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DOE OSTI2022

Quantum Krylov subspace algorithms for ground- and excited-state energy estimation

Quantum Krylov subspace diagonalization (QKSD) algorithms provide a low-cost alternative to the conventional quantum phase estimation algorithm for estimating the ground- and excited-state energies of a quantum many-body system. While QKSD algorithms typically rely on using the Hadamard test for estimating Krylov subspace matrix elements of the form $\langle \phi_i|e^{-\widehat{H}τ}|\phi_j\rangle$, the associated quantum circuits require an ancilla qubit with controlled multiqubit gates that can be quite costly for near-term quantum hardware. In this paper, we show that a wide class of Hamiltonians relevant to condensed-matter physics and quantum chemistry contain symmetries that can be exploited to avoid the use of the Hadamard test. We propose a multifidelity estimation protocol that can be used to compute such quantities, showing that our approach, when combined with efficient single-fidelity estimation protocols, provides a substantial reduction in circuit depth. In addition, here we develop a unified theory of quantum Krylov subspace algorithms and present three quantum-classical algorithms for the ground- and excited-state energy estimation problems, where each algorithm provides various advantages and disadvantages in terms of total number of calls to the quantum computer, gate depth, classical complexity, and stability of the generalized eigenvalue problem within the Krylov subspace.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2015

Development and Testing of Prototype Commercial Gasifier Sensor

This report presents the results of the sensor development and testing at the Wabash River gasifier. The project work was initiated with modification of the sensor software (Task 2) to enable real time temperature data acquisition, and to process and provide the obtained gasifier temperature information to the gasifier operators. The software modifications were conducted by the North Carolina State University (NCSU) researchers. The modified software was tested at the Gas Technology Institute (GTI) combustion laboratory to assess the temperature recognition algorithm accuracy and repeatability. Task 3 was focused on the sensor hardware modifications needed to improve reliability of the sensor system. NCSU conducted numerical modeling of the sensor probe’s purging flow. Based on the modeling results the probe purging system was redesigned to prevent carbon particulates deposition on the probe’s sapphire window. The modified design was evaluated and approved by the Wabash representative. The modified gasifier sensor was built and installed at the Wabash River gasifier on May 1 2014. (Task 4) The sensor was tested from the startup of the gasifier on May 5, 2015 until the planned autumn gasifier outage starting in the beginning of October, 2015. (Task 5) The project team successfully demonstrated the Gasifier Sensor system’s ability to monitor gasifier temperature while maintaining unobstructed optical access for six months without any maintenance. The sensor examination upon completion of the trial revealed that the system did not sustain any damage.

47 OTHER INSTRUMENTATION↗

DOE OSTI2020

Deep Learning for Automated Identification of Eels in Sonar Data

Freshwater eels, such as the American eel (Anguilla rostrata) present numerous challenges related to safe downstream fish passage at hydroelectric facilities. One of those challenges is effective monitoring of their abundance, movements, and behavior to facilitate design and operation of eel protection and passage facilities. A previous EPRI study documented the ability of human analysts to reliably identify American eels in data obtained with a 1100/1800 kHz, multibeam sonar. This report describes a project to develop deep learning (a subset of artificial intelligence) tools to automate the time-consuming, subjective process of eel identification in multibeam sonar data. The project exploited new data collected in the laboratory and the existing data from the prior EPRI field study to develop and test deep learning and other data analytic tools, including wavelet filtering, differencing for static object removal, and convolutional neural network analysis. The analysis of the laboratory data demonstrated feasibility of the approach, revealed object characteristics observed with the sonar that distinguish eels from similarly sized and shaped acoustic targets, and provided additional data for algorithm selection and training. Deep learning algorithms trained and tested on the laboratory data alone achieved accuracy rates of greater than 98% when classifying acoustic images of eels and similar-sized neutrally buoyant sticks. The algorithm trained and tested on the pre-existing field data alone, and yielded classification accuracy of 9.3% false positives and 13.3% false negatives when distinguishing between eels and sticks/PVC pipes based on video clips (i.e., multiple, consecutive images). This performance is comparable to the classification accuracy achieved by human analysts in the prior study. The deep learning algorithm trained on a combination of video clips obtained in the laboratory and the field and tested on video clips from the field, was able to distinguish eels from sticks and PVC pipes (a river debris analog) of similar size with 100% accuracy. Outreach to the hardware, software, and end-user communities early in the project helped to identify needs and specify the application space. Outreach to those communities at the end of the project communicated project results and opportunities for further development. The project achieved proof of concept for automated identification of eel in multibeam sonar data. Future work should focus on acquisition of additional data for more robust algorithm training and testing; modification of the software tools to accommodate multiple acoustic targets in the acoustic field at a given time; identification of additional object classes; incorporation of motion in the object identification and classification algorithms; operationalizing the software tools, including integration with other existing sonar data analysis tools; and partnering with hardware and software providers for distribution of the software tools with their commercial products.

