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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2

Artificial Intelligence for Power Electronics in Electric Vehicles: Challenges and Opportunities

We report progress in the field of power electronics within electric vehicles has generally been driven by conventional engineering design principles and experiential learning. Power electronics is inherently a multidomain field where semiconductor physics and electrical, thermal, and mechanical design knowledge converge to achieve a practical realization of desired targets in the form of conversion efficiency, power density, and reliability. Due to the promising nature of artificial intelligence in delivering rapid results, engineers are starting to explore the ways in which it can contribute to making power electronics more compact and reliable. Here, we conduct a brief review of the foray of artificial intelligence in three distinct subtechnologies within a power electronics system in the context of electric vehicles: semiconductor devices, power electronics module design and prognostics, and thermal management design. The intent is not to report an exhaustive literature review, but to identify the state of the art and opportunities for artificial intelligence to play a meaningful role in power electronics design from a mechanical and thermal standpoint, as well as to discuss a few promising future research directions.

33 ADVANCED PROPULSION SYSTEMS↗

MLSPICE: Machine Learning based SPICE Modeling Platform for Power Magnetics

Electrical power converters are critical to a wide range of applications ranging from renewable integration to transportation electrification, and can be a key factor determining the size, weight, and efficiency of energy conversion systems. Magnetic components are typically the largest and least efficient components in power electronics. While there have been major strides in the modeling and analysis of power semiconductor devices and circuit simulations, the necessary advances in the design of power magnetics have lagged. In this project, we have transformed the modeling and design of power magnetics with machine learning enabled methods and catalyze simultaneous disruptive improvements for ML-based power electronics design tools. A fully automated open-source machine learning based magnetics modeling platform – the MagNet project - with innovations in full stack have been developed to greatly accelerate the design process and provide new insights to magnetic material and geometry design. The ARPA-E funded MagNet platform contains three major building blocks: 1) a ML-Integrated Data Acquisition System (MIDAS): a highly automated data acquisition testbed which is capable of measuring a large number of magnetic cores with a wide range of electrical circuit excitations; 2) a ML-integrated Core Loss Model (MICLM): a machine-learning trained modeling method for modeling the core loss and saturation effects of magnetic materials for arbitrary excitation waveforms; 3) ML-guided Magnetics SPICE Simulation Tool (PMSPICE): a fully integrated CAD tool which can simulate the magnetics in SPICE. It can help the designers to quickly model the linear and non-linear characteristics of magnetic components and evaluate their behavior in SPICE simulations. The developed MagNet system has fully demonstrated the proposed performance target and has been open sourced to the entire power electronics community to advance the modeling and design of power magnetics from many different angles.

36 MATERIALS SCIENCE↗

Two dimensional thermal and charge mapping of power thyristors

The two dimensional static and dynamic current density distributions within the junction of semiconductor power switching devices and in particular the thyristors were obtained. A method for mapping the thermal profile of the device junctions with fine resolution using an infrared beam and measuring the attenuation through the device as a function of temperature were developed. The results obtained are useful in the design and quality control of high power semiconductor switching devices.

Hu, S. P.↗

Design of power electronics for TVC EMA systems

The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

Nelms, R. Mark↗

A Control Scheme to Mitigate the Dead-Time Effects in a Wireless Power Transfer System

In practice, a dead-time is always provided between the complementary switching instances of the inverter phase-leg devices. At higher operating frequencies, the dead-time issues in wireless power transfer (WPT) systems become critical, especially as the power level increases. In certain operating conditions, the dead-time effect in wireless power transfer system affects the switching characteristics. Consequently, the switching losses in the power semiconductor devices increase and also impact the efficiency of the overall system. In this paper, a simple control scheme is proposed to eliminate the dead-time effect (or voltage polarity reversal) in the WPT inverter. The proposed control scheme monitors the inverter output voltage, and the switching frequency is auto-tuned to eliminate the undesired switching instances in the inverter voltage. The proposed control scheme is validated using the closed-loop simulations in PLECS, and the experimental results on a 5.6 kW WPT prototype are also presented. After eliminating the voltage-polarity-reversal at the inverter output, the inverter losses were reduced by ~40%, and the overall system losses were reduced by ~17%.

