Traditional Switching Research Articles

Compact 2×2 parabolic multimode interference thermo–optic switches based on fluorinated photopolymer**Project supported by the National Key Research and Development Program of China (Grant No. 2016YFB0402502), the National Natural Science Foundation of China (Grant Nos. 61575076, 61475061, 61605057, and 61675087), and the Jilin Provincial Industrial Innovation Special Fund Project, China (Grant No. 2016C019).

In this work, a dual-side parabolic structural (DSPS) multimode interference (MMI) thermo–optic (TO) waveguide switch is designed and fabricated by using novel low-loss fluorinated photopolymer materials. Comparing with the traditional dual-side linear structural (DSLS) MMI device, the effective length of the MMI coupling region proposed can be effectively reduced by 40%. The thermal stability of the waveguide material is analyzed, and the optical characteristics of the switching chip are simulated. The actual performances of the entire MMI switch are measured with an insertion loss of 7 dB, switching power of 15 mW and an extinction ratio of 28 dB. In contrast to the traditional MMI optical switch, the new type of parabolic structural MMI TO waveguide switch exhibits lower power consumption and larger extinction ratio. The compact fluorinated polymer MMI TO switches are suitable well for realizing miniaturization, high-properties, and lower cost of photonic integrated circuits.

Software switches: novel hands-free interaction techniques for quadriplegics based on respiration–machine interaction

The majority of interaction techniques for individuals with disabilities to control a computer require an additional dedicated hardware like switches beyond standard computer peripherals. Furthermore, each traditional hardware switch emulates different keyboard characters or mouse clicks depending on its manufacturer. There is no commonly agreed standard on this; while some switch accessible programs expect to receive enter character, other programs expect to receive mouse left click. Switch manufacturers, therefore, distribute software drivers, which allow users to assign expected characters, with switches to overcome this standardization problem by making them adaptable. As software drivers are developed for a specific switch, they are not compatible with the other manufacturers’ switches. On the other hand, for the ones with a very limited motor activity but a complete respiration activity, sip-and-puff switches are efficient solutions. However, they are expensive and invasive systems with tubes, that have to be changed regularly due to the hygiene concern, inside users’ mouth. Although invasive respiration-based systems (sip-and-puff devices) caught enough attention by researchers over the years, using non-invasive respiration-based interaction techniques is an underestimated approach in general. In this study, we proposed two novel non-invasive interaction techniques as software switches (PuffCam and PuffMic) compatible with any switch accessible software. Both techniques are respiration operated, where a hard puff, detected by a microphone or an adapted camera, is considered as ‘switch-on’ like a puff switch. We have also collected the objective data by an evaluation software namely TestBed. A user study (conducted with 46 participants with/out disabilities) revealed that the accuracy, precision, recall, and false positive rate of our interaction techniques were quite impressive, and PuffCam performed better than PuffMic for all metrics. According to questionnaire findings, comfort assessment of interaction techniques by participants was rated quite satisfactory. All participants agreed that the idea of controlling a computer via breathing without purchasing any dedicated hardware sounded very promising. Because most interaction techniques for computer control require extra dedicated devices and there is not any adaptable (i.e., compatible with most switch accessible software) software switch to the best of our knowledge, proposed interaction techniques can help community in an open access manner without purchasing any device.

A Complete Switching Analytical Model of Low-Voltage eGaN HEMTs and Its Application in Loss Analysis

Low-voltage enhancement-mode gallium nitride high electron mobility transistors (eGaN HEMTs) are a kind of promising devices to realize high-efficiency and high-power-density conversion because of their fast switching speed, low conduction, and switching losses. Since the reverse conduction loss of eGaN HEMTs accounts for a large part of switching losses, it is of great importance to improve the traditional switching analytical model to predict the reverse conduction loss. In this paper, a complete and accurate switching analytical model of low-voltage eGaN HEMTs is presented, which considers the effects of low-parasitic inductances, nonlinear junction capacitances and nonlinear transconductances. The turn- on and turn- off switching processes are described in detail, and the resulting equations are solved by using mathematical software such as MATLAB to predict the switching waveforms during the switching periods. And an accurate loss calculation method based on the proposed model is proposed including the reverse conduction loss. The accuracy of the proposed model is validated by comparing the predicted switching waveforms and the efficiency of a synchronous buck converter with the experimental results, respectively. Moreover, the proposed model is compared with the traditional model, which proves the advantages of the proposed model. In the end, according to the proposed complete model, the effect of the top switch (TS) gate resistance, the TS drain-source capacitance, power loop inductance, current ripple, the bottom switch (BS) gate resistance, the BS drain-source capacitance, and dead time on the loss breakdown of the synchronous buck converter is explored and some qualitative suggestions are given to improve the conversion efficiency based on these analyzing results.

A 16-Bit 1-MS/s Pseudo-Differential SAR ADC With Digital Calibration and DNL Enhancement Achieving 92 dB SNDR

This paper presents a 16-bit 1 MS/s pseudo-differential Successive-Approximation-Register Analog-to-Digital Converter (SAR ADC) achieving an ENOB of 15-bit. To accommodate the pseudodifferential input, a differential DAC utilizing both monotonic and traditional switching is designed. For both dynamic and static performance improvement, three techniques are proposed. First, a foreground digital selfcalibration method is described to eliminate the capacitor mismatch errors. Some of the LSBs capacitors are utilized to measure and calculate the bit weights of other capacitors. Second, a DNL enhancement technique is presented. The fractional value capacitors are used to subtract an analog voltage from the DAC before the conversion is finished, which cancels out the consequent effect when the fractional part of the digital output is discarded before final output. Third, a low-offset low-noise comparator is designed. A reset timer with DAC settling replica is proposed to make the pre-amplifier in the comparator to start to amplify the DAC summing node voltage right after the DAC has fully settled. A prototype ADC is fabricated in a 0.18-μm 5-V CMOS process. It measures a 92.3-dB SNDR and a 107.9-dB SFDR. The DNL and INL are within ±0.3 LSB and ±0.72 LSB, respectively. The overall power consumption, drawn from the 5 V power supply, is 40 mW.

