HVDC Distribution Study of Intelligent Power System

University of Dayton Research Institute

SCOPE
High Voltage Direct Current (HVDC) aviation electrical power systems (EPS) provide many advantages, particularly in the area of weight savings. Despite the advantages, there are technical challenges for these systems as the power and dynamic response demanded by high power and more-electric loads increases. High power HVDC systems require low source impedance which makes larger fault energy available to the system. In addition, flight and mission critical loads demand constant power and fast response by a tightly regulated EPS. These loads on a HVDC distribution can cause dynamically negative resistance resulting in poor power quality and/or loss of system stability.

OBJECTIVES
AFRL’ s objective is to develop an intelligent power system to advance the state of the art in system efficiency and safety. This is a far-reaching and broad area of research that is best served by the participation of multiple research institutions that have developed expertise in specific areas. To that end, this Statement of Objectives outlines work where Michigan Technological University (MTU) has demonstrated outstanding research.
Specific areas of research that AFRL is interested in having MTU participate in this program are outlined below. The results of this research and development effort shall be available to all other parties collaborating on the AFRL Intelligent Power System Program as well as industry concerns involved with United States aviation power systems so that best practices and recommendations can be incorporated in future power system design concepts.

RESEARCH TASKS
1.1 Analysis, Design, and Control of components (ns – ms level)
1.2 Distributed management/optimization of source and loads (ms – s level):
1.3 Mission level load planning(> 1 s level)
1.4 Energy Storage (ES) for pulsed power loads

Investigators: Wayne Weaver, Gordon Parker

On Integrating Object Detection Capability into a Coastal Energy Conversion System

U.S. Department of Defense, Office of Naval Research

Project Summary
Near-shore wave energy converter arrays may be designed to provide uninterrupted power to a number of coastal sensing applications, including sensors monitoring meteorological conditions, sea-water chemical/physical properties, tsunamis and storm surges, fish and other marine life, coastal and sea-floor conditions, etc. Active control seeking near-optimum hydrodynamic operation has been shown to enable a dramatic reduction in device size for required amounts of power. Certain features of the control strategies developed make them particularly amenable to incorporation of additional sensing capability based on the wave patterns generated by intruding submerged objects (at distances on the order of 1000 m), in particular, the phase changes to the approaching wave field that occur in the presence of an object.

This project investigates schemes for actively controlled wave energy converter arrays in coastal waters which enable detection of intruding marine vessels by monitoring the spatial and temporal energy conversion rates over the arrays. The proposed approach mainly utilizes a linear-theory based understanding of wave propagation, body hydrodynamics, and controller design, but also incorporates nonlinear extensions based on Volterra series modeling. Of particular interest, is using small device sizes, for which response nonlinearities can be significant. Therefore, it is proposed to exploit the nonlinearities to enhance energy generation. Furthermore, also investigate ways to utilize features of the nonlinear response that enable preferential coupling to certain phase signatures, so that energy conversion by certain array elements would imply the presence of an object. Analysis and simulation results on arrays of moored devices will be extended to free-floating arrays.

The first objective of the overall effort is to evaluate the proposed techniques through analysis and simulation. For near-shore sea areas to be identified, two categories or types of array designs with their own particular control strategies will be investigated, using Hydrodynamics and Controls based analytical techniques and detailed simulations (linear and nonlinear). Necessary in this process is the characterization of the phase-change signatures of various submerged objects when stationary and when in translation. This knowledge will provide the test parameters for the designs to be investigated. The first two years of the overall, 4-year long, effort are expected to provide the groundwork for the development of a prototype system. Prior to ‘at-sea’ prototype testing, first test the prototype in a wave-basin environment. To provide reliable designs for the testing in the wave basin, wave tank testing under simplified conditions is also proposed. The overall testing sequence from wave tank tests through wave-basin tests to ‘at sea’ tests is expected to occur over years 3 and 4.

