Rolling mill drive-trains, driven by AC or DC motors, have historically experienced premature component fatigue failures even when the perceived operating load is well below the design limit. This is often related to low damped torsional vibrations, especially to self-excited vibrations in rolling slippage (especially during threading and tailing out of a rolled piece), overloading the elements of the drive-train. Long transmission shafts make these vibrations become more critical. A regulator aimed at damping the torsional vibrations of the rolling mill drive-train and thus reducing the electric motor speed fluctuations is presented in this paper. The proposed regulator relies on a reduced order state observer able to estimate the shaft torque amplifications due to the working process. The capability of the regulator to damp out torsional vibrations has been verified through simulations on a lumped parameter torsional model of a single-stand rolling mill accounting for torsional deformability of the power-train shafts.

In a growing number of battery-driven applications the need of removing any position and speed transducer is taking over due to space, cost and mechanical reliability constraints, further than making the installation easier as requiring less wiring. This paper presents the development of a sensorless algorithm capable of running an Interior Permanent Magnet Synchronous Machine (IPMSM), assuring constant torque production in the whole speed range, form standstill to high speeds. This is achieved with an hybrid method: at standstill and very low speeds the saliency of the IPM is exploited through an High Frequency Signal Injection (HFSI), which assures a robust estimation of the rotor position. At medium to high speeds an advanced V-I estimator is adopted in order to enhance the motor performances. The developed algorithm comes out of being highly scalable as it requires very little tuning, resulting in a multi-purpose application which can be employed with any motor size.

The Field Oriented Control algorithm needs accurate estimation of motor state variables in order to ensure full torque performances and good efficiency. On electric vehicle traction drives, Induction motor Field Oriented Control is widely adopted. Good control results are strongly related to parameter values used by observers or estimators, which vary according to machine working conditions and temperature. The most important parameter is the rotor resistance. The paper shows and compares two different MRAS rotor resistance estimators, based on reactive power and motor torque, studied by means of a sensitivity analysis for different load and speed operating conditions. A nonlinear correction algorithm has been proposed in order to assure a good rotor resistance estimation convergence also under dynamic conditions. Sensitivity analysis, simulation and experimental results are reported for the proposed methods. The estimation algorithm has been also experimentally tested on a prototypal electric vehicle to demonstrate its validity under dynamic condition during a real driving cycle.

This paper develops an energy control strategy based on a multi-parametric programming control algorithm for a parallel hybrid heavy-duty truck. First, based on the non-linear characteristics and multiple working modes of the heavy-duty truck, a set of piecewise linear models including longitudinal dynamics, engine and electric motor are established and synthesised to a mixed logical dynamic (MLD) model. Then, an objective function for achieving the best fuel economy is formulated and the optimal control law is analytically calculated using a multi-parametric programming algorithm. Finally, the simulation of the hybrid heavy-duty truck model is conducted under UDDSHDV drive cycle and the result shows that the multi-parametric programming energy control strategy can effectively improve fuel economy compared to the traditional heavy-duty truck simulation model with the same engine.

The use of road vehicles has always represented a major contribution to the growth of modern society: it facilitates goods and people mobility, meeting most of the daily needs and it represents a backbone for the development of world economy, (i.e. the industrial field). Nowadays, this mean of transportation, however, given the high number of vehicles on the roads, has a negative impact both on the environment and on the quality of human life. Moreover it leads to an increase in additional costs (i.e. the costs related to environment pollution, global warming and depletion of resources). Such a negative aspect is due to the fact that the drive systems are often characterized by high variability of the load, hence the propulsion system works in areas with low efficiencies and high pollutant emissions. In order to overcome these problems, and to allow the compliance of the road transport system with new European guidelines (i.e White paper, and Horizon 2020), it is necessary to develop innovative technologies able to: - increase the overall powertrain efficiency; - introduce a sustainable alternative fuels strategy including also the appropriate infrastructure; - reduce carbon emission through a decarbonisation approach; In this perspective, in recent years, the technology of electric and hybrid vehicles has been developed, and nowadays it has become a feasible solution in the context of means of transportation. Car/truck-makers and operators look at further developments and innovation in this field in order to optimise the existing solutions and reduce the production costs. The current solution for hybrid vehicles aims to couple a conventional engine with an electrical motor; these two propulsion system are coordinated by an opportune algorithm in order to let the conventional engine operate in its higher efficiency range. Hence the technology foresees the action of endothermic and electrical motors. It is then pivotal for the success of this transport the optimisation of the whole system (electrical and endothermic) in terms of efficiency, sizing and of the control algorithm that coordinate the two propulsion systems. For the modeling of the internal combustion engine conventional approaches, based on the numerical simulation of the combustion process, cannot be used because of their complexity in term of time needed for computing activity. For hybrid power train the general approach to simulated a drive cycle, that usually last at least a few minutes, is based on engine map approach [1–2]. The main burden to the described process is the identifications of maps of torque and consumption for the internal combustion engine, which are normally not predictable in detail, nor are provided by the manufacturers, but they can only be determined by means of experimental tests. Such a process can become extremely expensive and time consuming. Hence in this work the concept of virtual optimisation is introduced basing on the identification of torque and fuel consumption maps for internal combustion engines on analytical methods considering the similarities with engine of the same class. In this regard, a model of the system is developed based on the “Willans Line Method” approach, subsequently to a theoretical definition of the model, the identification of maps is carried out for two different engines (one diesel heavy-duty engine and one spark ignition engine) in order to consider the existing configurations of hybrid vehicles. Eventually the calculated maps are validated considering experimental data from existing experimental campaign. Providing the validity of the method and its usefulness in the hybrid vehicle design.

