Browse Topic: Switches

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Arc Damage Assessment of Arc Plume and Physical DamageAIR6982 (Current)11/26/2025
Describes the relative measurement of assessing the damage zone of arc plasma to determine appropriate separation/segregation requirements between a wire harness and nearby components
AE-8A Elec Wiring and Fiber Optic Interconnect Sys Install
Crane Boom Hoist Disengaging DeviceJ999_202109 (Current)9/20/2021
This SAE Standard applies to cranes which are equipped to adjust the boom angle by hoisting and lowering means through rope reeving.
Cranes and Lifting Devices Committee
Coordination Control Strategy for Mode Switching of a Parallel Hybrid Electric System Based on Continuously Variable Transmission02-13-02-00108/11/2020
This study aims to solve the problem of impact in a parallel hybrid electric system based on the continuously variable transmission (CVT) during switching from pure electric mode to engine-driven, power-generating mode. Taking into account the torque response characteristics of the engine and motor and the dynamic characteristics of the wet clutch hydraulic control system, the mode switching process is divided into six stages, namely, pure electric mode, wet-clutch free travel, engine start-up, engine speed synchronization, clutch combination, and engine intervention drive. A coordination control strategy is developed based on the model predictive control algorithm to ensure smooth mode switching. The effectiveness of the control algorithm is verified using Matlab/Simulink and the AMESim co-simulation platform. Results show that with the mode switching coordination control strategy, the components of the system work harmoniously. The maximum impact is reduced by 52.0% at the speed synchronization stage and by 84.3% at the clutch coupling stage compared with the uncoordinated control situation.
Zeng, Xiaohua, Li, Xiaojian, Dong, Bingbing
Design of a Flexible Hybrid Powertrain Using a 48 V-Battery and a Supercapacitor for Ultra-Light Urban Vehicles2020-01-04454/14/2020
Global warming has put the transport sector, a major contributor of CO2 emissions, under high pressure to improve efficiency. In this context, ultra-light vehicles weighting less than 500 kg, as well as hybrid powertrains, are nowadays seen as promising development trends. The design process of the powertrain of a vehicle combining the advantages of the two concepts is presented in this paper. Through a performance study based on a simple MATLAB model, and mathematical simulation, a proposal is made. A powertrain using a battery and supercapacitor 48V dual power source network, two electric motors and clutches to switch between conventional, parallel, series and full electric modes proves to be an interesting system in terms of performance and costs. A simulation study conducted on a scenario with different outcome possibilities showed that high modularity of the system allows to achieve fuel efficiencies equivalent to approximately 3 l/100 km on the Artemis cycle. Finally, integration, packaging and cost are considered and some hints for further powertrain efficiency improvements are presented.
El Ganaoui-Mourlan, Ouafae, Miliani, El Hadj, Carlos Da Silva, Daniel, Couillandeau, Matthieu, Gonod, Charlie, Miller, Guillaume
Transistors Both Process and Store InformationTBMG-359602/1/2020
A computer chip can process and store information using two different devices. If these devices could be combined into one or put next to each other, there would be more space on a chip, making it faster and more powerful. Engineers have developed a way that the millions of tiny switches used to process information (transistors) could also store that information as one device.
Photonic Switch Increases Speed and Efficiency of Light Through Optical FibersTBMG-3570612/1/2019
A photonic switch was developed that can control the direction of light passing through optical fibers faster and more efficiently than ever. This optical “traffic cop” could improve how information travels through high-performance supercomputers used for artificial intelligence and other data-intensive applications.
Simulation Analysis of Single-Phase Matrix Converter for Cycloconverter Operation Using SPWM with Under and Over Modulation Technique2019-28-012010/11/2019
This paper discusses the implementation of ac-ac converter using a matrix converter. A MATLAB Simulink model of single-phase matrix converter has been developed for matrix converter with a step up and step down of input frequency. Selection of power switches differentiates the conventional cycloconverter from that of matrix converter based cycloconverter. Conventional cycloconverters requires thyristors whereas matrix converter based cycloconverter requires IGBT which is formed as a bidirectional switch module. The performance of matrix converter based cycloconverter using Sinusoidal Pulse Width Modulation Technique (SPWM) has been analyzed for resistive and inductive loads at varying frequency. This paper presents the output results for various frequencies such as 12.5 Hz, 25 Hz (step-down operation) and 100 Hz (step-up operation).
