Guido Benetti

Real-Time Modeling and Control of Electric Vehicles Charging Processes

This paper presents a method for the real-time management of electric vehicles (EVs) charging processes. The proposed method aims to limit the peak load and to increase the number of rechargeable EVs with respect to the scenario in which no coordination action is performed, while achieving given constraints on the power distribution system. The approach is based on a tight interaction between a scheduling algorithm and a power-flow evaluation procedure. The scheduling algorithm finds the best charging periods for each EV. The power flow procedure checks the achievement of electrical constraints and evaluates the operational parameters of the grid. Simulations are carried out on a real electricity distribution system of a medium-sized Italian city. The results show that the proposed approach increases the number of rechargeable EVs up to 33%. At the same time, the peak load is reduced by 25%. The scheduling algorithm requires an average of 50 ms to evaluate each charge request on an ordinary computer, therefore allowing its use in real-time conditions.

Luminous Tiles: A New Smart Device for Buildings and Architectures

Advanced building materials are nowadays an active research domain. The integration of traditional materials and technologies in the field of electronics, photonics and computer science are leading to a new class of smart components that provide advanced functionalities and enable original applications. The LUMENTILE H2020 EU funded Project aims at the integration of existing and state-of-the-art technologies in the domain of large area electronic circuits, LED based lighting, embedded systems and communication. These technologies are blended with advancements in the manufacturing of ceramic tiles to obtain a new building component that can be managed as a common tile, while providing the possibility to self-illuminate and to sense the neighbor environment by means of dedicated sensors. The applications of these new material and technologies include indoor and outdoor architectural design, smart environments (also targeting improved safety and security issues), smart and high-efficiency lighting and art installations. State-of-the-art advancements are expected in the field of large area circuits and successful integration of heterogeneous materials, mainly focusing on ceramics and electronics.

Peak load optimization through 2-dimensional packing and multi-processor real-time scheduling

The use of real-time scheduling methods to coordinate a set of power loads is being explored in the field of Cyber-Physical Energy Systems, with the goal of optimizing the aggregated peak load of power used by many electric loads. Real-time scheduling has attractive features in this domain. Thanks to its inherent resource optimization, which limits the number of concurrent tasks that are running at the same time, real-time scheduling provides direct benefits to peak load optimization. This paper shows the combined use of a two-dimensional bin-packing method and an optimal multi-processor real-time scheduling algorithm to coordinate the activation of electric loads. The result is an effective global scheduling approach where the activation of loads is organized into a pattern that takes into account the timing constraints of the loads and the actual combination of active loads. The validation is done by scheduling a set of thermal loads (heaters) in a building, with accurately modeled temperature dynamics. The proposed method is shown to achieve a significant peak load reduction, up to around 70%, w.r.t. the traditional thermostat controller.

Design of a lighting system with high-power LEDs, large area electronics, and light management structure in the LUMENTILE European project

LUMENTILE (LUMinous ElectroNic TILE) is a project funded by the European Commission with the goal of developing a luminous tile with novel functionalities, capable of changing its color and interact with the user. Applications include interior/exterior tile for walls and floors covering, high-efficiency luminaries, and advertising under the form of giant video screens. High overall electrical efficiency of the tile is mandatory, as several millions of square meters are foreseen to be installed each year. Demand is for high uniformity of the illumination of the top tile surface, and for high optical extraction efficiency. These features are achieved by smart light management, using a new approach based on light guiding slab and spatially selective light extraction obtained using both diffusion and/or reflection from the top and bottom interfaces of the optical layer. Planar and edge configurations for the RGB LEDs are considered and compared. A square shape with side length from 20cm to 60cm is considered for the tiles. The electronic circuit layout must optimize the electrical efficiency, and be compatible with low-cost roll-to-roll production on flexible substrates. LED heat management is tackled by using dedicated solutions that allow operation in thermally harsh environment. An approach based on OLEDs has also been considered, still needing improvement on emitted power and ruggedness.

Design of a backlighting structure for very large-area luminaries

A novel approach for RGB semiconductor LED-based backlighting system is developed to satisfy the requirements of the Project LUMENTILE funded by the European Commission, whose scope is to develop a luminous electronic tile that is foreseen to be manufactured in millions of square meters each year. This unconventionally large-area surface of uniform, high-brightness illumination requires a specific optical design to keep a low production cost, while maintaining high optical extraction efficiency and a reduced thickness of the structure, as imposed by architectural design constraints. The proposed solution is based on a light-guiding layer to be illuminated by LEDs in edge configuration, or in a planar arrangement. The light guiding slab is finished with a reflective top interface and a diffusive or reflective bottom interface/layer. Patterning is used for both the top interface (punctual removal of reflection and generation of a light scattering centers) and for the bottom layer (using dark/bright printed pattern). Computer-based optimization algorithms based on ray-tracing are used to find optimal solutions in terms of uniformity of illumination of the top surface and overall light extraction efficiency. Through a closed-loop optimization process, that assesses the illumination uniformity of the top surface, the algorithm generates the desired optimized top and bottom patterns, depending on the number of LED sources used, their geometry, and the thickness of the guiding layer. Specific low-cost technologies to realize the patterning are discussed, with the goal of keeping the production cost of these very large-area luminaries below the value of 100

Luminous tiles: a new building device for smart architectures and applications

/sqm.

