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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

NASA's Magnetic Gearing Research for Electrified Aircraft Propulsion

This paper presents an overview of the magnetic gearing research being conducted at NASA. First, the research is motivated through an in-depth discussion of the Agency-level aeronautics vision, the benefit of geared drivetrains, the barriers to applying mechanical gears in future aircraft concepts with electrified aircraft propulsion, and the characteristics of magnetic gears that allow them to overcome said barriers. Next, the principles of operation and current limitations of magnetic gears are discussed in the context of future electrified aircraft. Then, the authors' vision for the magnetic gearing research that will be needed to enable the next generation of electrified aircraft is presented. Lastly, the recent and ongoing magnetic gearing research at NASA is described, with a focus on the development and capabilities of a new rotating test rig and new static measurements of an in-house prototype. Results and lessons learned thus far are summarized.

geared motors↗
NASA NTRSDate not supplied

Update on Subsonic Single Aft Engine (SUSAN) Electrofan Trade Space Exploration

NASA is conducting an ongoing trade study analysis of the SUSAN Electrofan aircraft concept, which utilizes 20-MW-class electrified aircraft propulsion to enable propulsive, aerodynamic, and control benefits while retaining the range, speed, and size of typical narrow-body regional aircraft. The study is constrained by the ground rules of operating within the current airport and airspace infrastructure. This ongoing study seeks to find a configuration and combination of technologies that yield significant fuel burn and emissions benefits. Another key goal is to reduce cost per passenger mile. Currently, the study is focused on a configuration that utilizes jet A or sustainable aviation fuels, however, we plan to consider other fuel alternatives in the future. This presentation describes the progress in defining the architecture of the aircraft, engine, power system, control system, and initial understandings of the sensitivity of the potential configurations to technology assumptions based on key performance parameters. Additionally, progress towards definition and refinement of driving operational, economic, infrastructure, certification, and technical requirements is discussed.

Ralph H. Jansen↗
NASA NTRS2024

AC and DC Fault Management for Megawatt Electrified Aircraft Electrical Powertrains - Task 2: Power Quality Filtering Using Nanocrystalline Soft Magnetic Inductor

The NASA RTAPS program on AC and DC Fault Management for Megawatt Electrified Power Train is a multi-year joint project with Pratt & Whitney (P&W), Collins Aerospace (CA), and RTX Technology Research Center (RTRC). This research program focuses on the high-voltage distribution issues that present a significant technological obstacle in the adoption of Electrified Aviation Propulsion (EAP) systems. One challenge to the adoption of high-voltage distribution systems with power electronic converters is the need for filter elements to limit the generation and propagation of noise, protect the cable systems from premature aging and prevent against excessive heating within subcomponents due to high-frequency induced currents. While increased distribution voltages aide in reducing the cable mass for a fixed power system, the associated mass with the filtering elements for power electronic converter can grow with increasing distribution voltages – thereby mitigating any benefit associated with increasing the distribution system voltage. To enable high-voltage distribution systems with high system specific power densities, new magnetic materials must be developed. Therefore, the second task of the NASA RTAPS program is associated with the design and application of advanced soft magnetic components for Megawatt class electric propulsion systems, specifically the motor drive system. This report covers the collaborative work between NASA Glenn Research Center (GRC), RTRC, P&W and CA in the development of three types of magnetic components over the span of the three-year program. These critical magnetic components are the DC side EMI filter, which limits the propagation of harmful electromagnetic noise to the rise of the distribution system, and the AC side damping with the dv/dt filter, which limits the fast rise time of the power electronic converter output voltage to limit the degradation on the cable/motor insulation systems. Each of these components are investigated from component level design and are optimized at the system level with a combined modelling and testing effort. In the final experimental evaluation of the NASA developed soft magnetic material with a dv/dt filter, a commercial-off-the-shelf (COTS) magnetic core and the GRC magnetic core are optimized and loaded at 320Arms to evaluate their difference in performance. After a run time of 30 minutes in a MW-class motor driver at RTRC, the NASA GRC cores were found to not only offer a lower temperature rise of nearly 25°𝐶, but also a reduction in measured core loss of 25% (12.75W to 9.5W).