Nallathambi, Kalaiarasi, Daniel, Anitha, Rangarajan, Uthra
Using Monolithic Filters to Address EMI in Medical DevicesTBMG-351009/1/2019
Many factors are conspiring to increase the amount of “noise” or interference that can disturb the functionality and even damage electronic devices, starting with the sheer number used in our vicinity at any given time. Today’s Wi-Fi or Bluetooth-enabled medical instruments and even medical implants provide a prime example.
Guarding of Starter System EnergizationJ1493_201908 (Current)8/8/2019
This SAE Standard describes guarding to help prevent hazardous machine movement caused by activation of the starter motor by bypassing the starter control system. This document is applicable to off-road, self-propelled work machines, as identified in SAE J1116, and agricultural tractors, as defined in ANSI/ASAE S390, which have the potential for hazardous machine movement as a result of bypassing the starter control system and powering of the starter motor.
OPTC1, Personnel Protection (General)
Tiny Device Speeds up Memory While Saving PowerTBMG-348878/1/2019
Smart objects are required to store and retrieve massive amounts of data quickly without consuming too much power. Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved functionality in a material called molybdenum ditelluride. The two-dimensional material stacks into multiple layers to build a memory cell.
Integrated Silicon Photonic Switch Demonstrates Lowest Signal Loss Ever in High-Speed Data TransmissionTBMG-347707/1/2019
Experimental photonic switches developed at UC Berkeley have shown promise toward the goal of fully optical, high-capacity switching for future high-speed data transmission networks. The switch developed and tested for this research demonstrated capabilities not seen before in photonic switches. Key to this success, is the scale-up of a 240 × 240 integrated silicon photonic switch. The device is so-named because it accepts 240 optical communication input channels and sends them into 240 output channels.
Fast Accurate Non-Destructive Measurement of Absorber Impedance and Absorption2019-01-15846/5/2019
Cabin acoustic comfort is a major contributor to the potential sales success of new aircraft, cars, trucks, and trains. Recent design challenges have included the increased use of composites, and the switch to electrically powered vehicles, each of which change the interior noise spectral content and level. The role of acoustic absorption in cabins is key to the optimisation of cabin acoustic comfort for modern vehicles, with acoustic impedance data needed in order to assess and optimise the impact of each component of a given lay-up. Measurements of absorbing interior trim are traditionally performed using either sample holder tests in a static impedance tube (impedance and absorption), or through tests in reverberation rooms (absorption only). Both of these procedures present challenges. In-tube absorption and impedance measurements are destructive, requiring highly accurate sample cutting and sealing. Reverberation room absorption measurements are subject to the effects of varying room diffusion, along with the impact of edge diffraction, sample geometry, and location. Finally, while non-destructive methods using hand-held probes also measure absorption, they are not able to measure impedance accurately. This paper describes fast non-destructive tests using a portable flanged impedance tube, and how they be used to quantify and optimise the absorption of interior trims. Measurements are made on non-locally reacting lay-ups, with the results corrected to equivalent in-tube results using a flanged-to-sample holder correction factor. The corrected flanged tube results are then compared with baseline in-tube measurements. Discussions address data quality and how the non-destructive measurements may be used to optimise lay-ups for increased absorption.
Murray, Paul B., Alexander, Jon, Kunio, Jason, Larsen, Flemming
All-Fiber, Optically Controlled Optical SwitchTBMG-346226/1/2019
An optical switch is a device where information-bearing light may be directed to one of several outputs. Prior art optical switches have mainly been integrated optical waveguide structures such as titanium-diffused (Ti) waveguides in lithium-niobate (LiNbO3) or gallium-arsenide (GaAs) structures, or other compound semiconductors.
ONR Short Pulse Research, Evaluation and non-SWaP Demonstration for C-sUAV Study19AERP06_096/1/2019
Research project is designed to map small unmanned aerial vehicle (sUAV) effects space, empirically and by simulation, as a function of high power microwave (HPM) waveform to develop effective countermeasures. Office of Naval Research, Arlington, Virginia The OSPRES (ONR Short Pulse Research, Evaluation and non-SWaP) program performed fundamental work in the areas of Silicon (Si) and Gallium Nitride (GaN) based photoconductive switch development, measurement of HPM waveform dependent effects on small unmanned aerial vehicle (sUAV), adaptive design of experiments, noise injection, RF coupling to sUAV's, minimally dispersive wave theory, and positive feedback non-linear transmission line (NLTL) development. The photoconductive solid state switch (PCSS) subgroup worked to develop a fundamental understanding of the limitations of Silicon and Gallium Nitride based photoconductive switches and their application to pulsed power. With an estimated 2 megawatts (MW) peak power generation (benchtop equivalent), the Si-PCSS subgroup has succeeded in achieving one-third of the peak power required for an individual element in the envisioned phased array required to meet mission needs.
