Multistage Switching Research Articles

Scalable SOA-based Banyan optical space switch on InP membrane on silicon (IMOS).

Optical switches (OS) are vital for meeting modern data centers' capacity and latency needs, overcoming the bandwidth and speed limitations that electronic switches encounter. To this end, this work proposes a semiconductor optical amplifier (SOA)-based OS on the IMOS, a unique platform with a combination of high refractive index contrast for compactness and monolithic active-passive integration for active functionalities, thereby enabling the creation of compact SOA-based OSes. An 8 × 8 Banyan SOA-based OS is integrated on a 4 × 4 mm2 area on the standard 4 × 6 mm2 IMOS cell. This marks the first application of the IMOS technology platform for SOA-based OSes and sets the stage for compact and large-scale monolithic photonic integrated OS circuits. The basic 2 × 2 switch module delivers a high optical signal-to-noise ratio (OSNR) and an extinction ratio (ER) above 45 dB. Employing NRZ-OOK routing on the 2 × 2 basic OS module, a 15 dB input power dynamic range (IPDR) is achieved within a 1 dB power penalty at 12.5 Gb/s. Data routing at higher data rates of 25 Gb/s and 40 Gb/s incurs power penalties of 0.8 and 1.4 dB, respectively. Furthermore, data routing for a 3-stage 8 × 8 switch operating at 25 Gb/s results in a power penalty of 1.2 dB. Compared to the 1-stage 2 × 2 switch, only a 0.4 dB additional penalty is observed despite incorporating 2 additional SOAs in the cascade. This indicates that the switch can scale to higher radix to accommodate multi-stage switches with numerous ports, large bandwidth, and fast speed, which is essential in modern large-scale data centers.

Silk Fibroin-Based Multiple-Shape-Memory Organohydrogels.

Organohydrogels (OHGs) are intriguing materials due to their unique composition of both hydrophilic and hydrophobic domains. This antagonistic nature endows the OHGs with several remarkable properties, making them highly versatile for various applications. We present here a simple and inexpensive approach to fabricate silk fibroin (SF)-based OHGs with multistage switching mechanics and viscoelasticity. The continuous hydrophilic phase of the OHG precursor consists of an aqueous SF solution, while the hydrophobic droplet phase consists of a crystallizable n-octadecyl acrylate (C18A) monomer and several long-chain saturated hydrocarbons (HCs) with various chain lengths between 14 and 32 carbon atoms, namely, n-tetradecane, n-octadecane, n-docosane, n-dotriacontane, and 1-docosanol. After the addition of a C18A/HC mixture containing Irgacure photoinitiator into the continuous aqueous SF phase under stirring, a stable oil-in-water emulsion was obtained, which was then photopolymerized at 23 ± 2 °C to obtain nonswelling OHGs with multiple-shape-memory behavior. By changing the chain length and mass proportion of HCs, a series of OHGs with tunable transition temperatures could be obtained, meeting various applications. OHGs containing dimer, trimer, and quadruple combinations of in situ-formed poly(C18A) and HC microinclusions exhibit effective triple- or quintuple-shape memory whose shape-recovery temperatures could be adjusted over a wide range, e.g., between 7 and 70 °C.

Research on Conduction Delay Time Characteristics of Double-Gap Surface Flashover Triggered Multistage Vacuum Switch

Due to the insulation saturation effect of a vacuum gap, the series connection is the main method to improve the capability of the triggered vacuum switch (STVS) to withstand voltage. In this paper, a double-gap surface flashover triggered multistage vacuum switch (DMVS) is constructed based on a removable vacuum chamber. The DMVS consists of a surface flashover triggered vacuum gap (STG) and a self-breakdown vacuum gap (SBG) in series. The trend in DMVS conduction delay time under different operating parameters and gap distances is firstly measured through experiments, and then the conduction delay time characteristics of DMVS and single-gap STVS compared. The test results show that increasing the trigger current and operating voltage and decreasing the gap distance of each vacuum gap can optimize the conduction delay time of the DMVS, but the voltage division ratio between the STG and the SBG has no obvious influence on the conduction delay time. The comparison result between the DMVS and the STVS shows that increasing the number of series gaps increases the conduction delay time but, for a certain vacuum gap distance, DMVS exhibits superior conduction delay time characteristics compared to STVS.

