Review of Electric Vehicle Charging Technologies, Configurations, and Architectures

Electric Vehicles (EVs) are projected to be one of the major contributors to energy transition in the global transportation due to their rapid expansion. The EVs will play a vital role in achieving a sustainable transportation system by reducing fossil fuel dependency and greenhouse gas (GHG) emissions. However, high level of EVs integration into the distribution grid has introduced many challenges for the power grid operation, safety, and network planning due to the increase in load demand, power quality impacts and power losses. An increasing fleet of electric mobility requires the advanced charging systems to enhance charging efficiency and utility grid support. Innovative EV charging technologies are obtaining much attention in recent research studies aimed at strengthening EV adoption while providing ancillary services. Therefore, analysis of the status of EV charging technologies is significant to accelerate EV adoption with advanced control strategies to discover a remedial solution for negative grid impacts, enhance desired charging efficiency and grid support. This paper presents a comprehensive review of the current deployment of EV charging systems, international standards, charging configurations, EV battery technologies, architecture of EV charging stations, and emerging technical challenges. The charging systems require a dedicated converter topology, a control strategy and international standards for charging and grid interconnection to ensure optimum operation and enhance grid support. An overview of different charging systems in terms of onboard and off-board chargers, AC-DC and DC-DC converter topologies, and AC and DC-based charging station architectures are evaluated

Analysis, Design and Control of a Modular Full-Si Converter Concept for Electric Vehicle Ultra-Fast Charging

L'abstract è presente nell'allegato / the abstract is in the attachmen

Digital Multi-Loop Control of an LLC Resonant Converter for Electric Vehicle DC Fast Charging

This paper proposes a digital control strategy for LLC resonant converters, specifically intended for EV battery charging applications. Two cascaded control loops, i.e. an external battery voltage loop and an internal battery current loop, are designed and tuned according to analytically derived expressions. Particular attention is reserved to the output current control analysis, due to its extremely non-linear behaviour. The well known seventh-order LLC small-signal model, derived with the extended describing function (EDF) method, is simplified to an equivalent first-order model at the resonance frequency. In theseconditions,whichareproventobethemostunderdamped, the current control loop is tuned taking into account the delays introduced by the digital control implementation. Moreover, the adoption of a look-up table (LUT) in the feed-forward path is proposed to counteract the system non-linearities, ensuring high dynamical performance over the full frequency operating range. Finally, the proposed control strategy and controller design procedure are verified both in simulation and experimentally on a 15 kW LLC converter prototype

The state of the art of battery charging infrastructure for electrical vehicles: Topologies, power control strategies, and future trend

Electric vehicle battery (EVB) charger topologies play a vital role to increase the penetration of EVs. This paper reviews the status quo of EV battery (EVB) chargers in term of converter topologies, operation modes, and power control strategies for EVs. EVB Chargers are classified based on their power levels and power flow direction. Referring to power ratings, EV chargers can be divided into Level 1, Level 2 and Level 3. Level 1 and Level 2 are normally compatible with on-board chargers while Level 3 is used for an off-board charger. Unidirectional/bidirectional power flow can be obtained at all power levels. However, bidirectional power flow is usually designed for Level 3 chargers as it can provide the huge benefit of transferring power back to grid when needed. Moreover, the different operation modes of an EVB charger are also presented. There are two main modes: Grid-to-Vehicle (V1G or G2V) and Vehicle-to-Grid (V2G). The V2G mode helps bring EV batteries to become active distributed sources in smart grids and is the crucial solution for a high EV penetration. Future trend and authors\u27 recommendations with preliminary simulation and experimental results are demonstrated in this paper

Electric Vehicles Charging Technology Review and Optimal Size Estimation

AbstractMany different types of electric vehicle (EV) charging technologies are described in literature and implemented in practical applications. This paper presents an overview of the existing and proposed EV charging technologies in terms of converter topologies, power levels, power flow directions and charging control strategies. An overview of the main charging methods is presented as well, particularly the goal is to highlight an effective and fast charging technique for lithium ions batteries concerning prolonging cell cycle life and retaining high charging efficiency. Once presented the main important aspects of charging technologies and strategies, in the last part of this paper, through the use of genetic algorithm, the optimal size of the charging systems is estimated and, on the base of a sensitive analysis, the possible future trends in this field are finally valued

Analysis and Development of Multiple Phase Shift Modulation in A SiC-Based Dual Active Bridge Converter

