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Lysine succinylation is a kind of post-translational modification (PTM) that plays a crucial role in regulating the cellular processes. Aberrant succinylation may cause inflammation, cancers, metabolism diseases and nervous system diseases. The experimental methods to detect succinylation sites are time-consuming and costly. This thus calls for computational models with high efficacy, and attention has been given in the literature to develop such models, albeit with only moderate success in the context of different evaluation metrics. One crucial aspect in this context is the biochemical and physicochemical properties of amino acids, which appear to be useful as features for such computational predictors. However, some of the existing computational models did not use the biochemical and physicochemical properties of amino acids. In contrast, some others used them without considering the inter-dependency among the properties. The combinations of biochemical and physicochemical properties derived through our optimization process achieve better results than the results achieved by combining all the properties. We propose three deep learning architectures: CNN+Bi-LSTM (CBL), Bi-LSTM+CNN (BLC) and their combination (CBL_BLC). We find that CBL_BLC outperforms the other two. Ensembling of different models successfully improves the results. Notably, tuning the threshold of the ensemble classifiers further improves the results. Upon comparing our work with other existing works on two datasets, we successfully achieve better sensitivity and specificity by varying the threshold value. [ABSTRACT FROM AUTHOR]

This article presents a study on real-time testing of synchrophasor-based "wide-area monitoring system's applications (WAMS application)." Considering the growing demand of real-time testing of "wide-area monitoring, protection, and control (WAMPAC)" applications, a systematic real-time testing methodology is formulated and delineated in diagrams. The diagrams propose several stages through which an application needs to be assessed (sequentially) for its acceptance prior to implementation into a production system. However, only one stage is demonstrated in this article which comprises the use of a prototyping software toolchain and whose potential is assessed as sufficient for preliminary real-time testing (PRTT) of WAMS applications. The software toolchain is composed of two components: the MATLAB software for application prototyping and other open-source software that allows ingesting prerecorded phasor measurement unit (PMU) signals. With this software toolchain, a PRTT study is presented for two WAMS applications: "testing of the PMU/phasor data concentrator (PDC)" and "testing of wide-area forced oscillation (FO) monitoring application." [ABSTRACT FROM AUTHOR]

All proteomes contain both proteins and polypeptide segments that don't form a defined three-dimensional structure yet are biologically active—called intrinsically disordered proteins and regions (IDPs and IDRs). Most of these IDPs/IDRs lack useful functional annotation limiting our understanding of their importance for organism fitness. Here we characterized IDRs using protein sequence annotations of functional sites and regions available in the UniProt knowledgebase ("UniProt features": active site, ligand-binding pocket, regions mediating protein-protein interactions, etc.). By measuring the statistical enrichment of twenty-five UniProt features in 981 IDRs of 561 human proteins, we identified eight features that are commonly located in IDRs. We then collected the genetic variant data from the general population and patient-based databases and evaluated the prevalence of population and pathogenic variations in IDPs/IDRs. We observed that some IDRs tolerate 2 to 12-times more single amino acid-substituting missense mutations than synonymous changes in the general population. However, we also found that 37% of all germline pathogenic mutations are located in disordered regions of 96 proteins. Based on the observed-to-expected frequency of mutations, we categorized 34 IDRs in 20 proteins (DDX3X, KIT, RB1, etc.) as intolerant to mutation. Finally, using statistical analysis and a machine learning approach, we demonstrate that mutation-intolerant IDRs carry a distinct signature of functional features. Our study presents a novel approach to assign functional importance to IDRs by leveraging the wealth of available genetic data, which will aid in a deeper understating of the role of IDRs in biological processes and disease mechanisms. Author summary: Intrinsically disordered regions (IDRs) in proteins are typically not considered to be functionally as important as the structured parts. However, it is becoming evident that both structured and disordered regions are essential for the repertoire of protein functions. Nevertheless, most of these largely flexible and functionally dynamic protein regions remain uncharacterized. Nevertheless, most of these largely flexible and functionally dynamic protein regions remain uncharacterized. Here, informed by human genetic diversity (i.e., genetic variations from the general population and patients), we identified the IDRs that are more frequently mutated in patients than in relatively healthy individuals, and further show that they carry a set of characteristic functional features. This approach provides a different and effective means to identify unannotated disordered protein segments that are biologically important and lead to pathogenesis upon mutation. [ABSTRACT FROM AUTHOR]

A simple and sensitive spectrophotometric method for the determination of a mesalazine in the aqueous solution. The method is based on the oxidative coupling reaction between mesalazine and Phenothiazine in the presence of potassium dichromate as oxidizing agent to forming a green color water soluble dye showing maximum absorbance at 610nm. Beer's law is obeyed in the concentration range of (0.1-11) (U+03BC) g/ml, with Correlation confection (R2) value more than 0.999.Molar absorptivity (2.055x10) L.mole-1.cm-1 and Sandall's sensitivity (0.007451) (U+03BC) g/cm2. This method has been successfully applied for the determination of mesalazine in various pharmaceutical preparations. [ABSTRACT FROM AUTHOR]

Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is caused by proliferation of smooth muscle cells in the wall of small mesenteric veins and venules with accumulation of a proteoglycan matrix leading to a non-thrombotic, non-inflammatory venous occlusion resulting in venous ischemia. IMHMV is a rare and poorly understood disease, with <20 case reports in the literature. The purpose of this report is to describe the case of a 63-year-old man who presented with this condition that resulted in colonic ischemia necessitating surgical resection. The cause of IMHMV in this patient was attributed to a Chinese herbal supplement used for degenerative osteoarthritis of the knees. A brief review of the literature is provided along with the case report. [ABSTRACT FROM AUTHOR]

This paper proposes a new winding layout for high-power medium-voltage nine-phase induction machines (IMs) based on a single-layer concentrated winding layout having a unity winding factor. The machine is fundamentally an asymmetrical nine-phase IM, where phases are connected in such a way as to provide six terminals that are fed from two three-phase inverters. Compared to a conventional asymmetrical six-phase IM with the same stator and copper volumes, it provides improved torque density, a higher torque/current ratio, and a simpler winding layout. Finite-element simulation is used to compare the proposed winding layout with a conventional split-phase six-phase IM to assess the claimed merits. A 1.5-hp prototype IM is also used for experimental verification. The experimental results are given under both healthy and fault conditions, where the faulty converter is completely disabled. The achievable derating factors under this case are then given and compared with those of conventional six-phase IMs. [ABSTRACT FROM PUBLISHER]