Investigators: Umesh Korde, Rush Robinett, Ossama Abdelkhalik

Modeling and Control Development for Electric Vehicle and Smart Grid Integration

Argonne National Laboratory

Summary:
Further develop modeling and control in the EV-Smart Grid Interoperability Center.
1. To prepare for the next phase of controller-in-the-loop, an additional communication mechanism between Opal-RT and CIP.io will be explored. Currently, the Opal-RT simulator can communicate with
CIP.io through Modbus TCP/IP. To enable the Opal-RT simulator directly communicating with an
MQTI broker, the implementation of an MQTI client in Opal-RT will be developed.
Deliverables:
•Fully functional, tested and debugged Opal-RT MQTI communication blocks for interfacing an
MQTI broker with an Opal-RT simulation (publish and subscribe).
2. CIP.io Node-Red Node Development
The contractor will develop Node-Red Nodes to further integrate networked devices into CIP.io. All source code will be open-sourced and posted the IOC GitHub account.
Deliverables:
•Fully functional, tested and debugged BACnet Node-Red node.

Investigator: Bo Chen

CAREER: An Ecologically-Inspired Approach to Battery Lifetime Analysis and Testing

National Science Foundation

Overview
Batteries are increasingly relied upon to provide multiple services during applications (e.g. traction in an electric vehicle, vehicle-to-grid, ancillary services) and to act as the ultimate resiliency element (e.g. electric vehicles used as power units during Hurricane Sandy). However, the ability to perform these diverse services is compromised by battery aging phenomena that eventually lead to failure. Understanding of how service conditions and context affect battery aging is limited due to a) battery high context dependency on generation and load dynamics, and environmental conditions; b) the multi-scale cell and module nature of battery systems; and c) the fact that a battery itself varies with age, as batteries are repurposed after a first life (e.g. electric vehicle) into a second life (e.g. grid or residential).

This CAREER project aims to understand battery aging dynamics as context-dependent, and to provide a unified theory that links application-level events and conditions with cell- and module-level aging events. The Pl hypothesizes that a battery electrochemical nature and aging, multi-scale system, observability challenges, and its context-dependency can all be modeled using ecological tools, with ecology defined as a branch of biology that explores organism relationships to one another and to their environment. Therefore, methods proven useful to study ecological relationships are well suited to study battery life, and can provide new knowledge, testing and estimation techniques. This project draws from two pertinent areas in ecology: 1) multi-scale field testing and 2) modeling of interrelationships among ecosystem elements to understand coupled effects and improve remaining life predictions. Hence, the research objectives are: 1 ) Identify a battery context and its observability through sensors and data in real deployment conditions for two lives (electric vehicle and grid); 2) Optimize a methodology to translate real-life conditions into the laboratory; 3) Design a large multi-scale testing platform in the laboratory for new and aged cells and modules that mimics real-life conditions; 4) Explore multi-scale battery dynamics and aging by developing reasoning networks that capture the whole battery context variations throughout its scales, reaching the application level; develop theories that link these networks across lives; design battery management systems that can learn to construct and apply these networks to improve their decision making and prediction.

Intellectual Merit
This novel project will provide knowledge and perspectives to two fields by capitalizing upon the similarities between battery context-dependencies, battery life, and ecological systems. This new outlook will provide a unified theory for testing, estimation and management of batteries across cell, module, pack, and application scales and life scales in a research field that up to this point has been disconnected between scales. Testing approaches, interrelationship models, and estimation methods used in ecology are predicted to improve upon present, state-of-the-art battery research methods to provide economic, resiliency and environmental benefits by better understanding and leveraging the unique, time-dependent relationships each battery has with its context.

Broader Impacts
This work will benefit all battery portable, transportation, and grid applications as well as multiple sectors. It will include the emerging battery repurposing sector, by providing tangible methods to improve testing, estimation and management techniques. The result will be longer battery life, better performance, and less environmental waste. Educational impacts include active learning opportunities for undergraduate and graduate students via research and educational interactions with individualized testing boards linked to the newly created large multi-scale testing platform. This strategy will enable low cost, highly distributed testing environments. The Pl will disseminate tools via national education conferences to improve the nearly nonexistent battery testing training of students. This project will facilitate new paths in multi-disciplinary graduate courses. The Pl has a passion to increase representation of Hispanic females in STEM. Outreach will include hosting 4 diverse Community College students for summer research through the Michigan College and University Partnership, and participating in Society for Hispanic Professional Engineers conferences, specifically in the female Hispanic track.