Renewable energy adoption is a popular topic to release the stress of climate change caused by greenhouse gas. Electricity is ideal secondary energy for clean primary energy such as nuclear, wind, photovoltaic, and so on. To extend the application of electricity and reduce fossil energy consumption by transportation sectors, electric vehicles (EVs) become promising technology that can further inspire the development of renewable energy. Battery as the core in an EV provides the energy to the motor and all on-board electric equipment. The battery charger is mainly composed of a power factor correction (PFC) and isolated DC-DC converter. Therefore, power electronics equipment plays an important role in automotive products. Meanwhile, in recent years, the market capacity for wide band-gap devices, SiC MOSFET, continues to increase in EV applications. Dual active bridge (DAB) is an excellent candidate for isolated DC-DC converter in EV battery charger. The characteristics include an easy control algorithm, galvanic isolation and adjustable voltage gain. Different modulation strategies are developed to improve the performance and stability by using multiple phase shift (MPS) control. This thesis focuses on the utilization of different modulation strategies to realize smooth transition among MPS control in full operational range with securing zero-voltage-switching (ZVS) to eliminate the crosstalk in the hard-switching process. The influence of MPS control on ZVS resonance transient is also addressed to find out the accurate minimum required energy of the inductor to finish the ZVS transition. Furthermore, a general common-mode voltage model for DAB is proposed to analyze the impact of MPS control on the common-mode performance

Development of a Resonant High Power Charging Station for Fleet Vehicles

C onventional vehicles chargers are based on plugging the car battery using wire to the electricity grid through some conversion levels. In general, this system is an interface between the AC grid and the battery which requires DC voltages. The focus of this research is on wireless power charging technology. The wireless configuration benefits the system by providing electric isolation between transmitter and receiver side, and by making the charging process more convenient for the users. One major drawback of the wireless charging systems in compare to the conventional system is the lower efficiency of these systems. The resonant high power charging configuration of this study is designed to tackle this problem by enabling soft switching to minimize the switching loss. In this research a resonant LLC configuration is used for the EV charging application. The configuration and the step by step design of the resonant circuit is illustrated and analyzed. Also, other different topologies of the wireless charging systems have been introduced and compared with the proposed topology. The converter is modeled and simulated for different modes of operation. The optimal frequency selection which is dictated by the resonant circuit and magnetic design is obtained based on the mathematical model of the circuitry. The simulation results show that the designed converter improves the efficiency significantly using the resonant wireless charging configuration

Development of a Resonant High Power Charging Station for Fleet Vehicles

C onventional vehicles chargers are based on plugging the car battery using wire to the electricity grid through some conversion levels. In general, this system is an interface between the AC grid and the battery which requires DC voltages. The focus of this research is on wireless power charging technology. The wireless configuration benefits the system by providing electric isolation between transmitter and receiver side, and by making the charging process more convenient for the users. One major drawback of the wireless charging systems in compare to the conventional system is the lower efficiency of these systems. The resonant high power charging configuration of this study is designed to tackle this problem by enabling soft switching to minimize the switching loss. In this research a resonant LLC configuration is used for the EV charging application. The configuration and the step by step design of the resonant circuit is illustrated and analyzed. Also, other different topologies of the wireless charging systems have been introduced and compared with the proposed topology. The converter is modeled and simulated for different modes of operation. The optimal frequency selection which is dictated by the resonant circuit and magnetic design is obtained based on the mathematical model of the circuitry. The simulation results show that the designed converter improves the efficiency significantly using the resonant wireless charging configuration

Review on classification of resonant converters for electric vehicle application

The conventional hard-switching converters suffer from the limitations like the upper limit on switching frequency, high electromagnetic interference (EMI), more switching losses, large size, increased weight and low efficiency. To overcome these limitations, resonant converters are popularly used in chargers of electric vehicles (EVs). However, the detailed classification of resonant converters used in EVs is not sufficiently discussed in the literature. The guideline to select a resonant converter based topology required to charge an EV on the basis of its rating is not mentioned. To fill this gap, this paper presents a state-of-art literature survey of various resonant converter based topologies used in chargers of EVs. This paper focuses on a detailed classification of resonant converters used in the second stage of EV chargers. Further, it provides a guideline to designers to choose a converter topology used in the first stage and the second stage of EV charger required based on wattage, unidirectional and bidirectional power flow. Depending on the number of reactive elements present in a given resonant converter topology, these are classified as two-element, three-element, and multi-element resonant converters. Depending upon the connection of inductive (L) and capacitive (C) elements with respect to transformer winding, these converter topologies are further categorized as series, parallel (two-elements), inductor–inductor–capacitor (LLC) (three-element) and capacitor–inductor–inductor–capacitor (CLLC) (Multi-elements). However, the LLC type resonant converters offer high efficiency, zero-voltage switching (ZVS turn-on, turn-off) and low voltage stress on switches and high power density. Therefore, this paper mainly focuses on LLC type resonant converter topology. In addition, various modulation schemes and control schemes for LLC, CLLC resonant converter along with control of active power and reactive power are discussed for vehicle-2-grid (V2G) mode of operation