Investigations on trigger process of triple-gap laser triggered multi-stage vacuum switch

To develop high voltage pulsed power closing switch utilizing the advantages of vacuum gap, a laser triggered multi-stage vacuum switch (LTMVS) is proposed in this paper. Trigger process of triple-gap LTMVS is analyzed based on a detachable vacuum chamber. Closing processes and time-delay characteristics of different gaps in LTMVS are studied later. The results convey that, trigger process of LTMVS can be separated to two periods, the trigger of laser triggered gap, and the cascade breakdown of series connected short gaps under impulse voltage with DC superimposition. Breakdown sequences of cascade gaps are not in stable order, and its delay time mainly depends on the initially breakdown gap. The increase of laser energy and operating voltage benefit to both reducing the delay time of triggered gap and cascade gaps. Under 30 mJ laser energy, delay time of 4 mm laser triggered gap can be controlled within 25.8 ± 1.3ns, and breakdown delay time of 0.8 mm vacuum gap reaches 79 ± 2.5ns. Suggestions for the developments of LTMVS are given based on above researches.

Study of operation mode and breakdown characteristics for multi-stage gas switch

Multi-stage gas switches (MSGSs) are widely used in megavolt pulsed power systems due to their advantages of high withstand voltage, fast establishing time and relatively high operating frequency. Multiple operation modes, which are induced by the different breakdown sequences at each stage, are found to affect the breakdown characteristics of the gas switch. Based on the theoretical analysis of the working principle, the classification of the operation mode and the factors determining the operation mode of the MSGS are proposed. Methods for investigating the output waveform for MSGS are established by simulating lumped parameters and studying the breakdown time sequence of individual stages. In comparison with the intended mode of operation, the disadvantages of the unintended modes of operation for MSGS, including error-breakdown and non-triggering mode, are revealed. For unintended modes, the distortion of the output waveform, which determines the efficiency of energy transmission through the switch and the increased delay time jitter, which determines the synchronization of the gas switch, are further investigated. The possibility of non-triggering and its mechanism on surface flashovers induced by drifting electrons are also analyzed. Based on this study, design principles and methods are proposed to ensure the intended operation of the MSGS.

A Hybrid Clustered Ant Colony Optimization Approach for the Hierarchical Multi-Switch Multi-Echelon Vehicle Routing Problem with Service Times

In this paper, the Hierarchical Multi Switch Multi Echelon Vehicle Routing Problem with Service Times (HMSME-VRP-ST) is presented. This novel problem considers distribution applications in which goods are delivered either directly from a central depot or through intermediate facilities called switch points. Commodities are loaded into interchangeable containers called swap bodies at the central depot, and can be transferred from one vehicle to another at the switch points. The goal is to minimize fixed and variable costs of the vehicle fleet and swap-bodies while serving a predetermined set of customers. The routes are constrained by time and swap bodies by loading capacity. A mathematical model of the HMSME-VRP-ST is presented, and a Hybrid Clustered Ant Colony Optimization (HCACO) algorithm is proposed to address the complexity of the problem. The approach utilizes the ant-based clustering algorithm, combining the density and connectivity properties of clustering for creating promising neighborhoods with the solution construction methodology and pheromone-based memory of the Ant Colony Optimization framework. Additionally, two local search schemes based on Variable Neighborhood Descent are incorporated to further improve the generated solutions. The behavior of each HCACO variant is analyzed, and their results are compared to a Greedy Randomized Adaptive Search Procedure metaheuristic in 36 newly generated benchmarks comprising of clustered, uniformly random, and mixed clustered-random instances.

An adjustable multistage resistance switching behavior of a photoelectric artificial synaptic device with a ferroelectric diode effect for neuromorphic computing.