Investigator: Lucia Gauchia

CAREER: Autonomous Underwater Power Distribution System for Continuous Operation

National Science Foundation

Overview:
Success of numerous long-term robotic network missions in space, air, ground, and water is measured by the ability of the robots to operate for extended time in highly dynamic and potentially hazardous operating environments. The proposed work responds to the urgency for development of innovative mobile power distribution systems that lower deployment and operating costs, while simultaneously increasing mission efficiency, and supporting the network’s need to be responsive to changing physical conditions. The overall CAREER goal is to develop a power distribution system that responds to individual robot needs, as well as, overall robotic network goals to guarantee persistence of long-term operation in uncertain and unstructured environments.

The proposed work is informed by the hypothesis that network persistence hinges on the ability to establish stable energy transfer cycles necessary to accomplish coverage specifications, while simultaneously dealing with physical and environmental constraints. To test this hypothesis and as an example of such a system, this work will focus on creating a reliable autonomous recharging system for autonomous underwater vehicles (AUVs) that enables continuous real-time marine observation and data collection in the presence of continuously changing underwater environmental circumstances. The key challenges are two-fold: there are fundamental hardware challenges connected to energy transfer in the harsh underwater environment, but more importantly there are basic network science needs that are novel to a mobile power network. The specific research thrusts for this CAREER work include: 1) Task and Energy Routing Scheduling for Persistent Mission Planning. 2) Efficient Network Path Planning and Coordination to Accomplish Persistent Mission Plan. 3) Experimental Validation through Test-bed Development. 4) Design-based, Research-integrated Education Plan for Broadening Underrepresented Participation in STEM.

Intellectual Merit:
This project builds a roadmap to achieve robust continuous marine autonomy that advances unmanned marine systems ability to perform autonomous long-term missions. More specifically the proposed work will provide: 1) resource based task scheduling, 2) path planning formation for mission and charging, and 3) integration tools for testing. Expected outcomes will overcome the current challenge of significant interruptions during underwater missions due to battery limitations and recharging needs. Through this CAREER proposal, the Pl will establish the theoretical, computational, and experimental foundation for mobile power delivery and onsite recharging capability for autonomous underwater vehicles (AUVs). The developed power distribution system will be able to reconfigure itself depending on the scope of the mission, as well as, the energy consumption needs of the network, the number of operational AUVs and required operation time, recharging specifications, communication and localization means, and environmental variables.

Such a system will play a vital role in real-time controlled applications across multiple disciplines, such as: sensor networks, robotics, and transportation systems where limited power resources and unknown environmental dynamics pose major constraints. All developed tools will be suited for the capabilities of not only low-cost AUVs with limited sensing and computational resources, but also high-tech AUVs with state of the art sensor packages.

Broader Impacts:
The developed active power distribution system focuses on underwater scenarios, but will be transferrable to space, air, and ground missions as well. This type of feasible power distribution solution can be used to optimize: 1) immediate high-risk disaster recovery missions like the Fukushima nuclear plant accident; 2) search missions that require vast underwater inspection and detection like the Malaysia MH370 passenger aircraft; and 3) long-term space observation and monitoring like that of the lunar skylight or Europa space mission. The findings from this project will be disseminated through publications, software sharing, and technology commercialization. The project provides interdisciplinary training opportunities for graduate, undergraduate, and pre-college students, including those from underrepresented groups. Research activities will be integrated with education through curriculum development, outreach and improved GUPPIE design.