13 HYDRO ENERGY↗

DOE OSTI2026

Captan+X Data Converter Integration

Fermi National Accelerator Laboratory's CAPTAN (Compact And Programmable daTa Acquisition Node) series provides a flexible hardware platform for data acquisition across a range of experiments and facilities. The latest iteration, CAPTAN+X, is built around a Kintex-7 FPGA supporting four FPGA Mezzanine Card (FMC) connections. As part of a broader laboratory effort to bring facility systems under a Model-Based Systems Engineering (MBSE) framework, CAPTAN+X is one of several systems slated to be incorporated into this modeling environment in the near term. A necessary step toward that goal is incorporating the platform's core functionality, which centers on integration with the LXD31K4 FMC, a data converter module combining dual AD9652 analog-to-digital converters and dual AD9142A digital-to-analog converters. Achieving compatibility required resolving pin-mapping conflicts between the LXD31K4's High Pin Count connector and the CAPTAN+X's available pin types, adapting a Board Support Project originally written for an UltraScale-class evaluation board to the Kintex-7 architecture, replacing incompatible primitives, restructuring clock distribution, and manually configuring chip initialization in place of an unsupported soft-processor-based approach. Functional verification of the ADC and DAC channels, followed by closed-loop testing combining both converters with real-time filtering, confirmed correct operation of the integrated system. These results establish a working hardware and firmware baseline for the CAPTAN+X platform, positioning it for future inclusion in the laboratory's growing MBSE modeling effort.

Espinoza, David [Illinois U., Urbana (main)]↗

DOE OSTI2026

CAPTAN+X Data Converter Integration

Espinoza, David [Illinois U., Urbana (main)]↗

DOE OSTI2025

A compact low-level RF control system for advanced concept compact electron linear accelerator

A compact low-level RF (LLRF) control system based on RF system-on-chip (RFSoC) technology has been designed for the Advanced Concept Compact Electron Linear-accelerator (ACCEL) program, which has challenging requirements in both RF performance and size, weight, and power consumption (SWaP). The compact LLRF solution employs the direct RF sampling technique of RFSoC, which samples the RF signals directly without any analog upconversion and downconversion. Compared with the conventional heterodyne based architecture used for the LLRF system of a linear accelerator (LINAC), the elimination of analog mixers can significantly reduce the size and weight of the system, especially with LINAC requiring a larger number of RF channels. Based on the requirements of ACCEL, a prototype LLRF platform has been developed, and the control schemes have been proposed. The prototype LLRF system demonstrated magnitude and phase fluctuation levels below 1% and 1° on the flattop of a 2 μs RF pulse. The LLRF control schemes proposed for ACCEL are implemented with a prototype hardware platform. In conclusion, this paper will introduce the new compact LLRF solution and summarize a selection of experimental test results of the prototype itself and with the accelerating structure cavities designed for ACCEL.