ONR Short Pulse Research, Evaluation and non-SWaP Demonstration for C-sUAV StudyTBMG-345296/1/2019
The OSPRES (ONR Short Pulse Research, Evaluation and non-SWaP) program performed fundamental work in the areas of Silicon (Si) and Gallium Nitride (GaN) based photoconductive switch development, measurement of HPM waveform dependent effects on small unmanned aerial vehicle (sUAV), adaptive design of experiments, noise injection, RF coupling to sUAV's, minimally dispersive wave theory, and positive feedback non-linear transmission line (NLTL) development.
Data-Driven Optimal Basis Clustering To Characterize Cycle-to-Cycle Variations in Dynamic Stall MeasurementsF-0075-2019-145345/13/2019
Pitching airfoil measurements are known to exhibit significant scatter at near- and post-stall angles of attack. Applying data-driven algorithms revealed the presence of bimodal distribution within the data scatter, suggesting that the statistical mean and standard deviation often used to represent cycle-to-cycle variations are incorrect. Considering the historical significance of dynamic stall measurements, a thorough assessment was undertaken to ascertain that the observed furcation in the data is not a result of facility or post processing error. Once confirmed, cluster-averages, associated variances, and group probability were identified as the best alternative to represent groups in the data. Several existing clustering techniques were tested, however, their shortcomings led to the development of two new data-driven algorithms. A uniqueness that is common to both of the new algorithms is that the clustering process is based on the flow phenomena that contribute the most energy to the overall flow variations. By operating in the optimal basis that maximizes the variance in the measurements, separation of clusters became efficient. When applied to several test cases, the clusters revealed the causes for such grouping, such as the variations in the separation location, occurrence of LE/TE stall, presence/absence of a dynamic stall vortex (or vortices), reattachment angle, etc. In all the cases, the physical processes and their effects were obscured by the phase-average curves. Further analyses to study the effects of Mach number, reduced frequency, mean angle and amplitude of oscillation revealed trends in the group probability. Aerodynamic damping, peak values of pitching moment and lift were substantially different between the clusters, as well as with the phase-average. Considering future semi-empirical models that need to account for cycle switching from one group to another, Markov process (and chain) was studied.
Ramasamy, Manikandan, Harms, Tanner, Sanayei, Armaun, Wilson, Jacob, Martin, Preston, Nikoueeyan, Pourya, Naughton, Jonathan
Singlet-Based Magnet for Enhanced Data StorageTBMG-344045/1/2019
Anew type of magnet — called a singlet-based magnet — was discovered that differs from conventional magnets in which small magnetic constituents align with one another to create a strong magnetic field. By contrast, the singlet-based magnet has fields that pop in and out of existence, resulting in an unstable force, but one that potentially has more flexibility than conventional counterparts.
Understanding the “Black Art” of RF and Microwave Switching19AERP04_064/1/2019
Understanding RF, especially microwave switching, can be a challenge. In many cases, test systems have been compromised because a test engineer did not consider all the components of their test system: instruments, switching, cabling, Mass Interconnect (test fixture interface), fixture design, and so on. Each component has its own set of characteristics. With RF and microwave components, effects including insertion loss, VSWR, bandwidth, and so on all need to be considered as well. Higher bandwidth is a constant demand. The most obvious current example is the emergence of 5G systems that will be hitting the market in the near future, but there are many defense systems - often with their own protocols - that are now operating at RF and high-frequency bandwidths. In short, the need to employ repeatable, accurate RF and microwave switching systems is only going to increase, and while this may appear to be a “sexy” subject, without a proper appreciation of the challenges involved, test systems designers could find themselves facing a lengthy process involving a great many iterations while inconsistencies and failures are ironed out.
Understanding the “Black Art” of RF and Microwave SwitchingTBMG-341264/1/2019
Understanding RF, especially microwave switching, can be a challenge. In many cases, test systems have been compromised because a test engineer did not consider all the components of their test system: instruments, switching, cabling, Mass Interconnect (test fixture interface), fixture design, and so on. Each component has its own set of characteristics. With RF and microwave components, effects including insertion loss, VSWR, bandwidth, and so on all need to be considered as well.
