Special section on electric vehicle technology

published_or_final_versio

Evaluation of rapid electric battery charging techniques

Battery powered electric vehicles are gaining popularity worldwide. This is trend is driven by several factors including the need to reduce air and noise pollution, and dependence on fossil fuels. The main drawback of today\u27s electric vehicle is its limited range, and the long time duration that is required to charge the electric batteries. This thesis addresses the latter problem. In recent years, significant progress (through research and development) has been made to accelerate the charging time of the electric vehicle batteries through pulse charging rather than supplying continuous current and/or voltage. Some patented fast charging techniques demonstrated reduced charging times from 8 hours down to 45 minutes, and the current goal is to reduce this to the 10-minute range. This thesis will evaluate the published fast charging techniques in terms of their efficiency, accuracy of state of charge, threat of overcharge and impact of life cycle. The merits of the various battery interrogation techniques will be analyzed through modeling and computer simulation

Modeling and Control PV-Wind Hybrid System Based On Fuzzy Logic Control Technique

As energy demands around the world increase, the need for a renewable energy sources that will not harm the environment is increased. The overall objective of renewable energy systems is to obtain electricity with competitive cost and even benefit with respect to other energy sources. The optimal design of renewable energy system can significantly improve the economical and technical performance of power supply. This paper presents the power management control using fuzzy logic control technique. Also, a complete mathematical modeling and MATLAB/Simulink model for the proposed the electrical part of an aquaculture system is implemented to track the system performance. The simulation results show the feasibility of control technique

Unified model of lithium-ion battery and electrochemical storage system

Nowadays, energy storage systems are of paramount importance in sectors such as renewable energy production and sustainable mobility because of the energy crisis and climate change issues. Although there are various types of energy storage systems, electrochemical devices such as electric double layer capacitors (EDLCs), lithium-ion capacitors (LiCs), and lithium-ion batteries (LiBs) are the most common because of their high efficiency and flexibility. In particular, LiBs are broadly employed in many applications and preferred in the mobility sector, where there is a need for high energy and high power. To ensure good operating conditions for a battery and limit its degradation, it is important to have a precise model of the device. The literature contains numerous equivalent circuit models capable of predicting the electrical behavior of an LiB in the time or frequency domain. In most of them, the battery impedance is in series with a voltage source modeling the open circuit voltage of the battery for simulation in the time domain. This study demonstrated that an extension of a model composed exclusively of passive elements from the literature for EDLCs and LiCs would also be suitable for LiBs, resulting in a unified model for these types of electrochemical storage systems. This model uses the finite space Warburg impedance, which, in addition to the diffusion process of lithium\lithium ions in the electrodes\electrolyte, makes it possible to consider the main capacitance of the battery. Finally, experimental tests were performed to validate the proposed model

Calendar Aging Effect on the Open Circuit Voltage of Lithium-Ion Battery

In recent years, lithium-ion batteries (LiBs) have gained a lot of importance due to the increasing use of renewable energy sources and electric vehicles. To ensure that batteries work properly and limit their degradation, the battery management system needs accurate battery models capable of precisely predicting their parameters. Among them, the state of charge (SOC) estimation is one of the most important, as it enables the prediction of the battery's available energy and prevents it from operating beyond its safety limits. A common method for SOC estimation involves utilizing the relationship between the state of charge and the open circuit voltage (OCV). On the other hand, the latter changes with battery aging. In a previous work, the authors studied a simple function to model the OCV curve, which was expressed as a function of the absolute state of discharge, q, instead of SOC. They also analyzed how the parameters of such a curve changed with the cycle aging. In the present work, a similar analysis was carried out considering the calendar aging effect. Three different LiB cells were stored at three different SOC levels (low, medium, and high levels) for around 1000 days, and an analysis of the change in the OCV-q curve model parameters with the calendar aging was performed

Dynamic Modeling of Sodium Sulfur Battery Grid Storage Units

Due to the development of a high-technology-society, power demand has been increasing year after year. Therefore, new materials and development approaches in battery systems seek for a solution to store large amounts of energy. Among these new battery types, sodium sulfur batteries are a new practical and economical competitive solution in electrical energy storage systems. However, development of new batteries is a slow and an expensive practice.;The purpose of this study is to adapt a transient lumped computational model for a sodium sulfur battery cell to multi-cells of sodium sulfur battery module by using MATLAB/Simulink. Based on a non-linear battery model, different battery modules are presented and analyzed to predict the electrochemical behavior of the cells. Case studies are validated with simulations and experimental results from literatures. Presented model is designed to aid in the design process and calculation of state of charge of sodium sulfur battery storage units

STATE OF CHARGE BASED DROOP SURFACE FOR OPTIMAL CONTROL OF DC MICROGRIDS

For a microgrid with a high penetration level of renewable energy, energy storage use becomes more integral to the system performance due to the stochastic nature of most renewable energy sources. This thesis examines the use of droop control of an energy storage source in dc microgrids in order to optimize a global cost function. The approach involves using a multidimensional surface to determine the optimal droop parameters based on load and state of charge. The optimal surface is determined using knowledge of the system architecture and can be implemented with fully decentralized source controllers. The optimal surface control of the system is presented. Derivations of a cost function along with the implementation of the optimal control are included. Results were verified using a hardware-in-the-loop system

Design and Simulation of a DC Electric Vehicle Charging Station Interconnected with a MVDC Network

Due to a rapidly aging electric transmission and distribution infrastructure, an increased demand for energy, an increased awareness of climate change and greenhouse gas pollution, and an increased cost of fuel there is a need to produce and deliver energy more efficiently. This thesis attempts to provide a solution to these constraints through advancements in DC power architectures. Medium Voltage Direct Current (MVDC) infrastructure serves as a platform for the interconnection of renewable electric power generation, including wind and solar. Abundant loads such as industrial facilities, data centers, commercial office buildings, industrial parks, and electric vehicle charging stations (EVCS) can also be powered using MVDC technology. MVDC networks are expected to improve efficiency, through reductions in power electronic conversion steps and by serving as an additional layer between the transmission and distribution level voltage for which generation sources and loads could directly interface with smaller rated power conversion equipment. This thesis provides an introduction to battery energy storage system technology, and primarily investigates an EVCS powered via a MVDC bus. A bidirectional DC-DC converter with appropriate controls serves as the interface between the EVCS and the MVDC bus. Two scenarios are investigated for testing and comparing EVCS operation: 1) EVCS power supplied by the interconnected MVDC model and 2) EVCS power supplied by an equivalent voltage source. The ability of the battery charger (synchronous buck converter) to isolate faults in next generation DC power systems is explored. Each of the investigated components is modeled and simulated utilizing the PSCAD simulation environment then analytically validated