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While working at Sandia National Laboratories as a graduate intern from September 2014 to January 2015, most of my time was spent on two projects. The first project involved designing a test fixture for circuit boards used in a recording device. The test fixture was needed to decrease test set up time. The second project was to use optimization techniques to determine the optimal G-Switch for given acceleration profiles.
In one aspect, a hybrid circuit protection device for current-limiting a fault current between a source and a load during a fault is provided. The hybrid circuit protection device includes an input configured to couple to the source, an output configured to couple to the load, a return configured to couple the source to the load, a main switch configured to selectively couple the input to the output, a switching network coupled in parallel with the main switch, and a controller. The controller is configured to determine that the main switch has opened in response to the fault current, where the fault current has an initial value, and activate the switching network to current-limit the fault current to less than the initial value during the fault.
The International Technology Roadmap for Semiconductors (ITRS) Emerging Research Materials (ERM) and Emerging Research Devices (ERD) Technology Workgroups have identified materials and devices that could enable continued increases in the density and performance of future integrated circuit (IC) technologies and the challenges that must be overcome; however, this will require significant advances in metrology and characterization to enable progress. New memory devices and beyond CMOS logic devices operate with new state variables (e.g., spin, redox state, etc.) and metrology and characterization techniques are needed to verify their switching mechanisms and scalability, and enable improvement of operation of these devices. Similarly, new materials and processes are needed to enable these new devices. Additionally, characterization is needed to verify that the materials and their interfaces have been fabricated with required quality and performance.
Phase 1 was a concept definition effort to extend space-type dc/dc converter technology to the megawatt level with a weight of less than 0.1 kg/kW (220 lb./MW). Two system designs were evaluated in Phase 1. Each design operates from a 5 kV stacked fuel cell source and provides a voltage step-up to 100 kV at 10 A for charging capacitors (100 pps at a duty cycle of 17 min on, 17 min off). Both designs use an MCT-based, full-bridge inverter, gaseous hydrogen cooling, and crowbar fault protection. The GE-CRD system uses an advanced high-voltage transformer/rectifier filter is series with a resonant tank circuit, driven by an inverter operating at 20 to 50 kHz. Output voltage is controlled through frequency and phase shift control. Fast transient response and stability is ensured via optimal control. Super-resonant operation employing MCTs provides the advantages of lossless snubbing, no turn-on switching loss, use of medium-speed diodes, and intrinsic current limiting under load-fault conditions. Estimated weight of the GE-CRD system is 88 kg (1.5 cu ft.). Efficiency of 94.4 percent and total system loss is 55.711 kW operating at 1 MW load power. The Maxwell system is based on a resonance transformer approach using a cascade of five LC resonant sections at 100 kHz. The 5 kV bus is converted to a square wave, stepped-up to a 100 kV sine wave by the LC sections, rectified, and filtered. Output voltage is controlled with a special series regulator circuit. Estimated weight of the Maxwell system is 83.8 kg (4.0 cu ft.). Efficiency is 87.2 percent and total system loss is 146.411 kW operating at 1 MW load power.
The report presents the results of the development and field testing of a mobile test facility based on a helical magnetic cumulative generator (MCGTF). The system is designed for full-scale modeling of lightning currents to study the safety of power plants of any type, including nuclear power plants. Advanced technologies of high-energy physics for solving both engineering and applied problems underlie this pilot project. The energy from the magnetic cumulative generator (MCG) is transferred to a high-impedance load with high efficiency of more than 50% using pulse transformer coupling. Modeling of the dynamics of the MEG that operates in a circuit with lumped parameters allows one to apply the law of inductance output during operation of the MCG, thus providing the required front of the current pulse in the load without using any switches. The results of field testing of the MCGTF are presented for both the ground loop and the model load. The ground loop generates a load resistance of 2–4 Ω. In the tests, the ohmic resistance of the model load is 10 Ω. It is shown that the current pulse parameters recorded in the resistive-inductive load are close to the calculated values.
The Abisko project aims to develop an energy-efficient spiking neural network (SNN) computing architecture and software system capable of autonomous learning and operation. The SNN architecture explores novel neuromorphic devices that are based on resistive-switching materials, such as memristors and electrochemical RAM. Equally important, Abisko uses a deep codesign approach to pursue this goal by engaging experts from across the entire range of disciplines: materials, devices and circuits, architectures and integration, software, and algorithms. Here, the key objectives of our Abisko project are threefold. First, we are designing an energy-optimized high-performance neuromorphic accelerator based on SNNs. This architecture is being designed as a chiplet that can be deployed in contemporary computer architectures and we are investigating novel neuromorphic materials to improve its design. Second, we are concurrently developing a productive software stack for the neuromorphic accelerator that will also be portable to other architectures, such as field-programmable gate arrays and GPUs. Third, we are creating a new deep codesign methodology and framework for developing clear interfaces, requirements, and metrics between each level of abstraction to enable the system design to be explored and implemented interchangeably with execution, measurement, a model, or simulation. As a motivating application for this codesign effort, we target the use of SNNs for an analog event detector for a high-energy physics sensor.
