Conversion Stage Research Articles

Four-level Resonant Flying Capacitor Converter Operating under Resonance featuring Soft-Switching and Voltage Regulation capabilities

Multilevel resonant converter topologies have been addressed to increase the power density and efficiency of step-down intermediate conversion stages, for low-voltage (LV) systems, due to the higher current demand, in addition to its inherent benefit of soft-switching capability and fixed static-gain ratio, while operating at, or above, resonance. This work proposes an extension for the multilevel Resonant Flying Capacitor Converter (ML-RFLCC), by demonstrating the potential soft-switching and voltage regulation capabilities of a 1:3 RFLCC while operating under and at the resonance. Due to the increased number of state variables, it presents a comprehensive state diagram, and normalization framework, to demonstrate the operating principle, and dependencies, of the different set of LC resonant tanks. In order to achieve such an operation, this work proposes an operating condition coefficient \(\Lambda\) to derive a design methodology. To validate the proposed operation condition, a 400V 500W GaN-based 1:3 RFLCC is presented, illustrating the theoretical correlation and non-idealities while operating under resonance.

Impact of land conversion on environmental conditions and methane emissions from a tropical peatland.

Tropical peatlands are significant sources of methane (CH₄), but their contribution to the global CH₄ budget remains poorly quantified due to the lack of long-term, continuous and high-frequency flux measurements. To address this gap, we measured net ecosystem CH4 exchange (NEE-CH4) using eddy covariance technique throughout the conversion of a tropical peat swamp forest to an oil palm plantation. This encompassed the periods before, during and after conversion periods from 2014 to 2020, during which substantial environmental shifts were observed. Draining the peatland substantially lowered mean monthly groundwater levels from -20.0±14.2cm before conversion to -102.3±31.6cm during conversion and increased slightly to -96.5±19.3cm after conversion. Forest removal increased mean monthly soil temperature by 2.3 to 3.1°C, reducing net radiation (Rn) and raising vapor pressure deficit (VPD). Following the tree removal, controlled burning temporarily warmed air temperature by 8°C, increased VPD and significantly attenuated Rn, resulting in negative values owing to radiation interception by smoke and increased surface warming. Contrary to expectations that drainage would lower CH4 emissions, the site remained a consistent net source, with even higher emissions observed during and after conversion. The mean monthly NEE-CH4 during conversion (23.3±8.6mg C m-2 d-1) was about 2-times higher than before conversion (12.1±5.3mg C m-2 d-1) and about 1.5-times higher than after conversion (16.3±4.1mg C m-2 d-1). The heightened CH4 release is likely attributable to emissions from drainage ditches, underscoring their significant role in post-conversion CH4 dynamics. Despite its short duration, controlled burning substantially elevated NEE-CH4, ranging from 0.04 to 0.91mg C m-2s-1. Our findings highlight the substantial impact of land conversion on peatland CH4 dynamics, emphasizing the need for accurate flux measurements across various conversion stages to refine global CH4 budgets.

PRMT5 Inhibitor EPZ015666 Decreases the Viability and Encystment of Entamoeba invadens.

Protein arginine methyltransferase 5 (PRMT5) is an enzyme that produces monomethyl arginine (MMA) and symmetric dimethyl arginine (sDMA), post-translational modifications that regulate several cellular processes, including stage conversion in parasitic protozoans. Entamoeba histolytica, the etiologic agent of human amebiasis, has two stages in its life cycle, the trophozoite, which is the replicative form, and the cyst, corresponding to the infective phase. The study of the molecular mechanisms that regulate differentiation in this parasite has been overdue because of a lack of efficient protocols for in vitro encystment. For this reason, Entamoeba invadens, a parasite of reptiles, has been used as a differentiation model system for the genus. Here, we demonstrated the presence of sDMA in E. invadens, which increases during encystment, and identified the PRMT5 of this microorganism (EiPRMT5). In addition, we performed 3D modeling of this enzyme, as well as its molecular docking with the PRMT5 inhibitor EPZ015666, which predicted the affinity of the drug for the active site of the enzyme. In agreement with these findings, EPZ015666 reduced trophozoite viability and encystment. Therefore, EiPRMT5 is a potential target for inhibiting the spread of amebiasis.