Kavimandan, Utkarsh↗

Design Considerations for High-Voltage Insulated Gate Drive Power Supply for 10-kV SiC MOSFET Applied in Medium-Voltage Converter

High-performance gate drive power supply (GDPS) plays a crucial role in ensuring the reliability and safety of the gate driver for power semiconductor devices. This article focuses on the design of a high-voltage-insulated GDPS for the 10-kV silicon carbide MOSFET in medium-voltage (MV) application. Design considerations, including insulation scheme, high-voltage-insulated transformer design, and load voltage regulation scheme, are proposed. In addition, the performance of the secondary-side-regulated (SSR) GDPS and that of the primary-side-regulated (PSR) GDPS are compared for several aspects, including interwinding capacitance, load voltage regulation rate, conversion efficiency, and hardware complexity. Finally, an SSR GDPS and a PSR GDPS, with an insulation voltage of 20 kV, are built in the lab. Furthermore, the test results demonstrate that the PSR GDPS is more preferable because of lower interwinding capacitance, lower load voltage regulation rate, higher conversion efficiency, and simpler control circuit.

42 ENGINEERING↗

A Simple Control to Reduce the Voltage Stress of Non-Conducting Switches in Three-Level ANPC Converter

With the development of wide band-gap (WBG) technology, the switching speed of power semiconductor devices is increased, which makes circuits more sensitive to parasitics. For three-level active neutral point clamped (3L-ANPC) converters, the over-voltage of non-conducting switches can be an issue. This paper analyzes the multiple commutation loops in 3L-ANPC converter and summarizes the impact factors of the over-voltage for the non-conducting switch. It is found that the nonlinearity of the output capacitance of the device can significantly influence the over-voltage. A simple control without introducing any additional hardware circuit is proposed to attenuate the impact of the nonlinearity. With the proposed control, the peak over-voltage of the non-conducting switch can be reduced significantly. Multi-pulse test is conducted for a 3L- ANPC converter built with silicon carbide (SiC) MOSFETs. The testing results show that the peak over-voltage decreases from 892 V to 624 V with the proposed control. More detailed analysis and experimental results will be provided in the final paper.

SiC MOSFET↗

Hermetic-coaxial package design for microwave transistors

Semiconductor package has been developed for high power semiconductor devices that operate in the GHz-frequency range at several watts. Package includes stud, insulating ring, electrically conductive washer, insulating washer, braze ring, and cap. It is mechanically strong and can be used with variety of circuits.

Jacobson, D. S.↗

Growth of diamondlike films for power applications

Diamond has a high thermal conductivity (approximately 5 times that of copper) and is an ideal heat sink material for high power semiconductor devices as well as being of interest as a semiconductor material. Numerous vacuum deposition processes are being evaluated by NASA-LeRC which have demonstrated the capability to deposit carbon films having some of the properties of diamond. Current activities include Investigation of high deposition rate vacuum processes suitable for synthesis of diamondlike carbon films. The results of recent film characterization tests are reported.

Banks, B. A.↗

Status of utility-interactive photovoltaic power conditioning technology

Design options for utility-interactive photovoltaic power conditioning technology for unit ratings from 2kW to 5 MW are compared. Line- and self-commutated inverter designs for both single and three-phase applications are described. Efficiency, weight, and cost projections are provided for comparing the design options. New circuit designs that take advantage of advances in power semiconductor devices are found to be the most promising. Hardware efficiencies from 95 percent for single phase to 98 percent for three-phase applications are found.

Key, T. S.↗

High-Performance Power-Semiconductor Packages

A 600-V, 50-A transistor and 1,200-V, 50-A diode in rugged, compact, lightweight packages intended for use in inverter-type power supplies having switching frequencies up to 20 kHz. Packages provide low-inductance connections, low loss, electrical isolation, and long-life hermetic seal. Low inductance achieved by making all electrical connections to each package on same plane. Also reduces high-frequency losses by reducing coupling into inherent shorted turns in packaging material around conductor axes. Stranded internal power conductors aid conduction at high frequencies, where skin effect predominates. Design of packages solves historical problem of separation of electrical interface from thermal interface of high-power semiconductor device.

Renz, David↗

IEEE P2988: Recommended Practice of Use and Functions of Virtual Synchronous Machines

Power systems are going through a paradigm shift from centralized generation to distributed generation. This brings unprecedented challenges to power systems stability, reliability, and security. Operating power electronic converters as Virtual Synchronous Machines (VSMs) can bring backward compatibility to power systems, unify and harmonize the integration and interaction of future power systems players, and improve power system stability, reliability, and security. This is vital for the large-scale adoption of distributed energy resources, the advancement of sustainability, and the development of a low-carbon economy. This IEEE 2988 Recommended Practice will define the fundamental principles, mandatory functions, and optional functions of a VSM, i.e., a power electronic converter that is operated to behave like conventional synchronous machines. It will not describe or specify power semiconductor devices, hardware topologies, or micro-controllers that are used to build a VSM. This talk will discuss the activities and development plan for IEEE 2988 with the aim to engaging broad stakeholders and widening participation.

