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Abstract Harmonics and electromagnetic interference (EMI) pose serious threats to the safety and efficiency of grid‐tied inverters. Although the inductor‐capacitor‐inductor (LCL) filter offers commendable harmonic suppression, it does not sufficiently mitigate leakage current and EMI caused by high‐frequency pulse‐width modulation (PWM). This paper examines the use of a symmetrical LCL filter to reduce the AC side leakage current in grid‐tied inverters. The symmetrical structure bolsters the conducted EMI suppression capability of the LCL filter. A magnetic integration scheme for symmetric LCL filters is introduced, and through thoughtful structural design, it achieves filter inductance integration on the EIE magnetic core. An experimental platform, equipped with a high‐frequency SiC‐MOSFET voltage source inverter with a 600 W output, is utilized. The LCL filter, symmetric LCL filter, and magnetic integrated symmetric LCL filter are contrasted, proving the effectiveness and feasibility of the proposed scheme. Furthermore, the experimental results demonstrate that the proposed magnetic integration scheme significantly reduces the filter's volume and weight, thereby enhancing the power density of the grid‐tied inverter system.

Abstract Purpose To investigate the value of CT urography (CTU) indicators in the quantitative differential diagnosis of bladder urothelial carcinoma (BUC) and inverted papilloma of the bladder (IPB). Material and methods The clinical and preoperative CTU imaging data of continuous 103 patients with histologically confirmed BUC or IPB were retrospectively analyzed. The imaging data included 6 qualitative indicators and 7 quantitative measures. The recorded clinical information and imaging features were subjected to univariate and multivariate logistic regression analysis to find independent risk factors for BUC, and a combined multi-indicator prediction model was constructed, and the prediction model was visualized using nomogram. ROC curve analysis was used to calculate and compare the predictive efficacy of independent risk factors and nomogram. Results Junction smoothness, maximum longitudinal diameter, tumor-wall interface and arterial reinforcement rate were independent risk factors for distinguishing BUC from IPB. The AUC of the combined model was 0.934 (sensitivity = 0.808, specificity = 0.920, accuracy = 0.835), and its diagnostic efficiency was higher than that of junction smoothness (AUC=0.667, sensitivity = 0.654, specificity = 0.680, accuracy = 0.660), maximum longitudinal diameter (AUC=0.757, sensitivity = 0.833, specificity = 0.604, accuracy = 0.786), tumor-wall interface (AUC=0.888, sensitivity = 0.755, specificity = 0.808, accuracy = 0.816) and Arterial reinforcement rate (AUC=0.786, sensitivity = 0.936, specificity = 0.640, accuracy = 0.864). Conclusion Above qualitative and quantitative indicators based on CTU and the combination of them may be helpful to the differential diagnosis of BUC and IPB, thus better assisting in clinical decision-making. Key points 1. Bladder urothelial carcinoma (BUC) and inverted papilloma of the bladder (IPB) exhibit similar clinical symptoms and imaging presentations. 2. The diagnostic value of CT urography (CTU) in distinguishing between BUC and IPB has not been documented. 3. BUC and IPB differ in lesion size, growth pattern and blood supply. 4. The diagnostic efficiency is optimized by integrating multiple independent risk factors into the prediction model.

Language transfer or crosslinguistic influence (CLI), referring to the influence of an L1 on the learning of an L2, is a significant aspect of Second Language Acquisition (SLA). Much work in this area is data-driven, and consequently, large L2 corpora have been constructed for use in CLI analyses. The field of Natural Language Processing, and in particular the specific task of Grammatical Error Correction (GEC), also has corpora that can be of use in these kinds of analyses. In this paper, we take the FCE corpus, a popular dataset of English as a Second Language (ESL) learner texts used for Grammatical Error Correction model training, and use it to analyse the relationship between the distributions of errors and the first languages of the ESL learners. We carry out a detailed analysis of three error types, and demonstrate that the errors made by ESL learners have a statistically significant relationship with linguistic characteristics of their first languages, suggesting the existence of both positive and negative transfer. The analysis aligns with results from the SLA literature, and validates the use of GEC corpora for use in CLI analysis.

