High-Temperature, High-Efficiency Electrical Starter/Generator

Navy SBIR 24.1 - Topic N241-021
NAVAIR - Naval Air Systems Command
Pre-release 11/29/23   Opens to accept proposals 1/03/24   Now Closes 2/21/24 12:00pm ET    [ View Q&A ]

N241-021 TITLE: High-Temperature, High-Efficiency Electrical Starter/Generator


The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop a high-temperature, high-efficiency ES/G and a system generator control unit (GCU), with the goal of optimizing heat load, output power, size, and/or weight of future power systems.

DESCRIPTION: The Navy is interested in pursuing new Electrical Power Generating System (EPGS) technologies for increasing efficiency, specific power, power density, and power capacity for 270 Vdc More-Electric Aircraft (MEA) systems. The EPGS is the main power source for MEA and the solution should provide motoring for main engine start capabilities. Improvements to the existing EPSG, or a new novel power generation system architecture/design, will be considered.

A 200-kW EPGS that converts rotational shaft power to 270 V is of interest. The generator should be able to produce this voltage and power across at 1.00-to-1.75 speed range—with the higher region of the speed range around 24,000 rpm. The generator should be capable of proving a stable power source for continuous and intermittent power across the operating speed range. It should be able to source stable electrical power into high step-load Constant-Power Loads (CPL) commensurate with MIL-PRF-22140B. The EPGS should also be able to maintain typical MIL-STD-704F power quality metrics while considering relevant line impedances for generating into the dynamic CPLs.

The offeror should show feasibility of the benefits and performance capability during Phase I using modeling, simulation, and analysis of the electromagnetic, thermal, rotor dynamics, reliability, fault conditions, etc. Careful consideration should be made that this is a mission-critical component for most MEA systems. The analysis should be provided for both steady-state and transient conditions.

The Navy requires new technologies to increase the efficiency and power capacity of today’s EPGS. The electrical starter/generator (ES/G) (ES/G) is the main power source for a MEA systems, providing motoring and main engine start capabilities for the aircraft. Improvements to the existing EPGS, or a new novel power-generation system architecture/design, will be considered. This effort should focus on providing an ES/G system to provide a minimum generator power output of: 200 kW (continuous), 250 kW (2-minute overload), 300-500 kW (5-second overload), and > 500 kW (0.5-second overload). The power generation operating range should be able to generate 270 Vdc and power across a 1.00 to 1.75 speed range (with peak speeds at roughly 24,000 rpm).

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by 32 U.S.C. § 2004.20 et seq., National Industrial Security Program Executive Agent and Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence and Security Agency (DCSA) formerly Defense Security Service (DSS). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances. This will allow contractor personnel to perform on advanced phases of this project as set forth by DCSA and NAVAIR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material during the advanced phases of this contract IAW the National Industrial Security Program Operating Manual (NISPOM), which can be found at Title 32, Part 2004.20 of the Code of Federal Regulations. Reference: National Industrial Security Program Executive Agent and Operating Manual (NISP), 32 U.S.C. § 2004.20 et seq. (1993). https://www.ecfr.gov/current/title-32/subtitle-B/chapter-XX/part-2004

PHASE I: Define generator design approach and develop an implementation plan. Validate approach analytically or provide test data or bench top hardware that would validate approach. Ensure maximum use of computer modeling and simulation techniques in this phase. Demonstrate a thorough working knowledge of applicable military standards. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Develop and demonstrate generator technology that can provide 200 kW of continuous power that can be fitted into the aircraft. Ensure that the generator package includes a GCU that is capable of controlling generator functionality. The package will be subjected to proof-of-concept testing at full qualification levels.

Work in Phase II may become classified. Please see note in Description paragraph.

PHASE III DUAL USE APPLICATIONS: Package and integrate new generator for use in the aircraft. Provide unit(s) to be subjected to full qualification testing and flight test profiles. The notable benefits include the increased efficiency and power capacity of the ES/G, reduction of system volume and weight, and interconnected complexity. It will improve thermal performance over the current system while also providing better engine and air vehicle performance. It will significantly reduce engine heat loads throughout the mission while focusing on heat rejection impacting the ES/G.

Specific industries, such as the automotive, marine, industrial machinery, agricultural machinery, and construction machinery, could benefit from this innovative ES/G technology. All of the above would provide significant benefits to both military and commercial aircraft applications.


  1. Brewer, R. (2016). High reliability electronics for demanding aircraft applications–an overview. Additional Papers and Presentations, 2016 (HiTEC), 000011-000017. https://doi.org/10.4071/2016-HITEC-11
  2. Department of Defense. (2006, February 28). DoD 5220.22-M National Industrial Security Program Operating Manual (Incorporating Change 2, May 18, 2016). Department of Defense. https://www.esd.whs.mil/portals/54/documents/dd/issuances/dodm/522022m.pdf

KEYWORDS: Generator; Generator Control Unit; Voltage Regulator; Electrical Power; Alternating Current; Direct Current


The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 24.1 SBIR BAA. Please see the official DoD Topic website at www.defensesbirsttr.mil/SBIR-STTR/Opportunities/#announcements for any updates.

The DoD issued its Navy 24.1 SBIR Topics pre-release on November 28, 2023 which opens to receive proposals on January 3, 2024, and now closes February 21, (12:00pm ET).

Direct Contact with Topic Authors: During the pre-release period (November 28, 2023 through January 2, 2024) proposing firms have an opportunity to directly contact the Technical Point of Contact (TPOC) to ask technical questions about the specific BAA topic. Once DoD begins accepting proposals on January 3, 2024 no further direct contact between proposers and topic authors is allowed unless the Topic Author is responding to a question submitted during the Pre-release period.

SITIS Q&A System: After the pre-release period, until January 24, 2023, at 12:00 PM ET, proposers may submit written questions through SITIS (SBIR/STTR Interactive Topic Information System) at www.dodsbirsttr.mil/topics-app/ by logging in and following instructions. In SITIS, the questioner and respondent remain anonymous but all questions and answers are posted for general viewing.

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Topic Q & A

1/16/24  Q.
  1. Is the maximum intermittent torque 500kW @ (24000rpm/1.75)= 350NM?
  2. Is the required starting torque less than the generator torque?
  3. 'The existing EPGS' is mentioned in the description, which platform is this?
  4. Has the new EPGS packaging volume been defined?
   A. 1: Yes
2: No, but won’t be defined now.
3: A platform is not being defined nor specified now.
4: No. But it should be able to be designed for flight-weight/worthy packaging.
12/04/23  Q. The topic title specifically calls out "high-temperature" and "high-efficiency" as key differentiators for proposed solution, but the solicitation does not outline specific objectives for operating temperature and/or total system efficiency. What is the best way for proposing teams to gain insight into the Navy's goals for this program?
   A. Efficiency: > 90% system efficiency from shaft power to 270 Vdc electrical power.
Temperature: If liquid cooled, the components must be able to tolerate greater than 120 degree C inlet oil temperature.

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