This article proposes an approach for realizing the power delivery scheme for an extreme fast charging (XFC) station that is meant to simultaneously charge multiple electric vehicles (EVs). A cascaded H-bridge converter is utilized to directly interface with the medium voltage grid while dual-active-bridge based soft-switched solid-state transformers are used to achieve galvanic isolation. The proposed approach eliminates redundant power conversion by making use of partial power rated dc–dc converters to charge the individual EVs. Partial power processing enables independent charging control over each EV, while processing only a fraction of the total battery charging power. Practical implementation schemes for the partial power charger unit are analyzed. A phase-shifted full-bridge converter-based charger is proposed. Design and control considerations for enabling multiple charging points are elucidated. Experimental results from a down-scaled laboratory test-bed are provided to validate the control aspects, functionality, and effectiveness of the proposed XFC station power delivery scheme. With a down-scaled partial power converter that is rated to handle only 27% of the battery power, an efficiency improvement of 0.6% at full-load and 1.6% at 50% load is demonstrated.

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An Approach Towards Extreme Fast Charging Station Power Delivery for Electric Vehicles with Partial Power Processing

Electrification has been a key component of technological progress and economic development since the industrial revolution It has improved living conditions, spurred innovation, and increased efficiency across all sectors of our economy and all aspects of our lives During the coming decades, electrification is expected to reach further and deeper into the transportation, building, and industry sectors, mainly motivated by the energy transition to a zero-carbonemission-based economy to mitigate climate change

Electric Vehicle Charging Infrastructure: From Grid to Battery

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

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

Electric vehicle (EV) adoption continues to rise, yet EV sales still represent a small portion of vehicle sales in most countries. An expansion of the dc fast-charging (DCFC) network is likely to accelerate this revolution toward sustainable transportation, giving drivers more flexible options for charging on longer trips. However, DCFC presents a large load on the grid, which can lead to costly grid reinforcements and high monthly operating costs—adding energy storage to the DCFC station can help mitigate these challenges. This article performs a comprehensive review of DCFC stations with energy storage, including motivation, architectures, power electronic converters, and detailed simulation analysis for various charging scenarios. The review is closely tied to current state-of-the-art technologies and covers both academic research contributions and real energy storage projects in operation around the world.

A Comprehensive Review of DC Fast-Charging Stations With Energy Storage: Architectures, Power Converters, and Analysis

In a battery-electric vehicle, the powertrain and different auxiliary components are powered by a high-voltage (HV) battery. Most of today's battery-electric vehicles use battery configurations, resulting in the 150-450-Vdc link voltage range, and this highvoltage configuration is often called the 400-V system. In contrast, in electrified truck and construction vehicles, the maximum dc link voltage can reach 870 V, and this configuration is often called the 800-V system. Currently, there are several high-end electric passenger vehicles under development utilizing the 800-V system. This article discusses the benefits and challenges of using the 800-V system in passenger vehicles. For example, the availability of the automotive qualified components for the 800-V system is limited. Therefore, automotive original-equipment manufacturers must assume additional development effort, time, and cost impact when applying the 800-V system to passenger vehicles.

Christian Jung

Papers

Power Up with 800-V Systems: The benefits of upgrading voltage power for battery-electric passenger vehicles