The combined star/pentagon connection of five-phase induction machines was recently demonstrated as a promising compromise between conventional star and pentagon connections. It combines the advantages of both star and pentagon connections without any additional hardware for winding changeover. This connection is based on two five-phase single layer concentrated winding sets shifted in space by π/10 and connected in a combined star/pentagon configuration to provide five-phase terminals. Since the combined star/pentagon connected induction machine is fundamentally an asymmetrical ten-phase machine, the machine mathematical model possesses additional subspaces, which affect the behavior of the machine especially under open line conditions. Starting from the conventional five-phase and m -bar squirrel cage induction machine model, the phase-variable model of the combined star/pentagon connection is introduced in this paper. The corresponding equivalent dq model with five decoupled subspaces, which can account for air gap harmonics up to ninth order, is then derived. Finally, it was shown that the machine model could be simply approximated with only two subspaces similar to a conventional five-phase induction machine with sinusoidally distributed winding, where the flux produced by the nonfundamental subspace could be neglected. The model is verified using a 1 kW prototype five-phase induction machine. [ABSTRACT FROM PUBLISHER]

A study on bubble growth mechanisms and underlying physical phenomena of flow boiling in silicon nanowire (SiNW) microchannels has been performed and compared these results with plainwall microchannels. A new approach in studying bubble dynamics and forces acting on liquid–vapor (L–V) interface of growing bubble has been proposed based on theoretical, experimental and visual studies. Bubble size, liquid film thickness, interfacial properties are measured and L–V interfaces are detected from high speed visualization data and results are analyzed by vision-based approach. Force analysis during instantaneous bubble growth from bubble nucleation to formation of annular flow regime has been performed for both the SiNW and plainwall microchannel configurations. Results from force analysis show the dominance of surface tension at L–V interface of growing bubble which resulted higher heat transfer contact area, lower thermal resistance and higher thin film evaporation. Whereas, inertia force is dominant at L–V interface of fully grown bubble and it helps in bubble removal process and rewetting before flow reversal. Significant differences between SiNW and plainwall microchannels have been observed in bubble growth mechanism, heat transfer mode and forces acting on L–V interface. [ABSTRACT FROM AUTHOR]

In many applications, interior permanent magnet synchronous machines (IPMSMs) with fractional slot concentrated windings (FSCWs) are considered promising candidates in terms of higher power density and efficiency. In addition, employing a multiphase stator winding improves the drive train availability and increases reliability. This study investigates the effect of applying stator shifting to five‐phase FSCW winding IPMSMs to suppress the effect of the slot harmonics by doubling the number of slots. In this case, the winding coil pitch will be two, which stands as a compromise between single‐tooth and distributed winding topologies. This highly improves the air gap flux distribution, significantly reduces both rotor core and magnet eddy current losses, and increases saliency ratio and reluctance torque component. Moreover, an improved performance under fault conditions, in terms of lower torque ripple, and core and magnet losses, adds to the main advantages of this technique. Various slot/pole combinations suitable for five‐phase machines are investigated. A full simulation case study based on two‐dimensional finite element analysis is applied to the 20‐slot/18‐pole stator with single‐tooth winding under both healthy and open‐circuit phase fault cases. [ABSTRACT FROM AUTHOR]

The steady-state modeling of multiphase induction machines (IMs) with m phases under open-line fault conditions is usually carried out based on symmetrical component theory. Hence, the estimation of the machine characteristic curves usually involves complex mathematical calculations and inversion of high-order matrices, which complicates the analysis. Moreover, the effect of the different subspaces’ impedances on the machine performance cannot be easily recognized using this modeling technique. Instead, this paper presents the first attempt to derive a simple equivalent circuit for a five-phase IM under open-line conditions that includes the effect of all subspaces in a single circuit. The derivation is carried out for both star and pentagon connections. The equivalent circuit can be a simple technique to explain the advantages obtained from a pentagon connection compared to the star connection under open-circuit faults. It can also be used to derive a simple expression for torque gain and torque ripple magnitude for different stator connections based on the circuit parameters. The derived equivalent circuits are verified using a 1-kW five-phase prototype machine. [ABSTRACT FROM PUBLISHER]

High-Voltage pulse generators are commonly used in biotechnology, medicine, industrial applications, food processing and drinking water purification. The dc-dc boost converter has been used before in pulsed applications for its ability to amplify a relatively low input dc voltage to a high-voltage output. A high-voltage solid-state chopping switch is then used to chop the generated high output voltage. In this work, a boost-converter based ringing circuit with high voltage gain is proposed for water treatment applications. The basic concept of the proposed approach depends on operating the boost converter under discontinuous current conduction. With the proposed approach, the chopping high-voltage switch at the output stage is eliminated, which positively affects the system cost and efficiency. A full-design of the circuit and passive components is presented to ensure that the desired pulse specifications are achieved. The proposed approach has been validated using simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a six-phase surface-mounted permanent-magnet machine with a 24-slot/10-pole fractional slot winding, which not only eliminates the air-gap flux subharmonics, but also minimizes the effect of slot harmonics, which highly affect both the core and magnet losses. The six-phase winding design also offers an improved drive train availability for electric vehicle applications due to its inherent high fault-tolerant capability. When compared with a three-phase design, the proposed winding offers approximately 3.5% improvement in torque density, a significant reduction in both the core and magnet losses, and an improved overall efficiency. The proposed winding is deduced based on the stator shifting concept of two 12-slot/10-pole stators with single tooth windings. The coil span of the resulting machine will be two slots, which stands as a compromise between single tooth and distributed windings. The concept of stator shifting is first presented, and then, a prototype machine is designed and simulated using the 2-D finite-element analysis to validate the proposed concept. A comparative study is also carried out to compare six-phase and three-phase designs with the same slot/pole combination and also with the 18-slot/10-pole combination, which was recently shown to be a competitive alternative. [ABSTRACT FROM AUTHOR]

This paper presents the steady-state mathematical model of a five-phase induction machine with a combined star/pentagon connection. The connection splits the stator winding into two five-phase windings displaced in space by $\pi$/10 and connected in a combined star/pentagon configuration. Recent work limited to an experimental investigation demonstrated that the connection possesses improved fault tolerance when compared to a conventional star-connected stator, as well as avoids the pentagon connection problems. Although the machine has five-phase terminals, it is intrinsically an asymmetrical ten-phase machine, which introduces additional subspaces in the machine's mathematical model. In order to theoretically investigate and thoroughly assess this connection against conventional connections, this paper introduces the steady-state mathematical model based on vector space decomposition and symmetrical component theory. Finite-element analysis is first used to investigate the different harmonic current components induced in the cage rotor circuit, upon which the effect of different subspaces can be clarified and the required transformation matrix from phase variables to their sequence components can be derived. The model is verified using a 1-kW prototype five-phase induction machine. [ABSTRACT FROM PUBLISHER]

