Criteria

Text:
Content:
Display:

Results

Viewing 1 to 30 of 83
2014-09-16
Technical Paper
2014-01-2213
Noriko Morioka, Hidefumi Saito, Norio Takahashi, Manabu Seta, Hitoshi Oyori
Abstract Electrical power management is a key technology in the AEA (All-Electric Aircraft) system, which manages the supply and demand of the electrical power in the entire aircraft system. However, the AEA system requires more than electrical power management alone. Adequate thermal management is also required, because the heat generated by aircraft systems and components increases with progressive system electrification, despite limited heat-sink capability in the aircraft. Since heat dissipation from power electronics such as electric motors, motor controllers and rectifiers, which are widely introduced into the AEA, becomes a key issue, an efficient cooling system architecture should be considered along with the AEA system concept. The more-electric architecture for the aircraft has been developed; mainly targeting reduced fuel burn and CO2 emissions from the aircraft, as well as leveraging ease of maintenance with electric/electronic components. The AEA should pursue more efficient and eco-friendlier systems, which are easier to maintain than those of conventional aircraft/MEA (More-Electric Aircraft), to enhance benefits for passengers and operators.
2014-09-16
Technical Paper
2014-01-2156
Arthur V. Radun
Abstract There is a continuing need to simulate power electronic circuits that include magnetic components. It is necessary to determine the interaction of the magnetic component with the rest of the power electronic system so that a dynamic circuit model of the magnetic components including material saturation and iron losses is required. Also, the magnetic component model must be valid when the magnetic component's excitation is not sinusoidal. A dynamic magnetic circuit model derived from Maxwell's equations along with useful theorems for building circuit models from the structure of the magnetic device is reviewed. The developed circuit models are general including magnetic saturation and iron losses. Simulation results for a DC/DC converter employing a conventional gapped inductor and a gapped coupled inductor are presented.
2014-09-16
Technical Paper
2014-01-2181
Christopher Ian Hill, Chris Gerada, Paolo Giangrande, Serhiy Bozhko
Abstract This paper presents the initial development of a Modelica Library for Electro-Mechanical Actuator system analysis. At present two main system components are described, these are the Power Electronic Converter and Electric Machine, although further components will be added. These models provide the user with the ability to simulate Electric Machine and Power Electronic Converter systems including physical effects, losses and fault conditions. Established modelling programs such as Saber and MATLAB SimPowerSytems are often unable to provide all the aspects required to accurately simulate real systems in an easy to use, flexible manner. Therefore this paper shows how Modelica has been used to create versatile models able to simulate many practical aspects such as Power Electronic Converter losses and Power Electronic Converter faults, Electric Machine losses and Electric Machine faults. Examples are included in order to demonstrate the use of these models within a variety of systems including an Electro-Mechanical Actuator.
2014-09-16
Technical Paper
2014-01-2176
Niloofar Rashidi Mehrabadi, Bo Wen, Rolando Burgos, Dushan Boroyevich, Chris Roy
Abstract The development of the concepts, terminology and methodology of verification and validation is based on practical issues, not the philosophy of science. Different communities have tried to improve the existing terminology to one which is more comprehensible in their own field of study. All definitions follow the same concept, but they have been defined in a way to be most applicable to a specific field of study. This paper proposes the Verification, Validation, and Uncertainty Quantification (VV&UQ) framework applicable to power electronic systems. Although the steps are similar to the VV&UQ frameworks' steps from other societies, this framework is more efficient as a result of the new arrangement of the steps which makes this procedure more comprehensible. This new arrangement gives this procedure the capability of improving the model in the most efficient way. Since the main goal of the VV&UQ process is to quantitatively assess the confidence in modeling and simulation, the second part of this paper focuses on uncertainty quantification.