In this paper the capacity fade of a Li-Ion battery for electric and hybrid vehicles is studied. The battery lifetime is a crucial characteristic for the usage of this technology on Full Electrical Vehicle (EV) or Hybrid Electrical Vehicle (HEV). Thanks to low costs and easy electronic devices design for small Li-Ion battery tests, many studies have established life prediction models. The aim of this paper is to verify whether these models can be used to predict capacity fade for a high capacity Li-Ion battery for full electric and hybrid vehicles, or not. During this study a test bench has been developed to control charge and discharge cell current. At last a comparison between different models will be provided.

The Field Oriented Controlled algorithm needs accurate estimation of motor state variables in order to ensure full torque and power performance. Good control results are strongly related to parameter values used by observers or estimators' algorithms, which vary according to the machine working conditions and the temperature. The most important parameter is the rotor resistance. The paper shows and compares two different MRAS rotor resistance estimators, based on reactive power and motor torque, studied by means of a sensitivity analysis for different load and speed operating conditions. A nonlinear correction algorithm has been proposed in order to assure a good rotor resistance estimation convergence. Since the algorithm has to be implemented on an electrical vehicle inverter, it has been defined taking into account that it has to operate under dynamic conditions, the typical situation occurring during a drive cycle. Sensitivity analysis, simulation and experimental results are reported for the proposed methods.

Low emission vehicles are an attractive research field for the automotive industry. A feasible solution for urban buses is a full electrical powertrain powered both by a supercapacitor, rechargeable at each bus stop while passengers are getting on and off, and, in the worst operating conditions such as traffic jams or long runs, by a conventional battery. The result is a hybrid energy system where an energy management function is required in order to divide the power request between the two onboard energy storage systems. Different energy management functions have been previously developed and validated using numerical simulation. This paper presents a comparison of various algorithms developed with an optimal algorithm defined using Dynamic Programming.

The dynamic behaviour of railway vehicles depends on the wheelset configuration, i.e. solid axle wheelset or independently rotating wheels (IRWs). The self-centring behaviour, peculiar of the solid axle wheelset, makes this kind of wheelset very suitable for tangent track running at low speed: the absence of the self-centring mechanism in the IRWs may lead to anomalous wheel/rail wear, reduced vehicle safety and passengers' discomfort. On the contrary, during negotiation of the sharp curves typical of urban tramways, solid axle wheelsets produce lateral contact forces higher than those of IRWs. This paper illustrates an electronic differential system to be applied to tramcar bogies equipped with wheel-hub motors which allows switching from solid axle in tangent track to IRWs in sharp curve (and vice versa). An electro-mechanical vehicle model is adopted for the design of the control system and for the evaluation of the vehicle dynamic performances.

Nowadays considerable resources have been invested on low emission passenger vehicle both for private and public transportation. A feasible solution for urban buses is a full electrical traction system fed by supercapacitor, that can be recharged at each bus stop while people are getting on and off. Moreover, in order to consider the worst operating condition for the bus (like traffic jam of higher distance to be covered), a conventional battery is also installed, obtaining an hybrid energy storage system. An energy management function, able to manage the two on board energy storage system based on fuzzy control logic, has been developed and validated by means of numerical simulations and compared to a previously presented one in order to evaluate its performances.