“Light-Written” Photonic Memory DevicesTBMG-339113/1/2019
Light is the most energy-efficient way to move information; however, light shows one big limitation: it is difficult to store. Data centers, for example, rely primarily on magnetic hard drives in which information is transferred at an energy cost that is increasing. A hybrid technology was developed that shows advantages of both light and magnetic hard drives.
MEMS Switch Extends Life of CellphonesTBMG-339173/1/2019
A new type of microelectromechanical system (MEMS) was developed that uses electrostatic levitation to provide a more robust system. All cellphones use MEMS switches for wireless communication, but traditionally there are just two electrodes. The switches open and close numerous times during just one hour, but their current lifespan is limited by the two-electrode system.
Gated Chopper Integrator (GCI)TBMG-3339212/1/2018
Microvolt-level signals require gains of at least a thousand. Offsets and noise in the amplifier chain will be amplified by the same amount, which can saturate the amplifier or swamp the signal so it is not resolvable. Other methods use chopping and/or autozero techniques to lower the offset and noise. The key disadvantages of these methods are they require filters before and/or after demodulation of the amplified signal and delay equalization to account for the delay through the amplifier(s) prior to the demodulator. The gain of these circuits is generally limited to fixed values determined by resistors. These methods are also susceptible to transient noise associated with the switching action of the modulator.
Ferroelectric Switching in 2D Tungsten Produces Spontaneous Electrical PolarizationTBMG-3325911/1/2018
The general public might think of the 21st century as an era of revolutionary technological platforms, such as smart-phones or social media. But for many scientists, this century is the era of another type of platform: two-dimensional materials, and their unexpected secrets.
Transient Stability Analysis of DC Solid State Power Controller (SSPC) for More Electric Aircraft2018-01-192710/30/2018
The solid state power controller (SSPC) is one of the most important power electronic components of the aircraft electrical power distribution (EPS) systems. This paper presents an architecture of the DC SSPC and provides the mitigation techniques for transient voltage overshoot during its turn-off. The high source side inductance carries breaking current (9xnominal current) just before turnoff and induces large voltage transient across the semiconductor devices. Therefore, the stored inductive energy needs to be dissipated in order to prevent semiconductor switches from over-voltage/thermal breakdown. Three different transient voltage suppression (TVS) devices to reduce voltage stress across switches are included in the paper for detail study. The comprehensive comparison of the TVS devices is presented. In addition, the thermal impact of the TVS devices on the semiconductor switches is also analyzed. Later, the transient simulation model of the SSPC is built in LT-Spice and the effectiveness of the proposed protection mechanisms is verified.
Adhikari, Jeevan, Yang, Tao, Rashed, Mohamed, Bozhko, Serhiy, Zhang, JiaWei, Wheeler, Patrick W.
Using Direct Current with Inverter Technology Reduces Costs and Improves ControlTBMG-3308610/1/2018
Resistance welding with direct current (DC) using inverter technology reduces costs by improving quality, reducing maintenance, and increasing productivity. Switching from traditional alternative current (AC) to DC with inverters also reduces a range of facilities costs and improves the process. Finally, it provides the ability to weld new materials, so it can add to a company's capability or product scope.
Polymer Nanofiber-Based Reversible Nano-Switch/Sensor Schottky Diode (nanoSSSD) DeviceTBMG-3311710/1/2018
Innovators at NASA's Glenn Research Center have developed a unique nano-structure device that operates as a nano-switch/sensor for detecting toxic gases and ultraviolet (UV) radiation. Conventional microsensors are limited by their short life, high cost and complexity, and unifunctional sensing task. Glenn's novel Polymer Nanofiber-Based Reversible Nano-Switch/Sensor Schottky Diode (nanoSSSD) technology offers the ability to respond to changing conditions and then revert to baseline operations when conditions return to normal. Glenn's nanoSSSD features no mechanical moving parts, and the sensors are reusable after annealing, extending their appeal for rapid-response, low-cost devices. This simple design provides an easily fabricated, mass-producible microsensor for use in numerous applications where replacement opportunities are limited.
Switch Controls Light on a Nanoscale for Faster Information ProcessingTBMG-3311110/1/2018
Photons, or units of light, are faster than electrons and could, therefore, process information faster from smaller chip structures. A switch was designed that bypasses a tendency for the unwanted absorption of light when using surface plasmons, or light coupled to oscillations of free electron clouds, to help confine light to a nanoscale. Even though plasmonics downsizes light, photons also get lost, or absorbed, rather than transferred to other parts of the computer chip when they interact with plasmons.