2014-09-16
Technical Paper
2014-01-2117
Michael L. Zierolf, Thomas Brinson, Andrew Fleming
Abstract Recent emphasis on optimization of engine technologies with ancillary subsystems such as power and thermal management has created a need for integrated system modeling. These systems are coupled such that federated design methods may not lead to the most synergetic solution. Obtaining an optimal design is often contingent on developing an integrated model. Integrated models, however, can involve combining complex simulation platforms into a single system of systems, which can present many challenges. Model organization and configuration control become increasingly important when orchestrating various models into a single simulation. Additionally, it is important to understand such details as the interface between models and signal routing to ensure the integrated behavior is not contaminated or biased. This paper will present some key learnings for model integration to help alleviate some of the challenges with system-based modeling.
2014-09-16
Technical Paper
2014-01-2139
Serhiy Bozhko, Seang Shen Yeoh, Fei Gao, Tao Yang, Christopher Hill
Abstract The paper reports the control design for an aircraft electric starter-generator system based-on high-speed permanent magnet machine operated in a flux-weakening mode and controlled by an active front-end rectifier. The proposed system utilizes advances of modern power electronics allowing the use of novel machine types and the introduction of controlled power electronics into the main path of energy flow. The paper focuses on control design for such system and includes development of flux weakening control of high-speed permanent magnet machine and droop control of the system output dc-link current. The achieved analytical design results and the expected system performance are confirmed by time-domain simulations.
2014-09-16
Technical Paper
2014-01-2113
Fei Gao, Serhiy Bozhko, Greg Asher
Abstract Stability is a great concern for the Electrical Power System (EPS) in the More Electric Aircraft (MEA). It is known that tightly controlled power electronic converters and motor drives may behave as constant power loads (CPLs) which may produce oscillations and cause instability. The paper investigates the stability boundaries for dc multi-source EPS under different power sharing strategies. For each possible strategy the corresponding reduced-order models are derived. The impedance criterion is then applied to study the EPS stability margins and investigates how these margins are influenced by different parameters, such as main bus capacitance, generator/converter control dynamics, cabling arrangements etc. These results are also illustrated by the root contours of reduced-order EPS models. Theoretical results achieved in the paper are confirmed by the time-domain simulations.
2014-09-16
Technical Paper
2014-01-2115
Brian C. Raczkowski, Benjamin Loop, Jason Wells, Eric Walters, Oleg Wasynczuk, Sean Field, Jason Gousy
Abstract Future more electric aircraft (MEA) architectures that improve electrical power system's (EPS's) source and load utilization will require advance stability analysis capabilities. Systems are becoming more complex with bidirectional flows from power regeneration, multiple sources per channel and higher peak to average power ratios. Unknown load profiles with large transients complicate common stability analysis techniques. Advancements in analysis are critical for providing useful feedback to the system integrator and designers of multi-source, multi-load power systems. Overall, a framework for evaluating stability with large displacement events has been developed. Within this framework, voltage transient bounds are obtained by identifying the worst case load profile. The results can be used by system designers or integrators to provide specifications or limits to suppliers. Subsystem suppliers can test and evaluate their design prior to integration and hardware development. By identifying concerns during the design phase, a more streamlined approach to hardware development can save on rework, integration delays and cost.
2014-09-16
Technical Paper
2014-01-2111
Shweta Sanjeev, Goutham Selvaraj, Patrick Franks, Kaushik Rajashekara
Abstract The transition towards More Electric Aircraft (MEA) architectures has challenges relating to integration of power electronics with the starter generator system for on-engine application. To efficiently operate the power electronics in the hostile engine environment at high switching frequency and for better thermal management, use of silicon carbide (SiC) power devices for a bi-directional power converter is examined. In this paper, development of a 50 kVA bi-directional converter operating at an ambient temperature of about 2000C is presented. The design and operation of the converter with details of control algorithm implementation and cooling chamber design are also discussed.