Investigator: Nina Mahmoudian

NRI: Co-Robots to Engage Next Generation of Students in STEM Learning

National Science Foundation

Overview:
Correctly, the 2009 Roadmap for US Robotics report predicted that robotics technology would transform the future of the US workforce and households. From Roomba vacuum cleaners to Wii video games, we increasingly see robotic technology in work spaces and homes. Yet, the US continues to lag behind China, South Korea, Japan, and European Union in its investment in robotics research and education. The Next Generation Science Standards for Today’s Students and Tomorrow’s Workforce responds to this critical need by providing a curricular framework for using crosscutting concepts and disciplinary ideas that: have broad importance across science and engineering disciplines; are taught around a key organizing concept (like health or water) and use key tool (pedagogical platform); have a significant context for students and are explicitly connected to societal needs; and are teachable and learnable over multiple grades. Informed by this framework, our proposed NRI aims to develop, test, and assess two co-robotic platforms with high impact potential and longevity as a pedagogical platform (use is applicable from 4th grade through graduate school learning). Two unique robotics educational platforms will be used to teach 6th-8th grade: an educational underwater glider called GUPPIE and a surface electromyography (sEMG)- controlled manipulator called Neu-pulator. Both of these platforms can be categorized as co-robot and cost less than $1000. GUPPIE is an unmanned vehicle that has application in monitoring and inspection of the environment and can be used to introduce students to the application of robots as co-explorers in everyday life. Neu-pulator is a human-interactive robot that uses electrical activity of human muscles to move a manipulator. It introduces students to assistive robots, which are a class of co-robots that aim to amplify or compensate for human capabilities. We hypothesize that meaningful contexts and hands-on learning with co-robotic platforms will broaden impact to diverse audiences and increase interest in critical STEM areas. The overall goal of the proposed NRI is to develop and evaluate the use of co-robotic platforms in learning contexts that are socially meaningful, especially for underrepresented students (female students from rural, low socioeconomic areas in the Upper Peninsula of Michigan). Our specific objectives are to: 1) Optimize Michigan Tech’s co-robotic platform designs for teaching STEM concepts. 2) Develop educational activities/curriculum utilizing Michigan Tech’s co-robotic platforms. 3) Investigate the co-robotic platforms effectiveness in engaging students in STEM learning.

Intellectual Merit:
The proposed work will develop a pedagogical platform and evaluation method that can be easily translated for classroom practice from grades 4th-12th and in undergraduate to graduate degree programs. Training teachers in platform use during teacher workshops will help schools respond to and integrate new science standards – efficiently and effectively using meaningful contexts. Continued online training and modules will be available to broadly disseminate platform applications for informal and formal learning contexts. The hardware development and programming of co-robots will teach critical analytical thinking. The nature of co-robotic platforms, on the other hand, will inspire students to become integrative designers. By exercising both analytical thinking and design skills, these co-robotic platforms will improve students’ ability for creative problem solving, and ultimately increase individual motivation for pursuing STEM academic and career pathways. The project will produce research that compares the effectiveness of mission-based and application-based robotics activities for engaging students in STEM.

Investigators: Nina Mahmoudian and Mo Rastgaar

Meta-Stability of Pulsed Load Microgrids

Sandia National Labs

Statement of Work
NAVSEA/ Military microgrids
Using the HSSPFC (Hamiltonian Surface Shaping and Power Flow Control) derived MATLAB/Simulink
tools develop a Reduced Order Model (ROM) to support control designs for pulse load applications for i)
up to (3) key ship modes of a ship power system operation and ii) a stable and unstable modes of
switching operations as a part of a survivability scenario.
Deliverables Tasks:
1. Provide ROM of meta-stable ship system.
2. Analyses and control design (feedforward and feedback) of meta-stable system.
3. Analyses and control design for multi-pulse load systems.
4. Analyses of the effects and potential benefits of non-linear magnetics in meta-stable system.
5. Develop and perform hardware testing on metastable laboratory benchtop system.
6. Develop networked Microgrid model for KIER/LUXCO scenario

Investigator: Wayne Weaver

Collaborative Research: On Making Wave Energy an Economical and Reliable Power Source for Ocean Measurement Applications

