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Stabilization of Generator Frequency under Pulsed Load Condition Using Regenerative Propeller Braking

2021 IEEE Electric Ship Technologies Symposium, ESTS 2021

Matthews, Ronald C.; Rashkin, Lee; Glover, Steven F.; Doerry, Norbert H.

In this paper, the effects and mitigation strategies of pulsed loads on medium voltage DC (MVDC) electric ships are explored. Particularly, the effect of high-powered pulsed loads on generator frequency stability are examined. As a method to stabilize a generator which has been made unstable by high-powered pulsed loads, it is proposed to temporarily extract energy from the propulsion system using regenerative propeller braking. The damping effects on generator speed oscillation of this method of control are examined. The impacts on propeller and ship speed are also presented.

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Reduced Order Model of a Four Zone Medium Voltage DC Electric Ship

2021 IEEE Electric Ship Technologies Symposium, ESTS 2021

Weaver, Wayne W.; Robinett, Rush D.; Wilson, David G.; Glover, Steven F.

The models of multi-zone electric ship is important to the development of ship operational capability and performance. However, there is not one best model type that can fit all the needs of the engineering process. High-fidelity models are needed to act as a digital twin to the system hardware for testing and validation purposes. However, a highly detailed digital model of a MVDC does not enable insight and development of analytical control and optimization algorithms. This paper presents a reduced order model (ROM) of a notional four-zone medium voltage ship. This ROM can be written in a closed-form analytical expression that is appropriate for analysis and high-level supervisory control synthesis.

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Energy storage design considerations for an MVDC power system

Journal of Marine Engineering and Technology

Rashkin, Lee; Neely, Jason C.; Wilson, David G.; Glover, Steven F.; Doerry, Norbert; Markle, Stephen; McCoy, Timothy J.

The U.S. Navy is investing in the development of new technologies that broaden warship capabilities and maintain U.S. naval superiority. Specifically, Naval Sea Systems Command (NAVSEA) is supporting the development of power systems technologies that enable the Navy to realise an all-electric warship. A challenge to fielding an all-electric power system architecture includes minimising the size of energy storage systems (ESS) while maintaining the response times necessary to support potential pulsed loads. This work explores the trade-off between energy storage size requirements (i.e. mass) and performance (i.e. peak power, energy storage, and control bandwidth) in the context of a power system architecture that meets the needs of the U.S. Navy. In this work, the simulated time domain responses of a representative power system were evaluated under different loading conditions and control parameters, and the results were considered in conjunction with sizing constraints of and estimated specific power and energy densities of various storage technologies. The simulation scenarios were based on representative operational vignettes, and a Ragone plot was used to illustrate the intersection of potential energy storage sizing with the energy and power density requirements of the system. Furthermore, the energy storage control bandwidth requirements were evaluated by simulation for different loading scenarios. Two approaches were taken to design an ESS: one based only on time domain power and energy requirements from simulation and another based on bandwidth (specific frequency) limitations of various technologies.

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Nonlinear Power Flow Control Design for Networked AC/ DC Based Microgrid Systems

Proceedings of the American Control Conference

Wilson, David G.; Weaver, Wayne W.; Robinett, Rush D.; Glover, Steven F.

This paper presents a control design methodology that addresses high penetration of variable generation or renewable energy sources and loads for networked AC /DC microgrid systems as an islanded subsystem or as part of larger electric power grid systems. High performance microgrid systems that contain large amounts of stochastic sources and loads is a major goal for the future of electric power systems. Alternatively, methods for controlling and analyzing AC/ DC microgrid systems will provide an understanding into the tradeoffs that can be made during the design phase. This method develops both a control design methodology and realizable hierarchical controllers that are based on the Hamiltonian Surface Shaping and Power Flow Control (HSSPFC) methodology that regulates renewable energy sources, varying loads and identifies energy storage requirements for a networked AC/DC microgrid system. Both static and dynamic stability conditions are derived. A renewable energy scenario is considered for a networked three DC microgrids tied into an AC ringbus configuration. Numerical simulation results are presented.

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Dynamic considerations of power system coupling through dual-wound generators

2017 IEEE Electric Ship Technologies Symposium, ESTS 2017

Rashkin, Lee; Neely, J.C.; Glover, Steven F.; Mccoy, T.J.; Pekarek, S.D.

Several technical power system architectures are being evaluated for the Navy's next generation all-electric warship. One concept being considered includes a scheme to power both port and starboard busses from a single generator with dual-windings. This approach offers redundancy and reduces the effects of prime mover light loading, but it inherently couples the two busses through the common generator. In this work, dynamic issues of galvanic and electro-mechanical coupling of power systems through a single dual-wound generator are discussed. Previous works focused on harmonics and galvanic coupling. Herein, focus is placed on average-value modeling of the galvanic coupling and on evaluation for fault response. Conclusions are presented from analysis, simulation, and experimental results.

