Randolf Mock

An interoperable architecture for mobile smart services over the internet of energy

The Internet of Energy (IoE) for Electric Mobility is an European research project that aims at deploying a communication infrastructure to facilitate and support the operations of Electric Vehicles (EVs). In this paper, we present three research contributions of IoE. First, we describe a software architecture to support the deployment of mobile and smart services over an Electric Mobility (EM) scenario. The proposed architecture relies on an ontology-based data representation, on a shared repository of information (Service Information Broker), and on software modules (called Knowledge Processors -KPs) for standardized data access/management. As a result, information sharing among the different stakeholders of the EM scenario (i.e. EVs, EVSEs, City Services, etc) is enabled, and the interoperability of smart services offered by heterogeneous providers is guaranteed by the common ontology. Second, we rely on the proposed architecture to develop a remote charging reservation system, that runs on top of mobile smarthphones, and allows drivers to monitor the current state-of-charge of their EV, and to reserve a charging slot at a specific EVSE. Finally, we validate our architecture through a benchmark framework, that supports the embedding of mobile EV applications and of real KPs into a simulated vehicular scenario, including realistic traffic, wireless communication and battery models. Evaluation results confirm the scalability of our architecture, and the ability to support EVs charging operations on a large-scale scenario (i.e. the downtown of Bologna).

An Integrated Simulation Framework to Model Electric Vehicle Operations and Services

At present, battery-charging operations constitute one of the most critical obstacles toward a large-scale uptake of electric mobility (EM), due to performance issues and implementation complexities. Although several solutions based on the utilization of information and communication technologies and on mobile applications have been investigated to assist electric vehicle (EV) drivers and to coordinate charging operations, there is still the problem of how to evaluate and validate such solutions on realistic scenarios, due to the lack of accurate simulators integrating vehicular mobility, wireless communication, and battery charging/discharging models. In this paper, we attempt to fill this gap by proposing a novel EV simulation platform that can assist in the predeployment of charging infrastructures and services on realistic large-scale EM scenarios. The simulation platform, which is realized within the ARTEMIS EU project “Internet of Energy for Electric Mobility,” supports two utilization modes, i.e., evaluation of EM scenarios and immersive emulation of EM-related mobile applications, due to a semantic architecture through which virtual and real components can be integrated in a seamless way. We provide three major contributions with respect to the state of the art. First, we extend the existing cosimulation platform composed of SUMO (a vehicular traffic simulator) and OMNET++ (a network simulator) with realistic models of EVs, electric vehicle supply equipment, and ontology-based communication protocols that enable the deployment of city-wide mobile services (e.g., charging reservation). Second, we validate the battery model against the consumptions data of target EVs, and we evaluate the operations of EVs on a large-scale scenario (the city of Bologna, Italy), by analyzing the effectiveness of the charging reservation process and the resulting impact to the smart grid. Finally, we introduce the Mobile Application Zoo, which is a sandbox through which EM-related mobile applications can be seamlessly integrated within the simulation platform to be validated on virtual environments before their deployment on real scenarios, and we describe the implementation of an Android application for battery monitoring and charging reservation.

Impact of Interdisciplinary Research on Planning, Running, and Managing Electromobility as a Smart Grid Extension

The smart grid is concerned with energy efficiency and with the environment, being a countermeasure against the territory devastations that may originate by the fossil fuel mining industry feeding the conventional power grids. This paper deals with the integration between the electromobility and the urban power distribution network in a smart grid framework, i.e., a multi-stakeholder and multi-Internet ecosystem (Internet of Information, Internet of Energy, and Internet of Things) with edge computing capabilities supported by cloud-level services and with clean mapping between the logical and physical entities involved and their stakeholders. In particular, this paper presents some of the results obtained by us in several European projects that refer to the development of a traffic and power network co-simulation tool for electro mobility planning, platforms for recharging services, and communication and service management architectures supporting interoperability and other qualities required for the implementation of the smart grid framework. For each contribution, this paper describes the inter-disciplinary characteristics of the proposed approaches.

Internet of Energy – Connecting Energy Anywhere Anytime

The forthcoming Smart Grid is expected to implement a new concept of transmission network which is able to efficiently route the energy produced from both concentrated and distributed plants up to the final user with high security and quality of supply standards. Therefore the Smart Grid is expected to be the implementation of a kind of “internet” in which the energy packets are managed similarly to data packets, across routers and gateways which autonomously can decide the best pathway for the packet to reach its destination with the best integrity levels. In this respect the “Internet of Energy” concept is defined as a network infrastructure based on standard and interoperable communication transceivers, gateways and protocols that allow a real time balance between the local and the global generation and storage capability with the energy demand, also allowing high level of consumer awareness and involvement. This paper presents some basic concept of the Internet of Energy and, in particular, its impact on Electric Mobility.