A Paper-Like LCD — Thin, Flexible, Tough, and CheapTBMG-328809/1/2018
Optoelectronic engineers in China and Hong Kong have manufactured a special type of liquid crystal display (LCD) that is paper-thin, flexible, light, and tough. With this, a daily newspaper could be uploaded onto a flexible paper-like display that could be updated as fast as the news cycles. It sounds like something from the future, but scientists estimate it will be cheap to produce, perhaps only costing $5 for a 5-inch screen.
Standard Rainflow File FormatJ2623_201808 (Current)8/24/2018
This SAE Standard provides a definition of a rainflow file format. This type of simple text file would contain all relevant information about the rainflow cycle content of a time history. Included information are Comments, Signal Range, Signal Mean, Number of Cycles, Signal Maximum, Signal Minimum. Rainflow cycle counting has become the most accepted procedure for identifying material fatigue relevant cycles in complex variable amplitude load time histories. The cycle counting methods account for the effects of material plasticity and material memory of prior deformation, and the resulting compressed history information is used by durability analysts to estimate the effects of a given service or test history. Standardization of the rainflow counting methods output files, which is the format addressed by the present standard, is important for reliable information transfer between test and design groups, or different calculation software packages, and thus forms a critical step in the evaluation of components and vehicles. Further background information can be found in the SAE publication AE-10 cited in 2.1.1.
Materials, Processes and Parts Council
Advances in Spintronic DevicesTBMG-325038/1/2018
Spintronic devices promise to solve major problems in today's computers, which use massive amounts of electricity to generate heat. This requires expending even more energy for cooling. By contrast, spintronic devices generate little heat and use relatively minuscule amounts of electricity. Spintronic computers would require no energy to maintain data in memory. They would also start instantly and have the potential to be far more powerful than today's computers.
Using Direct Current with Inverter Technology in Resistance WeldingTBMG-324718/1/2018
Resistance welding with direct current (DC) using inverter technology reduces costs by improving quality, reducing maintenance, and increasing productivity. Switching from traditional alternative current (AC) to DC with inverters also reduces a range of facilities costs and improves the process. Finally, it provides the ability to weld new materials, so it can add to a company's capability or product scope.
Design Issues with Wearables From the Perspective of Electromechanical ComponentsTBMG-297087/1/2018
Life Alert's “I've fallen and I can't get up®!” became one of the most famous infomercial catchphrases in the late 1980s. The company's device, targeted at senior citizens, provided users at the time with the simple, yet revolutionary ability to call for emergency assistance at the push of a button. As you may have guessed, this was one of the first mass-produced medical wearables available on the market.
Sensor-Free Smart WheelTBMG-290006/1/2018
Technology was developed that not only allows wheels to “know” when and how to rotate, but also enables them to work together in interactive teams. The new technology can be used wherever there is a need for additional support when pulling, pushing, or driving a system that uses wheels. Potential applications range from mobility aids such as wheelchairs, to dollies, wheelbarrows, and shopping carts. Monitoring the data generated when the motors inside the wheels rotate allows the motors and wheels to be controlled without the need for additional sensors.
Using Touchscreens in a Rotorcraft EnvironmentF-0074-2018-127425/14/2018
ABSTRACT This paper describes the flight test of a mounted touchscreen device in a UH-60 helicopter. The device assists crew chiefs in their fuel management tasks and provides situational awareness information regarding the route/flight plan, map data, external camera displays, publications and aircraft system information. The touchscreen tested was a 10.5" display and used Projected Capacitive for touch input. It was surrounded by 28 bezel switches. Eight current crew chiefs performed tasks using the device in flight. The participants wore gloves. Flight test evaluation results show that the subjects used and preferred the bezel switches over soft buttons on the touchscreens. Results also show that 16% percent of touchscreen presses required multiple presses to register the touch. Vibration did not appear to cause a problem with using the touchscreen. Gloves did present a problem in using the Projected Capacitive touchscreen.
Schutte, Paul
A Packaging Layout to Mitigate Crosstalk for SiC Devices2018-01-04624/3/2018
SiC devices have inherent fast switching capabilities due to their superior material properties, and are considered potential candidates to replace Si devices for traction inverters in electrified vehicles in future. However, due to the comparatively low gate threshold voltage, SiC devices may encounter oscillatory false triggering especially during fast switching. This paper analyzed the causes of false triggering, and also studied the impact of a critical parasitic parameter - common source inductance. It is shown that crosstalk is the main cause for the false triggering in the case and some positive common source inductance help to mitigate the crosstalk issue. A packaging layout method is proposed to create the positive common source inductance through layout of control terminals / busbars, and/or the use of control terminal bonded wires at different height.