Abstract Background Circular RNAs are highly stable regulatory RNAs that have been increasingly associated with tumorigenesis and progression. However, the role of many circRNAs in triple-negative breast cancer (TNBC) and the related mechanisms have not been elucidated. Methods In this study, we screened circRNAs with significant expression differences in the RNA sequencing datasets of TNBC and normal breast tissues and then detected the expression level of circRPPH1 by qRT‒PCR. The biological role of circRPPH1 in TNBC was then verified by in vivo and in vitro experiments. Mechanistically, we verified the regulatory effects between circRPPH1 and ZNF460 and between circRPPH1 and miR-326 by chromatin immunoprecipitation (ChIP), fluorescence in situ hybridization assay, dual luciferase reporter gene assay and RNA pull-down assay. In addition, to determine the expression of associated proteins, we performed immunohistochemistry, immunofluorescence, and western blotting. Results The upregulation of circRPPH1 in TNBC was positively linked with a poor prognosis. Additionally, both in vivo and in vitro, circRPPH1 promoted the biologically malignant behavior of TNBC cells. Additionally, circRPPH1 may function as a molecular sponge for miR-326 to control integrin subunit alpha 5 (ITGA5) expression and activate the focal adhesion kinase (FAK)/PI3K/AKT pathway. Conclusion Our research showed that ZNF460 could promote circRPPH1 expression and that the circRPPH1/miR-326/ITGA5 axis could activate the FAK/PI3K/AKT pathway to promote the progression of TNBC. Therefore, circRPPH1 can be used as a therapeutic or diagnostic target for TNBC.

Abstract The control technology of virtual synchronization generator (VSG) based on energy storage system is proposed to compensate for the inertia and damping loss caused by the grid connection of distributed generators. However, with the addition of virtual inertia and damping, VSG is prone to generate frequency and power oscillation, and the regulating ability is weakened. For the above problems, this paper analyzes the inertia and damping characteristics of the synchronous motor in the rotation of synchronous motors, and applies artificial neural network control to VSG. In intelligent control strategy, a multi‐input‐output radial basis function (RBF) neural network is first proposed to adaptively adjust virtual inertia and damping. Finally, an experimental platform with a rated power of 1 kW and a variable load of 1 kW was built to validate the proposed control strategy. The experimental results show that the artificial neural network control strategy has a better regulation ability.

Rare-earth-metal-based materials have emerged as frontrunners in the quest for high-performance hydrogen storage solutions, offering a paradigm shift in clean energy technologies. This comprehensive review delves into the cutting-edge advancements, challenges, and future prospects of these materials, providing a roadmap for their development and implementation. By elucidating the fundamental principles, synthesis methods, characterization techniques, and performance enhancement strategies, we unveil the immense potential of rare-earth metals in revolutionizing hydrogen storage. The unique electronic structure and hydrogen affinity of these elements enable diverse storage mechanisms, including chemisorption, physisorption, and hydride formation. Through rational design, nanostructuring, surface modification, and catalytic doping, the hydrogen storage capacity, kinetics, and thermodynamics of rare-earth-metal-based materials can be significantly enhanced. However, challenges such as cost, scalability, and long-term stability need to be addressed for their widespread adoption. This review not only presents a critical analysis of the state-of-the-art but also highlights the opportunities for multidisciplinary research and innovation. By harnessing the synergies between materials science, nanotechnology, and computational modeling, rare-earth-metal-based hydrogen storage materials are poised to accelerate the transition towards a sustainable hydrogen economy, ushering in a new era of clean energy solutions.