2014-09-16
Technical Paper
2014-01-2104
Jon Zumberge, John Mersch
Cost and performance requirements are driving military and commercial systems to highly integrated, optimized systems which require more sophisticated, highly complex controls. To realize benefits and make confident decisions, the validation of both plant and control models becomes critical. To quickly develop controls for these systems, it is beneficial to develop models and determine the uncertainty of those models so as to predict performance and stability. A process of model validation for a boost circuit based on acceptance sampling is presented here. The validation process described in this paper includes the steps of defining requirements, performing a screening and exploration of the system, completing a system and parameter identification, and finally executing a validation test. To minimize the cost of experimentation and simulation, design of experiments is used extensively to limit the amount of data taken without losing information. One key contribution in this paper is the use of tolerance intervals as an estimation of model accuracy.
2014-09-16
Technical Paper
2014-01-2120
Jennifer C. Shaw, Patrick Norman, Stuart Galloway, Graeme Burt
Abstract Radical new electrically propelled aircraft are being considered to meet strict future performance goals. One concept design proposed is a Turboelectric Distributed Propulsion (TeDP) aircraft that utilises a number of electrically driven propulsors. Such concepts place a new and significant reliance on an aircraft's electrical system for safe and efficient flight. Accordingly, in addition to providing certainty that supply reliability targets are being met, a contingency analysis, evaluating the probability of component failure within the electrical network and the impact of that failure upon the available thrust must also be undertaken for architecture designs. Solutions that meet specified thrust requirements at a minimum associated weight are desired as these will likely achieve the greatest performance against the proposed emissions targets. This paper presents a Fault Tree Analysis (FTA) based design approach for the electrical system and thrust reliability analysis of TeDP aircraft architectures.
2014-09-16
Technical Paper
2014-01-2141
Christine Ross, Michael Armstrong, Mark Blackwelder, Catherine Jones, Patrick Norman, Steven Fletcher
Abstract The Turboelectric Distributed Propulsion (TeDP) concept uses gas turbine engines as prime movers for generators whose electrical power is used to drive motors and propulsors. For this NASA N3-X study, the motors, generators, and DC transmission lines are superconducting, and the power electronics and circuit breakers are cryogenic to maximize efficiency and increase power density of all associated components. Some of the protection challenges of a superconducting DC network are discussed such as low natural damping, superconducting and quenched states, and fast fault response time. For a given TeDP electrical system architecture with fixed power ratings, solid-state circuit breakers combined with superconducting fault-current limiters are examined with current-source control to limit and interrupt the fault current. To estimate the protection system weight and losses, scalable models of cryogenic bidirectional current-source converters, cryogenic bidirectional IGBT solid-state circuit breakers (CBs), and resistive-type superconducting fault current limiters (SFCLs) are developed to assess how the weight and losses of these components vary as a function of nominal voltage and current and fault current ratings.
2014-09-16
Technical Paper
2014-01-2194
Ralf Cremer, Alfred Engler
Abstract The application of power electronics in aircraft is increasing in the latest aircraft developments. This contribution focuses on the recent advances of activities at Liebherr-Elektronik GmbH linked to power electronics: active power filter based on fast silicon carbide switches, open box design for unpressurized area, light weight housing, EMC management, partial discharge detection and mitigation, arc-fault detection and standardized innovative power cores with optimized sensors. These topics are derived from a roadmap based on beforehand identified key drivers. These key drivers will enable the future More Electric Aircraft (MEA) by focusing on weight, reliability and cost. New technologies as Silicon Carbide (SiC) and advanced integration will support this strategy.
2014-04-01
Technical Paper
2014-01-0228
Andreas Kiep, Marco Puerschel
Abstract The amount of electronics in vehicles is increasing, so is the amount of power electronics circuits, like inverters for electric motor drives or dc/dc converters. The muscles of these circuits are power transistors like MOSFETs and IGBTs - in each circuit are several of them. While MOSFETs and IGBTs have advanced over the years in terms of their performance, their wide product spectrum and feature spectrum as well as cost, they are still not unbreakable, but semiconductors which are more sensitive to electrical or thermal overstress than, a relay for instance. Especially electrical overstress, like overvoltage or over current, may damage a power transistor within a short time frame. Hence, electrical overstress must be avoided when designing the power electronics circuit. However, even a power transistor in a carefully designed power electronics circuit, may still be exposed to over current, short circuit, over voltage, over temperature and so forth. This may damage the power transistor and may have severe consequences for the application.