Zhong, Qing-Chang↗

Record-Low Thermal Boundary Resistance between Diamond and GaN-on-SiC for Enabling Radiofrequency Device Cooling

The implementation of 5G-and-beyond networks requires faster, high-performance, and power-efficient semiconductor devices, which are only possible with materials that can support higher frequencies. Gallium nitride (GaN) power amplifiers are essential for 5G-and-beyond technologies since they provide the desired combination of high frequency and high power. These applications along with terrestrial hub and backhaul communications at high power output can present severe heat removal challenges. The cooling of GaN devices with diamond as the heat spreader has gained significant momentum since device self-heating limits GaN’s performance. However, one of the significant challenges in integrating polycrystalline diamond on GaN devices is maintaining the device performance while achieving a low diamond/GaN channel thermal boundary resistance. In this study, we achieved a record-low thermal boundary resistance of around 3.1 ± 0.7 m 2 K/GW at the diamond/Si 3 N 4 /GaN interface, which is the closest to theoretical prediction to date. The diamond was integrated within ~1 nm of the GaN channel layer without degrading the channel’s electrical behavior. Furthermore, we successfully minimized the residual stress in the diamond layer, enabling more isotropic polycrystalline diamond growth on GaN with thicknesses >2 μm and a ~1.9 μm lateral grain size. More isotropic grains can spread the heat in both vertical and lateral directions efficiently. Using transient thermoreflectance, the thermal conductivity of the grains was measured to be 638 ± 48 W/m K, which when combined with the record-low thermal boundary resistance makes it a leading-edge achievement.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Power Switching Device

The MOS-Controlled Thyristor is a new type of power switching device for faster and more efficient control and management of power electronics. It enables power electronic switching at frequencies of 50 to 100 thousand times a second with much lower power losses than other semiconductor devices. Advantages include electric power savings and smaller space. The device is used in motor and power controllers, AC & DC motor drives and induction heating. Early development was supported by Lewis Research Center (LEW) and other agencies. General Electric''s power semiconductor operation, the initial NASA contractor, was later purchased by Harris Semiconductor.

Source record↗

Wide-Bandgap Semiconductor Amplifiers for Fusion Plasma Heating and Control

This paper discusses power electronics developed under the ARPA-E GAMOW program to support nuclear fusion power production. The goal of this project was to develop and assess the potential for wide-bandgap (WBG) semiconductor devices in power electronics to enable high-efficiency and high-voltage solid-state systems for fusion plasma generation, heating, and control. The power electronics use an architecture in which multiple high-power boards can be combined to produce megawatt-level power, where using multiple boards provides high reliability. Two main areas of power electronics boards are developed in this project for fusion plasma heating and control applications: (1) pulse generation and control and (2) radiofrequency generation. The first area is for boards capable of driving high-voltage millisecond pulses at high duty cycles. The envisioned application of these pulses is in plasma control of magnetohydrodynamic instabilities, plasma position, and edge-localized modes. Pulse-width modulation allows for the implementation of a wide variety of linear and nonlinear control systems. The boards developed for this project could actuate control coils based on digital input signals and can be parallelized to provide megawatts of output power. The design of the pulse generator is a low-side load switch. A load switch was designed and constructed that utilized 2-kV-rated field-effect transistor (FET)-based cascodes developed by Qorvo under this project to perform initial testing of these cascodes. The second area is being implemented using class E amplifiers with WBG devices and a reactance steering network to handle inductive or capacitive plasma loads. Applications include ion cyclotron resonance heating (ICRH) and high-harmonic fast-wave (HHFW) heating. A class E reactance steering network is demonstrated in modeling and experiment with a resistive-inductive load that models an inductively-coupled plasma. Power combining of boards with class E reactance steering networks is also simulated and demonstrated experimentally, to enable scaling up to high power. Modeling of high-power-density cooling and remaining useful life is conducted to enable reliable, effectively cooled high-power electronics for fusion applications.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Development of Electronics for Low Temperature Space Missions

The operation of electronic systems at cryogenic temperatures is anticipated for many future NASA space missions such as deep space probes and planetary surface exploration. For example, an unheated interplanetary probe launched to explore the rings of Saturn would reach an average temperature near Saturn of about -183 C. In addition to surviving the deep space harsh environment, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing payload development and launch costs. Terrestrial applications where components and systems must operate in low temperature environments include cryogenic instrumentation, superconducting magnetic energy storage, magnetic levitation transportation system, and arctic exploration. An on-going research and development program on low temperature electronics at the NASA Glenn Research Center focuses on the development of efficient power systems capable of surviving and exploiting the advantages of low temperature environments. Inhouse efforts include the design, fabrication, and characterization of low temperature power systems and the development of supporting technologies for low temperature operations, such as dielectric and insulating materials, semiconductor devices, passive power components, opto-electronic devices, as well as packaging and integration of the developed components into prototype flight hardware.

Patterson, Richard L.↗