Limit switch for reliable, low-travel, snap action with negligible arcing uses an electrically nonconductive permanent magnet consisting of a ferrimagnetic ceramic and ferromagnetic pole shoes which form a magnetic and electrically conductive circuit with a ferrous-metal armature.
Strain sensors that can be switched on and off were fabricated from p-channel IGFET on thin filament n-type silicon crystals with silicon dioxide layer sputtered over transistor for passivation. Applications include integration with microelectronic circuits for multiplexing.
An improved measurement system for electrical short-circuit current decay is presented that extends applicability of the method to silicon solar cells having an effective lifetime as low as 1 microsec. The system uses metal/oxide/semiconductor transistors as voltage-controlled switches. Advances in theory developed here increase precision and sensitivity in the determination of the minority-carrier recombination lifetime and recombination velocity. A variation of the method, which exploits measurements made on related back-surface field and back-ohmic contact devices, further improves precision and sensitivity. The improvements are illustrated by application to 15 different silicon solar cells.
A transient signal suppressor for use in a controls system which is adapted to respond to a change in a physical parameter whenever it crosses a predetermined threshold value in a selected direction of increasing or decreasing values with respect to the threshold value and is sustained for a selected discrete time interval is presented. The suppressor includes a sensor transducer for sensing the physical parameter and generating an electrical input signal whenever the sensed physical parameter crosses the threshold level in the selected direction. A manually operated switch is provided for adapting the suppressor to produce an output drive signal whenever the physical parameter crosses the threshold value in the selected direction of increasing or decreasing values. A time delay circuit is selectively adjustable for suppressing the transducer input signal for a preselected one of a plurality of available discrete suppression time and producing an output signal only if the input signal is sustained for a time greater than the selected suppression time. An electronic gate is coupled to receive the transducer input signal and the timer output signal and produce an output drive signal for energizing a control relay whenever the transducer input is a non-transient signal which is sustained beyond the selected time interval.
This paper will give a description and status of the Advanced Power Electronics Materials and Components Technology program being conducted by the NASA Glenn Research Center for future aerospace power applications. The focus of this research program is on the following: 1) New and/or significantly improved dielectric materials for the development of power capacitors with increased volumetric efficiency, energy density, and operating temperature. Materials being investigated include nanocrystalline and composite ceramic dielectrics and diamond-like carbon films; 2) New and/or significantly improved high frequency, high temperature, low loss soft magnetic materials for the development of transformers/inductors with increased power/energy density, electrical efficiency, and operating temperature. Materials being investigated include nanocrystalline and nanocomposite soft magnetic materials; 3) Packaged high temperature, high power density, high voltage, and low loss SiC diodes and switches. Development of high quality 4H- and 6H- SiC atomically smooth substrates to significantly improve device performance is a major emphasis of the SiC materials program; 4) Demonstration of high temperature (> 200 C) circuits using the components developed above.
What is an organic light emitting diode (OLED)? Why should we care? What are they made of? How are they made? What are the challenges in seeing these devices enter the marketplace in various applications? These are the questions we hope to answer in this book, at a level suitable for knowledgeable non-experts, graduate students and scientists and engineers working in the field who want to understand the broader context of their work. At the most basic level, an OLED is a promising new technology composed of some organic material sandwiched between two electrodes. When current is passed through the device, light is emitted. The stack of layers can be very thin and has many variations, including flexible and/or transparent. The organic material can be polymeric or composed small molecules, and may include inorganic components. The electrodes may consist of metals, metal oxides, carbon nanomaterials, or other species, though of course for light to be emitted, one electrode must be transparent. OLEDs may be fabricated on glass, metal foils, or polymer sheets (though polymeric substrates must be modified to protect the organic material from moisture or oxygen). In any event, the organic material must be protected from moisture during storage and operation. A control circuit, the exact nature of which depends on the application, drives the OLED. Nevertheless, the control circuit should have very stable current control to generate uniform light emission. OLEDs can be designed to emit a single color of light, white light, or even tunable colors. The devices can be switched on and off very rapidly, which makes them suitable for displays or for general lighting. Given the amazing complexity of the technical and design challenges for practical OLED applications, it is not surprising that applications are still somewhat limited. Although organic electroluminescence is more than 50 years old, the modern OLED field is really only about half that age – with the first high-efficiency OLED demonstrated in 1987. Thus, we expect to see exciting advances in the science, technology and commercialization in the coming years. We hope that this book helps to advance the field in some small way. Contributors to this monograph are experts from top academic institutions, industry and national laboratories who provide comprehensive and up-to-date coverage of the rapidly evolving field of OLEDs. Furthermore, this monograph collects in one place, for the first time, key topics across the field of OLEDs, from fundamental chemistry and physics, to practical materials science and engineering topics, to aspects of design and manufacturing. The monograph synthesizes and puts into context information scattered throughout the literature for easy review in one book. The scope of the monograph reflects the necessity to focus on new technological challenges brought about by the transition to manufacturing. In the Section 1, all materials of construction of the OLED device are covered, from substrate to encapsulation. In Section 2, for the first time, additional challenges in devices and processing are addressed. This book is geared towards a broad audience, including materials scientists, device physicists, synthetic chemists and electrical engineers. Furthermore, this book makes a great introduction to scientists in industry and academia, as well as graduate students interested in applied aspects of photophysics and electrochemistry in organic thin films. This book is a comprehensive source for OLED R&D professionals from all backgrounds and institutions.
