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January 2004 - June 2017
Publications
Publications (82)
The reversible use of a volumetric machine as a compressor and expander shows potential for micro-scale compressed air energy storage systems because of lower investment costs and higher operational flexibility. This paper investigates experimentally the reversible use of a 3 kW oil-flooded twin-screw compressor as an expander for a micro-scale com...
Torque measurement is a key task in several mechanical and structural engineering applications. Most commercial torquemeters require the shaft to be interrupted to place the sensors between the two portions of the shaft where a torque has to be measured. Contactless torquemeters based on the inverse magnetostrictive effect represent an effective al...
This study introduces a new method for real-time efficiency tracking and stable output power of Dynamic Wireless Power Transfer (DWPT) systems using variable capacitors. A preliminary detailed discussion and an analysis of the DWPT system are carried out to show how the system can optimize power transmission and efficiency when the relative positio...
This paper derives practical dynamic models for the glass industrial manufacturing process to be then included in model-based control solutions. In particular, the first section of the plant, that is, the glass melting furnace is investigated: silica sand and recovered glass are used as raw materials, and through methane and oxygen combustion melt...
In this paper, the experimental validation of an innovative clutch based on magnetorheological fluids (MRFs) excited by permanent magnets is described. The device, used in automotive applications to engage and disengage the vacuum pump, is tested using a standardized Worldwide harmonized Light-duty Test Cycle (WLTC). A test bench is built, and the...
This paper reports the design and optimization of a permanent magnet-based spring. The aim of the optimization, performed using a particular form of the self-organizing map (SOM) algorithm, was to determine the dimensions of a ring PM-based spring with a force–displacement curve similar to a desired one. For each step in the optimization process, a...
In this article, a novel axial flux double-stator switched reluctance motor (AFDSSRM) is presented and optimized for electric vehicle applications. AFDSSRM adopts the axial arrangement of double-stator and inner rotor structure with a full-pitch winding configuration. The flux generated by the two stators cancels each other at the unaligned positio...
Increasing energy efficiency requirements mandatory ask for optimizing energy utilization in many devices, which include internal combustion engines. One of the most investigated subjects is the energy recovery from the exhaust, such as turbo-compound systems, which usually consist in a secondary turbine located afterward the turbocharger. Here an...
In this contribution the authors use a Deep Neural Network based approach for the optimization of an electric motor, taking into account both electromagnetic and mechanical constraints, i.e. approaching the problem from the multiphysics point of view. In the design process of high speed electric motors, the mechanical design of the rotor is of note...
In electric vehicles with multiple motors, the torque at each wheel can be controlled independently, offering significant opportunities for enhancing vehicle dynamics behaviour and system efficiency. This paper investigates energy efficient torque distribution strategies for improving the operational efficiency of electric vehicles with multiple mo...
Solid armatures in electromagnetic rail launchers have to undergo severe electromagnetic, mechanical, and thermal stresses. These stresses are unevenly distributed in the armature mainly due to the velocity skin effect. Contrasting this effect reduces the peak to average ratio of the stresses and allows better performance of the device. In this art...
Tramway systems are more and more diffused today, to reduce pollution and greenhouse emissions. However, their electrical feeding substations can have significant margin for improvement. Therefore, it is questionable which kind of changes can be introduced, by changing their main features. First of all, transformer technology can be enhanced, by mo...
Multiphysics problems represent an open issue in numerical modeling. Electromagnetic launchers represent typical examples that require a strongly coupled magnetoquasistatic and mechanical approach. This is mainly due to the high velocities which make comparable the electrical and the mechanical response times. The analysis of interacting devices (e...
The computational cost of topology optimization based on binary particle swarm optimization is greatly reduced by the use of Deep Neural Networks (DNN). A first Convolutional Neural Network (CNN) is trained with data coming from Finite Element Analysis (FEA) with the aim of correctly estimating the output quantity (a motor torque in the proposed ca...
In this work a novel approach is presented for topology optimization of low frequency electromagnetic devices. In particular a surrogate model based on deep neural networks with encoder-decoder architecture is introduced. A first autoencoder deep neural network learns to represent the input images that describe the topology, i.e. geometry and mater...