Elecrified Aircraft Propulsion↗
NASA NTRSDate not supplied

Current Status and Future Plans for Electric Motors and Drives at NASA

Our work advances propulsion for aircraft while reducing energy consumption, noise, emissions and the cost of air travel. We are committed to investigating the use of alternative energy sources and improving the safety and expediency of flight. Electrified Aircraft Propulsion (EAP) is the use of propulsors (propellers or fans) driven by electric motors to propel aircraft ranging from air taxis to subsonic transports. NASA is developing technology, aircraft concepts, test aircraft, and ground test facilities to turn this idea from science fiction to- reality. Specifically, motors and/or generators (Electric machines) are needed on all electrified aircraft. And NASA is sponsoring or performing work to achieve power densities 2-3 times the state of the art for machines in the MW or larger class. Three major machine types are being developed: permanent magnet, induction, and wound field. Power converters are also an essential component in most EAP aircraft concepts, as they are used to convert from ac to dc power, or vice versa. Silicon carbide and gallium nitride convertors are being developed with conventional cooling as well as a cryogenically cooled converter. Future plans include demonstrating integrated flight-ready systems in both ground and flight tests; collaborating with and leveraging ARPA-E EAP programs; and supporting FAA standards development for market acceptance and safety.

Aircraft↗
NASA NTRSDate not supplied

Optimal Control Allocation for Distributed Electric Propulsion in A Series/Parallel Partial Hybrid Powertrain

The SUbsonic Single Aft eNgine (SUSAN) Electrofan is a NASA concept transport aircraft representative of technology anticipated for a 2040 entry-into-service date. The powertrain consists of a single thrust-producing geared turbofan engine with generators driving a series/parallel partial hybrid power/propulsion system. The architecture includes 16 underwing contrarotating fans, eight on each side. The distributed fans can be used by the flight control system to augment or replace the rudder function. This paper sets up the optimal control problem of setpoint determination for individual wingfans in the distributed propulsion system, accounting for electrical string efficiencies, saturations, and failures. The solution minimizes power consumption while maintaining thrust and torque on the airframe for maneuvering. Additionally, thrust that would have been lost due to temporary fan speed or power saturation is optimally redistributed to maintain overall desired thrust and torque on the aircraft. A simulation of a coordinated turn utilizing the distributed electric propulsion for yaw rate control in a multiple wingfan failure scenario demonstrates the robustness of the powertrain design to failures and helps define its limitations.

Distributed Electric Propulsion↗
NASA NTRSDate not supplied

Optimal Control Allocation for Distributed Electric Propulsion in A Series/Parallel Partial Hybrid Powertrain

The SUbsonic Single Aft eNgine (SUSAN) Electrofan is a NASA concept transport aircraft representative of technology anticipated for a 2040 entry-into-service date. The powertrain consists of a single thrust-producing geared turbofan engine with generators driving a series/parallel partial hybrid power/propulsion system. The architecture includes 16 underwing contrarotating fans, eight on each side. The distributed fans can be used by the flight control system to augment or replace the rudder function. This paper sets up the optimal control problem of setpoint determination for individual wingfans in the distributed propulsion system, accounting for electrical string efficiencies, saturations, and failures. The solution minimizes power consumption while maintaining thrust and torque on the airframe for maneuvering. Additionally, thrust that would have been lost due to temporary fan speed or power saturation is optimally redistributed to maintain overall desired thrust and torque on the aircraft. A simulation of a coordinated turn utilizing the distributed electric propulsion for yaw rate control in a multiple wingfan failure scenario demonstrates the robustness of the powertrain design to failures and helps define its limitations.

Distributed Electric Propulsion↗
NASA NTRSDate not supplied

Current Status and Future Plans for Electric Motors and Drives at NASA

Current Status and Future Plans for Electric Motors and Drives at NASA: Our work advances propulsion for aircraft while reducing energy consumption, noise, emissions and the cost of air travel. We are committed to investigating the use of alternative energy sources and improving the safety and expediency of flight. Electrified Aircraft Propulsion (EAP) is the use of propulsors (propellers or fans) driven by electric motors to propel aircraft ranging from air taxis to subsonic transports. NASA is developing technology, aircraft concepts, test aircraft, and ground test facilities to turn this idea from science fiction to reality. Specifically, motors and/or generators (Electric machines) are needed on all electrified aircraft. And NASA is sponsoring or performing work to achieve power densities 2-3 times the state of the art for machines in the MW or larger class. Three major machine types are being developed: permanent magnet, induction, and wound field. Power converters are also an essential component in most EAP aircraft concepts, as they are used to convert from ac to dc power, or vice versa. Silicon carbide and gallium nitride convertors are being developed with conventional cooling as well as a cryogenically cooled converter. Future plans include demonstrating integrated flight-ready systems in both ground and flight tests; collaborating with and leveraging ARPA-E EAP programs; and supporting FAA standards development for market acceptance and safety.

