Large-scale renewable power supply system design for remote hydrogen production is a challenging task due to the 100% power electronics sending-end subsystem. The proper grid-forming strategy for a sending-end system to achieve large-scale remote hydrogen production still remains a research gap. This study first designs two grid-forming strategies for the concerned renewable power supply system, with one being based on virtual synchronous generator (VSG) and another one being based on V/f control. Then, the impedance analysis is carried out for ensuring the small-signal stable operation of the sending-end system including wind power plant and PV plant. Numerical simulation results implemented on PSCAD verify that the VSG-based grid-forming strategy configured on the sending-end modular multilevel converter (MMC) station of the MMC-based high-voltage direct-current (HVDC) link has a larger transient stability margin. Hence, the MMC-HVDC-based grid-forming strategy is a better choice for the power supply of large-scale remote hydrogen production. The enhanced stability margin ensures more robust operation under disturbances, which is critical for maintaining continuous power supply to large-scale electrolyzers.

Wireless Electric Vehicle Charging (WEVC) systems have become a game-changing remedy aimed at enhancing the convenience, safety, and efficiency of electric vehicle (EV) charging. Unlike traditional plug-in systems, with WEVC, physical connectors are no longer necessary by utilizing wireless energy transfer technologies, such as resonant electromagnetic techniques, capacitive coupling, and inductive coupling. These technologies enable seamless power delivery from charging pads to onboard vehicle receivers, allowing EVs to be charged either in stationary or dynamic conditions without manual intervention. This review provides a comprehensive examination of recent advancements in WEVC systems, focusing on improvements in energy efficiency, power transfer capabilities, and adaptability with existing transportation infrastructure. Key innovations in coil design, alignment mechanisms, and power electronics have significantly improved the reliability and performance of these systems. Despite these advancements, several technical and economic challenges persist, including misalignment losses, electromagnetic interference, high implementation costs, and limitations in standardization and interoperability. The review further discusses the regulatory and safety factors that need to be taken into account in order to guarantee the secure implementation of WEVC technology, especially in urban and high-traffic environments. Additionally, the integration of WEVC with smart grid systems and renewable energy sources holds great promise for enhancing grid resilience and enabling energy-efficient transportation networks. The synergy between wireless charging and intelligent traffic management could further promote the development of sustainable, connected, and automated mobility solutions. By evaluating the current state of research and deployment, this review emphasizes the transformative potential of WEVC in supporting environmentally friendly transportation and contributing to the development of smart cities. Future research directions are proposed to overcome existing limitations and accelerate the widespread adoption of this innovative technology.

Self-healing solder joints in power electronics: Experimental validation of die-attach void effects on reliability

Rational design of high-performance dual-channel-layered InAlZnO thin-film transistors for low power and transparent electronics

Enhanced hydrogen sulfide corrosion resistance of large-area sintered nano-copper for power electronics module using atmospheric pressure plasma jet treatment

A review of recent AI applications in next-generation power electronics

Low-temperature sinterable silver paste for die-attachment of wide band gap power electronics

Electrostatic dielectric capacitors with high power density are the fundamental energy storage components in advanced electronic and electric power systems. However, simultaneously achieving ultrahigh energy density and efficiency poses a persistent challenge, preventing the capacitive applications towards miniaturization and low-energy consumption. Here we demonstrate giant energy storage properties in lead-free antiferroelectrics by designing hierarchical heterostructures to optimize polarization evolution paths. Through the design of antiferroelectric nanoclusters featuring interlocked polarization structure and fishbone polarization configuration, alongside order-disorder oxygen octahedral tilts, we increase polarization fluctuation and delay polarization saturation with nearly eliminated hysteresis under ultrahigh external electric fields. Leveraging this strategy, we achieve an ultrahigh energy density of 21.0 J cm-3 with an impressive efficiency of 90% in sodium niobate-based ceramics, underscoring the great potential of this methodology for designing high-performance dielectrics and other functional materials.