The control of soft surrounding rock stability has always been a hot academic issue. Soft rock has poor stability and low strength, and the deformation of a soft rock tunnel becomes more serious after it is affected by water for a long time. In this paper, the Jintong Coal Mine is taken as the research object, and nondestructive immersion experiments are used to study the change in mechanical properties of rock after being affected by water. The FLAC numerical model is used to analyze the stress evolution characteristics of the surrounding rock after being affected by water, and the results of the study show that the water absorption of siltstone is always higher than that of coarse-grained sandstone, and the uniaxial compressive strength of siltstone and coarse-grained sandstone decreases by 54.59% and 67.99%, respectively, under a state of saturated water compared with that under a state of dryness. Influenced by a T-shaped surface, the maximum principal stress concentration area occurs in the rock layer below the T-shaped surface and outside the joint. Concentrations of maximum shear stress occur within the “T” channel. Vertical stress concentration zones occur at the higher ground level and the bottom of the slope. The maximum shear stress of the roof fluctuates before the face reaches the surface of the “1” section, and continues to increase with and continues to increase with the distance of the face. After entering below the surface of the “1” section, the maximum shear stress of the roof increases rapidly, and the influence range is about 24 m. The maximum shear stress distribution plays a dominant role in the stability of the surrounding rocks of the two roadways. We analyze the principle of high-strength economic support, propose a “four-in-one” surrounding rock control technology based on “controlled hydrophobicity, structural adjustment, district management, and gradient control”, and propose a surrounding rock control scheme of district management. The measured data on site show that the roadway surrounding the rock is reasonably controlled. This provides a reference for the stable control of the surrounding rock of the roadway under similar conditions.

Hydrogen storage materials play a pivotal role in the development of a sustainable hydrogen economy. However, the discovery and optimization of high-performance storage materials remain a significant challenge due to the complex interplay of structural, thermodynamic and kinetic factors. Computational materials science has emerged as a powerful tool to accelerate the design and development of novel hydrogen storage materials by providing atomic-level insights into the storage mechanisms and guiding experimental efforts. In this comprehensive review, we discuss the recent advances in crystal structure prediction and performance assessment of hydrogen storage materials from a computational perspective. We highlight the applications of state-of-the-art computational methods, including density functional theory (DFT), molecular dynamics (MD) simulations, and machine learning (ML) techniques, in screening, evaluating, and optimizing storage materials. Special emphasis is placed on the prediction of stable crystal structures, assessment of thermodynamic and kinetic properties, and high-throughput screening of material space. Furthermore, we discuss the importance of multiscale modeling approaches that bridge different length and time scales, providing a holistic understanding of the storage processes. The synergistic integration of computational and experimental studies is also highlighted, with a focus on experimental validation and collaborative material discovery. Finally, we present an outlook on the future directions of computationally driven materials design for hydrogen storage applications, discussing the challenges, opportunities, and strategies for accelerating the development of high-performance storage materials. This review aims to provide a comprehensive and up-to-date account of the field, stimulating further research efforts to leverage computational methods to unlock the full potential of hydrogen storage materials.

Hydrogen energy, known for its high energy density, environmental friendliness, and renewability, stands out as a promising alternative to fossil fuels. However, its broader application is limited by the challenge of efficient and safe storage. In this context, solid-state hydrogen storage using nanomaterials has emerged as a viable solution to the drawbacks of traditional storage methods. This comprehensive review delves into the recent advancements in nanomaterials for solid-state hydrogen storage, elucidating the fundamental principles and mechanisms, highlighting significant material systems, and exploring the strategies of surface and interface engineering alongside catalytic enhancement. We also address the primary challenges and provide future perspectives on the development of nanomaterial-based hydrogen storage technologies. Key discussions include the role of nanomaterial size effects, surface modifications, nanocomposites, and nanocatalysts in optimizing storage performance.

An improved robust model predictive control (MPC) method for a three-phase four-leg active power filter (APF) is proposed in this paper. First, the decoupling model in abc coordinates of the four-leg APF is derived, and then an optimal control law is also deduced based on the calculation of the partial derivation of the cost function, which is composed of the current tracking error and control quantity with a weighted coefficient. In addition, repetitive control (RC) is introduced to eliminate the prediction error inherent in the model. Finally, the influence of control parameters on the stability of the system is analyzed by the Jury stability criterion, the performance of the proposed method has also been investigated with the perturbations of the filter inductor parameters, and strong robustness, fixed switching frequency and rapid dynamic response of the whole system can be obtained. Simulation and experimental results show the effectiveness and feasibility of the proposed method.