Technologies for capturing and storing carbon dioxide during conversion, use of fuel and gaseous waste from energy production

Relevance. The continued dependence on the combustion of carbon-based fuels for energy and industry leads to the need to develop various categories of technologies to reduce carbon dioxide emissions. Aim. Development of carbon capture and storage technologies for all stages of fuel conversion and processing, ensuring a low-carbon cycle for the production of electrical and thermal energy, as well as industrial and social facilities. Methods. Chemical, physical adsorption and absorption. Results and conclusions. For large industrial and energy producers, for small energy consumers, it is necessary to be guided by the principles of environmental friendliness and efficiency when implementing the production process, and to increase the percentage of carbon dioxide removal, implement decarbonization technologies at all stages of producing electricity and thermal energy. For the category of CO2 removal at the stage of preliminary fuel conversion, adsorbent compositions using predominantly environmentally friendly and inexpensive natural materials based on bentonite have been developed and tested. The collection capacity of the developed adsorbents is 85–98%. For the category of CO2 removal at the stage of fuel use, a hybrid energy system is presented, including a microgas turbine with heat recovery, a high-temperature fuel cell and other devices and material flows connecting them. A pilot industrial prototype of a 30 kW hybrid energy system will produce heat, electricity, steam, and hot water. In this embodiment, the hybrid system can work as an autonomous energy source for small social and commercial facilities, representing a pilot stage of the engineering and design implementation of the results of an industrial-level hybrid system. For the category of carbon dioxide removal at the stage of CO2 separation from the flue gas mixture after fuel conversion, a block for removing CO2 from flue gases using the absorption method was proposed. Solutions of 15% monoethanolamine, 15% ammonia solution, and 6% sodium hydroxide solution showed the best absorption capacity. It is proposed to equip the hybrid energy system with a CO2 capture unit for complete decarbonization of gas emissions based on closed-cycle technology. The proposed technology for capturing and storing carbon dioxide at the post-fuel conversion stage is characterized by ease of implementation and economic accessibility.

Simulation of Electric Vehicle to Vehicle Energy Transfer Using On-Board Converters

Electric vehicle-to-vehicle (V2V) charging is a recent approach for sharing energy among electric vehicles (EVs). ExistingV2V approaches with an off-board power-sharing interface add extra space and cost for EV users. Furthermore, V2V power transfer using on-board type-2 chargers reported in the literature is not efficient due to redundant conversion stages. This work proposes a new method for V2V power transfer by directly connecting the two EV batteries together for sharing energy through the type-2 ac charger input ports and switches. The active rectifiers of on-board type-2 chargers are not used for rectification during V2V charging, instead only a few switches are used as interfaces to connect the two EV batteries together, to avoid redundant power conversion and associated losses which effectively improve the overall V2V efficiency. The possible V2Vcharging scenarios of the proposed V2V approach are validated using a MATLAB/Simulink simulation study. Furthermore, a scaled experimental prototype is developed to validate the proposed V2V method practically.

Exploring dynamic customer requirement trend of buffet restaurant: a two-stage analysis from online reviews

PurposeCustomer expectations and preferences may evolve as they experience more. This study aims to analyze the dynamics of customer requirements (CRs) as customer experience familiarity increases, offering insights for enhancing product-service quality.Design/methodology/approachThis study categorizes dynamic requirements into two conversion stages: from new to repeat customers and from repeat to frequent customers. First, crawl online reviews (ORs) and determine each review’s conversion stage. Second, identify product-service attributes from reviews and conduct aspect-level sentiment analysis. Then, examine each attribute’s trend direction and magnitudes in the two stages. Finally, a dynamic-trend importance-performance analysis (DTIPA) model is developed to analyze the dynamic requirements and provide strategies for optimizing product services.FindingsThis study identifies eight attributes of buffet restaurants with varying requirement change trends. In particular, customer attention to “waiting time,” “variety of dishes,” “cost performance” and “taste” decreases in the first stage. In the second stage, “environment” and “freshness” increase differently from the first. Satisfaction with “cost performance” increases in the first stage but decreases in the perception of frequent customers. Improvement strategies are also provided based on these trends.Originality/valueResearch on dynamic requirement trends based on ORs and customer experience familiarity is scarce, particularly in the context of buffet restaurants. Moreover, existing methods have their limitations. This study proposes a novel approach for the progressive exploration and extraction of evolving CRs from ORs. By incorporating the trend direction and magnitude of attributes’ importance and satisfaction, DTIPA is developed to form strategies for optimizing buffet restaurant product services.