An apparatus is provided including a transformer including a first printed circuit board having one or more conducting layers, the one or more conducting layers forming, at least in part, a transformer coil; at least one inductor; and at least one continuous piece of conducting material external to the printed circuit board, where the at least one continuous piece of conducting material forms a connection between the transformer and the at least one inductor. A method is also provided for assembling a switched-mode power supply.
A test system is disclosed that enables the testing of microwave components in a controlled environment without disturbing that environment. The system includes a test fixture which holds the calibration standards and the component being tested, and environmental control chamber, and a microwave switching system. The system provides a coaxial connection to microwave testing equipment, such as an automatic network analyzer (ANA) and facilitates both calibration and testing while maintaining environmental integrity.
This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.
A computer program provides a high-level C-language interface to electronics circuitry that controls a SpaceWire interface in a system based on a space qualified version of the ADSP-21020 digital signal processor (DSP). SpaceWire is a spacecraft-oriented standard for packet-switching data-communication networks that comprise nodes connected through bidirectional digital serial links that utilize low-voltage differential signaling (LVDS). The software is tailored to the SMCS-332 application-specific integrated circuit (ASIC) (also available as the TSS901E), which provides three highspeed (150 Mbps) serial point-to-point links compliant with the proposed Institute of Electrical and Electronics Engineers (IEEE) Standard 1355.2 and equivalent European Space Agency (ESA) Standard ECSS-E-50-12. In the specific application of this software, the SpaceWire ASIC was combined with the DSP processor, memory, and control logic in a Multi-Chip Module DSP (MCM-DSP). The software is a collection of low-level driver routines that provide a simple message-passing application programming interface (API) for software running on the DSP. Routines are provided for interrupt-driven access to the two styles of interface provided by the SMCS: (1) the "word at a time" conventional host interface (HOCI); and (2) a higher performance "dual port memory" style interface (COMI).
The first board section comprises a switching module with heat-generating semiconductor switches associated with a first operational temperature range. The first board section has a first conductive layer of a first thickness. The second board section comprises a plurality of capacitors mounted on a second circuit board. The second board section has conductive traces for interconnecting the capacitors as a network. The capacitors are associated with a second operational temperature range that is lower than the first operational temperature range. A thermal isolation intermediary forms a barrier between, or adjoining, the first board section and the second board section, where the first board section and the second board section are spaced part from each other by the thermal isolation intermediary.
We report the hybrid electric bus (HEB) presents an emerging solution to exhaust gas emissions in urban transport. This paper proposes a multiport bidirectional switched reluctance motor (SRM) drive for solar-assisted HEB (SHEB) powertrain, which not only improves the motoring performance, but also achieves flexible charging functions. To extend the driving miles and achieve self-charging ability, photovoltaic (PV) panels are installed on the bus to decrease the reliance on fuelsbatteries and charging stations. A bidirectional front-end circuit with a PV-fed circuit is designed to integrate electrical components into one converter. Six driving and five charging modes are achieved. The dc voltage is boosted by the battery in generator control unit (GCU) driving mode and by the charge capacitor in battery driving mode, where the torque capability is improved. Usually, an extra converter is needed to achieve battery charging. In this paper, the battery can be directly charged by the demagnetization current in GCU or PV driving mode, and can be quickly charged by the PV panels and GCUAC grids at SHEB standstill conditions, by utilizing the traction motor windings and integrated converter circuit, without external charging converters. Finally, experiments on a three-phase 128 SRM confirm the effectiveness of the proposed drive and control scheme.