TECHNOLOGY AREA(S): Ground/Sea Vehicles

ACQUISITION PROGRAM: PMS 320 (Electric Ships Office) and the Power and Energy FNC Pillar

OBJECTIVE: Develop technology to provide affordable power-dense electrical rotating machines (motors and generators) for shipboard application.

DESCRIPTION: The Navy is embarking on an aggressive and innovative Power and Energy Program for application on future surface ships and underwater vehicles. Enabling an Integrated Power and Energy System (IPES) on smaller surface combatants will allow smaller ship classes to implement high-power/energy weapons and sensors, such as larger directed energy weapons, sensors with further range and fidelity, and higher-speed operations. With the advent of prime mover power generation and high-power directed weapons, the Navy is striving to distribute an order of magnitude increase in electrical power without increasing system space and weight, or reducing efficiency. Future Navy Ships will require more powerful rotating machines to fit within similar volumes as the current equipment to accommodate new high-power/energy weapons and sensor systems currently under development. The Navy seeks to develop technology necessary to support design, construction, and qualification of affordable power-dense electrical rotating machines (motors and generators) for shipboard application. Affordable is described as being similar in cost to current non-power-dense representative machines (motors or generators described below) chosen by the proposer. Large machines tend to be custom designs based on commercial practices ranging from hundreds of kW to tens of MW for motors and hundreds of kW to hundreds of MW for generators. Power density of the above electrical equipment must be increased in order to allow everything to fit on appropriately sized ships.

This increase in power density will require new techniques for heat removal, increased magnetic flux densities, and increased mechanical stresses simultaneously. Advances in power electronics have allowed reductions in power converter size. However, rotating machines have not seen comparable improvement due to physics limitations, lack of business case for typical commercial applications, and limited industry base. Increasing power density in the large rotating machines (generators, large motors) will make more space available for advanced weapons and sensor systems and the power distribution and conditioning equipment necessary to provide electrical power to them. Increased space availability is realized due to usage of a more power-dense machine. The increase in power density may also produce spatial savings within the distribution and power conditioning equipment by improving power quality and reducing the amount of power conversion equipment needed to meet mission system power requirements. A goal of this effort would be to deliver a system that provides 50% more power without an increase in weight or space requirements. This will enable high-energy weapons and sensors to be deployed on ship platforms that would otherwise not have sufficient margin to power these systems.

The Navy seeks technologies to develop a high-power density rotating machine that features an increase in power density of at least 50% more than the present state of the art (i.e., 1.5 times the power in the same volume as a current representative machine). The proposer will identify representative motors or generators that they will modify to meet the requirements of the topic. The proposer will also recommend test fixtures and methodologies to support environmental, shock, and vibration testing and qualification to meet the requirements covered under MIL-S-901 [Ref 3] and MIL-STD-167 [Ref 4]. The proposer will also provide related risk assessments and cost estimates for a fully developed shipboard unit. These technologies may include the use of high-energy Permanent Magnet materials and/or advanced cooling techniques such as liquid cooled rotors. The proposer should not focus on any changes that would increase the operating speeds for generators packaged with diesels and gas turbines above 15 MW and for motors used for propulsion directly coupled to the propeller shaft not less than 30 MW, as the effects of increased speed are known and the focus should be on developing other technology solutions. As the technology progresses past initial prototype development, the Navy will determine appropriate systems for replacement with the prototype developed by this STTR topic for operational evaluation, including required safety testing and certification.

PHASE I: Develop a concept for a high power density rotating machine and demonstrate the feasibility of the concept in meeting Navy needs, as well as establish that it can be feasibly developed into a useful product for the Navy.� Ensure that the concept discusses the salient features of the performance as well as the physical and functional characteristics of the proposed system. Submit modeling results for the proposed technology with best practice assumptions to estimate realistic efficiency numbers and best estimates of ancillary equipment. Develop a Phase II plan. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Based on the results of Phase I and the Phase II Statement of Work (SOW), develop, fabricate, test, and deliver a prototype of the machine as identified in the Description to the Navy for evaluation. Prior to delivery of the prototype to the Navy, perform lab testing to yield results for analysis to meet established specification requirements. Ensure that the prototype is of suitable scale to demonstrate the scalability to the larger power levels of shipboard power generation and propulsion and that it meets the performance goals established in the Description. Deliver the prototype to Navy personnel to be evaluated to determine its capability in meeting the performance goals defined in the Phase II SOW and Navy requirements for a high energy density rotating machine. Authenticate machine performance capabilities to meet detailed requirements through prototype evaluation (land-based testing) and modeling or analytical methods over the required range of parameters including numerous operating cycles. Use evaluation results to refine the prototype into an initial design that will meet Navy requirements. Conduct a risk assessment and develop a cost estimate for a naval shipboard unit. Prepare and develop a Phase III installation, testing, and validation plan to transition the technology to Navy use.

PHASE III DUAL USE APPLICATIONS: Support the Navy in evaluating the prototype delivered in Phase II and assist in transitioning this technology for Navy use. The Navy will determine appropriate systems for replacement with the prototype developed for operational evaluation, including required safety testing and certification. Working with the Government, provide detailed drawings and specifications and document the final product in a drawing package to the Navy for transition into demonstrations and development programs. As stated in the Description, past advances in power electronics have allowed reductions in power converter size. The Navy will be able to utilize these advances as well as the new solution that yields an increase in power density.

Other transition opportunities for this technology include commercial ship and offshore systems that could benefit from reduced volume of mechanical equipment. However, rotating machines have not seen comparable improvement due to physics limitations, lack of business case for typical commercial applications, and limited industry base.

REFERENCES:

1. Kuseian, John. �The 2015 Naval Power and Energy Systems Technology Development Roadmap.� http://www.navsea.navy.mil/Portals/103/Documents/Naval_Power_and_Energy_Systems_Technology_Development_Roadmap.pdf

2. Markle, Stephen P., PE, PMS 320 Director & Program Manager. �Surface Navy Electrical Leap Forward.� Sea-Air-Space Exposition Presentation 1.1., 03 April 2017. http://www.navsea.navy.mil/Portals/103/Documents/Exhibits/SAS2017/Markle-ElectricShips.pdf?ver=2017-04-03-155727-897.

3. Military Specifications: Shock Tests. H.I. (High-Impact) Shipboard Machinery, Equipment, and Systems, Requirements for (17 MAR 1989), MIL-S-901. http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-S/MIL-S-901D_14581/

4. DoD Test Method Standard: Mechanical Vibrations of Shipboard Equipment (Type I-Environmental and Type II-Internally (NOV 2005), MIL-STD-167-1A. http://everyspec.com/MIL-STD/MIL-STD-0100-0299/MIL-STD-167-1A_22418/

KEYWORDS: Rotating Machine; High Energy Density; High Power Density; Electric Ship; Electric Drive; Next Generation Integrated Power System (NGIPS)