Type of Award: SBIR Phase I; Phase II Proposal Accepted by NASA LeRC but Rejected by NASA Headquarters Contract Number: NAS3-25119 Agency: NASA LeRC Status: Completed Period: 1/21/87 to 7/21/87 Principal Investigator: Paul Krause Abstract: Recent technical advancements in the semiconductor device and power conditioning technologies have led to substantial improvements in terms of size, weight, efficiency and power quality of the power conditioning equipment which is being considered for space applications. With these advancements comes an abundance of design choices and increased degrees of freedom with respect to power system control. These degrees of freedom may be used advantageously to develop control strategies which improve the reliability and dynamic characteristics of the integrated power system by making it less sensitive to possibly large and abrupt changes in load. There are two main objectives associated with the Phase I research effort. The first is to develop a highly detailed computer simulation of a power generation, conditioning and distribution system suitable for space applications. The second is to investigate several innovative control system techniques involving feed forward voltage control and load sharing strategies which are aimed at maintaining precise regulation during steady state and transient conditions. The viability and effectiveness of these strategies will be tested by incorporating them into the computer simulation of the integrated power system developed as part of the first...
Read MoreModeling of Shipboard Electric Power Distribution System
Type of Awards: SBIR Phase I and Phase II, Contract Numbers: N00017-88-C-0031and N61533-89-C-0062 Agencies: U.S. Navy David Taylor Research Center and U.S. Naval Sea Command Status: Completed Periods: 1/14/88 to 7/14/88 and 6/30/89 to 9/30/91 Phase III: Dynamic Simulation of High-Power Machinery Systems; N00167-99-D-0100 Principal Investigator: Paul Krause Abstract: A detailed computer representation of the shipboard electric power distribution system was developed and verified in Phase I. This set the stage for developing reduced order models for the components of the shipboard electric power system and to use the detailed computer models as a means of verifying the reduced order models individually and in a system configuration. Development of reduced order models and the equations necessary to connect these models in any feasible system configuration is the first objective of the proposed research. The second is to begin defining transient and dynamic stability and system security for a finite inertia electric system for normal and emergency operating conditions. Achieving these goals is necessary in order to provide a means to design and investigate the performance of proposed shipboard electric power...
Read MorePhase I: Control of Resonance in a 20-Khz Space Power System and Investigation of Advanced Power Sources (MSFC) and Phase II: Investigation of Advanced Power Sources and Actuator Systems for Future Aerospace Vehicles (LeRC)
Type of Awards: SBIR Phase I and Phase II Contract Numbers: NAS8-38035 and NAS3-25962 Agencies: Phase I: NASA MSFC and Phase II:Â NASA LeRC Status: Completed Periods: 12/29/88 to 5/29/89 and 8/31/90 to 8/30/92 Principal Investigators: Phase I:Â Paul Krause; Phase II: Scott Sudhoff Phase III: Power Systems Modeling for Power-By-Wire Applications; NAS3-27203 Abstract: In Phase I, detailed computer simulations of two candidate 20-kHz spacecraft power systems (TRW and GD) were implemented on a Hybrid Computer/Power Systems Simulator and verified by comparison with experimental results. In the absence of filtering, both systems exhibit harmonic resonances due to an interaction between the switching of the source converter and the ac system. Methods of suppressing harmonic resonance and improving the waveform quality were demonstrated in both power systems studied. The primary objective of the proposed Phase II research is to investigate power system configurations for use in future aerospace vehicles including spacecraft and the all-electric airplane. The power systems will be investigated on an end-to-end basis including the source(s), transmission/distribution system, load converters, and electromechanical actuators. The computer models that are to be developed in Phase II will provide a convenient means of comparing competing power system configurations from the standpoint of stability, regulation, harmonic distortion, and system interactions, all on an end-to-end system...