Liu, C. [SLAC National Accelerator Laboratory (SLA↗

DOE OSTI2020

Face Recognition Oak Ridge (FaRO): A Framework for Distributed and Scalable Biometrics Applications

The facial biometrics community has seen a recent abundance of high-accuracy facial analytic models become freely available. Although these models' capabilities in facial detection, landmark detection, attribute analysis, and recognition are ever-increasing, they aren't always straightforward to deploy in a real-world environment. In reality, the use of the field's ever growing collection of models is becoming exceedingly difficult as library dependencies update and deprecate. Researchers often encounter headaches when attempting to utilize multiple models requiring different or conflicting software packages. Face Recognition Oak Ridge (FaRO) is an open-source project designed to provide a highly modular, flexible framework for unifying facial analytic models through a compartmentalized plug-and-play paradigm built on top of the gRPC (Google Remote Procedure Call) protocol. FaRO's server-client architecture and flexible portability allows easy construction of modularized and heterogeneous face analysis pipelines, distributed over many machines with differing hardware and software resources. This paper outlines FaRO's architecture and current capabilities, along with some experiments in model testing and distributed scaling through FaRO.

Bolme, David↗

DOE OSTI2024

PHIL Interface Design for Use With a Voltage-Regulated Amplifier

Power hardware-in-the-loop (PHIL) has emerged as a leading strategy to thoroughly assess the impact of proprietary inverter controls on a specific power system. The development of a PHIL test bed typically involves an inverter under test, a power amplifier, controllable DC supply, and a digital real-time simulator (DRTS) to simulate the power system under study. As a result of PHIL nonidealities, a form of digital compensation within the DRTS is used, which is commonly referred to as a PHIL interface. Many existing methods use legacy power amplifiers that do not contain internal voltage regulation. These existing interface methods are based around a voltage regulator within the DRTS and do not consider the interaction with the controls in newer amplifiers. In this study, a three-step approach of PHIL interface development for modern power amplifiers with built-in voltage regulation is introduced and is validated in hardware with a 30-kW grid-following inverter.

DRTS↗

DOE OSTI2019

Battery Model Parameterization Using Manufacturer Datasheet and Field Measurement for Real-Time HIL Applications

Here, this paper presents a novel battery model parameterization method using actual field measurement and manufacturer datasheet for real-time hardware-in-the-loop (HIL) applications. It is critical that real-time HIL models can accurately reproduce field test results so that tests can be conducted on HIL testbeds instead of in the field. In the past, numerical heuristic optimization algorithms were often used to derive parameters for battery models. However, the deterministic algorithms often reach a locally optimal solution and stochastic heuristic searching strategies suffer from low searching efficiency. Therefore, in this paper, we propose a global-local searching enhanced genetic algorithm (GL-SEGA). By applying the generalized opposition-based learning mechanism, GL-SEGA can efficiently explore the global solution space. By using the trust-region-reflective method to perform the local search, the GL-SEGA can improve the accuracy and convergence in its local exploitations. Field measurements and manufactory datasheets are used to test and validate the accuracy and robustness of the GL-SEGA algorithm.

25 ENERGY STORAGE↗

DOE OSTI2014

Impedance Measurement Box

The IMB 50V software provides functionality for design of impedance measurement tests or sequences of tests, execution of these tests or sequences, processing measured responses and displaying and saving of the results. The software consists of a Graphical User Interface that allows configuration of measurement parameters and test sequencing, a core engine that controls test sequencing, execution of measurements, processing and storage of results and a hardware/software data acquisition interface with the IMB hardware system.