The fast-growing integration of renewable energy sources into the utility grids jeopardizes the system’s performance and stability at risk. Particularly, the increasing tendency of power electronics converters in the current renewables-based power generation and their integration to utility grids through long sub-sea cables compromises the grid strength and amplifies the risk of system instability during disturbances. To sustain grid stability and ensure effective regulation during transients, grid-following (GFL) and grid-forming (GFM) control approaches have been extensively proposed for power systems with inverter-based resources (IBRs). The former approach is solely based on a phase-locked loop (PLL) to track the phase angle of grid voltage, which reduces the system stability margin, particularly in weak-grid scenarios. Consequently, grid-forming control is increasingly recognized for its ability to maintain stability and ensure reliable operation under weak-grid conditions. Droop control is one of the most widely used grid-forming control strategies owing to its capability to emulate the behavior of synchronous machines, achieve autonomous power sharing, and ensure stable voltage and frequency regulation even under varying grid conditions. This paper aims to evaluate the impact of grid impedance and its characteristics (i.e., resistive or inductive grid impedance) on the dynamic performance of a droop control GFM grid-connected converter. To that end, first, a detailed MATLAB/Simulink model of a voltage source converter implementing the proposed droop-based GFM control is developed. Then, the overall system will be validated by performing on distinct case studies including weak and stiff power grids with inductive, resistive and nonlinear impedances in response to various grid disturbances.

Silicon carbide (SiC) has been widely adopted in the semiconductor industry, particularly in power electronics, because of its high temperature stability, high breakdown field, and fast switching speeds. Its wide bandgap makes it an interesting candidate for radiation-hard particle detectors in high-energy physics and medical applications. Furthermore, the high electron and hole drift velocities in 4H-SiC enable devices suitable for ultra-fast particle detection and timing applications. However, currently, the front-end readout electronics used for 4H-SiC detectors constitute a bottleneck in investigations of the charge carrier drift. To address these limitations, a high-frequency readout board with an intrinsic bandwidth of 10GHz was developed. With this readout, the transient current signals of a 4H-SiC diode with a diameter of 141m and a thickness of 50m upon UV laser, alpha particle, and high-energy proton beam excitation were recorded. In all three cases, the electron and hole drift can clearly be separated, which enables the extraction of the charge carrier drift velocities as a function of the electric field. These velocities, directly measured for the first time, provide a valuable comparison to Monte Carlo-simulated literature values and constitute an essential input for TCAD simulations. Finally, a complete simulation environment combining TCAD, the Allpix2 framework, and SPICE simulations is presented, which is in good agreement with the measured data.

ABSTRACT Isolated bidirectional resonant converters play a crucial role in the domain of power electronics, particularly in the context of rapid charging and discharging applications for electric vehicles (EVs). However, in many instances, the demand for rapid charging results in increased charging current and larger converter volume, thereby reducing the efficiency and power density of the converters. This paper presents a novel analysis and design methodology of a converter employing sensorless synchronous rectification and applies a multi‐segment linearization analysis method to resonant converters, which is simpler than time‐domain analysis and more accurate than first harmonic approximation (FHA). This analysis provides a theoretical foundation for the implementation of synchronous rectification. It employs a hybrid control strategy of phase angle and frequency to regulate the switching on inverter and rectifier sides, significantly enhancing converter efficiency and broadening the gain range. A matrix transformer configuration is utilized to optimize thermal performance and enhance power density. Based on the proposed theory, the design of a 30 kW 660–860 V input to 250–500 V with 75 A max output prototype is discussed. The design outcomes indicate that employing synchronous rectification and matrix transformer with 10 PQ3548 cores, the converter can achieve a high power density of 8 kW/L (131 W/in) and peak efficiency of 98.4.

