Search results for "Storage system"

An Analysis of the Intertial Response of Small Isolated Power Systems in Presence of Generation from Renewable Energy Sources

2018

Renewable Energy Sources are posing critical issues related to the mining of power systems stability, essentially due to a decrement of the inertial response during system's contingencies. As a consequence, to preserve the security and the reliability of the system, it is necessary to adopt new frequency adjustments mechanisms. This issue becomes particularly critical in isolated power systems, like those of small islands not supplied by the main grid, in the case of high shares of production from unpredictable renewabies such as photovoitaic and wind sources. In this framework, the present work deals with the analysis of the variation of the inertia time constant of a small island in vario…

Modelling energy storage systems using Fourier analysis: An application for smart grids optimal management

2014

In this paper, a new and efficient model for variables representation, named F-coding, in optimal power dispatch problems for smart electrical distribution grids is proposed. In particular, an application devoted to optimal energy dispatch of Distributed Energy Resources including ideal storage devices is here considered. Electrical energy storage systems, such as any other component that must meet an integral capacity constraint in optimal dispatch problems, have to show the same energy level at the beginning and at the end of the considered timeframe for operation. The use of zero-integral functions, such as sinusoidal functions, for the synthesis of the charge and discharge course of bat…

Sensorless induction machine drive for fly-wheel generation unit based on a TLS-based non-linear observer

2016

This paper proposes a sensorless technique for an induction machine Flywheel Energy Storage System (FESS) based on a non-linear observer integrated with a total least-squares speed estimator taking into consideration the IM (Induction Machine) saturation effects. The nonlinear observer is based on an original formulation of the dynamic model of the IM including the magnetic saturation, rearranged in a space-state form, after assuming as state variables the stator current and the rotor magnetizing current space-vectors in the stator reference frame. The choice of the observer gain has been made by the use of Lyapunov's method. The speed signal needed by the non-linear observer for the flux e…

Design of a Battery/Ultracapacitor Energy Storage System for Electric Vehicle Applications

2018

The battery/ultracapacitors (UCs) integration is able to provide notable advantages in the power management of an electric vehicle (EV), in terms of capability of both high energy storage and readiness to deal with fast load variations. In order to manage the charge (or discharge) of the UCs from (or towards) a DC voltage bus, a proper bi-directional converter is required. In this paper, a bi-directional DC-DC converter in connection with a stack of UCs is described and some power simulation results are provided. The proposed converter is a B2R (buck-boost regulator) type. The load is represented by a 40kW peak power, kept for a time window of 3s, as required by the Worldwide harmonized Lig…

A Novel Operating Strategy for Customer-Side Energy Storages in Presence of Dynamic Electricity Prices

2015

In the wholesale energy market, electricity prices are determined by the balance between supply and demand. Normally, customers are not exposed to these variations but pay a constant electricity price. In an attempt to reduce demand peaks, several utilities are moving from a conventional fixed-rate pricing scheme to a new market-based model, based on time-of-use or real-time pricing, able to closely reflect the wholesale energy price. Electricity customers can thus take profit from the installation of storage systems, shifting their energy consumption from on-peak to off-peak periods. This paper presents a novel charging strategy to manage customer storage systems in presence of hourly elec…

Modeling and Performance Assessment of the Split-Pi Used as a Storage Converter in All the Possible DC Microgrid Scenarios. Part I: Theoretical Analy…

2021

The integration of an electrical storage system (ESS) into a DC microgrid using a bidirectional DC/DC converter provides substantial benefits but requires careful design. Among such converter topologies, the Split-pi converter presents several merits at the cost of non-isolated operation. However, the few works in the literature on the Split-pi presented only closed-loop control with a single control loop; furthermore, they neglected the reactive components’ parasitic resistances and did not perform any experimental validation. This work aimed at investigating the use of the Split-pi converter as a power interface between an ESS and a DC microgrid. Five typical microgrid scenarios are prese…

Extension and Tuning of Virtual Synchronous Machine to Avoid Oscillatory Instability in Isolated Power Networks

2020

The risk of oscillatory instability introduced by virtual synchronous machines (VSM) control in isolated power networks is investigated. The considered control is a common scheme widely studied in literature, in several configurations and for different case studies. The impact of the VSM control on the system stability is examined for the existing power network of a Mediterranean island. The VSM control is implemented within the power converters interfacing the energy storage systems (ESS) installed in the network. Simulations and analysis show the occurrence of oscillatory instability in the system, with the ESS-VSM and the synchronous machines of the network progressively swinging against…

Second life employment of a traction battery for load match optimisation of a residential building: Life cycle and operation applications

The increasing use of renewable energy technologies for the electricity generation in buildings will require a growing number of energy storage systems (ESSs) in the next years in order to reduce the mismatch between the highly variable on-site electricity generation and the building load. Retired electric vehicle batteries (EVBs), before recycling, can be used for this purpose, considering that they have about 80% of the original energy capacity. In this context, the study aims at examining an ESS made by retired EVBs, in order to identify its optimal size for reducing the mismatch in a net zero energy building equipped with a photovoltaic plant and to assess the life cycle energy and envi…

Environmental Assessment of a Hybrid Energy System Supporting a Smart Polygeneration Micro-grid

2022

To support the global transition towards a climate-neutral economy by 2050, countries all over the world are implementing low carbon and energy effi ciency policies. This is leading to a rapid increase in the installations of distributed generation technologies. A hybrid system consisting of two or more energy sources could provide a more reliable supply of energy and mitigate storage require ments. In this context, this paper develops an environmental early analysis by the employment of a simplified Life Cycle Assessment approach. The above mentioned approach is used to investigate the environmental performances of the hybrid energy system of the smart polygeneration micro-grid of the Univ…

Energy and environmental benefits of circular economy strategies: The case study of reusing used batteries from electric vehicles

2019

Abstract According to recent literature and technical analyses, used batteries from electric vehicles can still be used, before the final treatment at the end-of-life, in stationary applications that are usually less stressing than the automotive ones. In this framework, a circular economy inspired pathway is emerging between the building and the transportation sector, generally called “second life” of batteries. Used batteries from electric vehicles can be re-used in residential buildings together with renewable electricity generation technologies to improve the matching between the highly variable electricity generation from renewables and the electricity demand in buildings. This study a…