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Stability of high-bandwidth power electronic systems with transmission lines

2017 IEEE Electric Ship Technologies Symposium, ESTS 2017

Neely, Jason; Delhotal, Jarod J.; Rashkin, Lee; Glover, Steven F.

In most distributed power electronic systems, the transmission line effects associated with cabling are neglected due to the expectation that cables are sufficiently short to be modeled as a lumped parameter model. However, as converter switching speeds and control bandwidth increase, especially in large distributed power electronic based systems, the transmission line effects may become an important consideration when establishing margins of stability. In this work, immittance based stability analysis is applied to power electronic systems with long cables between source and load converter. In particular, the Energy Systems Analysis Consortium (ESAC) method is utilized to compute limits on cable length so as to maintain prescribed stability margins. Simulation results are presented in support of the approach.

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Evaluation of power flow control for an all-electric warship power system with pulsed load applications

Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC

Neely, J.; Rashkin, Lee; Cook, M.; Wilson, David G.; Glover, Steven F.

Future U.S. Navy ships will require power systems that meet more stringent agility, efficiency, scalability, controllability and resiliency requirements. Modularity and the ability to interconnect power systems having their own energy storage, generation, and loads is an enabling capability. To aid in the design of power system controls, much of what has been learned from advances in the control of networked microgrids is being applied. Developing alternative methods for controlling and analyzing these systems will provide insight into tradeoffs that can be made during the design phase. This paper considers the problem of electric ship power disturbances in response to pulsed loads, in particular, to electromagnetic launch systems. Recent literature has indicated that there exists a trade-off in information and power flow and that intelligent, coordinated control of power flow in a microgrid system (i.e. such as an electric ship) can modify energy storage hardware requirements. The control presented herein was developed to provide the necessary flexibility with little computational burden. It is described analytically and then demonstrated in simulation and hardware.

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Scoping Study: Networked Microgrids

Trinklei, Eddy T.; Parker, Gordon G.; Weaver, Wayne W.; Robinett, Rush D.; Babe Gauchia, Lucia B.; Ten, Chee-Wooi T.; Bower, Ward B.; Glover, Steven F.; Bukowski, Steve B.

This report presents a scoping study for networked microgrids which are defined as "Interoperable groups of multiple Advanced Microgrids that become an integral part of the electricity grid while providing enhanced resiliency through self-healing, aggregated ancillary services, and real-time communication." They result in optimal electrical system configurations and controls whether grid-connected or in islanded modes and enable high penetrations of distributed and renewable energy resources. The vision for the purpose of this document is: "Networked microgrids seamlessly integrate with the electricity grid or other Electric Power Sources (EPS) providing cost effective, high quality, reliable, resilient, self-healing power delivery systems."

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Hamiltonian control design for DC microgrids with stochastic sources and loads with applications

2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion, SPEEDAM 2014

Wilson, David G.; Neely, Jason C.; Cook, Marvin A.; Glover, Steven F.; Young, Joseph; Robinett, Rush D.

To achieve high performance operation of micro-grids that contain stochastic sources and loads is a challenge that will impact cost and complexity. Developing alternative methods for controlling and analyzing these systems will provide insight into tradeoffs that can be made during the design phase. This paper presents a design methodology, based on Hamiltonian Surface Shaping and Power Flow Control (HSSPFC) [1] for a hierarchical control scheme that regulates renewable energy sources and energy storage in a DC micro-grid. Recent literature has indicated that there exists a trade-off in information and power flow and that intelligent, coordinated control of power flow in a microgrid system can modify energy storage hardware requirements. Two scenarios are considered; i) simple two stochastic source with variable load renewable DC Microgrid example and ii) a three zone electric ship with DC Microgrid and varying pulse load profiles. © 2014 IEEE.

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Voltage and frequency regulation strategies in isolated AC micro-grids

Proceedings - 2012 IEEE International Conference on Cyber Technology in Automation, Control, and Intelligent Systems, CYBER 2012

Wasynczuk, O.; Rashkin, L.J.; Pekarek, S.D.; Swanson, R.R.; Loop, B.P.; Wu, N.; Glover, Steven F.; Neely, J.C.