Gallium nitride (GaN) offers significant advantages in power electronics due to its high electron mobility, high saturation drift velocity, and low relative permittivity, which enable faster switching speeds and lower conduction losses compared to silicon (Si). These properties position GaN as a strong contender against the traditional dominance of Si in the power electronics market, leading to the potential for smaller, lighter, and more efficient power systems. Currently, GaN is predominantly utilized in lateral, unipolar switching applications, particularly in high-electron mobility transistors (HEMTs). However, its implementation in vertical, bipolar switching devices has been limited due to two main challenges: the short minority carrier lifetime, typically around 1 ns, and the difficulty in achieving large-area devices with buried p-type material. Recent advances, such as minority carrier recombination lifetime control through quantum well-induced charge segregation and improved annealing techniques for buried p-type layers in oxygenated environments, have begun to address these challenges. As a result, the development of vertical GaN devices, including thyristors, insulated-gate bipolar transistors (IGBTs), and current-aperture vertical electron transistors (CAVETs), is becoming more feasible. These innovations could significantly expand the potential of GaN in power electronics to include high power pulsed applications as these challenges are overcome.In this work, we describe our efforts to address the challenges of bipolar device development in a III-nitride system. Specifically, the short minority carrier lifetime is being addressed through the use of the quantum-confined Stark effect (QCSE). We demonstrate the ability to “tune” the minority carrier lifetime based on the materials’ inherent polarization properties. Numerical simulations utilizing a Schrödinger-Poisson solver were conducted to predict carrier lifetimes in GaN quantum wells with varying widths, clad with Al.04Ga.96N barriers. These predict that the radiative lifetime increases up to three orders of magnitude in the GaN layers as a function of well width and the free carrier concentration. The maximum lifetime was found at a well width of approximately 30 nm, and the lifetime gradually approached the bulk lifetime value of 1 ns at larger well widths. To validate the simulation results, time-resolved photoluminescence (TRPL) measurements were performed on samples of varying well widths and excitation power densities. The TRPL experimental values agreed well with the numerical solution. The longest recorded carrier lifetime was approximately 500 ns for a 40 nm well width, demonstrating the significant potential of QCSE to extend carrier lifetimes in GaN.A parallel effort to address the challenge of activating buried p-type material has been underway. Due to H+ binding to the accepter dopant Mg- during metalorganic chemical vapor deposition (MOCVD) growth, the acceptor species is passivated and must be activated by diffusing out the H+. This happens due to three processes: dissociation, diffusion, and desorption. We report on recent advancements annealing in reactive ambients to achieve a higher rate of activation through desorption and thus more uniform and conductive buried p-GaN. This is demonstrated using an oxygen-rich diffusion tube containing N2:O2=4:1 at 800 °C for 30 minutes, resulting in a fully activated 100 µm-diameter buried pn junction. Additionally, fluorinated annealing ambients are being investigated. We have fabricated full thyristor structures with both p- and n-type drift regions. We will discuss the electrical characterization and a mixed-mode TCAD model that has been developed to inform the gate drive characteristics in the context of predicting performance. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy of the United States Government.