Optimal power utilization in hybrid microgrid systems with IoT-based battery-sustained energy management using RSA-PFGAN approach

The quantity of power electronics converters that interface with the various components of a hybrid microgrid system has a major impact on its efficiency. Minimizing power conversion stages and increasing system efficiency requires integrating a photovoltaic system with micro grids while maximizing the number of converters. This paper presents a hybrid approach for utilizing power in microgrid system with an Internet of Things (IoT) based battery sustained energy management scheme. The proposed hybrid technique combines the Reptile Search Algorithm (RSA) and Progressive Fusion Generative Adversarial Network (PFGAN). Thus, it is referred to as the RSA-PFGAN technique. The principal aim of the proposed approach is to minimize operating costs, improve voltage profiles, and reduce computation time and errors. The discharging and charging strategy of the battery is optimized by the RSA approach. The load demand is predicted using the PFGAN approach. Using MATLAB, the proposed method is evaluated and contrasted to other existing methods. The proposed approach determines better outcomes contrasted to existing techniques such as Wild Horse Optimization (WHO), Particle Swarm Optimization (PSO) and Seeker Optimization Algorithm (SOA). The proposed method achieves an efficiency of 85 %, significantly higher than the PSO's 55 %, WHO's 65 %, and SOA's 75 %. Additionally, the proposed approach exhibits a computation time of just 0.21 s, demonstrating its efficiency compared to PSO at 2.95 s, WHO at 0.87 s, and SOA at 0.43 s. These results indicates that the RSA-PFGAN method offers better performance in terms of cost, efficiency, and computation time for hybrid microgrid systems.

A New Proposed Triple Active Bridge Converter for Fuel Cell Applications

This paper deals with a new proposed three port converter structure dedicated for two-input source hybrid systems especially for fuel cell applications. This converter is made up of three-phase triple active bridges which are galvanically isolated by means of three single phase high frequency transformers. The present converter integrates a fuel cell as the primary power source with a battery that stores energy, harnessing the unique benefits of both sources to deliver reliable power to a DC load through a single power conversion stage. In order to control the power flow between the ports, a phase shift control technique has been carried out to generate the control signals of the load and battery side bridges in reference with those of the fuel cell bridge. A detailed analysis of the proposed converter has been presented in this paper. A novel proposed energy management algorithm has been developed. This algorithm provides a robust solution for managing and distributing power flow between the converter's ports, ensuring an optimal balance of power delivery. The algorithm has been rigorously validated through simulations and experimental test, using Dspace 1104 board.

Identification of two transcription factors that work coordinately to regulate early development in Entamoeba.

The protozoan parasite Entamoeba has a life cycle that switches between infective cysts and invasive trophozoites. Encystation, a crucial process in parasite biology, is controlled by different mechanisms including transcriptional control. We identified two nuclear proteins in Entamoeba invadens, EIN_066100 and EIN_085620, that regulate parasite development by binding to a DNA motif (TCACTTTC) in the promoter regions of genes upregulated in the first 8 h of stage conversion. Overexpression of EIN_066100, a homolog of MAK16 protein, resulted in reduced amoebic proliferation without affecting encystation efficiency. Overexpression of EIN_085620, a protein with an RNA-recognition motif (RRM), led to increased encystation efficiency. Glutathione S-transferase (GST) pull down assays revealed that EIN_066100 interacts with EIN_085620 both in vivo and in vitro, and this interaction is mediated by the EIN_085620 RRM domain. By evaluating truncated proteins with deletions at either the N-terminal or C-terminal regions of EIN_066100, we elucidated the importance of its N-terminal region in proper protein localization, proliferation, encystation, and interaction with EIN_085620. Taken together, these results indicate a coordinated role of EIN_066100 and EIN_085620 in regulating Entamoeba development. This work sheds light on the molecular mechanisms in the earliest stages of Entamoeba encystation.IMPORTANCEAn important biological process in the biology of Entamoeba is stage conversion, which plays a crucial role in disease propagation, facilitating parasite survival outside the host and spreading to new hosts. Multiple mechanisms contribute to controlling the expression of amebic stage-specific genes such as epigenetic and transcriptional control. Identification of early transcriptional control regulators is crucial to understanding the initiation of the encystation cascade. We identified two nuclear proteins, EIN_066100 and EIN_085620, involved in the proliferation and developmental regulation of E. invadens. These proteins work by direct binding to each other and mediating encystation efficiency. Study of new regulators involved in Entamoeba development represents an important advance in a critical aspect of parasite biology.

Blood-Based Biomarkers in Frontotemporal Dementia: A Narrative Review.

