This article attempts to cover the most recent advancements in multiphase drives (MPDs), which are candidates for replacing three-phase drives in electric vehicle (EV) applications. Multiphase machines have distinctive features that arouse many research directions. This article reviews the recent advancements in several aspects such as topology, control, and performance to evaluate the possibility of exploiting them more in EV applications in future. The six-phase drives are extensively covered here because of their inherent structure as a dual three-phase system, which eases the production process. This article presents different topologies used in dual three-phase drives and the modulation techniques used to operate them as well as the status of using MPDs in traction applications industrially and the upcoming trends toward promoting this technology more.

A Review on Multiphase Drives for Automotive Traction Applications

Traction inverter, as a critical component in electrified transportation, has been the subject of many research projects in terms of topologies, modulation, and control schemes. Recently, some of the well-known electric vehicle manufacturers have utilized higher-voltage batteries to benefit from lower current, higher power density, and faster charging times. With the ongoing trend toward higher DC-link voltage in electric vehicles, some multilevel structures have been investigated as a feasible and efficient option for replacing the two-level inverters. Higher efficiency, higher power density, better waveform quality, and inherent fault-tolerance are the foremost advantages of multilevel inverters which make them an attractive solution for this application. This paper presents an investigation of the advantages and disadvantages of higher DC-link voltage in traction inverters, as well as a review of the recent research on multilevel inverter topologies for electrified transportation applications. A comparison of multilevel inverters with their two-level counterpart is conducted in terms of efficiency, cost, power density, power quality, reliability, and fault tolerance. Additionally, a comprehensive comparison of different topologies of multilevel inverters is conducted based on the most important criteria in transportation electrification. Future trends and possible research areas are also discussed.

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A Review of Multilevel Inverter Topologies in Electric Vehicles: Current Status and Future Trends

Electric vehicles (EVs) are experiencing a rise in popularity over the past few years as the technology has matured and costs have declined, and support for clean transportation has promoted awareness, increased charging opportunities, and facilitated EV adoption. Suitably, a vast body of literature has been produced exploring various facets of EVs and their role in transportation and energy systems. This paper provides a timely and comprehensive review of scientific studies looking at various aspects of EVs, including: (a) an overview of the status of the light-duty-EV market and current projections for future adoption; (b) insights on market opportunities beyond light-duty EVs; (c) a review of cost and performance evolution for batteries, power electronics, and electric machines that are key components of EV success; (d) charging-infrastructure status with a focus on modeling and studies that are used to project charging-infrastructure requirements and the economics of public charging; (e) an overview of the impact of EV charging on power systems at multiple scales, ranging from bulk power systems to distribution networks; (f) insights into life-cycle cost and emissions studies focusing on EVs; and (g) future expectations and synergies between EVs and other emerging trends and technologies. The goal of this paper is to provide readers with a snapshot of the current state of the art and help navigate this vast literature by comparing studies critically and comprehensively and synthesizing general insights. This detailed review paints a positive picture for the future of EVs for on-road transportation, and the authors remain hopeful that remaining technology, regulatory, societal, behavioral, and business-model barriers can be addressed over time to support a transition toward cleaner, more efficient, and affordable transportation solutions for all.

https://iopscience.iop.org/article/10.1088/2516-1083/abe0ad/pdf

The rise of electric vehicles—2020 status and future expectations

Two of the main challenges for electric vehicle (EV) adoption include limited range and long recharge times. Ultrafast charging can help to mitigate both these concerns. However, for typical 400-V battery EVs (BEVs), the charging rate is limited by the practical cable size required to carry the charging current. To reach ultrahigh charge rates of 350 or 400 kW, 800-V BEVs are a promising alternative. However, the design of an 800-V EV requires careful new considerations for all electrical systems. This article reviews the current state of 800-V vehicle powertrain electrical design and performs an analysis of benefits, challenges, and future trends regarding multiple vehicle powertrain components. Specifically, detailed benefits and challenges related to the battery, propulsion motor, inverter, auxiliary power unit, and on- and off-board chargers are discussed.