The interior permanent magnet (IPM) machine equipped with a fractional-slot concentrated winding (FSCW) has met an increasing interest in electric vehicle applications due to its higher power density and efficiency. Torque production is due to both PM and reluctance torques. However, one of the main challenges of FSCWs is their inability to produce a high-quality magnetomotive force (MMF) distribution, yielding undesirable rotor core and magnet eddy-current losses. Literature shows that the reduction of low-order space harmonics significantly reduces these loss components. Moreover, it has been previously shown that by employing a higher number of layers, although causing some reduction in the winding factor of the torque-producing MMF component, both machine saliency and reluctance torque components are improved. Recently, a dual three-phase winding connected in a star/delta connection has also shown promise to concurrently enhance machine torque of a surface-mounted PM machine while significantly reducing both rotor core and magnet losses. In this paper, a multilayer winding configuration and a dual three-phase winding connection are combined and applied to the well-known 12-slot/10-pole IPM machine with v-shaped magnets. The proposed winding layout is compared with a conventional double-layer winding, a dual three-phase double-layer winding, and a four-layer winding. The comparison is carried out using 2-D finite-element analysis. The comparison shows that the proposed winding layout, while providing similar output torque to a conventional double-layer three-phase winding, offers a significant reduction in core and magnet losses, correspondingly a higher efficiency, improves the machine saliency ratio, and maximizes the reluctance toque component. [ABSTRACT FROM AUTHOR]

Background Opioids are frequently added to neuroaxial local anesthetics (LAs). Intrathecal (IT) opioid is not devoid of adverse effects such as postoperative nausea and vomiting (PONV), respiratory depression, and pruritis. IT atropine also carries a significant antiemetic effect, and this can be a valuable modality for the prevention of IT opioidrelated PONV. The antagonist of 5-HT3 receptors such as ondasetron which is usually used to decrease the incidence of nausea and vomiting was considered for the prevention and treatment of neuroaxial opioid-induced (PONV). Method 100 cases of ASA I-II aged 18 and 45 who planned to do elective perineal surgery, and receiving bupivacaine spinal anesthesia were randomly divided into two equal groups. Group (A) cases received IT hyperbaric bupivacaine (10mg 0.5%) in combination with morphine 250 μg and atropine sulphate 100 μg. Before anesthesia, group (B) participants received IT hyperbaric bupivacaine (10mg 0.5%) and 250 μg of morphine and 4mg IV ondansetron. Follow-up for PONV attacks, vital signs, and side effects in the two groups. Results The occurrence of postoperative nausea were 4 and 18% in group A and B, respectively (P value=0.049) while postoperative vomiting was 0 and 12% in group A and B, respectively (P value=0.027). The occurrence of sedation, mouth dryness, headache, and drowsiness were more in group A compared with group B. Conclusion IT atropine is more effective than IV ondasetron preoperative in relieving PONV related to IT morphine, sedation is the frequent side effect occurred in IT atropine, headache is the frequent side effect occurred in the ondasetron group [ABSTRACT FROM AUTHOR]

One of the main drawbacks of nonoverlapped coils in fractional slot concentrated winding permanent magnet (PM) machines are the high eddy current losses in both rotor core and permanent magnets induced by the asynchronous harmonics of the armature reaction field. It has been shown in the literature that the reduction of low space harmonics can effectively reduce the rotor eddy current losses. This paper shows that employing a combined star-delta winding to a three-phase PM machine with fractional slot windings and with a number of slots equal to 12, or its multiples, yields a complete cancellation to the fundamental magneto-motive force (MMF) component, which significantly reduces the induced rotor eddy current. Besides, it offers a slight increase in machine torque density. A case study on the well-known 12-slot/10-pole PM machine is conducted to explore the proposed approach. With the same concept, the general $n$ -phase PM machine occupying $4n$ slots and with a dual $n$ -phase winding is then proposed. This configuration offers a complete cancelation of all harmonics below the torque producing MMF component. Hence, the induced eddy currents in both rotor core and magnets are significantly reduced. The winding connection and the required number of turns for both winding groups are also given. The concept is applied to a 20-slot/18-pole stator with a dual five-phase winding, where the stator winding is connected as a combined star/pentagon connection. The proposed concept is assessed through a simulation study based on 2-D finite element analysis. [ABSTRACT FROM AUTHOR]

Direct-drive permanent magnet (PM) generators have become a strong contender in medium and large rating wind energy conversion systems as they not only provide higher efficiency and annual energy production, but also reduce the operational and maintenance cost. PM generators with nonoverlap single-layer windings provide a cost-effective design variation that eases manufacturing, reduces torque ripples, enhances voltage quality, and provides fault tolerant capability. The performance of such machines depends mainly on the proper selection of the pole and slot numbers, which results in negligible coupling between phases. The preferred slots per phase per pole (SPP) ratios eliminate the effect of low order harmonics in the stator magnetomotive force (MMF), and thereby the vibration and stray loss are reduced. This paper proposes a new three-phase winding configuration based on the 20 slots/18 poles five-phase PM machine. The proposed design is compared with the well-known 24 slots/20 poles three-phase PM machine. The comparison shows that the proposed generator offers reduced torque ripples, improved output voltage quality, and less core loss for the same machine volume. [ABSTRACT FROM PUBLISHER]

Five-phase induction machines are generally modeled using multiple dq planes or using a phase variable model. This paper considers modeling five-phase induction machines using a voltage-behind-reactance (VBR) configuration. This configuration lends itself suitable for time-domain circuit-based simulators as the MATLAB/Simulink SimPowerSystems (SPS) toolbox. The stator electrical dynamics are represented in five-phase coordinates, while the rotor electrical circuit is modeled using rotor flux linkage as the state variable and expressed in the dq stator reference frame. The VBR model is equivalent to a conventional dq model; however, it facilitates the connection of an external inductance without affecting numerical accuracy and calculation efficiency. It also facilitates the simulation of different winding connections, series-connected multimotors, and open phase(s) conditions. The model is, first, derived for a magnetically linear system and then it is extended to include the effect of magnetic saturation. The flux correction method is used to represent the effect of magnetic saturation with a simple modification to represent the effect of cross coupling between fundamental and third sequence planes due to saturation effect. The dynamic cross saturation is considered by adding compensating terms that depend on magnetizing inductance variation. The proposed model is experimentally verified using a prototype 1.5-hp five-phase induction machine under different operating conditions. [ABSTRACT FROM AUTHOR]