Neuromorphic computing, which mimics biological neural networks, is widely regarded as the optimal solution for addressing the limitations of traditional von Neumann computing architecture. In this work, an adjustable multistage resistance switching ferroelectric Bi2FeCrO6 diode artificial synaptic device was fabricated using a sol-gel method with a simple process. The device exhibits nonlinearity in its electrical characteristics, demonstrating tunable multistage resistance switching behavior and a strong ferroelectric diode effect through the manipulation of ferroelectric polarization. One of its salient advantages resides in its capacity to dynamically regulate its polarization state in response to an external electric field, thereby facilitating the fine-tuning of synaptic connection strength while maintaining synaptic stability. The device is capable of accurately simulating the fundamental properties of biological synapses, including long/short-term plasticity, paired-pulse facilitation, and spike-timing-dependent plasticity. Additionally, the device exhibits a distinctive photoelectric response and is capable of inducing synaptic plasticity by light signal activation. The utilization of a femtosecond laser for the scrutiny of carrier transport mechanisms imparts profound insights into the intricate dynamics governing the optical memory effect. Furthermore, utilizing a convolutional neural network (CNN) architecture, the recognition accuracy of the MNIST and fashion MNIST datasets was improved to 95.6% and 78%, respectively, through the implementation of improved random adaptive algorithms. These findings present a new opportunity for utilizing Bi2FeCrO6 materials in the development of artificial synapses for neuromorphic computation.

High anti-interference fault diagnosis method for PMSG drive system based on feature clustering optimization

Driven by the “double carbon” goal, the security of wind power integrated system is importance and highlighted. The open circuit fault in switch of PMSG drive system often occurs, with high concealment and obvious load characteristics. Generally, the data-driven diagnosis method needs try many times to find feature parameters, choose several of them and obtain large sample size to distinguish the fault. To solve these shortages, a fault diagnosis method based on cluster analysis is proposed to this paper. The features are projected into the 3-D space. These features, who can classify into 6 clusters, are retained. Further, the intra-class distance and the inter-class distance are used to measure the retained features. By this measurement, the distinguish ability and deformation degree of these features is assessed. In order to keep the highlight ability, the assessed features are composed to serval groups, which have two features with diffident codes. After the above process, the definitive features are chosen and used to train the BPNN. Finally, the open circuit fault diagnosis of PMSG drive system under multi wind speed and multi switch open circuit fault is realized by the trained BPNN. The definitive feature not only ensures the anti-interference performance of fault diagnosis, but also avoids the blindness of fault diagnosis feature extraction, which has certain engineering practical significance.

A 1-MV low-jitter high-reliability multi-stage equal breakdown probability gas switch

This paper presents the development of a novel megavolt-class equal breakdown probability (EBP) multi-stage self-discharge gas switch for high power microwave generation with low breakdown jitter and high reliability. With the joint distribution of breakdown probability for ‘n’ identical stages of EBP gas switch, the advantages of diminishing the breakdown jitter and omitting the complex breakdown order problem are hence disclosed in considerable details with the aid of probability computation method. Based on theoretical analysis, a 5 stages 1-MV EBP multi-stage gas switch is designed in which periodic cog profile cathode is proposed to further decrease the breakdown jitter. The performances of EBP switch are tested at the repetition rate of 1,10,20,50 Hz over 1000 successive pulses with breakdown jitter as low as 2.7% ,energy efficiency as high as 90% and pulse rising time as low as 5 ns. The overall performance of EBP gas switch shows great potential in compact and reliable high power microwave generating system.