Abstract The seasonal rainfall regime is a key factor control on local ecological and social processes and is commonly thought to be stable under long‐term climate changes. Here we present a unique high‐resolution rainfall record from the Thai‐Malay Peninsula, combined with a state‐of‐the‐art transient climate simulation, demonstrating a fundamental rainfall regime shift from summer to winter during the Holocene. Transient model simulation and new sensitivity experiments further reveal that westward migration of the boundary between summer and winter rainfall regimes results in a summer to winter rainfall regime shift forced by distinct changes in summer and winter monsoons. Our findings suggest that the seasonal rainfall regime could be unstable under climate change around the boundaries of rainfall regimes in the tropics and possibly worldwide, which might be more critical for shaping both past and future ecological environments.

The widespread use of single-base propellant may contribute to serious pollution of the environment. The study of single-base propellant pyrolysis could provide an in-depth understanding of the combustion mechanism, reveal the key steps and reaction kinetics of the combustion process, and reduce the damage when using single-base propellant to the environment. In the present study, the pyrolysis behaviors, pyrolysis characteristic parameters, kinetics, thermodynamics, and volatiles of single-base propellant pyrolysis in an argon atmosphere were studied. The results showed that the main temperature ranges of pyrolysis and heat variation were 400–700 K and 450–520 K, respectively. With the increase in the heating rate, the maximum/average reaction rate of pyrolysis increased, the maximum instantaneous heat flow and the heat flow integral increased, the pyrolysis and combustion performance increased, and the thermal stability decreased. The average global activation energy and pre-exponential factor of the pyrolysis were 202.82 kJ and 9.48 × 1021, respectively. Thermodynamic analysis showed that the single-base propellant pyrolysis was a spontaneous endothermic reaction with a low energy barrier and fast reaction rate, which was beneficial to the formation of active complexes. In addition, information on the main volatiles was obtained, including H2, CH4, C2H4, C2H6, H2O, HCN, HCOOH, NO2, HONO, and CO2.

This study investigates the sealing performance of a combined sealing structure under extremely high and low temperature conditions, considering potential issues like high-temperature aging and low-temperature brittle fracture, which can lead to sealing failure. EPDM rubber underwent uniaxial compression tests at high, low, and normal temperatures, then the sealing performance under extreme working conditions was compared with that under normal temperature conditions. Additionally, the influences of gasket parameters and gas pressure on the sealing performance were analyzed. The result shows that compared with the normal temperature conditions, the maximum von Mises stress is reduced by 65% and the effective sealing length and the maximum contact pressure is reduced by 40% under the high temperature conditions, while the maximum von Mises stress is increased by 7 times and the maximum contact pressure is increased by a remarkable 7 times under the low temperature conditions. In the range of 10–100 MPa, the increase in gas pressure aggravates the O-ring stress concentration and improves the sealing performance relatively. When the thickness of gasket is 0.85–1.05 mm, the stress concentration of the O-ring is lighter and the sealing performance is better.

This paper proposes a novel virtual inertia control strategy for distributed power systems with high penetration of renewable energy sources. The strategy uses a quasi-Z-source power converter to emulate the inertia response of a synchronous generator by regulating the DC-link capacitor voltage in proportion to the grid frequency deviation. This paper analyzes the effect of inertia on the frequency regulation of a single-area power system and derives the parameter design method and limitations of the virtual inertia. The paper also introduces the working principle and modulation technique of the quasi-Z-source power converter and presents the virtual inertia control scheme based on a voltage-frequency controller. The paper verifies the feasibility and effectiveness of the proposed strategy through MATLAB/Simulink simulations and dSPACE semi-physical experiments. The results show that the proposed strategy can reduce the frequency deviation and rate of change of frequency (RoCoF) by 20% and 50%, respectively, under load disturbances. The paper demonstrates that the quasi-Z-source power converter can provide flexible and adjustable virtual inertia for distributed power systems without additional energy storage devices.

