Abstract

Peak oil, climate change and the achievement of energy independence have set the world into a new energy transition seeking to decarbonize both the power generation and transportation sectors. The convergence and synergy between both sectors, an electrified transportation powered by renewable energy, holds true potential to significantly reduce the world’s dependence on fossil fuels and the consequent emission of greenhouse gases. Nonetheless the integration of electric vehicles on the power system is not a minor issue and its associated impacts need to be carefully analyzed and addressed. In this context the main objective of this thesis is to develop a smart charging solution to safely integrate Plug-in Electric Vehicles into low voltage distribution networks while mitigating their corresponding impacts. This is done by designing a control algorithm capable to simultaneously meet both voltage and thermal network constrains by managing the vehicle’s charging process in real-time, while at the same time being respectful to current charging standards, computationally light and implementable in any current radial distribution grid. The proposed charging algorithm is built under a “Multi-Agent System” architecture combining a local decentralized voltage management with a centralized thermal control conceived to minimize user impact under three alternative optimization techniques. The architecture is fully implemented and tested on a realistic environment using Simulink by modeling key elements such as the charging stations, the vehicles themselves, and the different dwellings. An extensive analysis of the algorithm’s performance is completed testing it under multiple relevant scenarios. Finally the control algorithm is transferred to a real-time simulator (dSPACE MicroLabBox) to be validated and further evaluate its behavior through hardware-in-the-loop (HIL) simulations using both real charging stations and Plug-in Electric Vehicles available in the laboratory A satisfactory validation of the algorithm’s execution under and compatibility with real hardware is revealed by the HIL tests. At the same time a successful management of the considered network voltage and thermal constrains is obtained under all implementations, causing a minimal impact over the participating users and effectively peak shaving their total aggregated demand. For a full vehicle penetration scenario, the proposed control successfully prevents over 200 voltage limit violations and achieves so while significantly reducing the total transformer loading deviation, almost halving it when compared to an equivalent unrestricted charging case, and ensuring a net zero impact to 95% of participating users under its most effective thermal implementation. The study also reveals that a full participation of all vehicle owners is not critical factor to ensure a proper grid operation under the designed algorithm, as satisfactory results are also obtained when only half of them are actively involved in network management. Finally an economic assessment covering the application of the designed control over conventional network reinforcements further demonstrates the advantages of such an active management approach reporting additional economic benefits to the DSO.

Abstract

This project describes an implementation of the third connection scheme described by the Low Voltage Regulation for the charging of electric vehicles in community parkings. This scheme allows to reduce installation and maintenance costs since all users share the installation and electric connection. Although, the fact that these types of installations currently follow the first scheme of this regulation, where each user performs an individual installation from the electric connection of his house, it is expected that in the near future these types of facilities will be prohibited and the trend is an installation as proposed. The proposed project is not only a novelty in that there are none similarly in the market, but also represents a challenge for the application of new technologies where a set of users must share and manage resources using communications networks, databases and control algorithms for the efficient management of the installation and the contracted power. The design has not been limited to the programming of these functions but has also been necessary in the design and implementation of the hardware of the charging stations following the restrictions of the current legislation.

Abstract

cooling system for a fuel cell (FC) powered car within the framework of a European project called INN-BALANCE is currently being developed at the German aeronautics and space research centre (DLR). Given a design of the cooling loop, a thermal model of it has been developed in this master thesis making use of the software Matlab Simulink™, as it is the official simulation program for the INN-BALANCE project and the one used to share all the models between the project partners. Once the thermal model was developed, a control system for the next key components of this cooling system has been designed: the 3-way valve (or bypass valve), the fan of the radiator, the main pump of the circuit and the pump and heater of a heating system meant to be used in very low ambient temperatures. The goal of this control system has been to keep the coolant inlet and outlet of the FC at temperatures of 68℃ and 80℃ respectively, or more specifically, to keep a maximum temperature difference between the FC inlet and outlet of 12K. The designed control system has been tested on a test bed whose components are slightly different to the ones that will be used on the resulting car of the INN-BALANCE project, however the goal was also to develop a control system robust enough to be able to cope with any changes on the dimensions and typology of the components. For this purpose, the test bench used has a heat exchanger whose coolant pressure loss between inlet and outlet is very similar to the one of the FC to substitute it. Another key component different on the test bench is the radiator, whose dimensions are not the definitive ones and the same applies for the fan that blows air through it. The experiments performed at the test bench showed a control system capable of keeping the temperatures at the desired levels as long as the heat dissipation capabilities of the cooling system are not surpassed. Outgoing

Abstract

Energy system has been going through a revolutionary transformation over the past years. The rising adoption of unpredictable, decentralised renewable energy sources is said to accelerate in the next decades. Variable renewable electricity production in many different locations, can often lead to unexpected and unsought for deviations of gird parameters: frequency and voltage. unsought for devi ations of gird parameters: frequency and voltage, or even congestion of the system. Thus, decentralised electricity system would have a surpassing need of flexibility of the system, which could assure proper regulation of frequency and voltage when needed. The consumption of electricity is also viable and not utterly predictable. To avoid the congestion of electrical grid the demand side response concept has been sprouting. One of the new concepts of demand side response measures is aggregation. Aggregated load regulation envisions gathering and managing numerous small loads, in a way that could stop deviations of frequency and voltage in the system or avoid congestion , without bringing any inconveniences for the owner of the load. EVs while charging, are t hose loads that are often mentioned as aggragatable. With the emerge of massive adoption of Electric Vehicle, secondary uses of it are being questioned. One of them is the idea of balancing the ever changing frequency and voltage in the grid with usage of flexibility created by creating various patterns of charging an electric vehicle. This process is known as Smart Charging. This study integrate s previously mentioned innovations of energy system and analyse the potential of aggregation of electric vehicle s for the purpose of providing flexibility to the electricity system. The thesis will be a technical and economic analysis of the possibility of unlocking this potential in Europe. The regulatory and technical aspects of possible demand side response aggr egation development are presented in the thesis , along with the analysis of Electric Vehicles market and its potential. Thereafter, one exemplary market is analysed further, through developed optimisation model, which allows to assess the value of most imp ortant factors for the aggregator. Three key changing variables are considered in the scheme of charge, those are : the targeted group of clients, the power of the used charger, and the scheme of charging. To assess the importance of those variables the stream of revenues as well as the environmental benefits in the form of potential CO 2 emissions savings are analysed against the variables. E 2 F easibility and market assessment for EV scheduling and aggregation in E uropean countries 2 The major aim and finding of this thesis is to answer the question whether it is plausible to profitab ly develop grid balancing with smart charging of electric vehicles in European Free Trade Association membership countries. The reader will only get to know the answer to that question after flicking through the pages of this paper