Xu, Zhuxian, Chen, Chingchi, Lei, Thomas
Natural DNA-Based Nonvolatile Resistive Switching MemoryTBMG-283842/1/2018
Motivated by the demand for an even larger storage capacity in the information era, research efforts have been devoted to the development of more efficient and cost-effective memory elements.
Soil Moisture Active-Passive Project Spacecraft Flight SoftwareTBMG-281601/1/2018
The Soil Moisture Active-Passive (SMAP) Project Spacecraft Flight Software controls all aspects of command and data handling (CDH) in the SMAP spacecraft. Required capabilities include uplink and command, telemetry and downlink, vehicle attitude control, science instrument control, onboard science data storage and downlink, spacecraft deployments, and spacecraft fault detection and response.
Device Heals Organs Through Cell Function ChangeTBMG-281781/1/2018
A new chip device called Tissue Nano-transfection (TNT) can generate any cell type of interest for treatment within the patient’s own body. This technology may be used to repair injured tissue or restore function of aging tissue including organs, blood vessels, and nerve cells. TNT can switch cell function to rescue failing body functions with a single touch by injecting genetic code into skin cells, turning those skin cells into other types of cells required for treating diseased conditions.
Silicon Carbide High-Voltage SwitchTBMG-281801/1/2018
High-voltage wide bandgap (WBG) semiconductor devices like 15-kV silicon carbide (SiC) MOSFETs have attracted attention because of potential applications in high-voltage and high-frequency power converters. These devices, however, are not commercially available, and their high cost due to expensive material growth and fabrication may limit their widespread adoption in the future.
Ultrathin Semiconductor Materials “Rust” to Insulate CircuitryTBMG-2798212/1/2017
Silicon has several qualities that have led it to become the bedrock of electronics. One is that it features a very good “native” insulator — silicon dioxide, or silicon rust. Exposing silicon to oxygen during manufacturing gives chip makers a way to isolate their circuitry. Other semiconductors do not “rust” into good insulators when exposed to oxygen, so they must be layered with additional insulators — a step that introduces engineering challenges. Two new ultrathin materials share that trait, making them promising materials for electronics of the future.
Device for and Method of Computer Intrusion Anticipation, Detection, and RemediationTBMG-2780111/1/2017
Initially, relatively powerful computers were constructed as unique mainframes operated by larger corporations on isolated networks. Then, computers with modest amounts of computing power were made available to individuals as standalone personal computers. The computing power of personal computers and the applications for which they could be used were increased by networking them with other computers throughout the world using ancillary devices (e.g., servers, routers, links, switches, hubs, etc.). An arrangement into which computer and ancillary devices are configured is called a topology. There are many different types of topologies (e.g., bus, ring, star, tree, mesh, etc.).
Analysis of Transition from HCCI to CI via PPC with Low Octane Gasoline Fuels Using Optical Diagnostics and Soot Particle Analysis2017-01-240310/8/2017
In-cylinder visualization, combustion stratification, and engine-out particulate matter (PM) emissions were investigated in an optical engine fueled with Haltermann straight-run naphtha fuel and corresponding surrogate fuel. The combustion mode was transited from homogeneous charge compression ignition (HCCI) to conventional compression ignition (CI) via partially premixed combustion (PPC). Single injection strategy with the change of start of injection (SOI) from early to late injections was employed. The high-speed color camera was used to capture the in-cylinder combustion images. The combustion stratification was analyzed based on the natural luminosity of the combustion images. The regulated emission of unburned hydrocarbon (UHC), carbon monoxide (CO) and nitrogen oxides (NOX) were measured to evaluate the combustion efficiency together with the in-cylinder rate of heat release. Soot mass concentration was measured and linked with the combustion stratification and the integrated red channel intensity of the high-speed images for the soot emissions. The nucleation nanoscale particle number and the particle size distribution were sampled to understand the effect of combustion mode switch.