The liner of a carbon fiber fully reinforced composite tank with thermoplastic liner (type IV) works in a hydrogen environment with varying temperature and pressure profiles. The ageing performance of the thermoplastic liner may affect hydrogen permeability and the consequent storage capacity, degrade the mechanical properties, and even increase the leakage risks of type IV tanks. In this paper, both testing procedures and evaluation parameters of an ageing test in a hydrogen environment required in several standards are compared and analyzed. Hydrogen static exposure in a high-temperature condition with a constant temperature and pressure is suggested to be a reasonable way to accelerate the ageing reaction of thermoplastic materials. A total of 192 h is considered a superior ageing test duration to balance the test economy and safety. The ageing test temperature in the high-temperature condition is suggested as no lower than 85 °C, while the upper limit of test pressure is suggested to be 1.25 NWP. In addition, the hydrogen permeation coefficient and mechanical properties are recognized as important parameters in ageing performance evaluation. Considering the actual service conditions, the influence of temperature/pressure cycling, depressurization rate, and humidity on the ageing performance of thermoplastics in hydrogen are advised to be investigated experimentally.

The scattered resistive elements residing in a dual-active-bridge (DAB) dc/dc converter can adversely affect its transient performance especially when the load change is large. Conventional phase-shift methods do not take the resistive impact into account in their modeling and analysis. In this paper, a comprehensive analysis of the detrimental influence on the transient performance of a DAB converter due to resistive elements is presented, based on which a modified phase-shift scheme is proposed to further optimize the transient response of the converter. A DAB prototype is designed to verify the resistive impact discussed and validate the proposed phase-shift scheme. The experimental results confirm that better transient response can be effectively achieved with the proposal.

The gob-side roadway technology is widely used in coal mining in China, as it can improves the recovery rate of coal resources and alleviate the shortage of mining replacement. However, it is still difficult to control the stability of surrounding rock in gob-side roadway under deeper mining depth and more complex stress environment. With the auxiliary transportation roadway 30207 (ATR 30207) of the Muduchaideng Coal Mine as engineering background, this paper introduces the engineering case of gob-side roadway characterized by deep buried, long-distance, and large section. Through comprehensive methods, we studied and put forward the efficient excavation-support cooperation technology for surrounding rock of gob-side roadway. The research shows that the head-on cutting of gob-side roadway causes the stress to transfer and gradually adjust in the heading face to form a steady-state advanced abutment stress field. The coupling effect of the advanced abutment stress and the lateral abutment stress of goaf are the main reasons for repeated hole collapse of anchor cable drilling in solid coal rib, development and expansion of the roof separation fracture, and the low excavation speed. Supposed that upon the heading face support is completed, the next excavation-support cycle is quickly started during the early stage of stress adjustment, and the time effect can be fully utilized to alleviate the disturbance intensity of the advanced abutment stress in the heading face, as well as reduce the damage of rock mass. This paper puts forward the time-effect collaborative control countermeasures of the roof and rib in gob-side roadway of “hole collapse anchor cable of solid coal rib lag construction and waits for pressure relief and rapid excavation-support cycle in the heading face.” Engineering practice shows that the mine pressure behavior of roadway roof and solid coal rib is effectively controlled, and the roadway forming speed is greatly improved, which can provide reference for the efficient excavation-support design of gob-side roadway under the conditions of deep buried, long-distance, and large section in similar deep mines.