In ac power systems, including micro-grids, it is important to regulate the amplitude and frequency of the voltages throughout the system. Many of the existing and proposed control strategies for micro-grids are patterned after the classic ac power system. That is, frequency regulation is achieved by designing micro-sources (commonly called Distributed Energy Resources or DERs) to exhibit an output-frequency-versus-power characteristic similar to the speed-versus-power (droop) characteristics of conventional turbo- and hydro-generators. Moreover, voltage regulation strategies are patterned after the output-voltageversus-reactive-power (droop) characteristics of the automatic voltage regulators (AVRs) used in conventional turbo- and hydrogenerators. In this paper, established approaches of frequency and voltage regulation are reviewed. Alternative strategies that utilize modern communication and control technologies are presented and discussed. © 2012 IEEE.

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Impact of time-varying loads on the programmable pulsed power driver called genesis

Digest of Technical Papers-IEEE International Pulsed Power Conference

Glover, Steven F.; Davis, Jean-Paul D.; Schneider, Larry X.; Reed, Kim W.; Pena, Gary P.; Hall, Clint A.; Hanshaw, Heath L.; Hickman, Randy J.; Hodge, K.C.; Lemke, Raymond W.; Lehr, J.M.; Lucero, D.J.; McDaniel, Dillon H.; Puissant, J.G.; Rudys, Joseph M.; Sceiford, Matthew S.; Tullar, S.J.; Van De Valde, D.M.; White, F.E.; Warne, Larry K.; Coats, Rebecca S.; Johnson, William Arthur.

The success of dynamic materials properties research at Sandia National Laboratories has led to research into ultra-low impedance, compact pulsed power systems capable of multi-MA shaped current pulses with rise times ranging from 220-500 ns. The Genesis design consists of two hundred and forty 200 kV, 80 kA modules connected in parallel to a solid dielectric disk transmission line and is capable of producing 280 kbar of magnetic pressure (>500 kbar pressure in high Z materials) in a 1.75 nH, 20 mm wide stripline load. Stripline loads operating under these conditions expand during the experiment resulting in a time-varying load that can impact the performance and lifetime of the system. This paper provides analysis of time-varying stripline loads and the impact of these loads on system performance. Further, an approach to reduce dielectric stress levels through active damping is presented as a means to increase system reliability and lifetime. © 2011 IEEE.

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Status of genesis a 5 MA programmable pulsed power driver

Digest of Technical Papers-IEEE International Pulsed Power Conference

Glover, Steven F.; White, F.E.; Foster, P.J.; Lucero, D.J.; Schneider, Larry X.; Reed, Kim W.; Pena, Gary P.; Davis, Jean-Paul D.; Hall, Clint A.; Hickman, Randy J.; Hodge, K.C.; Lemke, Raymond W.; Lehr, J.M.; McDaniel, Dillon H.; Puissant, J.G.; Rudys, Joseph M.; Sceiford, Matthew S.; Tullar, S.J.; Van De Valde, D.M.

Genesis is a compact pulsed power platform designed by Sandia National Laboratories to generate precision shaped multi-MA current waves with a rise time of 200-500 ns. In this system, two hundred and forty, 200 kV, 80 kA modules are selectively triggered to produce 280 kbar of magnetic pressure (>500 kbar pressure in high Z materials) in a stripline load for dynamic materials properties research. This new capability incorporates the use of solid dielectrics to reduce system inductance and size, programmable current shaping, and gas switches that must perform over a large range of operating conditions. Research has continued on this technology base with a focus on demonstrating the integrated performance of key concepts into a Genesis-like prototype called Protogen. Protogen measures approximately 1.4 m by 1.4 m and is designed to hold twelve Genesis modules. A fixed inductance load will allow rep-rate operation for component reliability and system lifetime experiments at the extreme electric field operating conditions expected in Genesis. © 2011 IEEE.

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Ferroelectric opening switches for large-scale pulsed power drivers

Reed, Kim W.; Glover, Steven F.; Pena, Gary P.; Rudys, Joseph M.

Fast electrical energy storage or Voltage-Driven Technology (VDT) has dominated fast, high-voltage pulsed power systems for the past six decades. Fast magnetic energy storage or Current-Driven Technology (CDT) is characterized by 10,000 X higher energy density than VDT and has a great number of other substantial advantages, but it has all but been neglected for all of these decades. The uniform explanation for neglect of CDT technology is invariably that the industry has never been able to make an effective opening switch, which is essential for the use of CDT. Most approaches to opening switches have involved plasma of one sort or another. On a large scale, gaseous plasmas have been used as a conductor to bridge the switch electrodes that provides an opening function when the current wave front propagates through to the output end of the plasma and fully magnetizes the plasma - this is called a Plasma Opening Switch (POS). Opening can be triggered in a POS using a magnetic field to push the plasma out of the A-K gap - this is called a Magnetically Controlled Plasma Opening Switch (MCPOS). On a small scale, depletion of electron plasmas in semiconductor devices is used to affect opening switch behavior, but these devices are relatively low voltage and low current compared to the hundreds of kilo-volts and tens of kilo-amperes of interest to pulsed power. This work is an investigation into an entirely new approach to opening switch technology that utilizes new materials in new ways. The new materials are Ferroelectrics and using them as an opening switch is a stark contrast to their traditional applications in optics and transducer applications. Emphasis is on use of high performance ferroelectrics with the objective of developing an opening switch that would be suitable for large scale pulsed power applications. Over the course of exploring this new ground, we have discovered new behaviors and properties of these materials that were here to fore unknown. Some of these unexpected discoveries have lead to new research directions to address challenges.