2014-04-01
Technical Paper
2014-01-1793
Chen Wang, Zhiguo Zhao, Tong Zhang, Xianjun Dai, Xiyue Yuan
Abstract Several types of power-split hybrid transmissions are outlined and the strengths and weaknesses of typical compound power-split prototype designs are summarized in this paper. Based on an modified Ravigneaux gear set, a novel compound power-split hybrid transmission with compact mechanical structure is presented, its dynamic and kinematic characteristics in equations and operating modes are described, and then equivalent lever diagrams are used to investigate the proposed compound power-split device. Control strategies in different operating modes are discussed with the simplified combined lever diagram, and a global optimization method is implemented to find the optimum operation point for the hybrid powertrain. To evaluate the fuel economy of a hybrid car equipped with this hybrid transmission, a forward powertrain simulation model is developed and real vehicle performance tests are conducted in the chassis dynamometer. Simulations and test results show that the proposed hybrid transmission can improve the efficiency of the powertrain and demonstrate lower fuel consumptions than the corresponding conventional vehicle.
2014-04-01
Technical Paper
2014-01-1910
Tim Fischer, Stefan Mueller
Abstract The domains of powertrain and brake systems are continuously merging due to the integration of electric drives and their ability to generate high acceleration and recuperative torque. However, high recuperative torque might lead to a locking motor and consequently cause a stability issue in electric and hybrid vehicles. This paper focuses on the special case of recuperation by coasting; i.e., the torque request is set after releasing the accelerator pedal. In this case the mechanical brake is not used. For off-highway vehicles this new feature in the inverter will suppress the slipping and locking up of the tires, without the need of additional external sensors. Slipping of the tires, e.g. when the tires lose grip, can occur due to excessive torque from the motor. In this case the motor torque exceeds the minimum feasible deceleration torque, given by road friction. We have developed a new non-linear control approach, which limits the requested torque directly inside the inverter (power electronic control unit).
2014-04-01
Technical Paper
2014-01-1888
Jürgen Fabian, Mario Hirz, Klaus Krischan
Discussions about the optimal technology of propulsion systems for future ground vehicles have been raising over the last few years. Several options include different types of technologies. However, those who are advocating conventional internal combustion engines are faced with the fact that fossil fuels are limited. Others favor hydrogen fuel as the solution for the future, either in combination with combustion engines or as an energy carrier for fuel cells. In any case, the production and storage of hydrogen is an ongoing challenge of numerous research works. Finally, there are battery-electric or hybrid propulsion systems in use, gaining more and more popularity worldwide. Ongoing advances in power electronics help to improve control systems within automotive applications. New developed or designed components enable more efficient system architectures and control. This paper includes a detailed comparison of different electric drive technologies, e.g. a DC motor, an asynchronous and synchronous motor in battery-electric or hybrid drivetrain configurations.
2014-04-01
Technical Paper
2014-01-1928
Adam Fogarty, Kevin Oswald
In order to continue the effort of converting traditional internal combustion engine (ICE)-based vehicles into hybrid-electric vehicles (HEV), it is important to consider a variety of design architectures in which hybrid-electric operation is achieved. Such architectures include power split, parallel, and series. Of the previously stated architectures, the Purdue EcoMakers of the EcoCar 2 international Advanced Vehicle Technology Competition (AVTC) have chosen a parallel-through-the-road architecture for their 2013 Chevrolet Malibu provided by General Motors. From this, the Purdue EcoMaker vehicle design will be used as a case study for the design challenges and optimization strategies that are experienced when choosing this specific architecture for a light-duty passenger vehicle. This paper will focus on the design procedure and structural analysis of the custom rear suspension cradle created by the Purdue EcoMakers. Additionally, this paper will consider the benefits and practicality of using the structure of the custom suspension cradle as a design format for future suspension cradles to be used in light-duty passenger vehicles.