Morrison, William↗

DOE OSTI2017

Experimental Pressure Measurements on Hydropower Turbine Runners

The range of hydrodynamic operating conditions to which the turbine is exposed results in significant pressure fluctuations on both the pressure and suction sides of the blades. Understanding these dynamic pressures has a range of applications. Structurally, the resulting dynamic loads are significant in understanding the design life and maintenance schedule of the bearing, shafts and runner components. The pulsing pressures have also been seen to have a detrimental effect on the surface condition of the blades. Biologically, the pressure gradients and pressure extremes are the primary driver of barotrauma for fish passing through hydroturbines. Improvements in computational fluid dynamics (CFD) can be used to simulate such unsteady pressures in the regions of concern. High frequency model scale and prototype measurements of pressures at the blade are important in the validation of these models. Experimental characterization of pressure fields over hydroturbine blades has been demonstrated by a number of studies which using multiple pressure transducers to map the pressure contours on the runner blades. These have been performed at both model and prototype scales, often to validate computational models of the pressure and flow fields over the blades. This report provides a review of existing studies in which the blade pressure was measured in situ. The report assesses the technology for both model and prototype scale testing. The details of the primary studies in this field are reported and used to inform the types of hardware required for similar experiments based on the Ice Harbor Dam owned by the US Corps of Engineers on the Snake River, WA, USA. Such a study would be used to validate the CFD performed for the BioPA.

13 HYDRO ENERGY↗

DOE OSTI2022

8-Plate Multi-Resonant Coupling Using a Class-E 2 Power Converter for Misalignments in Capacitive Wireless Power Transfer

Misalignment is a common issue in wireless power transfer systems. It shifts the resonant frequency away from the operating frequency that affects the power flow and efficiency from the charging station to the load. This work proposes a novel capacitive wireless power transfer (CPT) using an 8-plate multi-resonant capacitive coupling to minimize the effect of misalignments. A single-active switch class-E 2 power converter is utilized to achieve multi-resonance through the selection of different resonant inductors. Simulations show a widening of the resonant frequency band which offers better performance than a regular 4-plate capacitive coupling for misalignments. The hardware results of the 8-plate multi-resonant coupling show an efficiency of 88.5% for the 20.8 W test, which is 18.3% higher than that of the regular 4-plate coupling. Because of the wider resonant frequency band {455–485 kHz}, compared with the regular 4-plate coupling, the proposed design minimized the output voltage drop by 15% for a 10% misalignment. Even for large misalignments, the 8-plate performance improved by 40% compared with the 4-plate coupling.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2018