Automation and intelligent technologies provide an opportunity to improve the construction yard. The aim of this study is the development of smart machinery in construction projects, through technologies able to confer them autonomy and awareness. The system includes real-time recognition of individual activity by a smart plug equipped with a micro...
In this paper an innovative brake, based on magneto-rheological fluids, is described. A system of Permanent Magnets, properly arranged in the device, has been designed to maximize the excitation field inside the fluid. The system has been analyzed by means of a 3D FEM code. The results in terms of magnetic flux density inside the fluid and the brak...
Small scale power plants require component cost reduction to remain competitive in the energy market. Due to this scenario, the development of expander devices is usually derived from the technology of volumetric compressors, achieving the experimental analysis as a mandatory step to assess the techno-economic feasibility of a prototype. This work...
In this paper the authors introduce a semi-analytical model for the analysis and the design of a Permanent Magnet (PM) tubular linear generator intended for electrical energy generation from sea waves. The translator of the analyzed machine is constituted by axially magnetized ferrite PMs with alternating polarity and soft-magnetic pole-pieces in b...
Since there is a growing interest worldwide in reducing pollution from sea transport and sea ports activities, one of the biggest issues is to reduce energy consumption and emissions from ground transportation within ports to cranes and other logistic activities. In particular, Rubber Tired Gantry cranes with Diesel engine coupled with electric dri...
In this paper we present a new Permanent Magnets (PMs) bearing, which is composed of a rotor capable to levitate at a short distance from a dedicated stator. Proper configurations of PMs arranged on both the stator and the rotor allows having the magnetic suspension. Intrinsic mechanical instability characterizes the device; a passive stabilization...
In this paper, the stability analysis of a new permanent magnets (PMs) bearings is presented and discussed. The suspension is assured by the repulsive force of properly shaped PMs placed on both the stator and the rotor. Then, exploiting currents induced on a system of null-flux coils attached to the stator, a stabilizing force for the translation...
In this paper, the numerical analysis on an air-core pulsed alternator is presented. Since compulsators are characterized by very fast electromechanical transients, their accurate analysis requires strong coupling between the equations governing the electrical and the mechanical behaviors. The device is investigated by using a dedicated numerical c...
In this paper a novel evolutionary algorithm is used for the optimization of the performance of a magnetorheological (MR) device, capable to transmit torque between two shafts and powered by a system of Permanent Magnets (PMs). The stochastic, evolutionary, global optimization algorithm is based on a modified version of the self-organizing map. It...
In this paper the authors perform a comparison among three different stator structures for a Tubular Permanent Magnet Linear Machine. Each structure is characterized by its own lamination which is expected to contribute to the overall performance of the machine. A detailed analysis of the main figures of merit of the three configurations has been c...
The WAVE (Wave-powered Autonomous Vehicle for marine Exploration) project involves the development of a novel hybrid oceanographic glider/Autonomous Underwater Vehicle (AUV) with power recharging capabilities from environmental renewable sources, aiming at enhancing the endurance of a typical marine mission. In this paper we present a brief descrip...
Hybrid energy systems represent today one optimal solution for different mobility areas. This is shown in the paper by describing three applications. The first one refers to a tramway system: regenerative braking has been enhanced by introducing some stationary storage capability in correspondence of electrical feeding substations. The second one r...
The main purpose of this paper is to carry out a preliminary comparison between two linear tubular synchronous, three-phase generators for WEC (Wave Energy Converter) applications. The first device is a conventional one, with a single slotted stator and a mover which is composed of Permanent Magnets (PMs) arranged in an Halbach array. The second co...
This paper presents an analytical model for the investigation of the gyroscopic stabilization of the launch package in induction type coilguns. By a proper arrangement of coils and of their feeding currents, a traveling wave of flux density is produced, which is characterized by axial and azimuth components of velocity. The resulting action exerted...
A semi-analytical model of the Double Sided Tubular Linear Induction Motor (DSTLIM) is adopted for the optimization of the thrust force of the stages of an ElectroMagnetic Aircraft Launch System (EMALS). The model allows a fast and accurate prediction of all the electromagnetic quantities in the device, including the thrust force, the back-electrom...