2014-04-01
Technical Paper
2014-01-0797
Binghua Pan, Chee Keng Yeo
Power electronics products such as inverters and converters involve the use of Thermal Interface Materials (TIMs) between high power packages and a heat exchanger for thermal management. Conventional TIMs such as thermal greases, gels, solders and phase change materials (PCMs) face challenges to meet the need of these products to operate reliably at much higher temperatures. This has driven the development of new TIMs such as Transient Liquid Phase Sintering (TLPS) Conductive Adhesives. TLPS adhesives have been developed for many potential applications due to various advantages like lead free, flux-less and particularly their low temperature processability, which enables the use of heat sensitive components in the design. With all these motivations, a project was launched and completed to assess TLPS adhesives as a unique TIM for high temperature automotive applications due to its high bulk thermal conductivity and metallic joint formation at interfaces. This paper reports the evaluation of three different TLPS conductive adhesives with different formulations.
2013-09-17
Technical Paper
2013-01-2081
Richard Ambroise
The power plant is the area in an aircraft where they are a lot of power conversion. The power plant is the core of the aircraft from energy point of view. The engines allow to take off but not only, it also provides energy to the aircraft from many different manners. They are electrical, hydraulic, mechanical, …. The power plant is definitively a power generator but also a power consumer. Since now some years, the power electronic technology is spread into the aircraft. One can say that some pedigree has been collected with this technology embedded to the aircraft. For the power plant domain, it is different. This technology is really not usual for use. Our environment is really not friendly and even if the integration of the power converters has been improved over the last years, there is not a lot of space around the engines. These are probably the mains reason of the low deployment of the power electronic in this domain but not only. The reliability of the thrust function is expected to be very high; of course, for safety point of view but also for cost point of view.
2013-01-09
Technical Paper
2013-26-0075
Prakash S
As we all know the price of Cu alloy keep on increasing trend and in few products like motors, generators and power electronics. Cu price plays a vital role in determining the cost. Particularly in power electronics products for the hybrid electric vehicles the electrical/thermal conductivity property of Cu alloy needs to be enhanced since of high voltage requirement within a small space. Many research activities are ongoing to enhance the properties of Cu metal by addition of various alloys compositions. In addition to that the extra-ordinary properties of Carbon Nanotube (CNT) in Metal Matrix Composite (MMC) were main focus for science and technology. Few successful attempts have been made for Copper-Carbon nanotube (Cu-CNT) composites by powder metallurgy techniques, also it was reported the issues on the detoriation of the CNT's properties due to mechanical working. We employed electroplating method to prepare Cu-CNT composites wherein no mechanical working done on CNT, also the homogenous dispersion of CNT made on the Cu metal surfaces.
2012-10-22
Technical Paper
2012-01-2210
Steve Majerus, Daniel Howe, Steven Garverick, Walt Merrill, Kenneth Semega
Four application specific integrated circuits (ASICs) which provide sensing, actuation, and power conversion capabilities for distributed control in a high-temperature (over 200°C) environment are presented. Patented circuit design techniques facilitate fabrication in a conventional, low-cost, 0.5 micron bulk Complimentary Metal Oxide Semiconductor (CMOS) foundry process. The four ASICs are combined with a Digital Signal Processor (DSP) to create a distributed control node. The design and performance over temperature of the control system is discussed. Various applications of the control system are proposed. The authors also discuss various design techniques used to achieve high reliability and long life.
