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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records

Power Electronic Development Challenges for High Power Density Integrated Electric Drive Applications

The ever-increasing demand for compact, efficient, and high-performance traction drive systems for transportation applications has accelerated the development of integrated electric drives. In these systems, the electric machine and inverter are integrated within a single housing, offering significant advantages in electrical performance, volume, weight, cost, and overall system efficiency. Despite these benefits, such high levels of integration introduce a new set of challenges, particularly in power electronic design and component selection. This article presents an in-depth investigation of a highly integrated electric drive architecture with an internal stator-mounted inverter, highlighting key design considerations and trade-offs aimed exclusively at maximizing system power density.Based on a comprehensive review of the literature, the power density of a voltage-source-inverter-driven electric drive is primarily governed by the volumetric contributions of the power modules, heat sinks, and DC-link capacitors. Accordingly, this work focuses on the optimization of these three critical components to enhance the inverter's overall power density. The proposed design achieves a power density of 100 kW/L, demonstrating the effectiveness of the presented approach for next-generation integrated electric drive systems.

33 ADVANCED PROPULSION SYSTEMS↗

Electric-drive tractability indicator integrated in hybrid electric vehicle tachometer

An indicator, system and method of indicating electric drive usability in a hybrid electric vehicle. A tachometer is used that includes a display having an all-electric drive portion and a hybrid drive portion. The all-electric drive portion and the hybrid drive portion share a first boundary which indicates a minimum electric drive usability and a beginning of hybrid drive operation of the vehicle. The indicated level of electric drive usability is derived from at least one of a percent battery discharge, a percent maximum torque provided by the electric drive, and a percent electric drive to hybrid drive operating cost for the hybrid electric vehicle.

33 ADVANCED PROPULSION SYSTEMS↗

Climate Control Load Reduction Strategies for Electric Drive Vehicles in Cold Weather

When operated, the climate control system is the largest auxiliary load on a vehicle. This load has significant impact on fuel economy for conventional and hybrid vehicles, and it drastically reduces the driving range of all electric vehicles (EVs). Heating is even more detrimental to EV range than cooling because no engine waste heat is available. Reducing the thermal loads on the heating, ventilating, and air conditioning system will extend driving range and increase the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have evaluated strategies for vehicle climate control load reduction with special attention toward grid connected electric vehicles. Outdoor vehicle thermal testing and computational modeling were used to assess potential strategies for improved thermal management and to evaluate the effectiveness of thermal load reduction technologies. A human physiology model was also used to evaluate the impact on occupant thermal comfort. Experimental evaluations of zonal heating strategies demonstrated a 5.5% to 28.5% reduction in cabin heating energy over a 20-minute warm-up. Vehicle simulations over various drive cycles show a 6.9% to 18.7% improvement in EV range over baseline heating using the most promising zonal heating strategy investigated. A national-level analysis was conducted to determine the overall national impact. If all vehicles used the best zonal strategy, the range would be improved by 7.1% over the baseline heating range. This is a 33% reduction in the range penalty for heating.

30 DIRECT ENERGY CONVERSION↗

At A Glance: Electric-Drive Vehicles

Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. With the range of styles and options available, there is likely one to meet your needs. The vehicles can be divided into three categories: 1) Hybrid electric vehicles (HEVs), 2) Plug-in hybrid electric vehicles (PHEVs), and 3) All-electric vehicles (EVs).

all-electric vehicles↗

At A Glance: Electric-Drive Vehicles

Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. With the range of styles and options available, there is likely one to meet your needs. Electric vehicles (EVs) include all-electric vehicles and plug-in hybrid electric vehicles (PHEVs).

all-electric vehicles↗

At A Glance: Electric-Drive Vehicles

Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. With the range of styles and options available, there is likely one to meet your needs. The vehicles can be divided into three categories: 1) Hybrid electric vehicles (HEVs), 2) Plug-in hybrid electric vehicles (PHEVs), and 3) All-electric vehicles (EVs).