Multi-stage switched-inductor switched-capacitor high gain DC-DC converter

ABSTRACT This paper presents a Multi-stage Switch Inductor Switch Capacitor High Gain DC-DC Converter for microgrid application designed with integrated Active Switch Capacitor (ASC) and Active Passive Inductor Cell (APIC). The closed loop control of a proposed voltage lift DC-DC converter is performed to ensure the constant output voltage disregarding the change in input voltage. The new high gain extendable DC-DC boost converter topology is capable of providing high-gain voltage with low duty cycle and it is extendable by increasing the number of APIC network. Analytical modelling of the proposed converter is carried out to obtain the technical specifications. The open loop and closed loop simulation model of the proposed converter is developed in the MATLAB/Simulink environment to analyse the performance of the converter. The microcontroller-based hardware model of the proposed converter of power rated 200 W (18/200 V at 50% duty ratio) is developed and tested in open loop to validate the simulation results and experimental set-up results are reported.

Bending Modulated Ultralarge Magnetoresistance in Flexible La0.67Ba0.33MnO3 Thin Film Based Device.

Magnetoresistance based information devices have attracted much attention due to the ability to utilize spins as information carriers. To promote the magnetoresistance-based devices, ultrahigh magnetoresistance ratios are highly desirable for magnetic sensing, memory, and artificial intelligent devices, etc. However, today the magnetoresistance devices are facing the challenge of limited magnetoresistance ratio, low work temperature, or high magnetic field, which calls for proper theories and mechanisms. To address it, we first introduce the flexible bending-controlled magnetoresistance device based on the La0.67Ba0.33MnO3 film. Due to the anisotropic resistance of the La0.67Ba0.33MnO3 film and the nonlinear amplification effect of the Zener diode, the device has exhibited strong magnetoresistive performance (∼8725% at 1 T, 300 K). Combining the assist from mechanical bending and diode, high magnetic field sensitivity with large magnetoresistance ratio (∼1.7 × 104% at 1 T, 300 K) and low work current (∼0.15 mA) is simultaneously achieved at room temperature, which is over 104 times larger than that of the planar La0.67Ba0.33MnO3 film. Based on the above results, we propose one but not the only possible application as tunable multistage switch. Our findings may pave a strategy to develop flexible diode-enhanced magnetoresistance device with ultrahigh magnetoresistance ratios and bending tunable performances.

Effects of shape on magnetization switching in systems of magnetic elongated nanoparticles

The equilibrium magnetization of flat elongated magnetic nanoparticles of different shapes has been determined for a range of the static magnetic fields applied parallel to their long/easy axes. The behaviour of single particles has been compared with that of equidistant chains composed of the same particles. The shapes sharpened at the ends, i.e. elongated diamonds and two-sided swords, switch with minimal inhomogeneities of magnetization and with well rectangular hystereses. This may be useful in designing of binary memory devices. The narrowest hysteresis has been found for hourglass shapes, where the switching is preceded with inhomogeneities of magnetization so the hystereses are rounded. The shapes endowed with broadened heads, such as dumbbells and bones, show vortex-like inhomogeneities, marked with an interesting interplay of helicities, which result in a multi-stage switching with relatively large coercive fields.

Green Multi-Stage Upgrade for Bundled-Link SDNs With Budget and Delay Constraints

Upgrading a legacy network to a Software Defined Network in stages, and minimizing the energy consumption of a network are now of great interest to operators. To this end, this paper addresses a novel problem: minimize the energy consumption of a network by upgrading switches over multiple stages subject to the available monetary budget at each stage. Our problem considers (i) bundled links that can be powered-off individually, (ii) decreasing upgrade cost and increasing traffic demands over multiple stages, and (iii) rerouting demands to an alternative path with a delay that is within a predefined limit. Additionally, the link load on the path is no larger than a given maximum utilization. We formulate the problem as an Integer Linear Program and propose a greedy heuristic called Green Multi-Stage Switch Upgrade (GMSU). Experiment results on five actual network topologies show that: 1) our approaches reduce the energy consumption by up to 73.98%; 2) rerouting traffic demand via longer paths improves the energy saving by up to 9.6%; 3) GMSU produces results that are at most 4.83% from the optimal result; and 4) increasing the budget and the number of stages affect the total energy saved and the number of upgraded switches.