2012-10-22
Technical Paper
2012-01-2157
Serhiy Bozhko, Tao Yang, Greg Asher
The paper deals with the development of active front-end rectifier model based on dynamic phasors concept. The model addresses the functional modeling level as defined by the multi-layer modeling paradigm and is suitable for accelerated simulation studies of the electric power systems under normal, unbalanced and line fault conditions. The performance and effectiveness of the developed model have been demonstrated by comparison against time-domain models in three-phase and synchronous space-vector representations. The experimental verification of the dynamic phasor model is also reported. The prime purpose of the model is for the simulation studies of more-electric aircraft power architectures at system level; however it can be directly applied for simulation study of any other electrical power system interfacing with active front-end rectifiers.
2012-10-22
Technical Paper
2012-01-2159
Tao Yang, Greg Asher, Serhiy Bozhko
The more-electric aircraft (MEA) is the major trend for airplanes in the next generation. Comparing with traditional airplanes, a significant increase of on-board electrical and electronic devices in MEAs has been recognized and resulted in new challenges for electrical power system (EPS) designers. The design of EPS essentially involves in extensive simulation work in order to ensure the availability, stability and performance of the EPS under all possible operation conditions. Due to the switching behavior of power electronic devices, it is very time-consuming and even impractical to simulate a large-scale EPS with some non-linear and time-varying models. The functional models in the dq0 frame have shown great performance under balanced conditions but these models become very time-consuming under unbalanced conditions, due to the second harmonics in d and q axes. The dynamic phasor (DP) technique has been proposed to solve that problem. The DP technique is naturally a frequency-domain analysis method and has been successfully applied in modeling electromagnetic machines, flexible AC transmission systems, etc.
2012-10-22
Technical Paper
2012-01-2233
Michael Ballas, Fred Potter
Aircraft-level health management requires effective management of data flow. As future aircraft adopt conditioned base maintenance (CBM) and/or integrated vehicle health management (IVHM) protocols, there is need to manage infinitely more data communication on and off the aircraft. This paper explores the idea of employing an Electronic Power Distribution System (EPDS) as a “network backbone” for aircraft-level prognostics. Using EPDS to capture and distribute this data provides a practical solution that minimizes system hardware on future CBM/IVHM enabled aircraft. Employing the Electronic Circuit Breaker (ECB) in a more enhanced sensor state and as a data communication tool, provides tremendous value given its multipurpose capability. A “distributed” electronic power distribution architecture, is comprised of groupings of remotely operated electronic circuit breakers (ECBUs), System Control Interface Units (SCIUs), primary power distribution units (PDU), bus transfer contactors, and so on, all of which will play a future role in aircraft level health management.
2012-10-22
Technical Paper
2012-01-2208
Dennis P. Shay, Clive A. Randall
Mn and/or rare earth-doped xCaTiO₃ - (1-x)CaMeO₃ dielectrics, where Me=Hf or Zr and x=0.7, 0.8, and 0.9 were developed to yield materials with room temperature relative permittivities of Εr ~ 150-170, thermal coefficients of capacitance (TCC) of ± 15.8% to ± 16.4% from -50 to 150°C, and band gaps of ~ 3.3-3.6 eV as determined by UV-Vis spectroscopy. Un-doped single layer capacitors exhibited room temperature energy densities as large as 9.0 J/cm₃, but showed a drastic decrease in energy density above 100°C. When doped with 0.5 mol% Mn, the temperature dependence of the breakdown strength was minimized, and energy densities similar to room temperature values (9.5 J/cm₃) were observed up to 200°C. At 300°C, energy densities as large as 6.5 J/cm₃ were measured. These observations suggest that with further reductions in grain size and dielectric layer thickness, the xCaTiO₃ - (1-x)CaMeO₃ system is a strong candidate for integration into future power electronics applications. To further improve the high temperature, high field reliability of these material systems, rare earth donor doping has been utilized.