800-V Electric Vehicle Powertrains: Review and Analysis of Benefits, Challenges, and Future Trends

An overview of electricity powered vehicles: Lithium-ion battery energy storage density and energy conversion efficiency

Traction inverters are crucial components of modern electrified automotive powertrains. Advances in power electronics have enabled lower cost inverters with high reliability, efficiency, and power density, suitable for mass market consumer automotive applications. This paper presents an independent review of the state-of-the-art traction inverter designs from several production vehicles across multiple manufacturers. Future trends in inverter design are identified based on industry examples and academic research. Wide bandgap devices and trends in device packaging are discussed along with active gate driver implementations, current and future trends in system integration, and advanced manufacturing techniques.

Automotive Traction Inverters: Current Status and Future Trends

The electric revolution is underway in the transportation sector, and the aviation industry is poised to embrace fundamental disruption. Moving to electric aircraft brings undeniable benefits in terms of environmental impact, cost savings, maintenance, noise pollution, and safety. Nevertheless, several technical challenges are yet to be overcome to build electric airplanes that meet public needs while gaining acceptance and trust. From urban air mobility to long-haul flight applications, hundreds of projects are under research to push toward more electrification. At the heart of each aircraft architecture, power electronics plays a crucial role in the new era of transportation. This article aims to provide a comprehensive analysis of state-of-the-art power electronics in electric aircraft. A review of the current status of aircraft electrification will be provided, and technology surveys of power electronic converters will be detailed. Challenges for forthcoming power electronics in response to the future trends of the electrical network will be explained. Finally, emerging technologies regarding wide bandgap devices, advanced topologies and control, thermal management, passive components, and system integration will be discussed.

Power Electronic Converters in Electric Aircraft: Current Status, Challenges, and Emerging Technologies

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

A semi-active hybrid energy storage system, consisting of a Li-ion battery pack, dc/dc converter, and Li-ion capacitor pack is developed for a range extended plug-in vehicle application. The vehicle has a series-parallel drivetrain with two electric motors, a gas engine, gearbox, and a clutch to allow the engine to run decoupled from the gearbox in range extending mode. The peak dc electrical requirement of the electric drivetrain is about 175kW, which is similar to the peak power capability of the developed hybrid energy storage system. A model of the prototype hybrid energy storage system, which has the Li-ion capacitor pack connected directly to the motor drive's dc bus and the battery pack connected to the Li-ion capacitor pack via a dc/dc converter, is developed and used to determine the optimal power split between the battery and Li-ion capacitor packs. A dynamic programming algorithm is used to determine the optimal power split, with the optimization goals of reducing energy storage system loss, maximizing regenerative braking energy capture, and minimizing motoring power limiting. The hybridized system is shown to reduce battery pack losses and increase vehicle range compared to a system only utilizing the battery pack.

Optimal performance of a full scale li-ion battery and li-ion capacitor hybrid energy storage system for a plug-in hybrid vehicle

A semi-active hybrid energy storage system, consisting of a Li-ion battery pack, dc/dc converter, and Li-ion capacitor pack was developed for a range extended plug-in vehicle. The vehicle has a series-parallel drivetrain with two electric motors, a gas engine, gearbox, and a clutch to allow the engine to run decoupled from the gearbox in range extending mode. The peak dc electrical requirement of the electric drivetrain is about 175 kW, which is similar to the peak power capability of the developed hybrid energy storage system. A model of the prototype hybrid energy storage system, which has the Li-ion capacitor pack connected directly to the motor drive's dc bus and the battery pack connected to the Li-ion capacitor pack via a dc/dc converter, is developed and used to determine the optimal power split between the battery and Li-ion capacitor packs and for tuning the developed real-time control system. The real-time control system is shown through modeling and experimental testing of the full scale hybrid energy storage systems to reduce battery pack losses, increase vehicle range, and to have performance approaching that of the optimal control solution as calculated via dynamic programming.

John Reimers

Papers

Automotive Traction Inverters: Current Status and Future Trends

Power Electronic Converters in Electric Aircraft: Current Status, Challenges, and Emerging Technologies

A Review of Bidirectional On-Board Chargers for Electric Vehicles

Optimal performance of a full scale li-ion battery and li-ion capacitor hybrid energy storage system for a plug-in hybrid vehicle

Real-Time Control of a Full Scale Li-ion Battery and Li-ion Capacitor Hybrid Energy Storage System for a Plug-in Hybrid Vehicle