This narrative review explores the current landscape of blood biomarkers in Frontotemporal dementia (FTD). Neurofilament light chain (NfL) may be useful in the differentiation of behavioral variant FTD from primary psychiatric disorders (PPDs) or dementia with Lewy bodies (DLB). In prodromal FTD and presymptomatic mutation carriers (GRN, MAPT, C9orf72), elevated NfL may herald pheno-conversion to full-blown dementia. Baseline NfL correlates with steeper neuroanatomical changes and cognitive, behavioral and functional decline, making NfL promising in monitoring disease progression. Phosphorylated neurofilament heavy chain (pNfH) levels have a potential limited role in the demarcation of the conversion stage to full-blown FTD. Combined NfL and pNfH measurements may allow a wider stage stratification. Total tau levels lack applicability in the framework of FTD. p-tau, on the other hand, is of potential value in the discrimination of FTD from Alzheimer's dementia. Progranulin concentrations could serve the identification of GRN mutation carriers. Glial fibrillary acidic protein (GFAP) may assist in the differentiation of PPDs from behavioral variant FTD and the detection of GRN mutation carriers (additional research is warranted). Finally, TAR DNA-binding protein-43 (TDP-43) appears to be a promising diagnostic biomarker for FTD. Its potential in distinguishing TDP-43 pathology from other FTD-related pathologies requires further research.

All-fiber supercontinuum absorption spectroscopy for mid-infrared gas sensing

The development of compact fiber-based light sources emitting over a wide wavelength range in the mid-infrared and their application to the detection of greenhouse gases and volatile organic compounds still remain of critical interest. In the present work, we make use of several dedicated infrared fibers for implementing a mid-infrared optical device pumped by a thulium doped-fiber laser around 1.965 μm that simultaneously enables a first nonlinear stage of frequency conversion and supercontinuum generation and a second linear stage of gas absorption spectroscopy. As a proof-of-principle, we carry out mid-infrared supercontinuum absorption spectroscopy of methane around 7.7 μm by means of a hollow-core fiber-based gas cell combined to a commercial Fourier-transform infrared spectrometer. Our all-fiber configuration operating in the femtosecond regime at megahertz repetition rate allows the detection of methane concentrations as low as 20 ppm.

Photovoltaic to electrolysis off-grid green hydrogen production with DC–DC conversion

Green hydrogen (H2), being the product of water electrolysis powered by renewable energy sources, is expected to be an energetic vector of major importance toward a more sustainable energy mix. In this context, photovoltaic (PV) -based H2 production is a key element, where power electronics technologies are critical to enable its development. In off-grid applications, designing DC–DC power electronics converters with high efficiency and high power density is really important since it can impact significantly the global performance of the H2 production system. In this work, a two-stage DC–DC power conversion system composed by an unregulated DCX converter and a regulated partial power converter is considered to increase the H2 production system efficiency. The DCX converter works in open-loop at resonant frequency with a high DC–DC conversion ratio. A partial power converter (PPC), which regulates only a fraction of the total power between its input and output terminals, represents a improvement in PV-to-H2 direct conversion, particularly since the PV panels do not require regulation from zero to nominal voltage, and in this work, is introduced for regulation of the DCX-based system, by optimizing the PV produced power through a maximum power point tracking (MPPT) algorithm along with the current control of the electrolyzer. A comparison with state-of-the-art converters show an important improvement of the proposed DCX with PPC regulated system. Compared to the solution with classical interleaved-buck pre-regulator, significant improvements in terms of efficiency for the whole range of operation are obtained, up to 2.5% higher with the proposed system. Experimental evaluation of the proposed PPC and DCX two stage converter for PV-powered electrolysis system is provided, validating its feasibility and interest for off-grid green hydrogen production application.

Solar PV powered DC charger for electric vehicles with reconfigurable power electronic interface

ABSTRACT Global expansion of the EV market has led to widespread DC charging infrastructure. Consumers prefer DC charging over AC to reduce charging time per kilometer. However, grid-connected DC chargers can cause issues such as grid instability, power quality problems, demand imbalance, and conversion losses. This paper proposes an off-grid photovoltaic (PV) fed DC charger for EVs along with a battery energy storage system (BESS) to mitigate these challenges. The work aims to increase the use of clean energy for EV charging, to ensure uninterrupted EV charging with minimum power conversion stages, and to improve PV utilization. BESS serves as a backup power source that charges or discharges based on PV availability. Additionally, the system powers the non-critical adjustable loads of domestic/industrial sites with the available PV power when both EV and BESS are fully charged. The system can be reconfigured to operate in six distinct modes using two DC-DC converters and five relays. Among six modes, four modes operate in single-stage power conversion. A buck converter is used to extract power from PV. A bidirectional buck-boost converter is used to charge and discharge the BESS. The proposed system is validated through hardware prototype for both steady-state and transient conditions.