In this paper, a high-isolation multiple-input/multiple-output (MIMO) microstrip monopole antenna array is investigated. To reduce the mutual coupling between antenna elements, a novel composite parasitic element constituted by a T-shaped ground branch and an isolated branch was designed and analyzed. The proposed composite parasitic element is capable of generating a unique three-dimensional weak electric field, which can effectively suppress the mutual coupling between the antenna elements. To give an intuitive illustration about the design principle and decoupling strategy of the proposed antenna, the antenna design procedure was ingeniously divided into four steps, and three types of decoupling structures during the antenna evolution were meticulously analyzed at both the theoretical and the physical level. To validate the proposed decoupling concept, the antenna prototype was fabricated, measured, and evaluated. The reflection coefficient, transmission coefficient, radiation pattern, and antenna gain were studied, and remarkable consistency between the measured and simulated results was observed. The simulations showed that the antenna has a peak gain of 3.5 dBi, a low envelope correlation coefficient (ECC < 0.001), and a high radiation efficiency (radiation efficiency > 0.9). Parameters of the proposed MIMO antenna including electrical dimension, highest isolation level, and 20 dB isolation bandwidth were evaluated. Compared with the previous similar designs, the proposed antenna exhibits attractive features including compressed dimension (0.55λ0 × 0.46λ0), extremely high isolation level (approximately 43 dB), fabulous 20 dB isolation bandwidth (3.11–3.78 GHz, 19.4%), a high diversity gain (DG > 9.99 dB), an appropriate mean effective gain (−3.5 dB < MEG < −3 dB), and low design complexity.

Load frequency control (LFC) is playing an indispensable role to achieve the secure and economic operation of power grids. However, the existing LFC schemes either may rely on a nonlinear grid model under perfect operating condition with nominal parameters, or they may adopt a complicated control structure of high order. These LFC schemes may have poor control performance or even loss of stability in real-time implementation due to the grid uncertainties and the change of system operation scenarios. Consequently, a hybrid control method with two control loops considering various practical scenarios is originally proposed in this paper. In the inner loop, variable universe fuzzy logic control is applied to mitigate the impact of load disturbances on control performance. In the outer loop, an incremental genetic algorithm is employed to online optimize the control parameters. The performance of the proposed control method is comprehensively tested on a MATLAB/Simulink-based LFC model and a real-time digital simulator-based real-life 49-bus power system. The extensive results show that the proposed hybrid method exhibits comparatively better control performance than an adaptive fuzzy logic controller and an improved proportion integration controller.

Photovoltaic (PV)/battery hybrid power units have attracted vast research interests in recent years. For the conventional distributed power generation systems with PV/battery hybrid power units, two independent power converters, including a unidirectional dc-dc converter and a bidirectional converter, are normally required. This paper proposes an energy management and control strategy for the PV/battery hybrid distributed power generation systems with only one integrated three-port power converter. As the integrated bidirectional converter shares power switches with the full-bridge dc-dc converter, the power density and the reliability of the system is enhanced. The corresponding energy management and control strategy are proposed to realize the power balance among three ports in different operating scenarios, which comprehensively takes both the maximum power point tracking (MPPT) benefit and the battery charging/discharging management into consideration. The simulations are conducted using the Matlab/Simulink software to verify the operation performance of the proposed PV/battery hybrid distributed power generation system with the corresponding control algorithms, where the MPPT control loop, the battery charging/discharging management loop are enabled accordingly in different operating scenarios.

Many countries have larger land areas and scattered communities. Therefore, to electrify them, small standalone power systems are the more preferred and cost-efficient solution as compared to utility grid extensions. The main objective of a standalone power system is to supply cleaner, cheaper, and uninterrupted electricity. However, for standalone power systems, demand-side management always remains a challenging task. In this paper, a load scheduling algorithm driven by K-mean clustering and linear integer programming to schedule consumers’ appliances for the upcoming day is proposed. In addition, the basic power to run the necessary appliances is kept available in the system all the time. Furthermore, to assist the consumer in every situation, the battery storage system and the overall system size reduction are also taken into consideration. Consumer input is also used in scheduling the appliances. The proposed method is evaluated on the publicly available real-world dataset; the simulation results demonstrate that the proposed approach performs better, due to which the reliability and continuity of the system are increased.