An Experimental Investigation of Fuel Staging In A Model Gas Turbine Combustor

Modern gas turbine engines are typically operated in a lean-premixed configuration in order to meet emissions requirements. Lean operation makes gas turbines more susceptible to combustion instability, which can cause catastrophic hardware failure if left unchecked. The spatially uneven distribution of fuel in a gas turbine combustor, known as fuel staging, is an effective way of suppressing instabilities. This dissertation examines the effect of both steady-state and transient fuel-staging in a model gas turbine combustor. First, the steady-state effect of fuel staging on nominally unstable operating conditions is examined. At 200 degrees Celsius and a bulk flow velocity of 26 m/s, the combustor undergoes self-excited instabilities when the equivalence ratio is between φ = 0.70 and φ = 0.74 when all nozzles are fueled equally. These instabilities are suppressed when the center nozzle equivalence ratio is increased to φ Staging = 0.85 and the outer nozzle equivalence ratio maintained at φ = 0.70 or when the global equivalence ratio is maintained at φ = 0.70 by increasing the center nozzle equivalence ratio to φ Staging = 0.74 and decreasing the outer nozzle equivalence ratio to φ Staging = 0.69. The staged p' RMS amplitudes are found to decrease with increasing equivalence ratio and the damping rates found to increase with increasing equivalence ratio. Next, axisymmetric fuel staging transients are conducted valve opening/closing timescales of 1, 16, 58, 4,000, and 10,000 ms, and equivalence ratios of φ staging = 0.75, 0.80, 0.85. It should be noted that these valve opening/closing timescales, referred to as τ Transient , differ from the actual fuel convection timescale that are summarized in Table 5.2. It is found that the combustor pressure fluctuation at the end of the transient strongly depends on staging equivalence ratio but not on τ Transient . Increasing the staging equivalence ratio decreased the staged- stable combustor pressure amplitude, similarly to the steady-state results. The staged-stable damping rate trends are insensitive to to τ Transient and increased with increasing staging equivalence ratio. The timescale of the transition, τ, is found to be sensitive to both τ Transient and the staging equivalence ratio. For a Modern gas turbine engines are typically operated in a lean-premixed configuration in order to meet emissions requirements. Lean operation makes gas turbines more susceptible to combustion instability, which can cause catastrophic hardware failure if left unchecked. The spatially uneven distribution of fuel in a gas turbine combustor, known as fuel staging, is an effective way of suppressing instabilities. This dissertation examines the effect of both steady-state and transient fuel-staging in a model gas turbine combustor. First, the steady-state effect of fuel staging on nominally unstable operating conditions is examined. At 200 degrees Celsius and a bulk flow velocity of 26 m/s, the combustor undergoes self-excited instabilities when the equivalence ratio is between φ = 0.70 and φ = 0.74 when all nozzles are fueled equally. These instabilities are suppressed when the center nozzle equivalence ratio is increased to φ Staging = 0.85 and the outer nozzle equivalence ratio maintained at φ = 0.70 or when the global equivalence ratio is maintained at φ = 0.70 by increasing the center nozzle equivalence ratio to φ Staging = 0.74 and decreasing the outer nozzle equivalence ratio to φ Staging = 0.69. The staged p' RMS amplitudes are found to decrease with increasing equivalence ratio and the damping rates found to increase with increasing equivalence ratio. Next, axisymmetric fuel staging transients are conducted valve opening/closing timescales of 1, 16, 58, 4,000, and 10,000 ms, and equivalence ratios of φ staging = 0.75, 0.80, 0.85. It should be noted that these valve opening/closing timescales, referred to as τ Transient , differ from the actual fuel convection timescale that are summarized in Table 5.2. It is found that the combustor pressure fluctuation at the end of the transient strongly depends on staging equivalence ratio but not on τ Transient . Increasing the staging equivalence ratio decreased the staged-stable combustor pressure amplitude, similarly to the steady-state results. The staged-stable damping rate trends are insensitive to to τ Transient and increased with increasing staging equivalence ratio. The timescale of the transition, τ, is found to be sensitive to both τ Transient and the staging equivalence ratio. For a Modern gas turbine engines are typically operated in a lean-premixed configuration in order to meet emissions requirements. Lean operation makes gas turbines more susceptible to combustion instability, which can cause catastrophic hardware failure if left unchecked. The spatially uneven distribution of fuel in a gas turbine combustor, known as fuel staging, is an effective way of suppressing instabilities. This dissertation examines the effect of both steady-state and transient fuel-staging in a model gas turbine combustor. First, the steady-state effect of fuel staging on nominally unstable operating conditions is examined. At 200 degrees Celsius and a bulk flow velocity of 26 m/s, the combustor undergoes self-excited instabilities when the equivalence ratio is between φ = 0.70 and φ = 0.74 when all nozzles are fueled equally. These instabilities are suppressed when the center nozzle equivalence ratio is increased to φ Staging = 0.85 and the outer nozzle equivalence ratio maintained at φ = 0.70 or when the global equivalence ratio is maintained at φ = 0.70 by increasing the center nozzle equivalence ratio to φ Staging = 0.74 and decreasing the outer nozzle equivalence ratio to φ Staging = 0.69. The staged p' RMS amplitudes are found to decrease with increasing equivalence ratio and the damping rates found to increase with increasing equivalence ratio. Next, axisymmetric fuel staging transients are conducted valve opening/closing timescales of 1, 16, 58, 4,000, and 10,000 ms, and equivalence ratios of φ staging = 0.75, 0.80, 0.85. It should be noted that these valve opening/closing timescales, referred to as τ Transient , differ from the actual fuel convection timescale that are summarized in Table 5.2. It is found that the combustor pressure fluctuation at the end of the transient strongly depends on staging equivalence ratio but not on τ Transient . Increasing the staging equivalence ratio decreased the staged- stable combustor pressure amplitude, similarly to the steady-state results. The staged-stable damping rate trends are insensitive to to τT Transient and increased with increasing staging equivalence ratio. The timescale of the transition, τ, is found to be sensitive to both τ Transient and the staging equivalence ratio. For a given τ Transient , the decay timescale decreased with increasing staging equivalence ratio. For 1, 16, and 58 ms transients, τ does not depend on τ Transient , though it does strongly depend on direction, where instability onset cases have longer and more variable τ than instability decay cases. The same dependence of τ on direction is seen for the 4,000 and 10,000 ms transients. However, unlike the short duration transients, τ does depend on τ Transient as would be expected. Phase space reconstruction shows the instability is a harmonic limit cycle with a single frequency. The instantaneous phase images shows the center region of the combustor goes out-of-phase first followed by the rest of the combustor. Finally, asymmetric fuel staging tests are conducted. It is found that non-axisymmetric staging can be as effective as axisymmetric staging, although small hardware variations between nozzles can affect the the minimum staging equivalence ratio that consistently suppresses the instability. These changes in the bifurcation equivalence ratio can make staging configurations appear less effective; however, both axisymmetric and non-axisymmetric staging configurations exhibit similar staged-stable p' RMS , damping rates, and instability transition times for equivalence ratios greater than the bifurcation equivalence ratio. Instantaneous phase images show similar instantaneous phase relationship structures in the staged nozzle (center or outer), suggesting that the instability suppression mechanism is similar in each case. This result is surprising given that the time-averaged flame shapes are very different between axisymmetric and non-axisymmetric staging configurations. The similar effectiveness of axisymmetric and non-axisymmetric staging in this geometry is attributed to the fact that the instability mode is a nominally axisymmetric plane wave. It is hypothesized that non-axisymmetric staging configurations will likely be more effective than axisymmetric staging configurations when the instability mode shape is asymmetric (such as a circumferential wave).