The quest for improved energy savings is driving research into power converter high-efficiency operation under extremely light-load conditions. The use of multiple output converters to satisfy circuit needs and cost requirements adds additional complication to the standby mode power-consumption problem. This is due to the difficulty of satisfying both good cross-regulation under various load conditions as well as high efficiency in the standby mode simultaneously; because topologies that exhibit a good cross-regulation performance, such as resonant converters, generally have a poor efficiency problem under extremely light-loads. A secondary side post regulator (SSPR) is proposed to reduce the standby power consumption and to improve the cross-regulation performance of single- controller multiple-output channel power converters. It is capable of reducing the power consumption of the power converter as well as the SSPR. The SSPR is analysed using its operational principles and small signal models. A 110 W experimental prototype was built to verify the standby power consumption and cross-regulation performance using the proposed SSPR. [ABSTRACT FROM PUBLISHER]

Abstract: Real-time simulation and rapid prototyping of power electronics, critical loads, and control systems have prompted recent interest in accurate electrical terminal models of photovoltaic (PV) panels and array systems. Advancement in computing technologies, such as parallel computing and digital signal processing techniques for real-time simulations have allowed the prototyping of novel apparatus to be investigated in a virtual system under a wide range of realistic conditions repeatedly, safely, and economically. This paper accesses numerical iteration methods, selects appropriate techniques, and combines them with model construction methods well suited for boosting the computational speed of an electro-thermal dynamic model of a PV panel. The target computational engine is a parallel processor based real-time simulator to be used in a power hardware-in-the-loop (PHIL) application. Significant improvements resulting from the proposed modeling approach in computation time and numerical convergence speed are verified using experimental results for the target PV panel using Opal-RT’s RT-Lab Matlab/Simulink based real-time engineering simulator. [Copyright &y& Elsevier]

Fractional slot concentrated windings (FSCWs), or modular windings, have shown promise with permanent magnet machines. However, their inability to produce high quality travelling fields has limited their application from spreading to induction machines. This paper presents the design considerations and tradeoffs involved in applying FSCWs to five-phase induction machines using the conventional three-phase lap wound machine as a reference. Previous work has touched upon the application of modular windings to three-phase induction machines, concluding that a conventional distributed winding is superior in terms of torque production and rotor bar losses. In applications such as high frequency induction machines and manually wound electrical submersible pump motors, the proposed machine topology provides advantages that may warrant its application despite an apparent power density penalty. In this paper, a prototype five-phase modular winding induction machine designed to significantly reduce the effect of space harmonics is investigated through simulations and experimentally. [ABSTRACT FROM PUBLISHER]

The increased integration of fuel cells with power electronics, critical loads, and control systems has prompted recent interest in accurate electrical terminal models of the polymer electrolyte membrane fuel cell. Advancement in computing technologies, particularly parallel computation techniques and various real-time simulation tools, has allowed the prototyping of novel apparatus to be investigated in a virtual system under a wide range of realistic conditions repeatedly, safely, and economically. This paper builds upon both advancements and provides a means of optimized model construction boosting the computation speeds for a fuel cell terminal model on a real-time simulator which can be used in a power hardware-in-the-loop application. An elaborate simulation model of the fuel cell stack system has been developed, and a significant improvement in the computation time has been achieved. The effectiveness of the proposed model developed on Opal RT's RT-LAB MATLAB/Simulink-based real-time engineering simulator is verified using the experimental results with a Ballard Nexa fuel cell stack system. [ABSTRACT FROM AUTHOR]

In this paper, the application of a cascaded multilevel inverter as a dynamic voltage restorer (DVR) is investigated. Two discontinuous multilevel space vector modulation (SVM) techniques are implemented for DVR control and are shown to reduce inverter switching losses while maintaining virtually the same harmonic performance as the conventional multilevel SVM at a high number of levels. This paper also presents a mathematical relationship for computing the distortion at the point of common coupling (PCC) as a function of the distortion of the DVR. This enables the selection of the number of levels required for a certain application. An extended sag duration support compared to the two-level DVR is another advantage of the DVR with a cascaded multilevel inverter. The common-mode voltage (CMV) at the PCC has been evaluated for the three SVM techniques (the conventional multilevel SVM and the two discontinuous SVM), presenting a lower CMV for the second discontinuous SVM. A design example is presented for an 11-kV 5-MVA DVR multilevel cascaded inverter for up to 17 levels, employing the conventional multilevel SVM and the two discontinuous SVM techniques. [ABSTRACT FROM AUTHOR]

Investigates the selection criteria of induction machines for speed-sensorless drive applications. Details of the fundamental pole pair and rotor slot relationships for the generation of principal-slot-harmonic; Simulation results; Conclusions.

Examines the effects of pole pair and rotor slot numbers on the presence of different harmonics under healthy and eccentric conditions in a three phase induction motor with different rotor cages. Development of a theoretical approach; Simulation results using the winding function approach (WFA) and the modified WFA; Experimental results verifying the theory.

In horizontal well operations, the prevalence of stuck pipe incidents is largely attributed to inadequate hole cleaning, underscoring the critical need for a thorough understanding of this process to mitigate non-productive time and financial losses. Increasing fluid velocity, the major drilling parameter of hole cleaning, diminishes the formation of cuttings beds in a wellbore. This study primarily centered on the mechanical displacement and removal of solid particles, employing advanced image processing techniques to elucidate the dynamic behavior of solid particles in deviated wellbores. The core objective of this study was to experimentally scrutinize the effects of a downhole clamp-on tool on fluid velocity to improve hole cleaning practices. To address this challenge, a customized flow loop was designed and constructed to accurately replicate the conditions encountered in horizontal wells. Pure water was used to demonstrate the effects of the clamp-on tool on cuttings transport for lightweight drilling fluid conditions. Strategically deployed, the clamp-on tool played a pivotal role in agitating cuttings, mitigating their accumulation at the bottom of the borehole. The tool's agitation mechanism noticeably improved cuttings removal by increasing velocity, extending the perturbation of cuttings transport in the tool's downstream flow, and reducing bedding formation. At lower flow rates, the tool led to an over fourfold increase in average particle velocity within the tool and a twofold increase after the tool. Our results demonstrate the substantial potential of mechanical assistance to address hole cleaning challenges and significantly advance horizontal well operations. [ABSTRACT FROM AUTHOR]