Decrease of availability of fossil fuels and environment issues, push research towards the development of high efficiency power trains for vehicles that transport people, goods and mobile operating machines, like the concrete mixer trucks considered in this paper. Conventional concrete mixer trucks use diesel engine to move the truck and a hydraulic system which keep spinning the concrete drum. A hybrid powertrain based on battery-powered electrical drives can replace the conventional hydraulic system assuring an efficiency improvement. Furthermore, thanks to the reversibility of the electrical drives, it is possible to recover kinetic energy during the braking phases of the truck. Aim of this paper is to study and develop a hybrid powertrain for the concrete mixer drum. The study is based on a full energetic model of the vehicle developed for sizing the components and designing the control strategies. A model of the conventional hydraulic mixer truck has also been proposed in order to evaluate the benefit introduced by the proposed hybrid system. Simulation models have been validated comparing experimental data collected on a conventional mixer truck in different operating conditions.

Nowadays considerable resources have been invested on low emission passenger vehicle both for private and public transportation. A feasible solution for urban buses is a full electrical traction system fed by supercapacitor that can be recharged at each bus stop while people are getting on and off. Such vehicle covers a short distance between consecutive stops, usually less than half a kilometer. An energy storage system able to provide high power peaks and small amount of energy is required. For these reasons, supercapacitors, which are capable of fast charging during bus stops, appear the most appropriate storage devices [1]. In order to consider the worst operating condition for the bus (like traffic jam of higher distance to be covered), a conventional battery is also installed, getting an hybrid energy storage system. An energy management function, able to manage the energy storage system, has been developed and validated by means of a numerical simulation model.

Field Oriented Control (FOC) based induction motor drive is a good choice for electric vehicles especially if we consider its low cost, due to the absence of permanent magnets. The control algorithm needs a good motor state variables estimation, such as a proper flux orientation, to assure full torque and power performances. Usually observers or estimators are adopted, but good results are strongly parameters dependent. In the induction machine control one of the most important parameter is the rotor resistance, that is temperature-dependent and therefore time-varying. The paper shows and compares three different Model Reference Adaptive System (MRAS) rotor resistance estimation methods, based on total active power, reactive power and motor torque. The algorithms have been studied by means of a rotor resistance uncertain of estimation based sensitivity analysis for different load and speed operating conditions. A simulation analysis has been proposed since the algorithm has been defined in order to operate under dynamic conditions, the typical situation during an electric vehicle drive cycle. A simple non linear variable structure MRAS has been adopted for assuring a good rotor resistance estimation convergence. Full theoretical analysis are reported for all the proposed methods.

La presente invention a trait a un dispositif de connexion (13) dans un systeme de groupe motopropulseur hybride (1), lequel systeme de groupe motopropulseur hybride (1) comprend un moteur a combustion (2, 27), une transmission de groupe motopropulseur (4, 40) et un moteur electrique (10), laquelle transmission de groupe motopropulseur (4, 40) comprend une boite a engrenages (7, 24) et est concue de maniere a transferer la puissance mecanique provenant du moteur a combustion (2, 27) jusqu'a une unite d'entrainement finale (6, 33) au moyen de la boite a engrenages (7, 24), la boite a engrenages (7, 24) comprenant un arbre principal (22) qui est connecte au moyen d'une premiere extremite (26) au moteur a combustion (2, 27) et comprenant en outre un arbre secondaire (23) qui est connecte a l'unite d'entrainement finale (6, 33), laquelle boite a engrenages (7, 24) comprend en outre un logement de boite a engrenages (25) et une pluralite d'engrenages (24) respectivement montes sur ledit arbre principal (22) et sur ledit arbre secondaire (23) et concus de maniere a changer le rapport de transmission entre l'arbre principal (22) et l'arbre secondaire (23), lequel dispositif de connexion (13) est concu de maniere a transferer puissance d'entrainement du moteur electrique (10) jusqu'a la transmission de groupe motopropulseur (4, 40) en connectant le moteur electrique (10) a une seconde extremite (29) de l'arbre principal (22), a l'oppose de la premiere extremite (26) ; au moins un engrenage exterieur (30a, 30b) des engrenages (24) est place a l'exterieur du logement de boite a engrenages (25), et le dispositif de connexion (13) comprend une roue de transmission (43) qui est concue de maniere a tourner d'un seul tenant avec un element de transfert (52) mecaniquement connecte a un selecteur (50a, 50b, 51), qui est concu de maniere a mettre en prise cet engrenage (30a) de l'engrenage exterieur (30a, 30b) qui est monte sur l'arbre principal (22). La presente invention a en outre trait a un systeme de groupe motopropulseur hybride et a un vehicule hybride.