National Science Foundation

Work Plan:
Task 1: Wave-by-wave control and Multi-resonant control
(a-i) Wave-by-Wave Control: Generalize to conversion from relative oscillation in surge, heave, and pitch modes. This step places high expectations on geometry design, because the chosen geometry needs to maximize wave radiation (radiation damping) by relative oscillation in all three modes. Typically, for small axi-symmetric buoys, radiation damping in surge and pitch modes is considerably smaller than that in heave mode. Therefore, greater oscillation excursions are typically required for optimal conversion in these modes. In addition, the power requirements of the wave measurement hardware also need to be included in the daily/annual powver calculations. For the X-band Radar hardware applicable to the up-wave distances of interest to us (on the order of 1000 m), the power consumption is expected to be less than 300 W (average). This could pose a challenge in some wave conditions, but it is likely that the use of multiple modes and optimized geometries will help to provide sufficient usable power for the iFCB application we are pursuing in this work. We plan to extend the current simulations to address these needs.
(a-ii) Geometry Design: New geometry design/utilization approaches to maximize the radiation damping for the 3 relative oscillation modes are being considered. These will be evaluated through detailed simulations in the forthcoming period.
(b) Multi-resonant Control: Current implementations need to be extended to incorporate realistic oscillation constraints. Further extensions to 2-body systems with power capture from relative oscillation are also required, and are planned for the forthcoming period. Finally, the procedure also needs to be extended to investigate multiple-mode conversion (i.e. relative heave, pitch, and surge oscillations).
Task 2: Actuator Design and Energy Storage
Work is planned for the forthcoming period where propose to examine favorably interacting buoy-instrument cage geometries that will minimize the need for large amounts of reactive power to flow through the system. Particular attention will be given to hydrodynamic and mechanical coupling effects and ways to provide negative stiffness through geometry design.
In addition, non-polluting high-lubricity hydraulic fluids will be evaluated through actuator dynamic models over the frequency range of interest.
Task 3: Simulation of Complete System and Wave Tank Testing
This is an important part of the project. The complete system will be simulated following inclusion of multiple-mode relative oscillation conversion and more detailed actuator design. Besides the power requirements of the wave measurement system, all other non-function-critical power needs embedded within the overall system (on-board electronics, etc.) will be included in this simulation.
Wave tank tests are planned as part of this project. Preparations are currently underway to install a wave tank (with flap type absorbing wave makers) capable of providing accurate and repeatable sea states for this project. 1/2 or 1/5 scale models are planned.

Investigator: Umesh Korde

Hydrodynamic Control Using X-Band Radar for Wave Energy Converter Technology

U.S. Dept of Defense, Naval Facilities Engineering Command

The current approach for designing wave energy converters is to use a floating-body tuned to the wave climate, which results in a very large device that is expensive to build, service and deploy. Additionally, because the device is designed to be tuned to a specific climate, it will not work effectively in a different location ·with a different climate. Therefore, the current approach for designing wave energy converters is not conducive to long-term economic application.

Economically significant size reduction and year-round power increases are only possible through operation near theoretical efficiency limits in constantly changing wave conditions, which requires active hydrodynamic control. However, the wave-by-wave control necessary for best conversion is not possible without wave-elevation information up to some duration into the future (this in large part is because of the force due to the waves generated by body oscillation in response to the incident wave field). By incorporating wave-elevation prediction based on a deterministic propagation model that accounts for a realistic range of wave-group velocities in conjunction with wave measurements in the up-wave directions, we have been able to confirm, through simulations, a 10-fold increase in power conversion under a swept-volume oscillation constraint for an omni-directional heaving buoy type device.
Availability of instantaneous wave profile (“wave surface elevation” or “wave elevation”) measurements and wave surface elevation predictions is important to the success of the control approach being pursued in this work. Equally important is the near-optimal wave-by-wave control approach itself.