• Bubble dynamics in one single confined microchannel was experimentally investigated. • The effects of hydraulic diameter (D h) of channel, flow rate and heat flux on bubble dynamics are discussed. • The velocity and acceleration of L- V interface were estimated through the analysis of recorded videos using vision-based technique. • The interfacial heat transfer (Nu c) changes with re b during bubble growth and bubble shrinking. • An analysis of energy distributions by bubble dynamics is conducted, heat flux through interface counts over 96% of total input power. Bubble dynamics are fundamental to understand boiling heat transfer mechanism at microscale. In this study, bubble dynamics in one single confined microchannel was experimentally investigated through vision-assisted technique. Experimental studies were performed to understand the effects of hydraulic diameter (D h) of channel, flow rate and heat flux on bubble dynamics, which highly affect the boiling heat transfer performance. First of all, experimental results show that D h has a vital effect on the volume change rate of confined bubble, which can be used to compute the heat flux transported by single bubble. The liquid-vapor (L- V) interfaces were tracked by non-rigid image registration and the velocity and acceleration of L- V interface were estimated through the analysis of recorded videos using vision-based technique. To quantitatively evaluate the impact of bubble dynamics, transient heat transfer rates were presented at different flow rates. Furthermore, the interfacial heat transfer (Nu c) influenced by bubble dynamics was evaluated. Nu c changes with Re b during bubble growth and bubble shrinking. Finally, an analysis of energy distributions by bubble dynamics is conducted. Compared to energy transported by bubble and kinetic energy of bubble, heat flux through interface is significant, dissipating over 96% of total input power. [ABSTRACT FROM AUTHOR]

Wrapping a computation domain with a perfectly matched layer (PML) is one of the most effective methods of imitating/approximating the radiation boundary condition in the Maxwell and wave equation solvers. Many PML implementations often use a smoothly increasing attenuation coefficient to increase the absorption for a given layer thickness, and, at the same time, to reduce the numerical reflection from the interface between the computation domain and the PML. In discontinuous Galerkin time-domain (DGTD) methods, using a PML coefficient that varies within a mesh element requires a different mass matrix to be stored for every element and therefore significantly increases the memory footprint. In this work, this bottleneck is addressed by applying a weight-adjusted approximation to these mass matrices. The resulting DGTD scheme has the same advantages as the scheme that stores individual mass matrices, namely, higher accuracy (due to reduced numerical reflection) and increased meshing flexibility (since the PML does not have to be defined layer by layer), but it requires significantly less memory. [ABSTRACT FROM AUTHOR]

Nine-Switch inverter (NSI) has been recently introduced for independent control of dual ac motors. Although this topology reduces the number of active switches by 25% compared to conventional inverters, it has a main conceptual shortcoming due to voltage gain limitations. In NSI, the voltage gains of both outputs are relatively low, while their maximum achievable magnitudes depend on the phase angle between the two sets. In order to mitigate this problem, this article introduces a new dual output nine-switch boost inverter (NSBI) topology with a minimum number of passive elements. The detailed analysis of NSBI is presented, while the required modifications to conventional pulsewidth modulation (PWM) strategies of the NSI are explained to ensure an acceptable voltage boosting ratio while a high-quality voltage output is obtained. Among different PWM schemes, a modified discontinuous PWM scheme is found optimum with this proposed topology to minimize the voltage stress across switches and improve the input current and output voltage quality. The proposed topology is also validated under both common-frequency and different-frequency modes of operations. Moreover, a clear picture of the NSBI performance compared with other possible counterparts is introduced. The theoretical findings have been corroborated using simulation and experiments. [ABSTRACT FROM AUTHOR]

The nine-phase six-terminal induction machine has recently been proposed as a promising contender to the conventional six-phase asymmetrical winding machine in terms of torque density, phase current quality, stator winding simplicity, and fault-tolerant capability. However, the relatively lower dc-link voltage utilization of a single neutral arrangement in multiphase machines with multiple three-phase windings represents, in general, a technical challenge when compared to windings with isolated star points. Therefore, this paper proposes a new pseudo six-phase winding layout suitable for medium-voltage high-power induction machines, which employs quadruple three-phase stator winding sets, while providing the same terminal behavior of a nine-phase six-terminal winding. Additionally, like the traditional six-phase winding, two possible neutral arrangements can be configured. The proposed winding configuration provides the same dc-link voltage utilization as in conventional dual three-phase winding machines with isolated neutrals. The effect of the circulating zero-sequence current component experienced with a single neutral arrangement can also be avoided. A 1.5 Hp prototype induction machine is used to experimentally validate the proposed six-phase winding layout under both healthy and fault conditions. [ABSTRACT FROM AUTHOR]

In this article, three different types of pulse generators based on multimodule boost converter ringing circuit are presented, namely, interleaved, stacked, and interleaved–stacked with full design and operational concept. The interleaved version is advantageous in generating a burst of pulses with moderate voltage magnitude, where the used modules are fed from a common dc source. On the other hand, the stacked multimodule version can be used to generate high-voltage pulsed output from synchronized modules with a moderate voltage rating. This can be done by feeding the modules from isolated dc sources while connecting their outputs in series. Finally, the interleaved–stacked version can be used for generating a burst of pulses with high-voltage magnitude. The presented pulse generators are valid for resistive loads with exponential decay pulses. The suggested pulse generators are simple and require semiconductor devices with moderate voltage ratings. For given pulse specifications, a detailed design for the passive components of each version is presented in this article. The simulation and experimental results are used to validate the suggested topologies. [ABSTRACT FROM AUTHOR]

In electric drive applications that are based on high‐speed induction motors (IMs) with an extended speed range, stator winding pole‐changing is a possible technique to avoid oversizing the driving motor. The electronic pole changing employed in multiphase IMs has gained recent interest because it avoids physical winding reconfiguration. The effective number of poles of the air gap flux distribution can be electronically altered by simply changing the applied current sequence to a multiphase stator. The main problem associated with this technique is the significant increase in machine magnetising current with the increase in effective pole number when conventional multiphase distributed windings are employed. This study proposes a new fractional‐slot concentrated winding layout with a special stator connection suitable for pole‐amplitude modulated IMs that offers a 2:1 pole ratio while maintaining equal magnetising current for both winding pole pairs. Moreover, constant power operation can be achieved for a speed range of over 4 pu. The main concept is discussed and verified through simulations and experimentally. The machine mathematical model and the required vector space decomposition‐based controller are also presented. [ABSTRACT FROM AUTHOR]

