The fast development of electric vehicles (EVs) provides significant opportunities to further utilize clean energies in the automotive. On-board chargers (OBCs) are widely used in EVs because of their simple installation and low cost. Limited space in the vehicle and short charging time require an OBC to be power-dense and highly efficient. Moreover, the possibility for EVs to deliver power back to the grid has increased the interest in bidirectional power flow solutions in the automotive market. This paper presents a comprehensive overview and investigation on the state-of-the-art solutions of bidirectional OBCs. It reviews the current status, including architectures and configurations, smart operation modes, industry standards, major components, and commercially available products. A detailed overview of the promising topologies for bidirectional OBCs, including two-stage and single-stage structures, is provided. Future trends and challenges for topologies, wide bandgap technologies, thermal management, system integration, and wireless charging systems are also discussed in this paper.

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A Review of Bidirectional On-Board Chargers for Electric Vehicles

Electric vehicles use for urban mobility are rising with the new generation of 48 V powertrain technology. However, the challenge is to select onboard charger (OBC) topologies with less complex, economically feasible, and highly efficient battery chargers for these electric vehicles (EVs). At present, traditional multi-stage converters are being used by compromising efficiency, volume, weight, and cost. Single-stage OBC topologies can be designed by combining a few functions of a muli-stage coverter with a reduced number of components. They are aiming to eliminate issues related to multi-stage converters. However, the stress on power devices of single-stage OBCs can lead to other issues such as the requirement of expensive high power devices, thermal control, etc. This paper reviews single-phase, single-stage OBC topologies feasible for EVs with 48 V powertrain technology. Especially the isolated bidirectional AC–DC converters are considered as to include the vehicle-to-grid (V2G) capability.

A review on single-phase, single-stage OBC topologies for EVs with 48 V powertrains

This paper proposes a single-stage AC-DC rectifier with power factor correction (PFC), high-frequency isolation and bidirectional power conversion capability for on-board battery charger (OBC) applications. The proposed converter is based on the interleaving technique and the Dual Active Bridge (DAB) operation, applying the phase-shift control to regulate the power flow. In addition to topology, this article presents a control strategy for reducing low-frequency power ripples transferred to the secondary side without any additional component and hence maintaining overall size and cost. The single-phase OBC can interchange active power with the grid to charge batteries while performing grid-to-vehicle (G2V) functionality or transferring energy back to the grid via vehicle-to-grid (V2G) mode. The theoretical analysis of the converter including modulation strategy and feedback control scheme are presented. The proposed topology and control strategy have been verified by experimental results of a 650 W SiC-based prototype.

https://www.mdpi.com/2079-9292/11/4/650/pdf?version=1645249890

A Control Strategy to Smooth Power Ripple of a Single-Stage Bidirectional and Isolated AC-DC Converter for Electric Vehicles Chargers

A bidirectional isolated dc-ac converter that leverages the benefits of high-frequency (HF) power transfer to considerably reduce the size and weight of transformers is presented. The converter generates low-frequency grid compatible power output in a single conversion stage. Two sixleg inverters are connected across the open windings of three single-phase transformers, each with a center tap at the secondary. The inverters apply a differential-mode HF voltage across the windings to drive a HF current through the transformer, which is received by the secondary-side inverter to maintain the voltage of a dc capacitor. In addition, the secondary-side inverter generates a common-mode grid synchronized low-frequency voltage which drives the output current through the center tap of the secondary windings. A control scheme that independently operates on the HF power transfer and the low-frequency power output is presented. Simulation and experimental results of a 1.5-kW system are provided to validate the operation of the converter presented.

Bidirectional DC-AC Converter Using a High- Frequency Transformer with Multi-Frequency Decoupled Power Control

The dual-active-bridge (DAB) converters inherit favorite features including zero-voltage switching (ZVS) capability, wide voltage range, and natural bidirectional power flow. Facing different applications and high market requirements, conventional DAB topologies with various modulations are gradually inadequate, so topological modifications are emerged in the literature to deal with these situations. Based on their characteristics of these modified DAB topologies, in this article, we provide a comprehensive review and classification, and the methodology to modify DAB topologies is proposed. First, basic cells including input/output types, active bridges, transformers, and auxiliary high-frequency networks are introduced. Next, by combining these cells flexibly, modified DAB converters are derived, and they are classified in terms of structural characteristics and discussed in detail. Finally, the characteristics, merits, and demerits of the modified DAB converters are concluded. Evolvement history, future trends, and the derivation of new topologies are also analyzed. This article aims to present a clear picture of the general law and framework of the modified DAB topologies and give the inspiration to derive new DAB topologies to address specific requirements.

Review of Dual-Active-Bridge Converters With Topological Modifications

This paper presents a novel single-stage bidirectional isolated AC-DC converter with power factor correction (PFC). The proposed converter integrates the interleaving and the Dual Active Bridge converter, using the phase-shift control to regulate the power flow and to minimize power decoupling. A theoretical analysis is presented and validated through simulation.

A Bidirectional Single-Stage Isolated AC-DC Converter for Electric Vehicle Chargers

This paper presents the study of a single-stage bidirectional isolated AC-DC converter with power factor correction (PFC) and high frequency isolation. The proposed converter is based on the interleaved technique and the Dual Active Bridge converter (DAB) operation, using the phase-shift control to regulate the power flow between primary and secondary side of the transformer. A theoretical analysis is presented and simulation results are presented and discussed.

Leonardo Adriano Ramos

Papers

A Bidirectional Single-Stage Isolated AC-DC Converter for Electric Vehicle Chargers

Bidirectional isolated AC-DC converter for electric vehicles multifunctional chargers