Various β-Ga2O3-based power devices have been widely investigated because β-Ga2O3 has a large bandgap of ~4.9 eV and high breakdown electric field of 8 MVcm-1 [1-3]. It is well understood to be important to reduce the number of electrical defects at the Ga2O3/dielectric interface for n-β-Ga2O3/dielectric/metal capacitor. However. it was unclear which process in the fabrication of β-Ga2O3 capacitors caused these electrical defects. For example, surface cleaning of the β-Ga2O3 substrate, an Al2O3 film deposition as a dielectric by the atomic layer deposition (ALD) method, and high-temperature annealing (HTA) are considered. On the other hand, for GaN power device, we reported that Ga2O3 interfacial layer was generally grown at GaN/SiO2 interface and affected to electrical properties. And we recently proposed dummy SiO2 technique (d-SiO2 ) to improve the quality of the Ga2O3 layer on the GaN surface [4]. In this study, we tried to modify the Ga2O3/Al2O3 interface using the surface cleaning of β-Ga2O3 substrate, HTA at various annealing temperatures in O2 ambient, and d-SiO2 . We also discuss about influence of Ga2O3/Al2O3 interface on characteristic including physical and electrical properties for Ga2O3 capacitors.In the Ga2O3 surface cleaning process, the characteristics of β-Ga2O3/Al2O3/Pt capacitors fabricated by using with and without BHF treatment after Aceton and SPM treatment were firstly compared. No difference was observed in the surface roughness of the Ga2O3 substrate. Positive flatband voltage (Vfb) shift increased with increasing the BHF treatment time under positive bias stress (PBS). Based on these experimental data, the capacitor was generally fabricated using the standard process including the SPM treatment and maximum fabrication temperature at 300 °C (Standard). Next, after annealing β-Ga2O3 substrates at 800-1000 °C in O2, the Al2O3 capacitors were also prepared (HTA-capacitor). The large Vfb hysteresis of the HTA-capacitors increased from 1.6 to 1.9V at V-Vfb = 4.0V as annealing temperature increased while the Standard capacitor maintained Vfb hysteresis of 0.73V. It is thought that the number of trapped/detrapped electrons increased. Finally, characteristics of the capacitors fabricated by d-SiO2 were examined. After cleaning β-Ga2O3 substrate using SPM solution, a dummy SiO2 (5 nm) layer was deposited on β-Ga2O3 via plasma-enhanced ALD at 300 °C. Post annealing was carried out at 800-1000 °C in O2. Here, we confirmed that Ga diffused into SiO2 layer regardless of annealing temperature by SIMS analysis, indicating that Ga-O decompose to Ga atoms at Ga2O3 surface. A dummy SiO2 layer was removed using HF solution. Next, a 10-nm-thick Al2O3 dielectric was deposited on modified-Ga2O3 substrate via ALD at 300 °C, Pt gate electrode and Ti/Pt ohmic contact were formed. Finally, Post metallization annealing was performed at 300 °C (d-capacitor). The Vfb hysteresis of the d-capacitors significantly reduced to 0.4V at V-Vfb = 4.0V regardless of annealing temperature while the Vfb hysteresis of the Standard capacitor exhibited 0.73V, indicating that the modified Ga2O3 surface was able to decrease the number of trapped/detrapped electrons. To study reliability, the bias V-Vfb was applied to 2.0V under PBS. The Vfb shifted toward positive direction as the stress time increased from 0 to 300s, indicating the presence of some electron trapping sites at β-Ga2O3/Al2O3 interface of the capacitors. The d-capacitors exhibited significantly smaller Vfb shift value compared to the Standard and HTA-capacitors. We conclude that a stable Ga2O3 surface was formed by d-SiO2 and could be obtained a small Vfb hysteresis and superior reliability under PBS for β-Ga2O3/Al2O3 capacitor.This research was supported by the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT), through its "Creation of Innovative Core Technology for Power Electronics" Program Grant Number JPJ009777 and ARIM (JPMXP1223NM5088).Reference[1] M. Higashiwaki et al., Appl. Phys. Lett. 100, 013504 (2012).[2] K. Zeng et al., IEEE Electron Device Lett. 39, 1385 (2018).[3] H. H. Tippins, Phys. Rev. 140, A316 (1965).[4] Y. Irokawa t al., ECS J. Solid State Sci. Technol. 13, 085003 (2024).

Numerous studies have highlighted the significant potential of III-N High Electron Mobility Transistors (HEMTs) for power applications. Despite the commercialization of III-N HEMTs fabricated on silicon-based heterostructures, they have captured only a small share of the power electronics market. A major challenge is the introduction of electrically active defects, such as traps, during device fabrication and operation. These defects, which are unevenly distributed in the device heterostructure, contribute to device aging and severely impact reliability and operational lifespan. This work investigates the temperature dependence of key device characteristics in commercial III-N HEMTs. Using the generalized Unified Charge Control Model (UCCM), we extract temperature-dependent parameters, including electron mobility, output conduction, and maximum driving current, from in situ measured device characteristics. By distinguishing between two temperature-related effects, ambient operating temperature vs. self-heating, we found that at high drain-to-source and gate-to-source voltages, self-heating becomes the dominant factor. To account for this, we incorporate the self-heating phenomenon into the UCCM model and introduce a figure of merit for comparing the impact of self-heating across devices from different manufacturers. Additionally, we analyze the maximum driving current in relation to the material properties of III-N heterojunctions. The temperature profiles inside the HEMT devices (e.g., distribution of temperature along the channel) will be evaluated experimentally and by TCAD simulations combined with heat transfer finite element simulations. Future applications of our model aim to link self-heating with long-term reliability and lifetime, two critical factors that currently limit the broader adoption of III-N HEMTs in power electronics.