In this paper, the authors focus their attention on the way magnetic circuits and permanent magnets are usually treated in most textbooks and electrical engineering courses. This paper demonstrates how this important topic is too often presented simplistically. This simplistic treatment does not allow the students to develop a complete understandin...
An efficient method for monitoring online both mechanical and electrical parameters of a permanent-magnet motor drive is presented in this paper. The approach is based on the analysis of stationary oscillations induced with multiple relay feedback tests and without stopping the process. The simulations results illustrate the validity of the analyti...
This paper shows a new sensor based on infrared images for monitoring
pantograph catenary interaction. Due to the displacement of the contact point
with respect to the reference position an image processing analysis of each frame
is performed by using the Hough transformation in order to detect automatically
monitoring variables of interest (e.g. t...
The pantograph-overhead contact wire system is investigated by using an infrared camera. As the pantograph has a vertical motion because of the non-uniform elasticity of the catenary, in order to detect the temperature along the strip from a sequence of infrared images, a segment-tracking algorithm, based on the Hough transformation, has been emplo...
An experimental method is proposed to estimate all design specifications represented by circles in the Nyquist plane (e.g., phase margin, sensitivity, and closed-loop bandwidth) in case of closed-loop dc/dc switching converters. The method is based on the complete root contour (CRC) analysis in the root locus plane. All typical specifications for c...
In the framework of a recent Italian National Research Project focused on drive-by-wire systems for industrial vehicles, a high-torque electric actuator was searched complying with stringent requirements in terms of specific performances, cost and dependability. This paper describes the considerations and guidelines that led to the development of a...
In this paper a new performance index, based on a periodic evaluation of the integral of the absolute error, is proposed for monitoring switching DC-DC converters. Parameter variations or operating condition modifications can be easily estimated using a relay closed loop tests without stopping the process. An interesting practical application of su...
The aim of the work is to identify continuous average models of switching converters from input-output data. Among the various identification techniques, modulating functions were chosen due to their capability for revealing converter dynamics, even in the case of fast time constants. Due to its low-pass filtering property, such an identification t...
International interest is growing for improving performance of the rail transport system. A crucial problem for railway companies is to prevent damages to the overhead line equipment and to pantographs. A brief overview of our research activities is ad- dressed, in the fields of active pantographs and advanced methods for measuring the qual- ity of...
Nowadays, advanced applications of motion control often require a coordinated management of several mechanical degrees-of-freedom (DoF). This is conventionally achieved by using suitable mechanical devices and a separate actuator per each DoF. Electric actuators able to directly manage multiple DoF may provide appreciable benefits in terms of perfo...
This paper addresses the problem of the product quality improvement in hot rolling mills. The simplest scheme for modeling the rolling process considers the reduction of a strip thickness by passing the hot strip through a preset roll gap between two work rolls. Each rolling stand is driven by a DC motor, which is equipped with a speed controller....
This paper describes a model-based approach to detect electrical parameter changes in a brushless dc motor, controlled by a PWM inverter. A continuous identification method, based on the so-called modulating functions, is developed for estimating the parameters of the mathematical model of the motor from only input-output data. A real-time algorith...
An experimental performance-evaluation of controlled plants is a primary task for checking the validity of the controller design, especially in case of nonlinear plants, such as switching DC/DC converters. This paper presents a simple and automatic experimental method to estimate all circle-based design specifications (gain and phase margin, sensit...
A crucial problem for railway companies is the detection of the critical points of the overhead line for predicting excessive wear of the contact wire and for helping maintenance activities. An innovative tool, based on wavelet multiresolution analysis, is proposed in this paper for on-line monitoring of the quality of current collection. Wavelet d...
The transition from conventional mechanical-hydraulic actuation systems to innovative "x-by-wire" solutions in the treatment and transmission of pilot's commands represents a new leading edge for the automotive industry. Relevant improvements are indeed expected from the introduction of electrical drives suitably controlled by hierarchical computer...
This paper describes an advanced software simulation tool (ES-Sim) for analysis, design and control of electric scooters. ES-Sim is the acronym for Electrical Scooter Simulator and it was developed from Department of Electrical System and Automation, University of Pisa, for Piaggio S.p.A., innovative vehicle section, one of the European leading ind...