Research on Cascaded On‐Board DC/DC Converter Based on Three‐Phase Interleaved LLC

ABSTRACTThe on‐board DC/DC converter proposed in this research consists of a Buck converter and a three‐phase interleaved LLC resonant converter. This paper analyzes the average current and output current ripple characteristics of the rear‐stage converter in addition to explaining the topology and working principles of the front‐stage Buck converter and the rear‐stage three‐phase interleaved LLC resonant converter. To establish a single‐phase fundamental equivalent circuit for the rear‐stage converter, apply the fundamental wave analysis method, and it is essential for comprehending the impact of relevant system parameters on voltage gain characteristics and resonant operating regions. Conducting research on the two‐stage on‐board DC/DC converter's control strategy involves establishing small‐signal circuit models for both front and rear stage converters, derivation of parameters for double closed‐loop control, and determination of the control strategy employing phase‐shifted current sharing for the rear‐stage converter in cases where significant tolerance exists in resonant components. The simulation for a two‐stage on‐board DC/DC converter results indicates that under various conditions of resonant component tolerance, the converter is capable of achieving balanced phase currents and demonstrates minimal output current ripple prior to capacitor filtering. A 1.5‐kW experimental prototype has been fabricated, and the experimental findings indicate that the output voltage remains stable at 13.8 V despite fluctuations in input voltage. The highest efficiency of the prototype is about 96.27%, and the utilization of phase‐shifting current balancing control results in a notable reduction in output current ripple. This provides more evidence that the design of a two‐stage on‐board DC/DC converter is correct.

CeO2 enhanced performance of NiFe2O4-CaO for carbon capture and in-situ hydrogenation conversion to CO

NiFe2O4 exhibits excellent redox properties and is widely applied in CaO-NiFe2O4 chemical looping processes. However, rapid sintering of Ni-Fe alloy under reaction conditions limited its industrial applications. The CeO2-NiFe-CaO were synthesized through a physical mixing method with NiFe2O4 as a precursor, and its CO2 capture capacity and in-situ hydrogenation performance were conducted on ICCC-RWGS reaction under different conditions. 20CeO2-NiFe-CaO exhibited a CO yielding of 9.35 mmol/g at 650 °C. During the carbon capture stage, CO2 was adsorbed by CaO, leading to the formation of CaCO3. In the hydrogenation conversion stage, hydroxyl groups were generated on the surface, combining with CaCO3 to produce formate species, further generating H2O and CO. 15CNF-CaO exhibited superior cyclic ICCC-RWGS reaction performance compared to 15NF-CaO, with a CO yield of 1.88 mmol/g after 40 cycles. CeO2 inhibited the sintering of catalytic components, preserving a higher specific surface area and smaller particle size. Furthermore, CeO2 in 15CNF-CaO inhibited carbon deposition and enhanced in-situ hydrogenation performance, exhibiting better CaO regeneration capability and better cyclic stability. These results could provide insight for designing the DFMs for the ICCC-RWGS process.

Standalone Photovoltaic Water Pumping System using Induction Motor Drive

This paper presents a simple and efficient standalone photovoltaic (PV) water pumping system employing an induction motor drive. This system uses two power conversion stages linked by a DC-bus capacitor. The first is a DC-DC boost converter controlled by using a perturb-and-observe (P&O) maximum power point tracking (MPPT) technique; used to extract the available maximum power of the PV array. The second is a three-phase Pulse-Width Modulated Voltage Source Inverter (PWM-VSI) coupled to an induction motor for driving the centrifugal pump. This drive is controlled by the indirect field oriented control (FOC) which ensures high dynamic and static performances. The DC-bus voltage is regulated at a required level by using a proportional-integral (PI) controller. The reference speed is estimated from the affinity law and the DC-bus voltage control. The performances of the system are verified by digital simulation under Matlab/Simulink environment in steady-state and dynamic operating conditions.