33 ADVANCED PROPULSION SYSTEMS↗

Electric-Drive Vehicles

Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

33 ADVANCED PROPULSION SYSTEMS↗

Electric-Drive Vehicles

Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

hybrid, HEV, plug-in, PHEV, electric vehicle, EV, ↗

Electric-Drive Vehicles

Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: All-electric vehicles and Plug-in hybrid electric vehicles (PHEVs). Together, PHEVs and EVs can also be referred to as electric vehicles (EVs).

hybrid, HEV, plug-in, PHEV, electric vehicle, EV, ↗

Socially optimal electric driving range of plug-in hybrid electric vehicles

Our study determines the optimal electric driving range of plug-in hybrid electric vehicles (PHEVs) that minimizes the daily cost borne by the society when using this technology. An optimization framework is developed and applied to datasets representing the US market. Results indicate that the optimal range is 16 miles with an average social cost of 3.19 per day when exclusively charging at home, compared to 3.27 per day of driving a conventional vehicle. The optimal range is found to be sensitive to the cost of battery packs and the price of gasoline. Moreover, when workplace charging is available, the optimal electric driving range surprisingly increases from 16 to 22 miles, as larger batteries would allow drivers to better take advantage of the charging opportunities to achieve longer electrified travel distances, yielding social cost savings. If workplace charging is available, the optimal density is to deploy a workplace charger for every 3.66 vehicles. Finally, the diversification of the battery size, i.e., introducing a pair and triple of electric driving ranges to the market, could further decrease the average societal cost per PHEV by 7.45% and 11.5% respectively.

33 ADVANCED PROPULSION SYSTEMS↗

Integrated Electric Drive with HV 2 Modular Electric Machine and SiC Based Power Converters (Final Report)

An innovative high performance, high speed electric drive is designed, fabricated and tested. The drive is based on the modular multilevel converter (MMC) topology and is synthesized using power electronic building blocks (submodules) that utilize the newest generation of silicon-carbide (SiC) semiconductors. Power modules from two suppliers are investigated, characterized and the one showing better performance selected. A prototype MMC submodule is designed, built and tested in the lab. Simultaneously, control hardware and software are implemented and tested using real-time simulators. After verification of each of the subsystems, all subsystems are integrated to form a DC/AC converter-based drive. Multiple configurations are assembled and tested, and operation in variable voltages and frequencies, up to 4,160 V (line-to-line, rms), 140 A (rms) and 0-1,000 Hz is achieved. The efficiency of the drive system accomplished in the project is higher than 99.2% and the volume is 70% smaller than that of state-of-the art drives made using conventional technologies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Electric Drive Dynamic Thermal System Model for Advanced Vehicle Propulsion Technologies: Cooperative Research and Development Final Report, CRADA Number CRD-09-360

Electric drive systems, which include electric machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the dependence of the U.S. transportation sector on petroleum. However, to penetrate the market, these electric drive technologies must enable vehicle solutions that are economically viable. The push to make critical electric drivesystems smaller, lighter, and more cost-effective brings respective challenges associated with heat removal and system efficiency. In addition, the wide application of electric drive systems to alternative propulsion technologies ranging from integrated starter generators, to hybrid electric vehicles, to full electric vehicles presents challenges in terms of sizing critical components andthermal management systems over a range of in-use operating conditions. This effort focused on developing a modular modeling methodology to enable multi-scale and multi-physics simulation capabilities leading to generic electric drive system models applicable to alternative vehicle propulsion configurations. The primary benefit for the National Renewable Energy Laboratory (NREL) is the abilityto define operating losses with the respective impact on component sizing, temperature, and thermal management at the component, subsystem, and system level. However, the flexible nature of the model also allows other uses related to evaluating the impacts of alternative component designs or control schemes depending on the interests of other parties.

33 ADVANCED PROPULSION SYSTEMS↗

Electric Drive Technology Trends, Challenges, and Opportunities for Future Electric Vehicles

The transition to electric road transport technologies requires electric traction drive systems to offer improved performances and capabilities, such as fuel efficiency (in terms of MPGe, i.e., miles per gallon of gasoline-equivalent), extended range, and fast-charging options. The enhanced electrification and transformed mobility are translating to a demand for higher power and more efficient electric traction drive systems that lead to better fuel economy for a given battery charge. To accelerate the mass-market adoption of electrified transportation, the U.S. Department of Energy (DOE), in collaboration with the automotive industry, has announced the technical targets for light-duty electric vehicles (EVs) for 2025. This article discusses the electric drive technology trends for passenger electric and hybrid EVs with commercially available solutions in terms of materials, electric machine and inverter designs, maximum speed, component cooling, power density, and performance. Additionally, the emerging materials and technologies for power electronics and electric motors are presented, identifying the challenges and opportunities for even more aggressive designs to meet the need for next-generation EVs. Some innovative drive and motor designs with the potential to meet the DOE 2025 targets are also discussed.