2012-10-22
Technical Paper
2012-01-2209
Brice R. McPherson, Robert Shaw, Jared Hornberger, Alex Lostetter, Roberto Schupbach, Brad Reese, Ty McNutt, Takukazu Otsuka, Yuki Nakano, Takashi Nakamura
The demands for high-performance power electronics systems are rapidly surpassing the power density, efficiency, and reliability limitations defined by the intrinsic properties of silicon (Si)-based semiconductors. The advantages of silicon carbide (SiC) are well known, including high temperature operation, high voltage blocking capability, high speed switching, and high energy efficiency. These advantages, however, are severely limited by conventional power packages, particularly at temperatures higher than 175\,DC and ≻100 kHz switching speeds. Here, APEI, Inc., presents the design process and testing data of its newly developed high performance HT-2000 SiC power module for extreme environment systems and applications. This advanced power module, targeted for high performance commercial and industrial systems such as hybrid electric vehicles or renewable energy applications, implements a novel low parasitic packaging approach that enables high switching frequencies in excess of 100 kHz.
2012-04-16
Technical Paper
2012-01-0340
Prakash H. Desai, Sean Bartolucci, Marzia Fatema, Ronald Weiss
GM has recently developed two kinds of vehicle electrification architectures. First is VOLTec, a heavy electrification architecture, and second is eAssist, a light electrification architecture. An overview, of IGBT power modules & inverters used in VOLTec and eAssist, is presented. Alternative power modules from few cooperative suppliers are also described in a benchmarking study using key metrics. Inverter test set up, procedure and instrumentation used in GM Power Electronics Development Lab, Milford are described. GM electrification journey depends on Power Electronics lab' passive test benches; double pulse tester, inductive resistive load bench and active emulator test cell without electric machines. Such test benches are preferred before dyne test cells are used for inverter software/hardware integration and motor durability tests cycles. Specific test results are presented. Power modules reliability tests; power cycle, intermittent operation life and thermal air shock, as specified by GM and performed by Tier 1/2 suppliers are also described.
2012-04-16
Technical Paper
2012-01-0337
Hideo Matsuki, Kensaku Yamamoto, Masanori Nagaya, Hiroki Watanabe, Eiichi Okuno, Toshimasa Yamamoto, Shoichi Onda
This paper describes the reliability of silicon carbide (SiC) MOSFET. We clarified the relation between the lifetime of the gate oxide and the crystal defects. We fabricated MOS diodes using thermal oxidation and measured their lifetimes by TDDB (Time Dependent Dielectric Breakdown) measurement. The wear-out lifetime is sufficient for hybrid vehicle but many MOS diodes broke in shorter time. The breakdown points were defined by Photo-emission method. Finally, we classified the defects by TEM (Transmission Electron Microscopy). A TSD (Threading Screw Dislocation) plays the most important role in the lifetime degradation of the gate oxide. The lifetime of the gate oxide area, in which a TSD is included, is shorter by two orders of magnitude than a wear-out breakdown. The mechanism by which threading dislocations degrade the gate oxide lifetime was not discovered. To explain the degradation, we assumed two models, the shape effect and the oxide quality degradation.
2012-04-16
Technical Paper
2012-01-0339
Jan Vetrovec, Amardeep Litt
We have previously reported on the development of a novel active heat sink (AHS) for high-power electronic components offering unparalleled capacity in high-heat flux handling and temperature control. AHS employs convective heat transfer in a working fluid circulating in a miniature closed and sealed flow loop. High flow velocity, good flow attachment, and relatively high thermal conductivity of working fluid lead to ultra-low thermal resistance around 0.1 deg C/W. AHS appears very suitable for directly interfacing a hybrid electric vehicle (HEV) inverter to engine coolant loop. Alternatively, AHS may be used to interface inverter electronics to an air-cooled heat exchanger. As a result, the traditional dedicated liquid coolant loop for thermal management of the inverter can be eliminated, the inverter subsystem can be greatly simplified, and the power train electronics made much more compact. Our previous work focused on AHS with working fluids based on liquid metals. This paper reports on AHS development testing with water-based working fluid, which are more suitable for automotive applications.
Viewing 1 to 30 of 83

Filter