Creep Relaxation of an Elastic–Perfectly Plastic Hemisphere in Fully Plastic Contact

A set of finite element simulations was performed to analyze the creep behavior of an elastic-perfectly plastic hemisphere in contact with a rigid flat. This study focuses on the time-dependent stress relaxation of a fully plastic asperity. Assuming a Garofalo (hyperbolic sine) type material creep law, the asperity shows two distinct phases of relaxation. In the first phase, the asperity creeps with an accelerated creep rate and shows a contact area increase similar to that of a cylindrical geometry. In the second phase, no contact area change can be measured and the asperity creeps with a slower rate. Empirical evolution laws for the asperity creep behavior are presented, analyzing the influence of both material and geometrical parameters. The results are interpreted in terms of transient friction.

Transient Friction Effects Due to Variable Normal Load in a Multi-Scale Asperity-Creep Friction Model

The study of multi-scale and fractal contact geometries holds many insights into the nature of surface contact. As a common feature of most fractal contact models, the presence of small-scale, plastically loaded asperities has emerged. The latter are, due to their loading close to the yield strength of the material, subject to creep deformation which is often held responsible for transient friction effect like dwell time- or velocity-dependent friction. In this paper, the transient behavior of friction under varying normal force will be studied in the framework of a multi-scale contact model with fractal input parameters. An advanced asperity creep model from previous research is used, yielding the time-dependent creep enlargement of the asperity contact area in response to arbitrary load transients.Copyright

A Novel Dynamic Friction Model Based on Asperity Creep

We present a novel approach for the simulation of dynamic friction in engineering systems, based on a new surface asperity model including creep effects. Our novel friction model aims at understanding the link between the microscopic origins of friction dynamics and the response of the engineering-level friction induced vibrations. The approach is based on the assumption that the time- and velocity-dependent friction coefficient is mainly caused by creep growth of surface asperity contacts (microscopic contact patches between two rough surfaces) as proposed by Kragelskii, Rabinowicz, Scholz and others. At the heart of our approach is a new asperity model that includes creep effects. Based on the pioneering work of Etsion et al., we conducted extensive FEM simulations to analyze the creep behavior of an elastic-perfectly plastic hemisphere in contact with a rigid flat. The new asperity model is used as a building block for a fractal model for the contact between rough surfaces. The model yields the time- and velocity-dependent macroscopic friction coefficient. We demonstrate the practical applicability of the new dynamic friction model in a simple block-on-conveyor test case to analyze friction induced vibrations.Copyright

The effect of inhomogeneous substrate-temperature distribution on the signal response of oxygen sensors

Abstract Temperature has a major influence on the electrical conductivity and response times of high-speed oxygen sensors comprising thin, sputtered films of semiconductive metal oxides such as SrTiO 3 . As it is undesirable in the majority of applications, the temperature sensitivity is usually eliminated by incorporating a heating element in the sensor in order to maintain a constant temperature. A homogeneous temperature distribution across the sensitive film is crucial for the reproducibility of the sensor signals and can be achieved by calculating the geometry of the heating element with the aid of the finite element method. The temperature distributions calculated in this way can be verified by thermographic and IR photography.

Inaudible cooling: A novel approach to thermal management for power electronics based on acoustic streaming

A new approach for forced convection cooling based on “Reynolds streaming” is presented, which allows for additional heat dissipation in situations where conventional active cooling devices (e.g. fans) are not suitable. The system operates inaudible, has no moving parts and is therefore durable and immune to dust. Its operation is dependent on numerous influences that have been identified and analyzed through experiment and simulation. It employs a new kind of acoustic driver delivering high intensity fields within air, while maintaining a small build volume. This transducer was designed and optimized using FEM-Simulation and verified with real-world prototypes at each major simulation milestone. All of the taken measures improved the performance by a factor of nearly 2 while reducing the system size by a factor of over 6 at the same time when compared to the first working system. This last generation device delivers comparable cooling performance.

Interactions of large scale EV mobility and virtual power plants

The complex interactions between electric mobility on a large scale with the electric distribution grid constitute a considerable challenge regarding the feasibility, the efficiency and the stability of smart electric distribution grids. On the one hand, the steadily increasing share of decentralized power generation from renewable sources entails a move away from electro-mechanical generators with huge inertia towards systems with distributed small-and medium-scale generators which are coupled to the grid via inverters. On the other hand, large-scale electric mobility which interacts with such a decentralized grid will have a huge impact on the power generation, storage potential and consumption patterns of a grid. Grid infrastructure simulations which take into account the details of these interactions and which are backed by comprehensive demonstrators may help to shed light on crucial aspects of both energy and information exchange between the traffic and the electric energy infrastructure regime. This will be highlighted by selected topics which intend to shed light on the scope and the challenges inherent in this area of simulation.