Culler, Wyatt↗

DOE OSTI2022

Final Scientific/Technical Report-FREE-piston Zero Emissions Refrigerator (FREEZER)

The FREE-piston Zero Emissions Refrigerator (FREEZER™) is a natural refrigerant Stirling-cycle cooler developed by AMSC in partnership with Heatcraft, targeted as a replacement refrigeration system for walk-in coolers or freezers found commonly in restaurants, convenience stores, supermarkets, etc. The FREEZER™, combined with a closed-loop CO2 heat-transfer system, had the goal to provides an efficient (Target COP = 1.4), zero ODP (Ozone Depletion Potential) and near zero GWP (Global Warming Potential) refrigeration solution with no synthetic, flammable, or toxic refrigerants. Other near zero GWP refrigeration systems do not exist at the scale and performance level of FREEZER. ARPA-E Continuation Funding enabled the design and fabrication of one Advanced Development Unit (ADU) cooler and two Field Test Unit (FTU) coolers, and a new revised Field Test Unit (new FTU). Heatcraft was to extensively test the various coolers at their facilities, which closely simulate real-world conditions. The original plan was to install and operate FREEZER FTUs alongside a traditional cooling solution at one or more customer locations to obtain data on direct performance comparisons with existing commercial refrigeration systems. Success in this FREEZER refinement and field-test project will establish the basis for a new class of environmentally friendly refrigeration systems that will revolutionize the industry. The hardware developed under the program is shown below in Figure 1. Five Stirling-cycle machines were built within the program, with a sixth cooler still under construction. The original DU and the ADU coolers met the performance target with a coefficient of performance (COP) of 1.2. The FTU was underperforming during the initial tuning of the free-piston Stirling cycle dynamics when there was a catastrophic failure of the fasteners on pressure boundary. This caused a pause to the program while the failure mechanism was investigated. The root cause was an inadequate flange design that allowed an excessive cyclic loading on the fasteners, leading to a fatigue failure. It was determined that existing FTU design could not be reasonably salvaged in a safe manner, and that fact, combined with the lower-than-expected performance of the new experimental heat exchanger modules lead to the design of the “new FTU” with a more conventional shell-and-tube heat exchanger design which should get close to the design target COP of 1.4, but have a higher overall machine cost. The program ran out of time before the fabrication of the new FTU was completed, but AMSC is still working on the cooler, with the majority of the parts fabricated, and hopes to have the unit under test sometime in early 2022, after which it will be shipped to Heatcraft for additional testing.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2019

