Ottorino Veneri

Charging infrastructures for EV: Overview of technologies and issues

This paper presents an overview of issues and technologies related to the proper design of charging infrastructures for road electric vehicles. The analysis is carried out taking into account that the recharging stations of electric vehicles might be integrated in smart grids, which interconnect the main grid with distributed power plants, different kinds of renewable energy sources, stationary electrical storage systems and electric loads. The study is introduced by an analysis of the main characteristics concerning different kinds of storage systems to be used for stationary and on-board applications. Then, different charging devices, modes and architectures are presented and described showing their characteristics and potentialities. DC and AC configurations of charging stations are compared in terms of the issues related to their impact on the main grid and the design of their main components. Specific attention was devoted also to the ultra-fast DC architecture, which appears a possible solution to positively affect a wide spread of plug-in hybrid and full electric road vehicles.

Overview of electric propulsion and generation architectures for naval applications

This paper presents an overview of the most common electric propulsion and generation architectures for naval applications. This analysis was specifically devoted to ships in the range of length overall from boats of few meters up to mega-yachts of about 60 meters. The study starts with an analysis of the traditional technologies for the electric propulsion and generation for different typologies of ships, and then presents the main characteristics of new architectures to produce electric energy on board to supply either the on board auxiliaries and the electric propulsion systems. Finally, some details about the use and integration on board of renewable energy sources are reported.

ZEBRA battery based propulsion system for urban bus applications: Preliminary laboratory tests

In this paper some preliminary experimental results on a Zebra battery based propulsion system for urban bus applications are presented. The tests were carried out using a laboratory 1:1 scale test bench, composed by a 65 kW electric drive, specifically designed for urban bus applications, supplied by two 20 kWh Zebra batteries connected in parallel. The electric power train was tested on a laboratory bench, connected through a fixed ratio gear box to a 100 kW regenerative electric brake provided with speed and torque controls, in order to evaluate the propulsion system performance in steady state operative conditions. The obtained preliminary experimental results were utilized to implement a Matlab-Simulink model of urban bus, which might be powered by the same electric propulsion system studied. Thanks to this model it was possible to evaluate the dynamic behavior of the urban bus, working on standard driving cycles, taking into account the resistant forces represented by proper vehicle/road/aerodynamic parameters. An evaluation of the expected real vehicle driving range was also estimated in different road conditions.

RFLP Approach in the Designing of Power-Trains for Road Electric Vehicles

This paper is focused on the designing process of propulsion systems for road electric vehicles, by means of the RFLP approach for System Engineering. The process starts from the analysis of the main requirements for the vehicle considered, in relation to its specific mission. The vehicle behavior is then simulated on standard driving cycles, evaluating the performance figures of different power-train configurations, under different operative conditions. The presented designing procedure reaches the 3D CAD model of the identified propulsion system, coupled with a specific laboratory test bench, based on an eddy current brake and flywheel for the simulation of the vehicle inertia. The obtained simulation results show the good performance of the power-train in terms of vehicle speed following its reference on driving cycle and vehicle autonomy.

Experimental performance assessment of Pb, Li[NiCoMn]O 2 and LiFePO 4 batteries for road vehicles

In this paper the performance figures of lead acid and lithium ion batteries with two different cathode materials (Li[NiCoMn]O2 and LiFePO4) were compared from the point of view of their application on road vehicles. The experimental tests were performed in stationary and dynamic conditions using a cycle tester, based on an AC/DC converter, and supplying an electric power train. The experiments on the power train were carried out on a laboratory test bench provided with an electric brake, in order to simulate the real vehicle behavior and road characteristics on predefined driving cycles. The obtained results evidenced the advantages of using lithium batteries, especially when the load conditions require high values of battery currents, with different behavior between the two cathode materials.

Vehicle Electrification: Main Concepts, Energy Management, and Impact of Charging Strategies

In this chapter the main issues related to the displacement of conventional vehicles in favor of electric vehicles, which is needed for the eventual decarbonization of the transportation sector, are discussed. First, an introduction to the various vehicle propulsion concepts and their pros and cons is provided, followed by smart energy management considerations for plug-in electric vehicles. Then, energy systems, economic and environmental considerations, as well as the impacts of charging strategies on the electric grid are discussed. Finally, some further issues which are important for the acceptance of electric vehicles—including safety, battery lifetime and optimal sizing, charging infrastructure, and business models—are analyzed.

Main issues with the design of batteries to power full electric water busses

This paper presents an analysis of the main issues related to the design of battery pack supplying full electric vessels, such as water busses. After an assessment of the energy storage systems technologies available to power marine applications, battery design aspects are investigated. Hence, a probabilistic battery design method is discussed, taking properly into account the battery lifetime and the inherent economical evaluation. The method is based upon accelerated life tests and allows to face with the randomness of the power load in a suitable way. The optimal size of the battery is determined by tailoring an optimization procedure which ensures the desired robustness against the stochastic load parameters. In the last part of the paper, this probabilistic methodology is applied to a case study represented by a water bus for the public transportation service in the canals of the Venetian lagoon. The numerical results allow to confirm the feasibility and the goodness of the probabilistic approach.

Management issues of direct hydrogen Fuel Cell Systems for application in automotive field

In this paper Fuel Cell Systems (FCS) based on H2/air Proton Exchange Membrane (PEM) stacks of 2.5 and 12 kW were experimentally analyzed with the aim to elucidate the system design and management concerns to be considered for automotive application. The effects of the main operative conditions on stack performance were preliminarily examined, while the experimental analysis of the overall FCS permitted the energy losses related to the main system components to be specified. The possible strategies for control of air feeding, fuel purge, cooling and membrane humidification were discussed, with particular reference to the interaction between some specific devices, such as rotary vane compressor and membrane humidifier, whose characteristics were evidenced to be compatible with automotive applications because of low energy consumption and reliable FCS performance.

Experimental set-up of DC PEV charging station supported by open and interoperable communication technologies

This paper is focused on a laboratory smart power architecture designed to experiment fast charging and V2G operations for road electric and plug-in hybrid vehicles. The analysed power configuration is based on a DC bus architecture, which presents the main advantage of an easy integration of renewable energy sources and buffered storage systems. The energy management of this system is supported by open and interoperable communication technologies, which adopts Open Charge Point Protocol (OCPP) as network communication and application protocol. This allows the PEV charge point to exchange data and commands with any central management system over the Internet with the goal of ensuring truly interoperability and scalability. Furthermore, both short- and long-range wireless communication technologies are supported, which facilitates easy integration into existing communication infrastructures.

Case Study B: Fuel Cell Power Train for Cars

This chapter reports the results of an experimental analysis on a 30 kW fuel cell power train for city cars. The electric energy is generated by using a laboratory fuel cell system (FCS) based on a 20 kW H2/air PEM stack, realized taking into account the design criteria discussed in Chap. 4. The FCS experimental characterization provides results about the effect of different operative parameters on stack performance, and indications regarding the causes of energy losses associated with auxiliary components of the FCS. Moreover, reactant feeding, membrane humidification, and cooling issues are discussed, evidencing in particular the role of air compressor, fuel purge, temperature control, and humidification strategy in stack management in both steady state and dynamic conditions. The dynamic performance of the whole fuel cell traction system are tested on the European R40 driving cycle, evaluating the effect of different hybrid configurations on efficiency of single subsystems and of the overall propulsion system.