This paper proposes a simple and systematic procedure for identifying averaged large-signal models of resonant converters. The nonlinear behaviour of the converter is modelled via Hammerstein models, i.e., the model is represented by a static nonlinearity, followed by a linear transfer function. The parameters of the approximating structure are ide...
A framework to explore how the information supplied by circles in the Nyquist plane can be recovered in the RL plane. In this article, all circle criteria (including off-axis circles) in the frequency domain can be reformulated as complete root contours. In this way, some difficulties of analysis in the frequency domain are overcome by means of the...
A successful implementation of a low-cost PI-fuzzy controller for
a Cuk converter is presented in this paper. Properties of the proposed
controller are robustness around the operating point, good performance
of transient responses in changing load conditions and/or input voltage,
and invariant dynamic performance in the face of varying output
opera...
Aim of the paper is to build mathematical models of class E<sup>2</sup> resonant DC/DC converters from input-output data. Among the various identification techniques, the modulating functions were chosen, due to their capability for revealing converter dynamics even in case of fast time constants. Each obtained model was tested around its working p...
In many situation of industrial interest, the control designer needs qualitative information on the process to be controlled (e.g., linearity/nonlinearity, time delay, dominant poles). In this contribution, three different procedures are proposed for modeling plants in terms of generic Wiener/Hammerstein nonlinear models with time delay. In order o...
A new measurement system able to detect the occurrence of arcing between the pantograph and the overhead contact line was studied and set up. The system uses photomultiplier tubes to measure the duration of the ultraviolet emission due to electric arcing. The major advantages of the system proposed are
its non-invasivity with respect to the pantogr...
Accurate modeling of electrical drives for online testing is a
relevant problem, because of their nonlinear behavior. Efficient
modeling for simulation, performance evaluation, and testing must
consider accurate as well as simple models. This paper proposes the
application of auto-tune methods to identify equivalent Hammerstein
models, where the no...
The availability of software for symbolic computation, as Maple,
allows new approaches in the filter analysis and design. This paper
shows how it is possible to perform a complete analysis of a family of
aperiodical filters by computing a set of normalized diagrams (showing
typical time and frequency indexes) and also the set of related
formulae. C...
Hammerstein processes are represented by a static nonlinear element followed by a dynamic linear system. This paper proposes the application of modulating function method to identify Hammerstein models, in the hypothesis of a nonlinear element approximated by a polynomial function. The linear dynamic system can include the presence of unknown time...
A phase looked loop is introduced in ATV technique in order to replace the relay block but retaining the control on the phase shift and on the amplitude of self-oscillations. In this way the troubles due to a poor approximation on the ultimate gain frequency given by the harmonic linearization of a relay are completely avoided. The performance of t...
This article describes an utterly innovative methodology for detecting the electric arc due to pantograph-contact line slipping. This system is based on the utilisation of a photo-tube pick-up device. The device is exclusively sensitive to the ultraviolet frequencies in the wave lenght 290 nm-330 nm: after being properly set in laboratory it is pos...
Current collection covers an essential importance, especially in high speed railway lines characterised by 3 kV d.c. feeding systems in which the current value can rise up to 2.5 kA. The collection system can even reach the critical limits in these operative conditions. The present paper describes the traditional equipment and the measure methodolo...
The stability improvement of a round rotor synchronous machine by using a two-way parallel eld winding is examined. The characteristic machine parameters are derived varying the electrical angle between the two magnetic axes of the eld windings. By using a simplied mathematical model, a comparison between a conventional synchronous machine and t...
In this paper an innovative active pantograph for high-speed trains is proposed. The results presented are based on extensive simulation tests. The parameters used in the simulation are those of a real pantograph for high-speed trains: the pantograph model is modified by adding a wire actuation, in order to exert a constant contact force between th...
The identification of continuous systems with multiple-input
delays is discussed. A batch algorithm for parametric identification of
both multiple time delays and unknown parameters is proposed using the
modulating function approach. If the unknown delay is expressed as a
linear combination of a bank of known delays, it is proven that the
distribut...