Nowadays the greatest part of the efforts to reduce pollutant emissions is directed toward the hybridification of automotive drive trains. Such topic has a particular relevance while looking at vehicles that operate in urban environment, like light commercial vehicles. In particular the design of an hybrid vehicle requires a complete system analysis including the optimization of the electric and electronic devices installed on the vehicle and the design of all the mechanical connection between the different power sources to reach required performances. The aim of this paper is to develop an energetic model to develop optimized strategies able to reduce pollutions emissions, design and control of a Plug-In Hybrid Electrical commercial Vehicle (PHEV) with particular attention paid to energy and power fluxes between the different devices. The model described in the paper has been experimentally validated on a Plug-in HECV, realized, in prototypal version, at the Mechanical Department of the Politecnico di Milano. The proposed validated model would be then exploited in order to develop an optimized energy management strategy with the aim to reduce pollutant emission of commercial vehicles that are used to deliver goods in urban areas.

Nowadays, the greatest part of the efforts to reduce pollutant emissions is directed toward the hybridization of automotive drive trains. Plug-in Hybrid Electric Vehicle (PHEV) seems to be a good short term solution for replacing the conventional combustion engine propelled vehicles, in order to improve fuel economy and reduce pollution emissions. Such topic has a particular relevance while looking at vehicles that operate in urban environment, like light commercial vehicles used for goods delivering even in limited traffic areas. In order to obtain a wide range, full performance, high efficiency vehicle and, at the same time, reduce pollutant emissions, the most feasible solution, at present, is the PHEV, which combines batteries (that can be charged during the night or enough long stops directly from the electric power grid) that feed electrical drive together with a standard Internal Combustion Engine (ICE). In fact today Full Electric Vehicles can not assure the basic requirements of driving range, performance and load capability needed for a commercial vehicle operating in urban environments, mainly because of the low energy density of actually available batteries. Considering the average daily mission of a commercial vehicle delivering goods in urban environments, PHEV can cover even long distances from the hub to the city centre, exploiting the hybrid driving mode (which can increase the efficiency with respect to standard ICEVs) and then use its pure electric driving range (30-60 km) to deliver goods inside the city centre. Since the PHEV has two on-board engines (electric and endothermic) and two energy storage systems (the electrochemical batteries and the fuel tank), energy control strategies have to be developed and introduced in order to find out the most efficient one. The full energetic model of a Plug-In Hybrid Electric Commercial Vehicle, presented in previous papers [1] and already validated exploiting experimental tests performed on a prototype developed at the Mechanical Engineering Department of Politecnico di Milano, will be used in this paper. It will be used to develop energy flows control strategies able to allow the commercial vehicle to perform its daily mission in hybrid and pure electric driving modes.

Over the last years, energy saving has become a very important issue. One possibility for limiting energy consumption is recovering it from systems where it is dissipated (energy harvesting). One of the most effective methods for implementing energy harvesting is to convert kinetic energy produced by mechanical vibrations into useful electric energy which can be stored in accumulators and then used to power sensors and/or active systems and/or on board auxiliary electrical loads. The application of an energy harvesting device to a road vehicle suspension system is presented in this paper. The device consists in a mass damper excited in resonance, a linear permanent magnet alternator and a power factor controlled rectifier (electromagnetic vibration driven generator). In a first stage of the research, the capability of the device of recovering energy from road induced vibrations of the suspension unsprung mass has been explored. The parameters of the device have then been tuned in order to optimize energy harvesting, taking into account the physical constraints concerned with the application (suspension geometry, electromagnetic vibration driven generator mass, etc.).

The dynamic interaction between a pantograph and a catenary influences the quality of the current collection; in particular, when two pantographs are used to collect current, the second pantograph is subjected to the disturbances originated on the overhead line by the transit of the first pantograph, generally causing a deterioration of current collection quality. Under these conditions, the occurrence of continuous sparking, contact loss, and arcing cause an increase of wear for both contact wire and collector strips, but also cause variations of contact voltage and feed current that in turn produce interferences on the on-board electrical systems like drive motors and signalling system. In order to investigate the latter, a procedure for the correlation of the quality of current collection with the level of electrical interference is proposed in this article. The procedure is based on experimental and numerical models combining relationships obtained by means of laboratory tests with simulation tools. An application to a real case of double pantograph collection is presented.