In order to overcome the limitations of the existing classical and solid-state Marx pulse generators, this paper proposes a new modular multilevel voltage-boosting Marx pulse generator (BMPG). The proposed BMPG has hardware features that allow modularity, redundancy, and scalability as well as operational features that alleviate the need of series-connected switches and allows generation of a wide range of pulse waveforms. In the BMPG, a controllable, low-voltage input boost converter supplies, via directing/blocking (D/B) diodes, two arms of a series modular multilevel converter half-bridge sub-modules (HB-SMs). At start up, all the arm's SM capacitors are resonantly charged in parallel from 0 V, simultaneously via directing diodes, to a voltage in excess of the source voltage. After the first pulse delivery, the energy of the SM capacitors decreases due to the generated pulse. Then, for continuous operation without fully discharging the SM capacitors or having a large voltage droop as in the available Marx generators, the SM capacitors are continuously recharged in parallel, to the desired boosted voltage level. Because all SMs are parallelly connected, the boost converter duty ratio is controlled by a single voltage measurement at the output terminals of the boost converter. Due to the proposed SMs structure and the utilization of D/B diodes, each SM capacitor is effectively controlled individually without requiring a voltage sensor across each SM capacitor. Generation of the commonly used pulse waveforms in electroporation applications is possible, while assuring balanced capacitors, hence SM voltages. The proposed BMPG has several topological variations such as utilizing a buck–boost converter at the input stage and replacing the HB-SM with full-bridge SMs. The proposed BMPG topology is assessed by simulation and scaled-down proof-of-concept experimentation to explore its viability for electroporation applications. [ABSTRACT FROM AUTHOR]

In this study, a cost‐effective HVDC shunt tap with low‐number of relatively low‐voltage semiconductor devices and small‐sized passive components is proposed. The proposed architecture is based on employing three single‐phase half‐bridge Modular Multilevel Converters (MMCs), where the DC sides of MMCs are connected in series across the total DC‐link voltage. The MMCs are adopted instead of conventional Two‐Level Voltage Source Converters (2L‐VSCs) to avoid the complications of series connection of Insulated Gate Bipolar Transistors (IGBTs). The involved MMCs in the suggested architecture are operated with the conventional 2L modulation, which results in insignificant arm inductors and Sub‐Modules (SMs) capacitances (in range of µH and µF, respectively). This, in turn, affects positively the converter cost and footprint. Each arm of the involved MMCs can be considered as a high‐voltage valve of a 2L‐VSC. To maintain the balance of SMs capacitors, each arm of the involved (N + 1)‐level MMC has an extra SM (a balancing SM) to select N out of N + 1 SMs during the turn‐off condition. The operational concept, design, and assessment of the proposed architecture are presented in this study. Simulation results are provided for substantiation of the proposed concept. Finally, a scaled down single‐phase prototype is used for experimental validation. [ABSTRACT FROM AUTHOR]

Because of its potential benefits in lowering process energy consumption, freezing desalination as a seawater desalination method has attracted a lot of attention. However, significant mass loss caused by extensive washing is a fundamental problem preventing the development of freezing desalination technologies. For freezing desalination technology to be widely adopted, the washing process must be eliminated. In this study, a fluid-layer-based method for separating ice is introduced. The density differences between the generated ice and the silicon oil intermediate fluid layer facilitate the separation of the product water without the need of conventional crushing or washing processes. The aim of this work is to study the feasibility and applicability of using silicon oil as an intermediary fluid layer in ice separation during the freezing desalination process. The outcomes show promise for a feasible freezing desalination technique utilizing silicon oil as an intermediate separation layer. It was also observed that as feed salinity decreases, the desalination rate increases. For instance, the distillation rate is 50.89 % and 67.3 % at an initial feed salinity equal 45,000 and 10,000 ppm, respectively. Overall, the initial feed salinity and COP are found to have an impact on specific energy usage. • Intermediate fluid layer for ice separation • Silicon oil for ice production in freezing desalination • Specific energy consumption is affected by initial salinity and COP. • Specific energy consumption 57.412 kWh/m3 [ABSTRACT FROM AUTHOR]

This paper presents a drive system based on a modular multilevel converter (MMC) with high-frequency magnetic channels between adjacent-arm submodules (SMs), suitable for medium-voltage, high-power three-phase variable-speed machines. The configuration employs chains of dual half-bridge (DHB) modules linking adjacent SMs of three-phase symmetrical arms. The DHB modules are operating as power channels enabling energy exchange to restore the power imbalance among the SM capacitors. This allows arms’ ripple-powers to be entirely decoupled through bidirectional power transfer between adjacent-arm SMs, resulting in a near ripple-free SM capacitor voltage profile. Therefore, the MMC common problem of wide voltage fluctuation across SM capacitors is comprehensively solved, independent of the operating frequency. Additionally, a significant reduction in the sizing requirement of SM capacitance is achieved. The configuration is able to drive multimegawatt machines from standstill to the rated speed at the rated torque operating condition. The operating principle of the proposed MMC configuration is explained and necessary mathematical analysis is derived. Features and viability of the proposed drive system are verified through simulation and experimentation. [ABSTRACT FROM AUTHOR]

The application of multiphase machines in high-power applications is now a recognized alternative, thanks to their higher fault-tolerance when compared with standard three-phase systems. Although multiphase machines with multiples of three-phase winding sets have been favored in many applications, literature has shown that machines with a prime number of phases, such as five-phase machines, generally outperform other phase orders, especially in terms of machine torque density. One of the major problems when dealing with a prime number of phases either in academic research or industrial applications is the special stator design. This paper provides a general technique to rewind standard off-the-shelf three-phase stator frames with any general prime phase order while preserving the same copper volume. The proposed winding layout is derived using the star of slots theory and the concept of stator winding shifting. Finite-element simulations are used to investigate examples with different phase orders, while experimental investigation is carried out to corroborate the proposed concept by rewinding a standard three-phase stator as a five-phase machine. [ABSTRACT FROM AUTHOR]

The nine-phase six-terminal induction machine (IM) has been recently proposed as a promising contender to the conventional asymmetrical six-phase type in terms of torque density, stator winding simplicity, and fault-tolerant capability. The stator is composed of nine phases, which are connected in a fashion to only provide six stator terminals. Therefore, this connection combines the high performance of a nine-phase winding with the terminal behavior of a six-phase machine. This paper introduces the machine mathematical model based on the vector space decomposition (VSD) modeling approach. The required current and voltage sequence transformation matrices are derived such that the machine is mathematically regarded as an equivalent six-phase IM with only three decoupled subspaces. This way, the same VSD-based controller structures conventionally applied to six-phase-based systems can be preserved. A 1.5-hp prototype IM is used to experimentally validate the machine model under both healthy and open-phase conditions. [ABSTRACT FROM AUTHOR]