Read MoreDynamic Simulation of High-Power Machinery Systems
Type of Awards: SBIR Phase I and Phase II Contract Numbers: N61533-95-C-0107 and N00024-97-C-4097 Agency: U.S. Naval Surface Warfare Center and U.S. Naval Sea Command Status: Completed Periods: 8/23/95 to 6/30/96 and 3/13/97 to 5/1/99 Principal Investigators: Paul Krause and Steve Pekarek Phase III: Dynamic Simulation of High-Power Machinery Systems; N00167-99-D-0100, Subcontracted: Purdue and PCKA Abstract: Over the past 7-8 years, PCKA has been heavily involved in the analysis and simulation of power/drive systems. This work has been done through SBIR’s and level-of-effort contracts for the Navy, Air Force, NASA, and, to a lesser extent, the Army. Considerable focus has been on developing models and modeling techniques. A major breakthrough by PCKA/Purdue, which has the potential of revolutionizing power/drive system analysis and simulation, has been the automatic state matrix generator as a “front end” to a differential-equation-based simulation language (ACSL). This state model generator (SMG) offers the potential of (1) a circuit-based input to a equation-based language (2) convenient and economical simulations, (3) automatic state-space averaging, (4) semi-automatic nonlinear reduced-order modeling, (5) automatic modal reduction, and (6) automatic model connection. Although all these features are promising concepts, none have been developed to the extent necessary for convenient utilization. The focus of the proposed work is to continue research toward the development of these techniques in ACSL and to make the SMG and the associate techniques compatible with MATLAB. The overall objective is to develop a user-interactive system modeler which will lead the system analyst through the steps to implement a system model making use of the potential offered by the SMG. Focus will be on the Navy IPS; however, this work will be valid for the power/drive systems being used or considered by other agencies. Moreover, this work not only represents a breakthrough in simulation, it also automatically provides the mathematical structure to analyze and develop linear and nonlinear controls for power/drive systems. Although the control aspects are not topics of the proposed work, the guidelines for the mathematical structure appropriate for analysis and design of nonlinear system controls will naturally...
Read MoreMulti-Level Heterogeneous Modeling of F22 Power Subsystem
Type of Awards: SBIR Phase I and Phase II with Enhancements:  (1) Inclusion of Easy 5 and Optimal Model Partitioning and Allocation and (2) Power and Cooling Turbo-Generator Contract Numbers: F33615-98-C-2849, and F33615-99-C-2911 Agency: U.S. Air Force Research Laboratory Status: Completed Periods: 5/3/98 to 11/3/98 and3/12/99 to 1/19/05 Principal Investigators: Brian Kuhn / E. A. Walters Phase III: Aerospace Power Scholarly Research Program; F33615-99-D-2974 Abstract: Techniques developed in Phase I allow, for the first time, the interconnection of any number of ACSL simulations implemented in conventional or dedicated computer networks. It appears that the same techniques may be used to parallel not only ACSL simulations but any combination of ACSL, Saber, and/or Matlab/Simulink models. The development of this distributed computing concept in Phase II will provide a marked increase in computation speed and a means of simulating large power-electronic based systems. Moreover, this will allow vendors to interconnection component simulations into a “public domain” system without sharing proprietary information. For example, vendors could simulate their component in any of the above mentioned languages and interconnect their simulation to a system model that would include, for example, sources, distribution network, loads, and associated controls that collectively comprise the core of the selected power system architecture. Virtual prototyping has suffered from the rightful desire of vendors to maintain their competitive edge. The concept proposed herein eliminates this proprietary problem and, for the first time, provides a workable prototyping environment. The Phase II goal is to develop an efficient distributed computer simulation of a F22-like power system and to demonstrate this new prototyping environment through an Industry...
Read MoreCryogenic System Stability
Type of Award: SBIR Phase I, Phase II Proposal Rejected Contract Number: F33615-98-C-2897 Agency: Ballistic Missile Defense Organization – WPAFB Managed Status: Completed Period: 7/24/98 to 2/24/99 Principal Investigator: Steven Glover Abstract: Cryogenic components are being proposed for ground-transportable radar (GTR) systems. Incorporating low-loss components into power-electronic based systems is a concern from the standpoint of system stability due to the inherent low resistance of the cryogenic components which may tend to destabilize the system due to reduced damping. The purpose of the work proposed herein is first to investigate the stability of this type of GTR system. This is to be accomplished by first defining a baseline GRT system configuration and then determining the parameters, and the variation thereof, in order, to approximate the operating characteristics of the proposed cryogenic GTR. The overall goal, however, is to conduct a first-look into optimizing performance, weight, and cost of a GTR system in regard to system stability. Optimization studies will focus first on small-disturbance stability and then on large-excursion stability with a pulsed load present. During this research, a new and innovative means of eliminating negative-impedance instability, which has recently been shown to be effective on a noncryogenic power-electronic based system, will be considered as a means of reducing the weight requirement’s by decreasing the number and size of the system capacitors for a low-loss GTR system. The possible use of this stabilizer control in a pulsed-load environment has not been investigated. Moreover, the possible interaction of the various system controllers, including the stabilizer control, will be investigated with, a focus on achieving optimum system performance through appropriate coordination or modification of the system...
Read More