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The transportation industry is experiencing a switch towards electrification. Availability of electric vehicle (EV) charging infrastructure is very critical for broader acceptance of EVs. The increasing use of OBCs, due to their cost-effectiveness and ease of installation, necessitates addressing key challenges. These include achieving high efficiency and power density to overcome space limitations and reduce charging times. Additionally, the growing interest in bidirectional power flow, allowing EVs to supply power back to the grid, highlights the importance of innovative OBC solutions. This review article provides a thorough analysis of the current advancements, challenges, and prospects in EV on-board charger technology. It aims to offer a comprehensive review of OBC architectures, components, technologies, and emerging trends, guiding future research and development. Addressing these challenges is essential to enhance the efficiency, reliability, and integration of OBCs within the broader EV ecosystem.

This paper proposes a novel 2-transformer (2-Trans)-based integrated on-board charger (OBC) and low-voltage DC/DC converter (LDC) system for electric vehicles. Conventional integrated OBC–LDC systems employing a three-winding transformer suffer from reduced light-load efficiency during standalone LDC operation because core losses dominate when designers size the transformer for high-power operation. In addition, concentrating multiple windings on a single magnetic core limits transformer design flexibility and causes complex magnetic coupling among the windings. To effectively reduce light-load losses and enhance transformer design freedom, this paper introduces a new integrated charging architecture that utilizes two independent transformers. The proposed system adopts a dual-active-bridge (DAB) converter for high-voltage battery charging and a phase-shift full-bridge (PSFB) converter for low-voltage battery charging. The system supports both simultaneous high- and low-voltage battery charging and standalone low-voltage battery operation, and a dual-phase-shift (DPS) control strategy enables independent and proper power flow control. Experimental results obtained from an 11 kW OBC and a 3 kW LDC prototype demonstrate up to a 33% reduction in light-load losses during standalone LDC operation and confirm the feasibility of improving power density through the proposed 2-Trans-based architecture.

In this paper, a model-based approach for the design of a bidirectional onboard charger (OBC) device for modern hybrid and fully electrified vehicles is proposed. The main objective and contribution of our study is to incorporate in the same simulation environment both modelling of electrical and thermal behaviour of switching devices. This is because most (if not all) of the studies in the literature present analyses of thermal behaviour based on the use of FEM (Finite Element Method) SWs, which in fact require the definition of complicated models based on partial derivative equations. The simulation of such accurate models is computationally expensive and, therefore, cannot be incorporated into the same virtual environment in which the circuit equations are solved. This requires long waiting times and also means that electrical and thermal models do not interact with each other, limiting the completeness of the analysis in the design phase. As a case study, we take as reference the architecture of a modular bidirectional single-phase OBC, consisting of a Totem Pole-type AC/DC converter with Power Factor Correction (PFC) followed by a Dual Active Bridge (DAB) type DC/DC converter. Specifically, we consider a 7 kW OBC, for which its modules consist of switching devices made with modern 900 V GaN (Gallium Nitrade) and 1200 V SiC (Silicon Carbide) technologies, to achieve maximum performance and efficiency. We present a procedure for sizing and selecting electronic devices based on the analysis of behaviour through circuit models of the Totem Pole PFC and DAB converter in order to perform validation by using simulations that are as realistic as possible. The developed models are tested under various operating conditions of practical interest in order to validate the robustness of the implemented control algorithms under varying operating conditions. The validation of the models and control loops is also enhanced by an exhaustive robustness analysis of the parametric variations of the model with respect to the nominal case. All simulations obtained respect the operating limits of the selected devices and components, for which its characteristics are reported in data sheets both in terms of electrical and thermal behaviour.

The rising Greenhouse Gas (GHG) emissions stemming from the extensive use of automobiles across the globe represent a critical environmental challenge, contributing significantly to phenomena such as global warming and the deterioration of air quality. To address these challenges, there is a critical need for research and development in electric vehicles (EVs) and their associated charging infrastructure, including off-board and on-board chargers (OBCs). This paper aims to bridge the gaps in existing review literature by offering a comprehensive review of both integrated and non-integrated OBCs for EVs, based on the authors’ knowledge at the time of writing. The paper begins by outlining trends in the EV market, including voltage levels, power ratings, and relevant standards. It then provides a detailed analysis of two-level and multi-level power converter topologies, covering AC-DC power factor correction (PFC) and isolated DC-DC topologies. Subsequently, it discusses single-stage and two-stage non-integrated OBC solutions. Additionally, various categories of integrated OBCs (iOBCs) are explored, accompanied by relevant examples. The paper also includes comparison tables containing technical specifications and key characteristics for reference and analysis.