In this paper, a dc–ac buck converter is proposed as a grid-side converter in high voltage dc (HVdc) transmission systems for high-power renewable energy source grid integration. The proposed architecture consists of multimodules of half-bridge voltage source converters (HB-VSCs). The dc terminals of the HB-VSCs are connected in series across the entire dc link (i.e., capacitor tapped), whereas their ac outputs are connected to multiwinding transformers to provide the three-phase terminals for ac grid integration. The proposed grid-connected capacitor-tapped multimodule converter (CT-MC) architecture, inspired from the HVdc shunt tap proposed by ABB, provides a dc–ac conversion with a relatively moderate voltage rating of semiconductor devices. It also provides operation with a lower number of semiconductor devices, gate driver circuits, voltage sensors, and lower total MVA rating of semiconductor devices (67%) compared with the conventional three-phase HB modular multilevel converter, which positively affects the system cost and reduces the computational burden of the employed controller. In this paper, the operational concept and control of the CT-MC are presented along with a capacitor voltage balancing approach. Simulation results are presented during normal and abnormal conditions to show the viability of the proposed architecture. Finally, a scaled down prototype for the CT-MC is employed to validate the converter operation. [ABSTRACT FROM AUTHOR]

This paper presents a dual modular multilevel converter (MMC) topology that utilizes energy exchange between adjacent-arm submodules (SMs), operating with out-of-phase modulation. The proposed configuration is applicable to medium-voltage high-power variable-speed drives incorporating open-end stator winding machines. A novel concept of power decoupling between adjacent-arm SMs in the dual MMC topology is realized through high-frequency transformer-based dc–dc converter modules. This concept offers a significant reduction in the sizing requirement of the SM capacitance and the stored energy in the MMC system, while avoiding the problem of wide voltage fluctuations of SM capacitors, especially at low operating frequencies. The proposed configuration can produce dc voltage; therefore, a machine speed range from zero speed to the rated speed is possible under the rated torque operating condition. The operating principles of the proposed dual MMC configuration are elaborated and necessary mathematical analysis is derived. Simulation and experimental results verify the concept of the proposed drive configuration. [ABSTRACT FROM AUTHOR]

In this paper, a new HVDC shunt tap is proposed. The proposed configuration consists of a unidirectional hybrid modular DC–DC converter followed by a voltage source converter for DC–AC conversion to feed a local AC network connected to the tap output terminals. The proposed DC–DC converter consists of a high-voltage valve, and series-connected unidirectional half-bridge Sub-Modules (SMs). Unlike Marx generator circuit concept, the DC–DC conversion in the proposed configuration is achieved by enabling simultaneous charging of series-connected capacitors (i.e. SMs capacitors), and sequential discharging of capacitors. Compared to Marx-generator based switched capacitor DC–DC converters, the proposed configuration has a lower number of semiconductor devices, which affects positively the system cost, and reduces the control complexity. Detailed illustration, design, and control of the proposed approach are presented. Simulation results are presented to validate the proposed approach. [ABSTRACT FROM AUTHOR]

This study proposes an isolated on‐board integrated battery charger using an interior permanent magnet (IPM) machine with a nine‐slot/eight‐pole combination or its multiples, and equipped with a non‐overlapped fractional slot concentrated winding. The proposed winding layout comprises three three‐phase winding sets that are connected in such a way as to provide six motor terminals. Hence, a six‐phase or two three‐phase converters will be required for propulsion. Under motoring mode, the machine can be effectively regarded as a six‐phase machine, which provides a high fault‐tolerant capability, and allows for a 'limp home' mode of operation. Additionally, all magneto motive force subharmonics are eliminated, which significantly reduces the induced rotor eddy current losses, when compared with a conventional three‐phase motor having the same slot/pole combination. In battery charging mode, the winding is reconfigured, so that the machine is considered as a three‐phase to six‐phase rotating transformer. A 40 kW IPM machine is designed and simulated under different modes of operation using two‐dimensional finite element analysis to validate the proposed concept. A small‐scale prototype machine is also used for experimental validation. [ABSTRACT FROM AUTHOR]

Conventionally, in order to reduce the ac components of the dc-link capacitors of the two-level Half-Bridge Voltage Source Inverter (HB-VSI), high dc-link capacitances are required. This necessitates the employment of short-lifetime and bulky electrolytic capacitors. In this paper, an analysis for the performance of low dc-link capacitances-based HB-VSI is presented to elucidate its ability to generate an enhanced fundamental output voltage magnitude without increasing the voltage rating of the involved switches. This feature is constrained by the load displacement factor. The introduced enhancement is due to the ac components of the capacitors' voltages. The presented approach can be employed for multi-phase systems through using multi single-phase HB-VSI(s). Mathematical analysis of the proposed approach is presented in this paper. To ensure a successful operation of the proposed approach, a closed loop current controller is examined. An expression for the critical dc-link capacitance, which is the lowest dc-link capacitance that can be employed for unipolar capacitors' voltages, is derived. Finally, simulation and experimental results are presented to validate the proposed claims. [ABSTRACT FROM AUTHOR]

High-voltage (HV) pulses are used in electroporation to subject pulsed electric field (PEF) onto a sample under treatment. Pulse-waveform shape, voltage magnitude, pulse duration, and pulse repetition rate are the basic controllable variables required for particular PEF application. In practice, a custom-made pulse generator is dedicated for each PEF application with limited flexibility in changing these variables. In this paper, a universal pulse-waveform generator (UPG) is proposed, where the controller software algorithm can manipulate a basic generated multilevel pulse waveform to emulate many different PEF pulse waveforms. The commonly used PEF HV pulse waveforms can be generated as bipolar or monopolar with controllable pulse durations, repetition times, and voltage magnitudes. The UPG has the ability to generate multilevel pulses that have controllable $dv/dt$, which allows reduction of the electromagnetic interference generated by the converter. The UPG topology is based on half-bridge modular multilevel converter (HB-MMC) cells forming two transition arms in conjunction with two bistate arms, together creating an H-bridge. The HB-MMC cell capacitors provide a controllable energy source which charge from the dc input supply and discharge across the load, while the two bistate arms allow charging the HB-MMC cell capacitors. Hence, the UPG topology offers modularity, redundancy, and scalability. The HB-MMC individual cell capacitance is low and the cell voltages are balanced by employing the sorting and rotating algorithm used in conventional HB-MMC topologies for HV dc transmission applications. The viability of the proposed UPG converter is validated by MATLAB/Simulink simulation and scaled-down experimentation. [ABSTRACT FROM PUBLISHER]