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Final report on development of Pulse Arrested Spark Discharge (PASD) for aging aircraft wiring application

Glover, Steven F.; Higgins, Matthew B.; Lockner, Thomas L.; Schneider, Larry X.; Pena, Gary P.

Pulsed Arrested Spark Discharge (PASD) is a Sandia National Laboratories Patented, non-destructive wiring system diagnostic that has been developed to detect defects in aging wiring systems in the commercial aircraft fleet. PASD was previously demonstrated on relatively controlled geometry wiring such as coaxial cables and shielded twisted-pair wiring through a contract with the U.S. navy and is discussed in a Sandia National Laboratories report, SAND2001-3225 ''Pulsed Arrested Spark Discharge (PASD) Diagnostic Technique for the Location of Defects in Aging Wiring Systems''. This report describes an expansion of earlier work by applying the PASD technique to unshielded twisted-pair and discrete wire configurations commonly found in commercial aircraft. This wiring is characterized by higher impedances as well as relatively non-uniform impedance profiles that have been found to be challenging for existing aircraft wiring diagnostics. Under a three year contract let by the Federal Aviation Administration, Interagency Agreement DTFA-03-00X90019, this technology was further developed for application on aging commercial aircraft wiring systems. This report describes results of the FAA program with discussion of previous work conducted under U.S. Department of Defense funding.

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Progress towards a 200 MW electron beam accelerator for the RDHWT/Mariah II Program

Reed, Kim W.; Pena, Gary P.; Glover, Steven F.; Lockner, Thomas L.; Lipinski, Ronald J.; Schneider, Larry X.

The Radiatively Driven Hypersonic Wind Tunnel (RDHWT) program requires an unprecedented 2-3 MeV electron beam energy source at an average beam power of approximately 200MW. This system injects energy downstream of a conventional supersonic air nozzle to minimize plenum temperature requirements for duplicating flight conditions above Mach 8 for long run-times. Direct-current electron accelerator technology is being developed to meet the objectives of a radiatively driven Mach 12 wind tunnel with a free stream dynamic pressure q=2000 psf. Due to the nature of research and industrial applications, there has never been a requirement for a single accelerator module with an output power exceeding approximately 500 kW. Although a 200MW module is a two-order of magnitude extrapolation from demonstrated power levels, the scaling of accelerator components to this level appears feasible. Accelerator system concepts are rapidly maturing and a clear technology development path has been established. Additionally, energy addition experiments have been conducted up to 800 kW into a supersonic airflow. This paper will discuss progress in the development of electron beam accelerator technology as an energy addition source for the RDHWT program and results of electron beam energy addition experiments conducted at Sandia National Laboratories.

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Assessment of the non-destructive nature of PASD on wire insulation integrity

Glover, Steven F.; Glover, Steven F.; Higgins, Matthew B.; Pena, Gary P.; Schneider, Larry X.; Lockner, Thomas L.

The potential of a new cable diagnostic known as Pulse-Arrested Spark Discharge technique (PASD) is being studied. Previous reports have documented the capability of the technique to locate cable failures using a short high voltage pulse. This report will investigate the impact of PASD on the sample under test. In this report, two different energy deposition experiments are discussed. These experiments include the PASD pulse ({approx}6 mJ) and a high energy discharge ({approx}600 mJ) produced from a charged capacitor source. The high energy experiment is used to inflict detectable damage upon the insulators and to make comparisons with the effects of the low energy PASD pulse. Insulator breakdown voltage strength before and after application of the PASD pulse and high energy discharges are compared. Results indicate that the PASD technique does not appear to degrade the breakdown strength of the insulator or to produce visible damage. However, testing of the additional materials, including connector insulators, may be warranted to verify PASDs non-destructive nature across the full spectrum of insulators used in commercial aircraft wiring systems.

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86 Results
86 Results