This paper deals with the design, tuning and implementation of a digital controller for an all-Si electric vehicle (EV) on-board battery charger operated in discontinuous conduction mode (DCM). This charger consists of two cascaded conversion stages: a front-end power factor corrector (PFC) with two interleaved legs and an isolated phase-shifted full bridge DC/DC converter. Both stages operate in DCM over the complete battery charging power range, allowing lower inductance values for both the PFC and the DC/DC filtering elements. Moreover, DCM operation ensures a large reduction of the reverse-recovery losses in the power diodes, enabling the adoption of relatively cheap Si devices. The main goal of the work is to address the well-known DCM control challenges, leveraging a novel control strategy for both converter stages. This control scheme counteracts the DCM system non-linearities with a proper feed-forward contribution and an open-loop gain adjustment, ensuring consistent dynamical performance over the complete operating range. The designed controllers are tuned analytically, taking into account the delay components related to the digital implementation. Finally, the proposed control strategy is implemented on a single general purpose microcontroller unit (MCU) and its performance is experimentally validated on a 3.3 kW battery charger prototype.

Climate change risks have triggered the international community to find efficient solutions to reduce greenhouse gas (GHG) emissions mainly produced by the energy, industrial, and transportation sectors. The problem can be significantly tackled by promoting electric vehicles (EVs) to be the dominant technology in the transportation sector. Accordingly, there is a pressing need to increase the scale of EV penetration, which requires simplifying the manufacturing process, increasing the training level of maintenance personnel, securing the necessary supply chains, and, importantly, developing the charging infrastructure. A new modular trend in EV manufacturing is being explored and tested by several large automotive companies, mainly in the USA, the European Union, and China. This modular manufacturing platform paves the way for standardised manufacturing and assembly of EVs when standard scalable units are used to build EVs at different power scales, ranging from small light-duty vehicles to large electric buses and trucks. In this context, modularising EV electric systems needs to be considered to prepare for the next EV generation. This paper reviews the main modular topologies presented in the literature in the context of EV systems. This paper summarises the most promising topologies in terms of modularised battery connections, propulsion systems focusing on inverters and rectifiers, modular cascaded EV machines, and modular charging systems.

Active power decoupling circuits have emerged to eliminate the inherent ripple power at twice the grid frequency in single-phase power electronics systems. However, this requires additional passive components and power switches, which increases the cost and volume of the system. This paper proposes a circuit configuration in an electric vehicle system to build power decoupling circuits that employ a reduced number of extra components. In this proposed circuit configuration, three inductors and six switching devices from the motor and the inverter circuit are used to build active power decoupling circuits during battery charging time. In addition, this paper proposes a robust voltage control method with a virtual d–q current controller and the interleaved pulse width modulation technique. The proposed system and its control method can improve control performance and achieve low-cost battery chargers with a high power density. MATLAB–Simulink simulations and experimental verifications based on hardware-in-the-loop-simulations and rapid-control-prototyping systems are performed to verify the effectiveness of the proposed system and control algorithm.

This paper presents operation and control systems for a new modular on-board charger (OBC) based on a SEPIC converter (MSOBC) for electric vehicle (EV) applications. The MSOBC aims to modularise the battery units in the energy storage system of the EV to provide better safety and improved operation. This is mainly achieved by reducing the voltage of the battery packs without sacrificing the performance required by the HV system. The proposed MSOBC is an integrated OBC which can operate the EV during traction and braking, as well as charge the battery units. The MSOBC is composed of several submodules consisting of a full-bridge voltage source converter connected on the ac side and SEPIC converter installed on the battery side. The SEPIC converter controls the battery segments with a continuous current because it has an input inductor which can smooth the battery’s currents without the need for large electrolytic capacitors. The isolated version of the SEPIC converter is employed to enhance the system’s safety by providing galvanic isolation between the batteries and the ac output side. This paper presents the necessary control loops to ensure the optimal operation of the EV with the MSOBC in terms of charge and temperature balance without disturbing the required modes of operation. The mathematical analyses in this paper are validated using a full-scale EV controlled by TMS320F28335 DSP.

This paper presents the design and control methods of a single-phase bidirectional on-board charger (OBC) using a hybrid starter generator (HSG) and an inverter in a hybrid electric vehicle (HEV). In an HEV, there are a number of components, including the combustion engine, transmission, traction motor, motor controller, OBC, and HSG system. The proposed design reconfigures the HSG system to provide battery-charging capability instead of a conventional OBC based on the use of additional power relays. As a result, the number of power converters is effectively reduced through the replacement of the conventional OBC, and, thus, the power density is increased. This paper also proposes a control method for enabling not only battery charging but also a reactive power support depending on the grid command. Compared with a conventional reactive power compensation method, the proposed method has an advantage because it is located near the principal reactive power source. The simulation and experimental results verify the validity and feasibility of the proposed bidirectional OBC design and its control methods.

Deploying independent plug-in chargers, wireless chargers and auxiliary power modules within a single Electric Vehicle (EV) leads to an increased system complexity, higher component count and reduced power density. Integrated charger architectures address these limitations by unifying multiple charging and power conversion functions within a common hardware framework. Such integration reduces hardware redundancy, improves volumetric efficiency and enables more compact and cost-effective EV designs. Recent studies have explored a wide range of integrated charger topologies, targeting improvements in power density, cost and charging flexibility, often involving trade-offs such as reduced efficiency in exchange for smaller size or lower complexity. This paper presents a review of recent integrated charging topologies for EV applications, emphasizing system-level insights, design trade-offs, emerging trends and key technical challenges with the objective of guiding the development of efficient and scalable next-generation EV charging systems.