This paper presents a buck-boost converter-based bipolar pulse generator, which is able to generate bipolar exponential pulses across a resistive load. The concept of the proposed approach depends on operating the involved buck-boost converters in discontinuous current conduction mode with high-voltage gain and enhanced efficiency. A full design of the pulse generator and its passive components is presented to ensure generating the pulses with the desired specifications (rise time, pulse width, and pulse magnitude) for a given load resistance and input dc voltage. In case of moderate pulsed output voltages (i.e. few of kV), one module of the presented bipolar generator can be employed. While in case of high-voltage pulsed output, multi-module version can be employed, where each module is fed from an isolated dc source and their outputs are connected in series. Simulation models for the proposed approach are built to elucidate their performance in case of one-module as well as multi-module based generator. Finally, a scaled-down prototype for one-module of buck-boost converter-based bipolar pulse generator is implemented to validate the proposed concept. [ABSTRACT FROM AUTHOR]

High-voltage (HV) pulse generators (PGs) are the core of pulsed electric field applications. Applying HV pulses produces electrical pores in a biological cell membrane, in which if the size of the pores increases beyond a critical size, the cell will not survive. This paper proposes a new HV-PG based on the modular multilevel converter with full-bridge submodules (FB-SMs). In order to alleviate the need of complicated sensorless or sensor-based voltage balancing techniques for the FB-SM capacitors, a dedicated self-regulating charging circuit is connected across each FB-SM capacitor. The individual capacitor charging voltage level is obtained from three successive stages, namely, convert the low-voltage dc input voltage to a high-frequency square ac voltage, increase the ac voltage level via a nanocrystalline step-up transformer, and rectify the secondary transformer ac voltage via a diode FB rectifier. The HV bipolar pulses are formed across the load in a fourth stage through series connected FB-SMs. The flexibility of inserting and bypassing the FB-SM capacitors allows the proposed topology to generate different pulse-waveform shapes, including rectangular waveforms with specifically reduced dv/dt and ramp pulses. The practical results, from a scaled-down experimental rig with five FB-SMs and a 1-kV peak-to-peak pulse output, validate the proposed topology. [ABSTRACT FROM PUBLISHER]

High-voltage (HV) pulses are used in pulsed electric field (PEF) applications to provide an effective electroporation process, a process in which harmful microorganisms are disinfected when subjected to a PEF. Depending on the PEF application, different HV pulse specifications are required such as the pulse-waveform shape, the voltage magnitude, the pulse duration, and the pulse repetition rate. In this paper, a generic pulse-waveform generator (GPG) is proposed, and the GPG topology is based on half-bridge modular multilevel converter (HB-MMC) cells. The GPG topology is formed of four identical arms of series-connected HB-MMC cells forming an H-bridge. Unlike the conventional HB-MMC-based converters in HVdc transmission, the GPG load power flow is not continuous which leads to smaller size cell capacitors utilization; hence, smaller footprint of the GPG is achieved. The GPG topology flexibility allows the controller software to generate a basic multilevel waveform which can be manipulated to generate the commonly used PEF pulse waveforms. Therefore, the proposed topology offers modularity, redundancy, and scalability. The viability of the proposed GPG converter is validated by MATLAB/Simulink simulation and experimentation. [ABSTRACT FROM PUBLISHER]

This paper presents a new high-voltage pulse generator, which is based on positive and negative buck-boost (BB) converters fed from a relatively low voltage dc supply. The proposed generator is able to generate unipolar or bipolar high-voltage pulses via operating the BB converters with series or parallel connected outputs respectively using a common input dc source. The components of each converter are rated at half of the pulsed voltage magnitude in the unipolar mode. The converters in the proposed pulse generator operate in discontinuous conduction mode. This enhances system efficiency, as the circuit only operates when it is desired to generate a pulsed output voltage, otherwise the circuit is switched to idle mode with zero current. Detailed illustration of the proposed approach is presented along with a full design of the system components for given output pulse specifications. Finally, simulation and experimental results are presented to validate the proposed concept. [ABSTRACT FROM PUBLISHER]

This paper proposes a new three-phase transformerless STATic synchronous COMpensator (STATCOM) for shunt reactive power compensation in medium/high-voltage applications. The proposed STATCOM is based on a hybrid Boost Modular Multilevel Converter (hybrid BMMC) with a reduced number of Full-Bridge SubModules (FB-SMs). Operating with almost zero displacement factor at the ac terminals of the converter guarantees sufficient charging and discharging time intervals for the Half-Bridge SMs (HB-SMs) which ensures well-balanced capacitor voltages. Conventionally, each arm in a hybrid BMMC contains FB-SMs and HB-SMs with a ratio of 2:1 respectively. In this work, a new hybrid BMMC with a ratio of 1:2 is employed, which enables operating with a reduced number of FB-SMs with the same boosting capability, therefore, enabling transformerless operation. Nonetheless, the tradeoff is the loss of the dc fault blocking capability compared to the 2:1 configuration. This may be acceptable in STATCOM applications, as the possibility of having a dc side fault in such application is limited, compared to, for instance, MMC in high voltage dc network applications. In this work, detailed illustration of the proposed STATCOM configuration along with its controllers are presented. Finally, simulation case studies are considered to demonstrate the effectiveness of the proposed approach. The simulation results show promising and satisfactory performance. [ABSTRACT FROM AUTHOR]

Bipolar repetitive high-voltage pulse generators are commonly used in modern pulsed power applications. Conventionally, bipolar high-voltage pulses can be generated by adding a high-voltage H-bridge at the output stage of a unipolar high-voltage pulse generator which increases complexity and cost of the bipolar high-voltage pulse generator. In this paper, a boost-inverter-based bipolar high-voltage pulse generator with high-voltage gain is proposed. The proposed generator can provide high-voltage bipolar output pulses with the desired specifications from a low input dc voltage. The proposed generator is based on employing two bidirectional boost dc–dc converters, where the load is connected differentially between the boost converters’ output terminals. In the proposed approach, four controlled switches are required. Only two out of these four switches are rated at the high-voltage output level which affects positively the system cost. A detailed illustration of the proposed approach along with the design of its passive components is presented in this study. Simulation and experimental results are used to validate the proposed approach. [ABSTRACT FROM AUTHOR]