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The paper presents methodology of early system validation for architecture of a modular controller through modeling and rapid prototyping techniques in a real time operating environment. The real time operating environment was used in development of a secondary electric power system (SEPDS) with solid state power controller (SSPC) technology. The System consists of multiple Line Replacement Units (LRUs) distributed across the aircraft; each LRU implements distributed controls with a modular configuration, named Line Replaceable Modules (LRMs). During the phase of redesign of the control architecture a real-time control using XPC target was developed. The challenges include interfacing the re-designed LRM with the existing backbone hardware and maintaining interface consistency for seamless exchange of the old hardware with new one.

In order to take full advantage of SiC, a high temperature package for power module using SiC devices was designed, developed, fabricated and tested. The details of the material selection and fabrication process are described. High temperature reliability test and power test shows that the package presented in this paper can perform well at the high junction temperature.

International Space Station (ISS) Payload Engineering Integration (PEI) organization adopted the advanced computation and simulation technology to develop integrated electrical system models based on the test data of various sub-units. This system model was used end-to-end to mitigate system risk for the integrated Space Shuttle Pre-launch and Landing configurations. The Space Shuttle carries the Multi-Purpose Logistics Module (MPLM), a pressurize transportation carrier, and the Laboratory Freezer for ISS, a freezer rack for storage and transport of science experiments from/to the ISS, is carried inside the MPLM. An end-to-end electrical system model for Space Shuttle Pre-Launch and Landing configurations, including the MPLM and Freezer, provided vital information for integrated electrical testing and to assess Mission success. The Pre-Launch and Landing configurations have different power supplies and cables to provide the power for the MPLM and the Freezer.

The International Space Station (ISS) Payload Engineering Integration (PEI) organization has developed the critical capabilities in dynamic circuit modeling and simulation to analyze electrical system anomalies during testing and operation. This presentation provides an example of the processes, tools and analytical techniques applied to the improvement of science experiments over-voltage clamp circuit design which is widely used by ISS science experiments. The voltage clamp circuit of Science Rack exhibits parasitic oscillations when a voltage spike couples to the Field-Effect Transistor (FET) in the clamp circuit. The oscillation can cause partial or full conduction of the shunt FET in the circuit and may result in the destruction of the FET. In addition, the voltage clamp circuit is not designed to detect the high current through the FET, and this condition can result in damage to surrounding devices. These abnormal operations were analyzed by dynamic circuit simulation and tests.

Distribution System Automation (DSA) is being carried out very seriously world over to enhance the reliability of the system and to minimize the huge losses that are occurring in the Distribution System. Feeder Reconfiguration (FR) is an important sub-problem of the over all distribution system automation process. Basic concept of feeder reconfiguration is to arrive at the best set of sectionalizing switches to be opened for a given set of tie switch such that the system performance is enhanced. In this paper a novel criterion is developed based on the slope of the curve between the feeder losses verses receiving end voltage. Application of this criterion results in the most minimal loss configuration for any given loading condition. A general MATLAB program is developed to obtain the best switching option. The results have been validated by comparison with the civinlar's loss reduction method.

This Department of Energy funded study represents the first significant investigation of polyimide flex as a substrate material for high temperature (>200°C) electronics packaging for downhole oil and gas exploration. This program examined at three key areas of package development: conductor adhesion to flex, through hole via reliability in flex, and high temperature interconnect methods for passive devices on flex. High temperature storage testing of different adhesion layers to flex was performed at 200 and 250°C in air and nitrogen for as long as 1000 hrs. Multiple adhesion materials and thicknesses were evaluated by measuring the peel strength of copper traces to polyimide. A Cr adhesion layer was selected due to its ability to maintain high peel strength during the high temperature storage testing. Thermal cycling of through hole vias between room temperature and 250°C for greater than 1200 cycles showed little degradation.

This paper will discuss using Astronics “Smart Panel” illuminated control panels to control an electronic power distribution system. A discussion of wiring simplification, automatic control possibilities and real time load monitoring is presented. The challenges of retrofitting the system into older aircraft will be covered as well. The paper also explains Electronic Circuit Breaker technology, arc fault protection, panel lighting technologies, control bus options, displays, and human input technology (buttons and knobs).

Seven encapsulants with operating temperatures up to 250°C were surveyed for use in planar packages for wide-bandgap dice. Two of the encapsulants failed processability test because they were not able to flow, and another two failed because they induced voids or cracks after curing. The dielectric results of the remaining three encapsulants showed that both dielectric strength and permittivity decreased almost 40% when the temperature was increased up to 250°C. As the three encapsulants were used to encapsulate a power module, it was proven that all of them could protect the package from early breakdown caused by the poor dielectric strength of air.

This paper presents follow-on material and conclusions to a previously published paper that presented work to develop and validate life prediction models for SiC device packaging [ 1 ]. The first step in this work was to determine the most probable failure modes in the device packaging. After determining the expected dominant failure modes of a SiC semiconductor packaging, appropriate models were identified and applied to the packaging in order to track remaining useful life. Once failure modeling was completed, the life prediction models were validated. Validation consisted of accelerated life testing designed to stress specific parts of the device package so as to stimulate the desired failure mechanism. This paper will review the three testing methodologies designed to excite the three dominant failure mechanisms in the electronic packaging. These tests can be broken into two types of general tests: power cycling and high temperature reverse bias testing (HTRB).