Parametric correction in the control system of the electric propulsion of autonomous underwater vehicles affected by random inputs

The paper deals with the problem of controlling a DC propulsion motor of an autonomous underwater vehicle using a bidirectional non-isolated DC-DC converter. An automatic speed control system with a parametric controller was developed in the Matlab / Simulink package. To reduce energy conversion stages, dc-dc converters are often used to control dc motors AUV. The result of the work is an adaptive control system for the speed of the AUV propeller, which would provide high accuracy for a wide range of speeds and at the same time limit the maximum current and voltage at the armature. The indicators of the quality of performance in various modes of operation were determined, maps of the controller settings were compiled, and parametric correction was introduced. The operation of the system is analyzed and drawbacks are eliminated, such as voltage surges when switching from one speed to another, a decrease in overshoot and settling time. The performance of the system is analyzed under the conditions of random inputs from the propeller. The description of the laboratory stand for the study of the control system is given. A description of the laboratory study of the operation of the "DC converter—engine" system under conditions of random fluctuations in the moments on the motor shaft is given. It is shown that the proposed system has shown itself well under laboratory conditions and the experimental results are consistent with modeling in Matlab / Simulink.

Formation path and kinetics of caking components from modified lignite in subcritical H2O–CO system

ABSTRACT Modification reaction of lignite in subcritical H2O–CO system can significantly increase its caking index to more than 90. Separating and extracting the caking components from modified lignite, exploring the formation path of caking components, and establishing a kinetic model for the generation of these components are of significant importance for lignite hydrogenation reaction control. The lignite modified reaction was carried out in subcritical D2O–CO systems using the isotope tracer method. The formation path of caking components was defined by solvent extraction–IRMS–GPC combination technology. The results show that the soluble substances of tetrahydrofuran (TS) and benzene (BS) are the main caking components causing the structural transformation of lignite (A). The separation of n-hexane soluble (NS) also has an effect on the caking index of the modified coal. In the hydrogenation caking component formation stage, the lignite pyrolysis fragments combine with active hydrogen generated by water gas shift reaction to form caking substances, that is, A → TS + BS + NS. The formation activation energy of caking components is in the range of 0.39–58.24 kJ/mol. In the polycondensation caking component conversion stage, three soluble substances are converted in the order of TS → BS → NS, and the activation energy for the formation of caking components is 31.710–57.616 kJ/mol.

Design, Simulation and Performance of a CSI Converter for Grid-Connected or Islanded Microgrids with High Step-Up Capability in PV Applications

In the context of energy conversion from renewable sources to distribution grids (insulated or not), a converter is often required to transfer energy from a low voltage source towards three-phase grids. This paper presents the HW design, the simulation results, and the conversion performance of a CSI converter intended to interface low-voltage renewable sources to three-phase grids. The main focus of this paper is to obtain the best performance in terms of voltage increase towards the output stage while maximizing the conversion efficiency. In comparison with the currently used energy conversion systems for small photovoltaic systems, hereafter some solutions were adopted to level and maximize the energy flow from the source to the DC-link and improve the quality of current supplied in terms of harmonic distortion. The proposed system is composed of two conversion stages: the first, voltage-to-current, the second current-to-current via a three-phase CSI bridge modulated with the SVM technique. The stages are not completely decoupled from an electrical point of view; therefore, in order to mitigate the effects of these interactions, synchronization strategies have been adopted.

Response of soil fungal-community structure and function to land conversion to agriculture in desert grassland.

Land conversion to agriculture is an important factor affecting soil ecological processes in the desert grasslands of northern China. However, soil fungal-community structure and function in response to Land conversion remain unclear. In this study, desert grassland, artificial shrubland, and land conversion were investigated in the western part of the Mu Us Sandland (Yanchi, Ningxia; Dingbian, Shaanxi). We found that land conversion significantly increased soil total carbon, nitrogen, and phosphorus, and available phosphorous and potassium contents. In the early stage of conversion to agricultural (April), soil fungal operational taxonomic units and abundance-based coverage estimator were lower than those of dessert grasslands and shrubland plots and had significant correlations with pH, electric conductivity, and available phosphorus and potassium. The dominant phyla strongly correlated with soil physicochemical properties. Concomitantly, the relative abundance of Glomeromycota was significantly lower, and the complexity of the network in the land conversion plots was lower than that in the shrubland plots. In the late stage of land conversion (September), soil fungal operational taxonomic units and abundance-based coverage estimator were lower in the conversion plots than in the desert grassland plots, with more complex network relationships compared to the desert grassland or shrubland plots. Symbiotrophic groups, a functional group of desert grassland soil fungi, can be used as a predictor of environmental change; in addition, land conversion decreases the relative abundance of arbuscular mycorrhizal functional groups. Our study highlights the response of soil fungal communities and functions to human disturbances in desert grasslands. Considering the potential of land conversion to agriculture to influence soil secondary salinization, there is a need for continued observation of soil ecological health over the time continuum of land conversion to agriculture.