The river sediment contains a lot of pollutants in many cases, and needs to be treated appropriately for the restoration of water environments. In this study, a novel method was developed to convert river sediment into denitrifying sludge in a sequencing batch reactor (SBR). The river sediment was added into the reactor daily and the hydraulic retention time (HRT) of the reactor was gradually reduced from 8 to 4 h. The reactor achieved in the NO3 –N removal efficiency of 85% with the NO3 –N removal rate of 0.27 kg N m−3 d−1. Response surface analysis represents that nitrate removal was affected mainly by HRT, followed by sediment addition. The denitrifying sludge achieved the highest activity with the following conditions: NO3 –N 50 mg l−1, HRT 6 h and adding 6 ml river sediments to 1 l wastewater of reactor per day. As a result, the cultivated denitrifying sludge could remove 80% NO3 –N for real municipal wastewater, and the high-throughput sequence analysis indicated that major denitrifying bacteria genera and the relative abundance in the cultivated denitrifying sludge were Diaphorobacter (33.82%) and Paracoccus (24.49%). The river sediments cultivating method in this report can not only obtain denitrifying sludge, but also make use of sediment resources, which has great application potential.

A patented bidirectional power converter was studied as an interface to connect the DC-bus of driving inverter, battery energy storage (BES), and ultracapacitor (UC) to solve the problem that the driving motor damages the battery life during acceleration and deceleration in electric vehicles (EVs). The proposed concept was to adopt a multiport switch to control the power flow and achieve the different operating mode transitions for the better utilization of energy. In addition, in order to improve the conversion efficiency, the proposed converter used a coupled inductor and interleaved-pulse-width-modulation (IPWM) control to achieve a high voltage conversion ratio (i.e., bidirectional high step-up/down conversion characteristics). This study discussed the steady-state operation and characteristic analysis of the proposed converter. Finally, a 500 W power converter prototype with specifications of 72 V DC-bus, 24 V BES, and 48 V UC was built, and the feasibility was verified by simulation and experiment results. The highest efficiency points of the realized prototype were 97.4%, 95.5%, 97.2%, 97.1%, and 95.3% for the UC charge, battery charge, UC discharge, the dual-energy in series discharge, and battery discharge modes, respectively.

In single phase DC-AC systems, double-line-frequency power ripple appears at the DC side inherently. Normally a large electrolytic capacitor can be used to reduce the power ripple at the DC side. But there are several problems with this method as it decreases the power density and reliability of the converter. In addition, a double-line-frequency current ripple appears in case a voltage source serves at the DC side, which is undesired in specific applications. This paper proposes a single phase DC-AC DAB (dual active bridge) converter with an integrated buck/boost stage for power decoupling purpose under low power condition. The proposed active power decoupling method is able to completely eliminate the double-line-frequency power ripple at the DC side. Therefore, a constant DC current can be obtained for requirements in specific DC-AC applications.

The grid-injected current total harmonics distortion (THD) and electromagnetic interference (EMI) noise must be considered in a transformer-less grid-connected inverter for a more electric aircraft (MEA) system. This paper develops a procedure for the design of the magnetic components of the LCL filter used in harmonic control and EMI reduction of the silicon carbide (SiC) grid-connected inverter in the MEA. The LCL filter is designed with effective harmonic attenuation and a compact size. To meet the space constraint requirement, specific design attention is focused on a customized amorphous cored inductor, with a comprehensive study of the relationships of inductor winding with respect to EMI noise. Reduced THD and EMI are verified through experiments performed on a 30 kW, 230 V/400 Hz three-phase grid-connected inverter prototype with the LCL filter.

A power factor correction (PFC) converter with interleaved multi-channel topology is gaining increasing attention due to its ability in reducing input and output current ripples, but an Electromagnetic Interference (EMI) noise filter is still required for suppressing the large high-frequency switching noise that could potentially degrade the input power quality of the supplying grid and cause malfunctions to other grid-connected systems. In this paper, a magnetic modeling of an interleaved PFC converter with an input differential mode (DM) EMI filter has been successfully implemented, which considers the nonlinear behavior of the inductive component in the EMI filter. The Jiles-Atherton (J-A) model is applied to describe the filtering inductor whose core displays saturation and hysteresis. The simulation results are verified with the experimental test.