This paper presents the results of a silicon-carbide-based 300V 5 kW fully functional three-phase inverter module operating at high temperatures and device junctions up to 200°C. Each phase power module employs eight SemiSouth 100 mΩ/1200V SiC JFETs (SJEP120R100) in parallel per switch position. The paper will highlight both the electrical and the thermo-mechanical design. Experimental results validating the overall design will also be discussed. The core of the electrical design was to take advantage of the low input capacitance, high switching frequency (50 kHz) and high temperature capability of the SiC JFET in order to obtain a high power density inverter. Since SemiSouth's SiC JFET is a relatively new device, computer models are not currently available from the manufacturer, which presents a hurdle during the design stage. In order to produce reliable performance predictions, the team has focused on developing a model for the SiC JFETs ultimately used.

Linear actuators can be controlled and monitored by an Electronic Power Distribution System with no additional sensors or wiring. Laboratory and field test results are provided showing how common faults can be detected and annunciated, and potential faults can be detected before becoming hazardous. Results of these tests are extrapolated to other types of motors, such as pumps and fans.

The more electric aircraft (MEA) concept has been employed to optimizing the airframe and engine systems of aircraft, and significant benefits have been achieved by replacing today's pneumatic, hydraulic, and electric airframe power systems predominantly with electric power[ 1 ][ 2 ][ 3 ][ 4 ]. Not only MEA, more and more sophisticated electronic equipment has been added to modern aircraft. The trend toward MEA and using advanced electronic technology creates growth in energy demands and has resulted in ongoing increases in weight, size, and cost of power distribution systems. It has been determined that future aircraft power systems should be significantly reduced in size, weight, and cost, without compromising power-increasing requirements. Optimization potential is seen for system architectures of higher integration even for more simplified architectures. This could be achieved by an improvement of the architecture design using a modular approach.

This paper illustrates the application of the generalized immittance space approach to the analysis of multi-bus interconnected power electronics based power distribution system. The paper sets forth the basic classifications of power converters in regard to stability analysis, a set of network reduction transformations, and illustrates the use of these reductions in order to analyze the stability of a zonal dc distribution system.

IPS has designed an air-cooled AC/DC Regulated Converter Unit (RCU) for the V-22 aircraft as a possible replacement of the existing RCU. The Converter receives 3 phase 115V, 400Hz power from the aircraft power distribution system and produces a 6kW, 28VDC output (per MIL-STD-704D). Within the constraints of the existing physical envelope, the design yields lower weight, lower cost, and lower power dissipation compared with the currently employed VRTR (Voltage Regulated Transformer Rectifier). The design utilizes nearly loss-less switching topology, active current sharing, and a modular approach.

The arcing faults on cables of aerospace power systems represent a major safety concern for spacecraft. To ensure the normal operation of the Power Management and Distribution (PMAD) system, it is necessary that remedial control strategies are developed and implemented. Most of the research in this area deal mainly with arcing faults in terrestrial distribution power systems that operate as AC systems rather than DC systems. The paper investigates the application of a new digital signal processing technique – Fast Fourier Transform (FFT) based energy spectrum estimation – to analyze the recorded signals of DC arcing faults. The data is collected from the DC arcing experiment at the NASA Glenn research center. The voltage level range is from 50Vdc to 150Vdc. This paper presents a feature extraction approach to transform the signal representation from time-domain into frequency-domain. Results demonstrate the distinctive difference between the pre-fault signal and post-fault signal.

In this paper a model of a three-phase inverter drive will be presented that is suitable for inclusion in a DC distribution system analysis. It will be shown that the drive can be accurately modeled on the electrical side by a capacitor, representing the bus capacitance of the inverter, in parallel with a current source. The current source consists of a DC component, corresponding to net power flow to and from the flywheel, plus high-frequency current harmonics generated by the operation of the switch-mode inverter. Closed-form expressions for the current harmonics can be derived by analyzing the AC currents in the electric machine and the switch-mode nature of the inverter, including the “dead-time” effect, and will be presented in the paper. Comparisons between edge-based and center-based pulse-width operation suggest that center-based PWM produces less harmonic content. It is shown that “dead-time” can have a significant effect on the harmonic content.

In this paper, a detailed technical description of a new hardware-based integrated power system testbed is presented. The testbed consists of an AC generation and propulsion system that is coupled to a DC zonal distribution system. A primary objective of the testbed is to provide a resource to the academic and industrial community by providing a non-proprietary system on which to demonstrate controls, survivability algorithms, and validate computer-aided design (CAD) tools.

Effective thermal management and removal of the waste heat generated at diode arrays is critical to the development of high-power solid-state lasers. Thermal design must be considered in the packaging of these arrays. Two different packages with heat dissipation through spray cooling are evaluated experimentally and numerically. Their overall performance is compared with other packaging configurations using different heat removal approaches. A novel packaging design is proposed that can fulfill the requirements of low thermal resistance, temperature uniformity among emitters in the diode array, low coolant flow rate, simplicity and low assembly cost. The effect of temperature uniformity on the pumping efficiency for gain media is examined for our novel packaging design. The thermal stress induced by temperature variation within an emitter is also considered.

This paper will address the parallel fault locating theories and subsequent fault locating system developments at General Dynamics. Since 1999, General Dynamics has been investigating technologies and methods for reducing the threat of electrical fires on board aircraft. Early in 2001, efforts were directed to employ technology findings towards tools that could be used by aircraft operators and manufacturers in maintenance or installation validation scenarios.

Power electronics based power distribution systems are inherently nonlinear often behaving as constant power loads. Stability analysis of such systems typically is limited to local behavior. Herein polytopic modeling techniques are presented. Classification of polytopic model equilibrium points is made and methods of determining uniform asymptotic stability are presented.