Proposed research:
1. A method for obtaining instantaneous wave surface elevation information on a wave-by wave basis using a low-cost X-band Radar (the state of the art, as represented by the commercially available WaMOS system is optimized to provide spectral information.
2. A method for providing constrained near-optimal wave-by-wave control for maximizing the energy conversion by small wave energy converters.
3. Although the focus of the proposed research is wave energy converter technology, the results of this work are expected to find application in other forthcoming Navy developments. Wave-by-wave surface elevation prediction and near-optimal power absorption techniques demonstrated in this effort can be extended to facilitate critical mid-sea shipboard operations such as helicopter/ aircraft landing, cargo handling, etc. The techniques demonstrated as part of this research will also provide technology to enhance and optimize seakeeping characteristics of Navy ocean platforms.

Investigator: Umesh Korde

Increasing Ship Power System Capability throught Exergy Control

U.S. Dept. of Defense, Office of Naval Research

The main objective of this effort is to develop an exergy control strategy, applied to a ship medium voltage de (MVDC) grid that exploits exergy flow coupling between multiple subsystems. This work involves: 1) exergy control strategy development and 2) mapping exergy control system performance to ship-relevant metrics. A ship power grid Challenge Problem model will be developed to illustrate and resolve the fundamental gaps of exergy control. The model will also compare and contrast feedforward and feedback exergy control with conventional strategies.

Introduction
Ship subsystems and mission modules perform energy conversion during their operation resulting in a combination of electricity consumption, heat generation and mechanical work. Mission module thermal management requirements further impact the ship’s electrical grid, for example, via chiller operation. Subsystems often have opportunities for performing an energy storage role during their operation cycle. A ship crane is one example where potential energy is stored in the raised load and can be converted into electrical energy during lowering. Whether subsystem requirements are dominated by electrical, thermal or mechanical functions, they are coupled through energy and information flows, often by the ship’s electrical power grid. Treating each subsystem as a disconnected entity reduces the potential for exploiting their inherent interconnection and likely results in over designed shipboard systems with higher than necessary weight and volume. Realizing the opportunity of coupled subsystem operation requires modeling and control schemes that are unavailable today, but that we believe should require few infrastructure changes. We propose that the design and control of coupled ship subsystems should be based on exergy- the amount of energy available for useful work. A recent study, applied to a room heating system, showed that exergy control increased the overall efficiency by 18%. Since the system was powered electrically, this translated directly to a decrease in the electrical load. The main objective of this effort is to develop an exergy control strategy, applied to a ship medium voltage de (MVDC) grid that exploits exergy flow coupling between multiple subsystems.

An exergy approach to control permits consideration of both mission modules and the platform infrastructure as mixed physics power systems that may act as loads, storage or sources depending on the situation. Instead of separately designed and managed subsystems that satisfy electrical and thermal requirements via static design margins a, multi-physics, unified system-of-systems approach is needed to enable affordable mid-life upgrades as requirements and mission systems evolve over the platform’s lifespan. Being able to translate the benefits of exergy control into savings in mass, volume, energy storage requirements and fuel usage is necessary for making rational design decisions for new ship platforms and for increasing the efficiency of legacy ship systems. Currently, there does not exist an analysis technique to map control system performance into ship-relevant performance metrics. This restricts ship designers from understanding the tradeoffs of adopting advanced control schemes that may exploit subsystem coupling. One of the objectives of this work is to develop a method for extrapolating control system performance into ship-relevant metrics that impact mass, volume, energy storage, and fuel usage.

As described above, there are two main thrusts to this work: (1) exergy control strategy development and (2) mapping exergy control system performance to ship-relevant metrics. We will develop a ship power grid Challenge Problem model that will illustrate the fundamental gaps of exergy control that will be addressed. The model will also be used to compare and contrast feedforward and feedback exergy control with conventional strategies. Techniques for mapping the results of the exergy control to weight, volume, and energy storage requirements will be developed and applied to the Challenge Problem throughout the project.

Investigators: Gordon Parker and Rush Robinett, and Ed Trinklein.