Wave tank and bench-top control testing of a wave energy converter

An increasing number of experiments are being conducted to study the design and performance of wave energy converters. Often in these tests, a real-time realization of prospective control algorithms is applied in order to assess and optimize energy absorption as well as other factors. This paper details the design and execution of an experiment for evaluating the capability of a model-scale WEC to execute basic control algorithms. Model-scale hardware, system, and experimental design are considered, with a focus on providing an experimental setup capable of meeting the dynamic requirements of a control system. To more efficiently execute such tests, a dry bench testing method is proposed and utilized to allow for controller tuning and to give an initial assessment of controller performance; this is followed by wave tank testing. The trends from the dry bench test and wave tank test results show good agreement with theory and confirm the ability of a relatively simple feedback controller to substantially improve energy absorption. Additionally, the dry bench testing approach is shown to be an effective and efficient means of designing and testing both controllers and actuator systems for wave energy converters.

16 TIDAL AND WAVE POWER↗

DOE OSTI2016

X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility

Our team has developed an experimental platform to evaluate the x-ray-generated stress and impulse in materials. Experimental activities include x-ray source development, design of the sample mounting hardware and sensors interfaced to the National Ignition Facility’s diagnostics insertion system, and system integration into the facility. This paper focuses on the X-ray Transport and Radiation Response Assessment (XTRRA) test cassettes built for these experiments. The test cassette is designed to position six samples at three predetermined distances from the source, each known to within ±1% accuracy. Built-in calorimeters give in situ measurements of the x-ray environment along the sample lines of sight. The measured accuracy of sample responses as well as planned modifications to the XTRRA cassette is discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2019

Bond Wire Damage Detection and State of Health Estimation of a 1200V, 900A Dual Pack IGBT Power Module using the RL-Equivalent Circuit

Electrical and environmental stresses are the two dominant contributors in aging and failure of power semiconductor devices. Insulated gate bipolar junction transistors (IGBTs) and metal-oxide semiconductor field effect transistors (MOSFETs) are two most commonly used switching devices in power converter circuits. A significant portion of research effort is given in inventing innovative methods to estimate the degradation and fatigue in these devices. Until today, no other existing techniques can determine the number of lifted bond wires and their locations in a live IGBT module, although this information is extremely helpful to understand the overall state of health of an IGBT power module. In this paper, we have proposed a reflectometry-based technique to overcome this hurdle. The RL-equivalent circuit to represent a bond wire has been developed for the device under test and simulated in CST Studio Suite to measure the reflection amplitudes. Experimental results were obtained using a prototype reflectometry hardware, and both the simulation and experimental results have been compared. These results prove that with these two sets of measurements, it is possible to locate the aged device inside a module and detect the number of bond wire lift-offs associated to that device.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2019

A Simple Control to Reduce Device Over-Voltage Caused by Non-Active Switch Loop in Three-Level ANPC Converters

With the development of wide band-gap (WBG) technology, the switching speed of power semiconductor devices increases, which makes circuits more sensitive to parasitics. For three-level active neutral point clamped (3L-ANPC) converters, the over-voltage caused by additional non-active switch loop can be an issue. This paper analyzes the multiple commutation loops in 3L-ANPC converter and summarizes the impact factors of the device over-voltage. The nonlinearity of the output capacitance of the device can significantly influence the over-voltage. A simple control without introducing additional hardware circuit or complex software algorithm is proposed to attenuate the effect of the nonlinear output capacitance. Multi-pulse test is conducted for a 3L-ANPC converter built with silicon carbide (SiC) MOSFETs. With the proposed control, the testing results show that the peak drain-source voltage of both active and non-active switches is reduced by more than 20% compared to the conventional control.

Gui, Handong↗