Adaptive Real-Time Scheduling of Cyber-Physical Energy Systems

Abstract Advanced building materials are nowadays an active research domain. The integration of traditional materials and technologies in the field of electronics, photonics and computer science are leading to a new class of smart components that provide advanced functionalities and enable original applications. The LUMENTILE H2020 EU funded Project aims at the integration of existing and state-of-the-art technologies in the domain of large area electronic circuits, LED based lighting, embedded systems and communication. These technologies are blended with advancements in the manufacturing of ceramic tiles to obtain a new building component that can be managed as a common tile, while providing the possibility to self-illuminate and to sense the neighbor environment by means of dedicated sensors. The applications of these new material and technologies include indoor and outdoor architectural design, smart environments (also targeting improved safety and security issues), smart and high-efficiency lighting and art installations. State-of-the-art advancements are expected in the field of large area circuits and successful integration of heterogeneous materials, mainly focusing on ceramics and electronics.

Design and implementation of a web-centric remote data acquisition system

This article addresses the application of real-time scheduling to the reduction of the peak load of power consumption generated by electric loads in Cyber-Physical Energy Systems (CPES). The goal is to reduce the peak load while achieving a desired Quality of Service of the physical system under control. The considered physical processes are characterized by integrator dynamics and modelled as sporadic real-time activities. Timing constraints are obtained from physical parameters and are used to manage the activation of electric loads by a real-time scheduling algorithm. As a main contribution, an algorithm derived from the multi-processor real-time scheduling domain is proposed to efficiently deal with a high number of physical processes (i.e., electric loads), making its scalability suitable for large CPES, such as smart energy grids. The cyber-physical nature of the proposed method arises from the tight interaction between the physical processes operated by the electric loads, and the applied scheduling. To allow the use of the proposed approach in practical applications, modelling approximations and uncertainties on physical parameters are explicitly included in the model. An adaptive control strategy is proposed to guarantee the requirements on physical values under control in presence of modelling and measurement uncertainties. The compensation for such uncertainties is done by dynamically adapting the values of timing parameters used by the scheduler. Formal results have been derived to put into relationship the values of quantities describing the physical process with real-time parameters used to model and to schedule the activation of loads. The performance of the method is evaluated by means of physically accurate simulations of thermal systems, showing a remarkable reduction of the peak load and a robust enforcement of the desired physical requirements.

Modeling and real-time control of an industrial air multi-compressor system

Data acquisition systems are fundamental components of modern distributed monitoring and control systems. The wide-spreading use of standard networking technologies in industrial scenarios, such as Ethernet, and the consolidation of web-based communication protocols, architectures and tools suggest the possibility to integrate out-of-the-box components to build a robust and reliable data acquisition system. This paper describes the design and implementation of a data acquisition system suitable to collect data from distributed embedded devices equipped with sensors based on a client-server architecture. The main feature of the proposed design is the integration of a set of technologies and tools widely adopted in the development of modern web services. The server component is based on Django, a popular Python web framework. While the backend runs a PostgreSQL database, the frontend includes data visualization tools leveraging the D3 JavaScript library. Metering points can be any embedded device able to interface with the desired sensors. The client-server communication architecture supports a RESTful API, as well as the ZeroMQ communication library. Messages are encapsulated in a human-readable JSON format. An important common characteristic of aforementioned technologies and tools is to be Free/Libre and Open Source Software (FLOSS). The proposed system thus represents a successful example of integration of FLOSS components to build a web-centric data acquisition system.

A self-configuration protocol for a cover made of smart tiles

This paper presents a control algorithm for an air multi-compressor system. The goal is to achieve adequate performance in terms of air pressure regulation by properly coordinating a set of compressors driven by fixed speed motors. The coordination is required to impose an upper bound to the activation frequency of electric drives. A multi-compressor system is intended to be a viable alternative to compressor systems based on Variable Speed Drives (VSD) operated by inverters, which suffer of several technical and economic drawbacks. The control strategy is based on the evaluation of the timing associated to activations/deactivations of each compressor. Such evaluation is determined by the values of physical variables that determine the system behavior, including air flows, pressures and temperature. The periodic measurement of the actual pressure is performed to dynamically adjust the estimation of relevant time instants in case of variations of working conditions. The algorithm takes into account the dynamics of the air pressure, as well as timing constraints on the minimum period between two subsequent activations of each compressor. The effectiveness of the multi-compressor solution is evaluated by simulation.