E. A. Walters, PC Krause and Associates, Inc; S. D. Pekarek, O. Wasynczuk, Purdue University; A. C. Koenig, PC Krause and Associates, Inc; P. T. Lamm, U.S. Air Force Research Laboratory Historically, the simulations of aircraft power systems have been divided into separate mechanical (turbine engine) and electrical subsystems, wherein the coupled dynamics have been neglected. However, for future high power concepts such as Directed Energy Weapons, a coupled multi-physics design and analysis capability is required to evaluate system feasibility and establish an optimal architecture. In this paper, such a simulation environment is set forth. The environment contains tools for creating rapid component/system-level simulations. These include a distributed heterogeneous simulation toolbox for interconnecting dynamic component models created using different simulation packages and/or operating systems, as well as a partitioned finite element technique that dramatically reduces computational effort. Herein, the multi-physics tools are demonstrated for a multi-MW gyrotron system. The impact of the gyrotron load on the electrical, mechanical, and energy storage are evaluated under both transient and steady-state conditions and an attempt is made to search for architectures/ designs that minimize weight subject to maintaining stable system performance. 8th Annual Directed Energy Symposium, November 14-18, 2005, Lihue,...
Read MoreMulti-Fidelity Models for Design and Analysis of Directed Energy Weapon Power Systems
E. Walters, PC Krause and Associates, Inc; S. Pekarek, O. Wasynczuk, Purdue University; A. Koenig, J. Wells, B. P. Loop, PC Krause and Associates, Inc; P. Lamm, U. S. Air Force Research Laboratory Historically, the design of aircraft electrical systems has been divided into separate mechanical (turbine engine) and electrical subsystems, wherein the coupled dynamics have been ignored until hardware integration. However, future loads such as Directed Energy Weapons (DEW), a coupled multi-physics design and analysis capability is required to evaluate system feasibility and establish optimal components in the context of a system-level architecture. In this paper, modeling and simulation techniques that provide a backbone for such design and analysis is set forth. Simulation techniques include a distributed heterogeneous simulation toolbox for interconnecting dynamic component models created using different simulation packages and/or operating systems. Modeling tools include a partitioned finite element technique and a field reconstruction technique that dramatically reduces the computational effort required to perform fields-based simulation of electric machines. Herein, the multi-physics tools are demonstrated for a multi-MW DEW system. The impact of the DEW load on the electrical, mechanical, and energy storage are evaluated under both transient and steady-state conditions and an attempt is made to search for architectures/ designs that minimize weight subject to maintaining stable system performance. 9th Annual Directed Energy Symposium, October 30-November 2, 2006, Albuquerque, NM. Contact Information:...
Read MoreGCU for Megawatt Class Directed Energy Weapons Pulse Generators
Lev Sorkin, Innovative Power Solutions, LLC; E. A. Walters, PC Krause and Associates, Inc. Directed Energy weapon (DEW) systems are being developed for both ground and airborne applications. Typically, they consist of microwave or laser powered guns. Both the microwave application and the diode based laser applications require significant amount of power. This power ranges from several hundred kilowatts (kW) for microwave applications to Megawatts (MW) for laser applications. The laser application requires that the full power be available for short duration, typically 5 seconds, which could be repeated several times with short pauses in between. The control of a generator, which delivers Megawatt of the intermittent power greatly differs from the of normal steady state generator control. It poses significant challenges. Application of power (and for this matter its removal) is a transient phenomenon that takes time and its effects ripple through the whole system. In the case at hand, the large applied power, which is required for a short duration, can have a more significant effect on the system. Furthermore, it is imperative that the full power will be available for the required duration with no degradation in quality on both ends (application and removal). There are four entities that interact affecting the performance of the...
Read MoreIntegrated Hardware-in-the-Loop Simulation of a Complex Turbine Engine and Power System
Suraj Ramalingam, Aaron Green, Peter Lamm, U.S. Air Force Research Laboratory; Hank Barnard, Scientific Monitoring, Inc; E. A. Walters, J. R. Wells, PC Krause and Associates, Inc. The interdependency between propulsion, power, and thermal subsystems on military aircraft such as the F-35 Joint Strike Fighter (JSF) and F-22 Raptor continues to increase as advanced war-fighting capabilities including solid-state radars, electronic attack, electric actuation, and Directed Energy Weaponry (DEW) expand to meet Air Force needs. Novel analysis and testing methodologies are required to predict these interdependencies and address adverse interactions prior to costly hardware prototyping. As a result, the Air Force Research Laboratory (AFRL) has established a dynamic hardware-in-the-loop (HIL) test-bed wherein transient simulations can be integrated through advanced real-time simulation with prototype hardware for integrated system studies and analysis. This paper details a test-bed configuration where a dynamic simulation of an aircraft turbine engine is utilized to control a dual-head electric drive stand. The drive stand is connected to an electric generator and associated power system implemented in hardware. The electromagnetic torque produced by the generator is measured and fed back into the turbine engine simulation as a load to the shaft. The HIL capability of this test-bed configuration enables reduced cost altitude testing, supports the design and analysis of integrated starter / generators and alternative power / propulsion architectures, and sets the stage for advanced integrated turbine engine / generator control design. 2006 SAE Power Systems Conference, November 7–9, 2006, New Orleans, LA. Paper...
Read MoreTransient Turbine Engine Modeling and Real-Time System Integration Prototyping
Michael Corbett, Jessica Williams, Mitch Wolff, E. A. Walters, J. R. Wells, PC Krause and Associates, Inc; Peter Lamm, U.S. Air Force Research Laboratory Aircraft power demands continue to increase with the increase in electrical subsystems. These subsystems directly affect the behavior of the power and propulsion systems and can no longer be neglected or assumed linear in system analyses. The complex models designed to integrate new capabilities have a high computational cost. This paper investigates the possibility of using a hardware-in-the-loop (HIL) analysis with real time integration. A representative electrical power system is removed from a turbine engine model simulation and replaced with the appropriate hardware attached to a 350 horsepower drive stand. In order to update the model to proper operating conditions, variables are passed between the hardware and the computer model. Using this method, a significant reduction in runtime is seen, and the turbine engine model is usable in a real time environment. Scaling is also investigated for simulations to be performed that exceed the operating parameters of the drive stand. Similar results are generated with and without the scale factor implemented. Excellent agreement is shown between the HIL and stand alone model results. These results validate the capability of HIL experimentation and provide the opportunity for significant future propulsion configuration studies with minimal cost. 2006 SAE Power Systems Conference, November 7–9, 2006, New Orleans, LA. Paper...
Read MoreImprovements in the Distributed Heterogeneous Simulation of Aircraft Electric Power Systems
B. P. Loop, C. E. Lucas, E. A. Walters, M. Hasan, PC Krause and Associates, Inc; S. Field , N. Kumbar, Naval Air Systems Command Two recent enhancements to Distributed Heterogeneous Simulation (DHS) are variable communication rates and higher-order predictors. Variable communication automatically controls the communication interval between any two subsystems in an attempt to achieve a desired accuracy during transient periods and maximize speed during steady-state periods. Higher-order predictors can better estimate the values of exchanged variables between data exchange instances, which can improve accuracy and possibly require fewer exchanges. A comparison between a single-computer simulation of an aircraft electric power system and an equivalent three-computer DHS show that the variable communication technique enables more accuracy and higher speed distributed simulations than fixed-step communication. In addition, higher-order predictors are shown to increase accuracy in some cases. 2006 SAE Power Systems Conference, November 7–9, 2006, New Orleans, LA. Paper...
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