An, Yanzhao, Vallinayagam, R, Vedharaj, S, Masurier, Jean-Baptiste, Dawood, Alaaeldin, Izadi Najafabadi, Mohammad, Somers, Bart, Johansson, Bengt
Products of Tomorrow: October 2017TBMG-2769210/1/2017
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
A Novel Hybrid SiC-GaN Based Full-Bridge DC-DC Buck Converter with Improved Efficiency2017-01-20319/19/2017
In aerospace applications, it is important to have efficient, small, affordable, and reliable power conversion units with high power density to supply a wide range of loads. Use of wide-band gap devices, such as Silicon Carbide (SiC) and Gallium Nitride (GaN) devices, in power electronic converters is expected to reduce the device losses and needs for extensive thermal management systems in power converters, as well as facilitate high-frequency operation, thereby reducing the passive component sizes and increasing the power density. A novel hybrid SiC-GaN based full-bridge dc-dc buck converter with improved efficiency for high power applications will be presented in this paper. With the current device manufacturing technology, GaN devices can only handle breakdown voltages up to 650 V, while SiC devices can handle up to 1200 V. GaN devices exhibit remarkable switching performance compared to SiC devices. This work aims to exploit both the high voltage capability of SiC devices and exceptional switching capability of GaN devices to improve the overall converter performance, by using SiC devices in the high-voltage primary side and GaN devices in the low-voltage secondary side. A 10 kW, 150 V full-bridge dc-dc buck converter with an input voltage 400 V ≤ VI ≤ 660 V operating in CCM at a switching frequency of 200 kHz will be designed and simulated using LTSpice circuit simulator. Simulation results will be presented for (1) SiC based (2) GaN based and (3) hybrid SiC-GaN based converter. As expected GaN based converter exhibited superior performance with an efficiency of 99 %. However, using only GaN devices is not a choice because of the high voltage stresses in the primary side. The proposed hybrid SiC-GaN based converter exhibited better performance compared with that of SiC based converter with a 1% increase in efficiency and lower switching transition times.
Kondrath, Nisha, Saini, Dalvir, Smith, Nathaniel
Design and Evaluation of a Novel Hybrid SiC-GaN Based Bidirectional Full-Bridge DC-DC Converter2017-01-20329/19/2017
Efficient, small, and reliable dc-dc power converters with high power density are highly desirable in applications such as aerospace and electric vehicles, where battery storage is limited. Bidirectional full-bridge (FB) dc-dc converters are very popular in medium and high-power applications requiring regenerative capabilities. Full-bridge topology has several advantages such as: Inherent galvanic isolation between input and output as well as high conversion ratio due to the transformer with a turns ratio n. Reduction in passive component sizes due to the increase in inductor current frequency to twice the switching frequency. Reduced voltage stresses on the low-voltage side switches and current stresses on the high-voltage side switches. However, due to the high number of switches, device losses increase. Use of wide-band gap (WBG) devices, such as Silicon Carbide (SiC) and Gallium Nitride (GaN) devices, in power electronic converters has shown to reduce device losses and need for extensive thermal management systems in power converters. SiC and GaN have complementary properties. SiC devices offer superior thermal performance due to their high thermal conductivity and GaN devices offer superior switching performance due to their high carrier mobility. However, state-of-the-art commercially available GaN devices can only withstand breakdown voltages up to 650 V, while SiC devices can handle up to 1700 V. Because of this shortcoming, GaN devices cannot be used in power converters for high voltage applications, despite GaN’s capability to operate at high switching frequencies with high efficiency. This work aims to exploit both the high-voltage capability of SiC devices and exceptional switching capability of GaN devices in a novel hybrid SiC-GaN based bidirectional full-bridge dc-dc converter with improved efficiency, reliability, and power density for high power applications. The proposed bidirectional converter rated at 5 kW will be designed and simulation results obtained using LT Spice circuit simulator will be presented.
Kondrath, Nisha
Low-Cost Chip Extends Life of Battery SensorsTBMG-272778/1/2017
A voltage detector chip was developed that requires only a few trillionths of a Watt (picowatts) to activate other circuits, enabling engineers to design sensors that continuously listen, without using power from a battery or mains. The result is smaller batteries, or a battery life that is extended, in some cases by years. The voltage detector can also eliminate standby power.
Solder Bond Packaging for High-Voltage Pulsed Power DevicesTBMG-270346/1/2017
The huge demand for switching components exceeding silicon's (Si) current density limitation of 200 A/cm2 has pushed the enhancement of alternative semiconductor materials such as silicon carbide (SiC), gallium nitride, and diamond. The enhanced material properties of SiC, such as high thermal conductivity, large critical field, wide bandgap, large elastic modulus, and high saturation velocity, make it a viable candidate for pulsed power systems. Using SiC would increase both current and power densities, improve dI/dt and dV/dt capabilities, reduce recovery time, and minimize switching losses in various power electronic systems. Furthermore, a significant reduction in the volume and weight of pulsed power systems can be realized by implementing SiC SGTOs, reducing the thermal management requirements of the pulsed power system.