Resistive Switching Effect of Multiferroic Complex Oxide Solid Solution Thin Films

Resistive switching in multiferroics has attracted increasing attention due to the potential application for next-generation nonvolatile memory and could lead to forms of computing. However, the resistive switching mechanism in solid solution oxides is unclear. In this article, we have successfully fabricated binary 0.72BiTi0.27Fe0.46Mg0.27O3-0.28LaFeO3 (BTFM-LFO) and ternary 0.625BiTi0.27Fe0.46Mg0.27O3-0.25LaFeO3-0.125La2MgTiO6 (BTFM-LFO-LMT) thin films with precise component control by the spin coating method. The solid solution films exhibit obvious ferroelectricity and magnetism at room temperature. Both binary and ternary solid solution films show switchable polarization, weak magnetism, and reversible and repeatable resistive switching effects. Multistage resistive switching behavior was observed. Four resistive switching states were obtained in the binary film; the highest Ion/off is up to 106. The influence of the film composition on the resistive switching effect was discussed. It is considered that the oxide vacancy/valance exchange-induced defects play a dominant role in the resistive switching effect of complex oxide thin films. This work provides an alternative pathway to explore the resistive switching in multiferroic oxides by fabrication of complex solid solution films.

ITO-based microheaters for reversible multi-stage switching of phase-change materials: towards miniaturized beyond-binary reconfigurable integrated photonics.

Inducing a large refractive-index change is the holy grail of reconfigurable photonic structures, a goal that has long been the driving force behind the discovery of new optical material platforms. Recently, the unprecedentedly large refractive-index contrast between the amorphous and crystalline states of Ge-Sb-Te (GST)-based phase-change materials (PCMs) has attracted tremendous attention for reconfigurable integrated nanophotonics. Here, we introduce a microheater platform that employs optically transparent and electrically conductive indium-tin-oxide (ITO) bridges for the fast and reversible electrical switching of the GST phase between crystalline and amorphous states. By the proper assignment of electrical pulses applied to the ITO microheater, we show that our platform allows for the registration of virtually any intermediate crystalline state into the GST film integrated on the top of the designed microheaters. More importantly, we demonstrate the full reversibility of the GST phase between amorphous and crystalline states. To show the feasibility of using this hybrid GST/ITO platform for miniaturized integrated nanophotonic structures, we integrate our designed microheaters into the arms of a Mach-Zehnder interferometer to realize electrically reconfigurable optical phase shifters with orders of magnitude smaller footprints compared to existing integrated photonic architectures. We show that the phase of optical signals can be gradually shifted in multiple intermediate states using a structure that can potentially be smaller than a single wavelength. We believe that our study showcases the possibility of forming a whole new class of miniaturized reconfigurable integrated nanophotonics using beyond-binary reconfiguration of optical functionalities in hybrid PCM-photonic devices.

A compact 4 GW pulse generator based on pulse forming network-Marx for high-power microwave application.

A compact PFN (pulse forming network)-Marx generator, which is based on mica capacitors, is constructed to generate intense electron beams for the purpose of high-power microwave generation. The key components of the generator, including a PFN-Marx, a trigger source, a multi-stage gas switch, and a load, are introduced in this paper. The PFN-Marx is composed of 19 PFN modules, which are formed by four mica capacitors in parallel. The temperature characteristics and pulse characteristics are tested in this study. The mica capacitor is insensitive to the temperature, and its lifetime is tens of thousands. Considering the influence of the ultraviolet light pre-ionization, gas gap switches are assembled in a nylon house. The trigger source, which is a mini-Marx generator based on the integration into the magnetic transformer and the magnetic switch, is used for increasing the stability of the switches. The generator has been tested on a water load and a relative magnetron. The experimental results show that this generator can deliver electrical pulses with the pulse width of 120ns and the amplitude of 400 kV on a 40-Ω water load at a repetition rate of 50Hz. In addition, utilizing the generator to drive a Ku band magnetron at a voltage level of 330 kV, a 500MW microwave pulse with the pulse width of 50ns at the frequency of 14.4GHz is obtained.