The use of hydrogen as an energy carrier for stationary and automotive applications is gaining increasing attention. Currently, generating hydrogen via electrolysis from electricity supplied by the grid is simply too expensive. Coupling electrolysis directly to renewables can avoid a number of costs incurred by both the renewable source as well as the electrolyzer. Specifically, PEM electrolysis coupled to off-shore wind has numerous synergies that have yet to be fully explored, quantified and modelled. Our study quantified these trade-offs while looking for optimal US locations for deployment.Through this project, we were able to develop and refine a model to calculate the LCoH under a variety of generation scenarios, including variable water depth, wind power output, distance to shore, and pipeline parameters, as well as investigate how those variables impact pricing for several hydrogen end use cases. We modeled the integration of hydrogen electrolyzers directly with a wind turbine to determine the optimal placement of the electrolyzers on a windfarm and evaluated the necessary power electronics under these various scenarios and the impact on total cost. An integrated system design was developed and evaluated. We also studied the tolerance of standard Pt and Ir catalysts for saltwater ions, as a function of catalyst loading and salt ion composition and concentration. Seawater intrusion tests were also performed to evaluate the sensitivity and recoverability of PGM catalysts in case of water purification system failure. Alternative catalysts with higher saltwater tolerance have also been investigated and optimized for long-term durability under operation. Integrated electrolyzer testing at NREL was performed by installing a 250 kW PEM electrolyzer at their ESIF facility for simulated wind turbine performance tests. Detailed wind turbine output simulations were prepared based on real wind turbine data, and integration of those simulations with the ESIF test bed electronics, including high frequency input and output logging was developed and installed. We performed 500 h conditioning, followed by 200 h of intermittency testing using simulated wind turbine power output to control the electrolyzer operation and assess the impact of rapid voltage modulation on electrolyzer performance and durability. Acknowledgement: The project was financially supported by the Department of Energy under Grant DE-SC0020786.

β-Ga2O3 power diodes inherently face challenges in balancing forward conduction loss and reverse blocking capability. To address this limitation, we developed a high-performance Cu2O/β-Ga2O3 heterojunction barrier Schottky (JBS) diode deploying a low work function copper (Cu) anode. The device simultaneously achieves a low turn-on voltage of 0.83 V, a breakdown voltage of 2345 V, and a power figure-of-merit of 1.22 GW/cm2. Additionally, temperature-dependent measurements confirm that the Pt/Cu2O structure enhances the barrier height and suppresses the reverse saturation current, further improving breakdown performance. Under a 200 V reverse stress at 425 K for 104 s, the JBS diode exhibits only a 1.316-fold increase in dynamic on-resistance and a 10.76% degradation in turn-on voltage, highlighting excellent long-term thermal and electrical reliability. These findings suggest a promising strategy for β-Ga2O3-based power electronics with superior performance and reliability.

The incorporation of rare earth elements such as scandium (Sc) can transform conventional III-nitride semiconductors to be ferroelectric. This new class of ferroelectric nitride semiconductors can be seamlessly integrated with well-established gallium nitride and Si electronics with promising applications in memory and logic devices as well as high power, high frequency, and high temperature electronics. Moreover, ferroelectric nitrides exhibit significantly enhanced piezoelectric and nonlinear optical response compared to AlN, which makes it attractive for high frequency resonators and filters and nonlinear optical processes. To date, however, there still lacks a fundamental understanding of their ferroelectric properties and domain energetics. In this talk, I will present recent advances of nanoscale ferroelectric III-nitride semiconductors, including ScAlN, ScGaN, YAlN, and their alloys. I will discuss the molecular beam epitaxy, structural, optical, electrical, and ferroelectric properties. The atomic configurations and electronic properties of electric-field-induced domain walls in ferroelectric nitrides will be presented. Our studies have revealed a charged domain wall with a buckled two-dimensional hexagonal phase. Their emerging electronic and photonic device applications will also be discussed.