33 ADVANCED PROPULSION SYSTEMS↗

Real-World Cyber Security Demonstration for Networked Electric Drives

In this article, we present the design and implementation of a cyber-physical security testbed for networked electric drive systems, aimed at conducting real-world security demonstrations. To our knowledge, this is one of the first security testbeds for networked electric drives, seamlessly integrating the domains of power electronics and computer science, and cybersecurity. By doing so, the testbed offers a comprehensive platform to explore and understand the intricate and often complex interactions between cyber and physical systems. The core of our testbed consists of four electric machine drives, meticulously configured to emulate small-scale but realistic information technology (IT) and operational technology (OT) networks. This setup both provides a controlled environment for simulating a wide array of cyber-attacks, and mirrors potential real-world attack scenarios with a high degree of fidelity. The testbed serves as an invaluable resource for the study of cyber-physical security, offering a practical and dynamic platform for testing and validating cybersecurity measures in the context of networked electric drive systems. As a concrete example of the testbed's capabilities, we have developed and implemented a Python-based script designed to execute step-stone attacks over a wireless local area network (WLAN). This script leverages a sequence of target IP addresses, simulating a real-world attack vector that could be exploited by adversaries. To counteract such threats, we demonstrate the efficacy of our developed cyber-attack detection algorithms, which are integral to our testbed's security framework. Furthermore, the testbed incorporates a real-time visualization system using InfluxDB and Grafana, providing a dynamic and interactive representation of networked electric drives and their associated security monitoring mechanisms. This visualization component not only enhances the testbed's usability but also offers insightful, real-time data for researchers and practitioners, thereby facilitating a deeper understanding of cyber-physical security dynamics in networked electric drive systems.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Development and Implementation of Degree Programs in Electric Drive Vehicle Technology

The Electric-drive Vehicle Engineering (EVE) MS degree and graduate certificate programs have been continuing to make good progress, thanks to the funding and the guidance from DOE grant management group, the support from our University and College administrations, and to valuable inputs and feedback from our Industrial Advisory Board as well as our project partners Macomb Community College and NextEnergy. Table 1 below lists originally proposed Statement of Project Objectives (SOPO), which have all been completed successfully. Our program and course enrollments continue to be good and increasing, as shown in later sections. Our graduating students continue to get good job offers from local EV-related companies. Following the top recommendation from our Industrial Advisory Board, we were fortunate enough to be accepted into the prestigious EcoCAR2 (http://www.ecocar2.org/) North America university design competition, and have been having some modest success with the competition. But most importantly, EcoCAR2 offers the most holistic educational environment for integrating real-world engineering and design with our EVE graduate curriculum. Such integrations include true real-world hands-on course projects based on EcoCAR2 related tasks for the students, and faculty curricular and course improvements based on lessons and best practices learned from EcoCAR2. We are in the third and last year of EcoCAR2, and we have already formed a core group of students in pursuit of EcoCAR”3”, for which the proposal is due in early December.

33 ADVANCED PROPULSION SYSTEMS↗

Low speed, long term tracking electric drive system has zero backlash

Electric drive system provides low speed, long term tracking of targets that move at a sidereal rate. It utilizes eddy-current energized actuators that are free from radio frequency interference generation and a solid state feedback amplifier with provisions for antibacklash biasing.

Richter, H. L.↗

FY2014 Electric Drive Technologies Annual Progress Report

The Electric Drive Technologies research and development (R&D) subprogram within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies under development. Research is focused on developing power electronics (PE), electric motor, and traction drive system (TDS) technologies that will reduce system cost and improve their efficiency in transforming battery energy to useful work. The R&D is also aimed at better understanding and improving how various components of tomorrow’s automobiles will function as a unified system to improve fuel efficiency.

33 ADVANCED PROPULSION SYSTEMS↗