Michael W. Corbett, Peter T. Lamm, U.S. Air Force Research Laboratory; Kyle L. Miller, PC Krause and Associates, Inc; J. Mitch Wolff, Wright State University; E. A. Walters, PC Krause and Associates, Inc. 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 in system analyses. The performance of the whole aircraft must also be considered with the combined interactions between the power and propulsion systems. The larger loading demands placed on the power and propulsion subsystems result in thrust, speed, and altitude transients that affect the whole aircraft. This results in different operating parameters for the engine. 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 of the aircraft/propulsion system. Using this method, a significant reduction in computational runtime is observed, and the airframe/turbine engine model is usable in a HIL environment. This also allows for a more complete analysis of the interactions between engine loading and aircraft performance by including some real hardware components. The dynamic interactions between aircraft subsystems highlight the need for system-level modeling using a combination of high-fidelity computer models and hardware in a real-time environment. 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, July...
Read MoreAn Automated Average-Value Modeling Methodology for Power Electronic Sources and Loads
N. Wu, O. Wasynczuk, Purdue University and PC Krause and Associates; Peter T. Lamm, U.S. Air Force Research Laboratory In this paper, an automated averaging modeling methodology is set forth applicable to power electronic converters of arbitrary complexity. The user-defined inputs consist of a circuit description similar to the SPICE netlist (network graph and branch parameters), whereupon the input/output impedance-versus-frequency characteristics are automatically and rapidly generated. In addition to eliminating the need for the analytical derivation of average-value models, this methodology readily permits the inclusion of secondary effects such as conduction losses, switching losses, and magnetic nonlinearities, to name a few. This methodology has been successfully applied to characterize the impedance of a one-quadrant dc/dc buck converter, a three-phase diode rectifier source with three different modes of operation, and a space-vector-modulated dc/ac inverter. SAE Transactions Journal of Aerospace, 2007, pp. 846-855 and 2006 SAE Power Systems Conference, November 7–9, 2006, New Orleans, LA. Paper...
Read MoreHardware-in-the-Loop Power Extraction Using Different Real-Time Platforms
John McNichols, Caleb Barnes, Mitch Wolff, T. Baudendistel, PC Krause and Associates, Inc; Michael Corbett, Peter Lamb, 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. Hardware-in-the-loop (HIL) is being used to investigate aircraft power systems by using a combination of hardware and simulations. This paper considers two different real-time simulators in the same HIL configuration. A representative electrical power system is removed from a turbine engine simulation and is replaced with the appropriate hardware attached to a 350 horsepower drive stand. Variables are passed between the hardware and the simulation in real-time to update model parameters and to synchronize the hardware with the model. Real-time simulation platforms from dSPACE and National Instruments (NI) are utilized for this investigation. Similar results are obtained when using HIL and a simulated load. Initially, noticeable differences are seen when comparing the results from each real-time operating system. However, discrepancies in test results obtained from the NI system can be resolved. This paper briefly details the underlying problem and its solution before discussing test results which show that both dSPACE and NI can be configured to match the baseline Simulink data. American Institute of Aeronautics and Astronautics 6th International Energy Conversion Engineering Conference, July 2008. Contact information:...
Read MoreMulti-Fidelity Modeling of Wound-Rotor Synchronous Machines
B. P. Loop, M. Hasan, M. Gualtieri, E. A. Walters, PC Krause and Associates, Inc. In this paper, methods for transitioning between different types of wound-rotor synchronous machines models are examined. The specific transitions investigated are (1) finite element to circuit-based machine models and (2) circuit-based to average value models of machine/rectifier systems. Good agreement between simulation results obtained using the different model types is achieved. This work sets the stage for a software environment that enables both component and system level analysis of electrical power systems. 2008 Electric Machines Technology Symposium, August 12-13, 2008, Philadelphia,...
Read MoreWater-Cooled Load Bank for Aircraft Power Systems Analysis
C. Barnes, G. Diehl, T. Baudendistel, PC Krause and Associates, Inc; J. Potter, L. Burich, U.S. Air Force Research Laboratory Using an air-cooled load bank in the high speed drive stand room at AFRL Building 18b Room 15 has presented several problems. It required significant floor space. It was designed only for 270VDC. It raised the temperature of the room to a high level due to its 82.5KW resistive load. Lastly, it applies a load in large 2.7kW steps. This presentation will cover a new 150KW load bank developed to address these issues. The new load bank that was developed is water cooled to transport heat out of the drive stand room by using 30 5KW heater elements configured in three banks of 10. Each element is switched on or off by a controller built into the load bank to meet the loading requirements. Three of the elements are controlled by a Pulse Width Modulation (PWM) circuit to provide 20W steps in loading. The load bank is equipped with rectifiers and adaptor plates to accommodate various generator configurations including single phase AC, 3-phase AC, and DC voltages. In order to minimize floor space used, the load bank is wall mounted above the drive stand. 2008 SAE Power Systems Conference, November 11-13, 2008, Bellevue,...
Read MoreElectrical Accumulator Unit for the Energy Optimized Aircraft
J. R. Wells, M. Amrhein, E. A. Walters, PC Krause and Associates, Inc; Steve Iden, Austin Page, Peter Lamm, U.S. Air Force Research Laboratory; Anthon Matasso, Lockheed Martin Corp. The movement to more-electric architectures during the past decade in military and commercial airborne systems continues to increase the complexity of designing and specifying the electric power system. In particular, the electrical power system (EPS) faces challenges in meeting the highly dynamic power demands of advanced power electronics based loads. This paper explores one approach to addressing these demands by proposing an electrical equivalent of the widely utilized hydraulic accumulator which has successfully been employed in hydraulic power system on aircraft for more than 50 years. 2008 SAE Power Systems Conference, November 11-13, 2008, Bellevue, WA. Paper...
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