Reaction process and characteristics for coal char gasification under changed CO2/H2O atmosphere in various reaction stages

During the operation of industrial gasifier, the concentrations of CO2 and H2O in gasification media vary with the change of stages, causing the gasification process being affected accordingly. Therefore, dividing the gasification process into different stages to study the effect of multi-stage switching atmosphere is significant. The conversion rate, reaction characteristics and reaction process for the gasification of Xiaolongtan (XLT) coal char in different atmospheres (CO2/H2O/N2) switching in the early, middle and late reaction stages were investigated using thermo-gravimetric analysis (TGA). The results indicated that the average reaction rate of coal char with H2O was approximately 3 times that of CO2. Increasing H2O concentration improved the reaction and conversion rate of coal char, which was the most obvious in the early stage. With the H2O concentration increasing from 0 to 95%, the increment of conversion rate in the early, middle, and late stages were 7.13%, 4.40%, and 3.92%, respectively. Thus, considering the problem of H2O corrosion in practical production, the H2O concentration could be appropriately increased in the early stage to improve efficiency. Compared with the random pore model, the shrinking core model fitted the gasification process of coal char better in a highly reactive 95% H2O/5% N2 atmosphere.

VLSI Design of A Chip With High Speed Atm Switch-A Review

In current computer communication network, it is overwhelmed by two technologies, in particular Asynchronous Transfer Mode (ATM) and Internet Protocol (IP). Association situated ATM is the awesome constant administrations which require ensured nature of-administration like video conferencing. Be that as it may, connectionless IP is more proficient than ATM for non-ongoing administrations like email. Right now, the significant exploration challenge is on the most proficient method to coordinate ATM and IP into a solitary network effectively. It is shown by the acknowledgment of the highlight of the A/I Net architecture: the A/I Switch. In this postulation, a VLSI execution of a multistage self-steering ATM switch texture which is one of the vital parts of the A/I Switch will be presented. The size of the switch model is 16x16. The chip is intended to work at the very least frequency of 100MHz and the framework is equipped for dealing with the OC-12 (622 Mbps) connect rate. In view of a piece cut architecture, the whole 16x16 switch is acknowledged utilizing four indistinguishable chips. It accomplishes elite by using dispersed control and accelerate with the input-output buffering technique. A need structure, which upholds four-level, permits the postponement delicate ATM cells to be switched with the briefest inertness. It likewise empowers the non-interleaving directing plan of IP cells.

Research on Scheduling Algorithm of Three-Stage Clos Switching Networks

The three-stage Clos switching network is a kind of multi-stage switching network which is commonly used to build a high-speed and large-capacity switching network, and the scheduling algorithm of the switching network affects the performance of the switching network. The article introduces and analyzes the research ideas of the scheduling algorithm of the three-stage Clos network, and provides a reference for further research on high-performance scheduling algorithms.

AI based Vector Control Method for BLDC Motor with Multi Switch Three-Phase Topology

Brushless direct current (BLDC) Motors are extensively used because of their characteristics. Such characteristics are high dynamic response and high-power density. BLDCM control system is a nonlinear, multi-variable, strong-coupling system. In this paper it is proposed that a neural network controller is used for the five level switch of the BLDC motor to enhance the power factor and reduce the current distortions with respect to its rise time, startup torque. This method is also done in comparison with the PID controllers. The working principle of the BLDC is with the help of five-switch control scheme can be implemented here. The different values of load were used to consider the total operation of the BLDC motor is to be controlled. After the completion of the training and testing of the neural network, it might be maintain the constant load values and its variables. To calculate the duty ratio of the DC-DC converter, it will be adjusted to regulate the speed of the BLDC motor. However the DC link of the five switching inverter is used here for the boosting of the voltage. The effectiveness of the proposed control technique can be realized with help of the speed sensor. Various tests have been conducted in the simulation the proposed technology is the robust technology and it is proven that very effective and suitable control technique.