-source inverters with LCL output filter. The inner control loops regulate the inverter output current and the filter capacitor voltage respectively, while the third, outer one regulates the current injected into the grid. The inner loops are g...

The parallel connection of multiple electronic power converters is typically used to connect renewable power sources to the electricity grid, like often done, for example, in photovoltaic farms. This interconnection of systems can be affected by instability issues above the fundamental grid frequency, which has detrimental effects on power quality,...

The European directive “Clean Energy for All Europeans” (November 2016) depicts for 2030 a new scenario for low-voltage distribution grids, where each end-user will have the right to trade energy and offer demand-response in the electrical market, either individually or in aggregation with others. This paradigm shift in the low-voltage electric mar...

The chapter deals with control of low-voltage microgrids with master-slave architecture, where distributed energy resources interface with the grid by means of conventional current-driven inverters (energy gateways, slave units), and a voltage-driven grid-interactive inverter (utility interface, master unit) governs the interaction between the util...

Owing to the increasing penetration of information and communication technologies and power electronics, low-voltage microgrids with distributed generation may progressively evolve to Local Area Energy Networks (E-LANs), that is, energy networks with degrees of flexibility, reliability, robustness, and readiness similar to LANs of digital devices....