Powertrain↗
NASA NTRS2023

Modeling and Mitigation of dv/dt and Transmission Line Effect for Motor Drive System in Electric Aircraft Propulsion

Due to constraints in space and structure as well as other practical limitations in aircraft system, the motor controller or electric motor are often installed far away from each other and interconnected via long cables. This amplifies the transmission line effect excited by the dv/dt PWM voltage and induces high voltage stress on the machine winding. This paper investigates the state-of-art modeling approaches for such systems, identifies several limitations in matching the tested voltage reflection waveform in terms of peak voltage, oscillation frequency and damping speed, and offers several key considerations not well covered in literature or in engineering practice. It then proposes a practical modeling methodology which, as validated by experimental results, truly captures these critical reflection voltage specs. To mitigate the high peak voltage and strong oscillation, dv/dt filter is applied and a parametric design optimization based on widely adopted LC-R topology is illustrated, which not only alleviates the voltage stress but also minimized the power loss of the passive damping resistor.

Inductor↗
NASA NTRS2019

Electrified Aircraft Propulsion Systems: Potential Failure Modes and Failure Mitigation Strategies

Electrified aircraft propulsion (EAP) systems hold great potential for the reduction of aircraft fuel burn, emissions, and noise. Currently, NASA and other organizations are actively working to identify and mature technologies necessary to bring EAP designs to reality. A requirement for the development of any civil aircraft and its systems is to ensure that potential hazards in the design are identified and appropriately mitigated to ensure that the system is safe. During aircraft development, a system safety assessment that consists of a functional hazard assessment is conducted to identify all potential failure conditions of each function, and classify those failures according to the severity of their effects on the aircraft or its occupants. The more severe a function's failure condition classification, the greater the development assurance level required for the function to ensure that the probability of the hazard is acceptably low. Today, aircraft engines and their control systems receive type certificate approval as a stand-alone system to signify their airworthiness. However, the complex coupling and distributed nature of EAP designs are expected to place added challenges on the certification of these systems. This presentation will provide an initial high-level review of the potential failure modes and hazards posed by a generic EAP system along with potential mitigation strategies for those failures. The EAP system is assumed to be a hybrid design consisting of gas turbine engines, mechanical drives, electric machines, power electronics and distribution systems, energy storage devices, and motor driven propulsors. The functionality provided by each of these EAP subsystems will be discussed along with the potential failure modes they may encounter. This will include a discussion of coupled failure effects, where a fault in one EAP subsystem effects the operation of other subsystems in the architecture. Next, potential failure mitigation strategies are discussed including both software-based and hardware-based mitigation strategies. The presentation will conclude with an example evaluation of the potential failure modes and mitigation strategies for a concept EAP system proposed by NASA.

Simon, Donald L.↗
NASA NTRSDate not supplied

Flight Deck Design of a Hybrid Turbine/Electric Aircraft

The SUbsonic Single Aft eNgine (SUSAN) program is being developed as a sustainable subsonic regional aircraft. NASA is conducting trade studies for this future hybrid single aisle passenger aircraft. The goal of reducing emission levels by 50% will be enabled through an advanced design. An aft mounted single turbine engine provides thrust and electric power to drive 16 wing mounted electric engines. Using the 16 counter-rotating electric fans will create an efficient, very high bypass ratio, engine. Electric engines allow for distributed thrust, reducing control surfaces and provide a greater dynamic response. Batteries provide boost for takeoff and climb, allowing a smaller, more efficient, turbine engine. As part of the SUSAN effort, two pilot-in-the-loop studies were conducted at NASA Langley Research Center in Virginia to explore flight deck design issues. In particular: how many throttles are required/desired for a 17-engine aircraft, does the hybrid electric design change the answer, what are the requirements for electric engine displays, what system pages are required, and what information is required to monitor the batteries. Objective and subjective data were collected after each scenario and at the end of the day with a guided set of questionnaires from sixteen crews paired by airline. Data along with pilot comments were used to improve the throttle and engine displays between the studies and used to make the final recommendations on flight deck configurations. This paper provides final design recommendations for the SUSAN flight deck and justification for each recommendation.

PAI↗