Lithium-ion batteries are the state-of-the-art electrochemical energy storage technology and applied in wide range of devices, including inter alia portable electronic devices, power tools, (hybrid) electric vehicles, and stationary storage installations [1–3]. However, this tremendous success also calls for further improvement concerning their energy and power density, sustainability, and cost efficiency. While large improvements have been and will be realized by advanced battery, cell, and electrode designs, the development of new active material candidates is at the forefront of scientific activities. This frequently involves also new charge storage mechanisms that have been unexplored so far, e.g., combined alloying and conversion reactions as well as novel insertion-type processes.Herein, the important role of operando and ex situ hard and soft X-ray absorption spectroscopy will be highlighted to develop an in-depth understanding of these new reaction mechanisms, including the impact of the elemental composition of such materials for the processes occurring in the bulk of these new materials and at the interface with the electrolyte.

Aiming at the dynamic characteristics and stability of smart distribution network stations under the combined effect of the uncertainty of new energy output and the control logic of power electronics, an adaptive dimensionally increasing linear dynamic modeling method based on Koopman theory is proposed. Firstly, a regional nonlinear model of an intelligent transformer integrating photovoltaic, wind power, battery, hydrogen fuel cell, and synchronous generator is constructed. The control logic of the virtual synchronous generator is then integrated to characterize the dynamic response of the power electronic interface. Secondly, by constructing a set of nonlinear observation functions, including high-order polynomials, exponents, and periodic functions, the dimensional upgrade mapping of the system state is carried out. The dynamic mode decomposition algorithm is adopted to adaptively extract the dominant dynamic modes in the dimensional upgrade space, achieving global linear approximation of complex nonlinear dynamical systems. Finally, the simulation example results show that the average RMAE error of the Koopman method proposed in this paper in voltage spatiotemporal reconstruction is 0.1419, and the maximum RMSE error is 0.1915, significantly improving the accuracy and stability of dynamic modeling.

AlGaN/GaN HEMTs are pivotal next-generation semiconductor technologies, driving advancements in RF power amplifiers and high-voltage power switching. While enhancement-mode devices with p-GaN gates have become reliable commercial products, critical aspects of device physics—such as electric field management via field plates and failure mechanisms in radiation environments—remain poorly understood. Our study introduces p-type NiOₓ as a cap layer in AlGaN/GaN HEMTs to address these gaps to enable enhancement-mode (normally-off) operation. This departs from the conventional depletion-mode Schottky gate design, offering a fresh approach to controlling the two-dimensional electron gas (2DEG) without relying on traditional techniques like gate recessing or Mg-doped p-GaN layers. The use of p-NiOₓ simplifies process integration by leveraging an etch-free fabrication process.The study begins with the development of a baseline model for a depletion-mode AlGaN/GaN HEMT featuring a Schottky gate, simulated using TCAD Sentaurus. This model accurately replicates the device’s electrical characteristics, including 2DEG formation driven by spontaneous and piezoelectric polarization, threshold voltage, and drain current behaviour, all validated against experimental data. Key physical parameters—such as Schottky barrier height, polarization charges, and trap effects—are meticulously incorporated to ensure the model’s reliability.Building on this foundation, the baseline model is adapted to incorporate p-GaN and p-NiO gate architectures, transitioning the device to enhancement-mode operation. Using TCAD Sentaurus, adjustments are made to account for the p-type doping effects of NiOₓ, which modify the band structure and deplete the 2DEG under zero bias. This optimization enhances gate control and minimizes leakage current. Simulation results illustrate the successful shift from depletion to enhancement mode, revealing improvements in threshold voltage alongside performance trade-offs. These findings provide valuable insights into the integration of p-NiO gates for next-generation GaN-based power electronics. The TCAD Sentaurus simulations are set to be validated against prior experimental reports and theoretical evaluations, ensuring robustness and applicability.