DC-Link Capacitor Sizing Considerations for HEV/EV e-Drive Systems2017-01-12343/28/2017
Dc-link capacitor sizing considerations are discussed for HEV/EV e-Drive systems. The capacitance value of the dc-link in HEV/EV e-Drive systems affects numerous factors. Some of the most significant are the system stability and the maximum tolerable dc-bus transient voltage with operating point change or with worst-case energy dump into the capacitor. Also requiring attention is the equivalent series resistance and inductance of the capacitor module. The former affects thermal behavior of the capacitor module and the latter affects voltage spikes occurring at every turn-off of a power semiconductor switch. In addition, these factors are dependent on other power-stage component parameters, control structures and controller gains. Also such effects and cross-couplings are operating-point dependent. This makes the dc-link capacitor sizing for HEV/EV e-Drive systems a complex task and it looks as if the task is done primarily by empirical manner with possibly more than enough safety margin. It appears accordingly that no systematic step-by-step methodology for the capacitor sizing has been discussed in the public domain. This paper attempts to present a list of the items to be considered for such a systematic dc-link capacitor sizing, and a detailed description follows for each item. The above-mentioned cross-coupling matters and the resulting trade-offs are briefly discussed. Potential issues caused by the use of emerging wide-bandgap semiconductors are mentioned as well. The target system taken as an example is an HEV e-Drive system, consisting of two electric machine drive inverters and a dc-dc converter, which share a common dc-link.
Sridharan, Srikanthan, Kimmel, Joseph, Kikuchi, Jun
Conceptual Design and Evaluation of a Hybrid Transmission with Power-Split, Series, and Two Parallel Configurations2017-01-11723/28/2017
A hybrid transmission may be in any combination of a power-split, series or parallel configuration. This study is aimed to develop a hybrid transmission with six possible configurations: power-split, series, two parallel configurations, and two EV configurations. The Function Power Graph (FPG) methodology was applied in this study. After creating and merging FPGs, a possible solution consisting of only one planetary gearset, one ICE, one MG1, one MG2, two rotating clutches, and one brake clutch was synthesized to satisfy all configuration requirements. This transmission was based on power-split configuration which can switch to other configurations. The parallel configuration I extracted more power from MG1 and ICE during lower speed driving in order to utilize the two sufficiently, and respond to the increased desire for horsepower in the market. Additionally, parallel configuration II was set up so that ICE can directly propel the vehicle during freeway cruising. Compared with power-split configuration, MG1 does not need to keep operating in parallel configuration II, which gives an additional opportunity to develop an energy management strategy. Moreover, both MG1 and MG2 could propel the vehicle in the two-motor EV configuration, thus costly electric machinery and power electronics were utilized more thoroughly. In conclusion, a design process of a multi-configuration hybrid transmission was proposed and the result was evaluated. This study provides some alternative hybrid concepts for further research.
Chen, Yan-Song, Chang, Joshua, Chen, I-Ming, Chen, Ming-Yen, Liu, Tyng
A Smart Gate Driver with Active Switching Speed Control for Traction Inverters2017-01-12433/28/2017
The IGBTs are dominantly used in traction inverters for automotive applications. Because the Si-based device technology is being pushed to its theoretical performance limit in such applications during recent years, the gate driver design is playing a more prominent role to further improve the traction inverter loss performance. The conventional gate driver design in traction inverter application needs to consider worst case scenarios which adversely limit the semiconductor devices' switching speed in its most frequent operation regions. Specifically, when selecting the gate resistors, the IGBT peak surge voltage induced by fast di/dt and stray inductance must be limited below the device rated voltage rating under any conditions. The worst cases considered include both highest dc bus voltage and maximum load current. However, the traction inverter operates mainly in low current regions and at bus voltage much lower than the worst case voltage. This paper proposes a low-cost and simple gate driver circuit that can actively adjust the turn-off switching speed based on IGBT current levels. The proposed circuit utilizes the current sensing pin which is widely available for IGBTs used in current generation traction inverters. When the current is low, the switching is speeded up to minimize loss. Under worst cases, it can keep the maximum surge voltage same as the value of conventional gate driver. For applications that the system operates mostly in low current regions, the proposed method can significantly improve the system efficiency.
Zhou, Yan, Chen, Lihua, Yang, Shuitao, Xu, Fan, Alam, Mohammed Khorshed
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