Research on Dynamic Coordination Active Mode Switching Control Strategy for Hybrid Electric Vehicle Based on Traffic Information

In traditional hybrid-vehicle mode switching, a switch when it changes in road conditions is sensed. Because of the delays in the control system, lags in switching and large impacts on the switching process occur, in what is referred to as “passive mode switching.” Via a combination of an intelligent networked hybrid vehicle with environmental sensing, “passive mode switching” can be converted into “active mode switching,” reducing the impact degree during the switching process and increasing ride comfort. Combined with the application of intelligent transportation system in current traffic, an intelligent traffic scene with optimal traffic-light control (OTLC) is established. The OTLC algorithm determines the future driving-state information of the hybrid vehicle in a built scenario and predicts the driving mode of the hybrid vehicle for the next moment. The current mode and future mode are compared, active control of key components, such as the engine, motor, clutch, and electric-mechanical continuously variable transmission (EMCVT), under the premise of different conditions, is made possible, and corresponding dynamic coordinate active-mode-switching control strategies are developed. The proposed control strategy is simulated and verified on a built-in hardware-in-the-loop (HIL) test platform based on traffic scenarios. The results show that the dynamic coordinated active-mode-switching control strategy presented in this paper is superior to the traditional mode-switching control strategy and that it can overcome the problem of switching lag due to delays in the control system and the large impact during the switching process, reducing the impact degree by about 21.2%, which improves ride comfort.

A New Phase Sequence Exchanging Control Method for Reducing Impulse Current and Voltage

Phase sequence exchanging technology (PSET) is a recently developed emergency control technology for out-of-step power systems. The PSET system does not satisfy the condition of synchronization however, and will produce impulse current and impact torque. In this paper, the impulse current and impact torque produced by PSET are calculated. Taking the three-phase short circuit at the generator outlet as a reference, the impulse current generated by PSET is determined to be less than half of the three-phase short circuit at the generator outlet, which is within the system's endurable range. When the system connection reactance is 0.543 times larger than generator direct axis sub-transient reactance, it can endure the impact torque produced by PSET. To reduce the impact and improve the practicability of PSET, a split-phase switching control method is proposed in this paper. The characteristics of fast breaking are utilized to turn off the solid-state circuit breaker separately when the three-phase current is at zero-crossing, and after exchanging the phase sequence, it is turned-on separately when two sides of the three-phase voltage are equal. An example is provided to verify that the impact of PSET can be dramatically reduced by using the proposed control method instead of the traditional simultaneous switching control method.

Triple-helix molecular-switch-actuated exponential rolling circular amplification for ultrasensitive fluorescence detection of miRNAs.

We have formulated a rapid and high-efficiency fluorescent biosensing platform based on a target-activated triple-helix molecular switch (THMS)-conformation-change-induced exponential rolling circular amplification (RCA) strategy for the ultrasensitive detection of miR-21. In this strategy, there are several aspects that are worthwhile. First, the functionalized THMS, comprising a typical triplex structure (T-A·T), specific recognition sequence for nicking endonuclease, complementary sequence for miR-21, and RCA product-annealing sequence, was concurrently used to perform signal transduction with one fluorophore and one quencher. As compared to the traditional double-helix molecular switches or molecular beacons, one of the biggest differentiating factors is that the properties of THMSs are independent of any specific binding sequence that they may contain. As far as we know, this is the first time that an ingeniously designed THMS not only contains the primer for exponential RCA, but also functions as the tracer for fluorescence assay. In the presence of miR-21, targets can induce conformation changes in THMS with the release of the trapped DNA segment (P), which, in turn, can activate the first run of the RCA process. Meanwhile, the RCA reaction is also initiated by the formation of a similar primer (SP) as the trapped DNA through a continuous "extension-nicking" reaction. Secondly, the resultant first-generation RCA product consists of numerous tandem repeated regions that can attach to countless THMSs, resulting in the release of the trapped DNA segment (P) for initiating the second run of the RCA reaction. Significantly, a large amount of THMSs were continuously consumed to yield a remarkably strong fluorescent signal. In addition, this biosensor was demonstrated to exhibit improved sensitivity owing to the high efficiency and rapid amplification kinetics of the exponential RCA and high selectivity toward miR-21 with a limit of detection as low as 1.1 aM. Hence, the target-mediated THMS-conformation-change-initiated exponential RCA strategy presents an optimal detection performance toward analytes for potential applications in related fundamental research and clinical diagnosis.

Seven-level NPC Inverter-based Neuronal Direct Torque Control of the PMSM Drives with Regulation Speed Using Neural PI Controller

In the scope of this work, a new structure of the direct torque control (DTC) technique scheme of permanent magnet synchronous motors (PMSMs) is proposed using a seven-level neutral point clamped (NPC) inverter and artificial neural networks (ANNs) controllers. This intelligent strategy was used to replace, on the one hand the integral proportional (PI) speed controller, on the other hand and the traditional switching table in order to reduce total harmonic distortion (THD) of voltage/current, stator flux ripple and electromagnetic torque ripples. The modeling and simulation of the proposed control scheme were carried out in Matlab/Simulink environment. The simulation results show that the proposed strategy scheme reduced harmonic distortion of stator voltage/current, stator flux and electromagnetic torque ripples compared to traditional DTC control scheme, DTC control scheme with space vector pulse width modulation (SVPWM) and three-level DTC control scheme. It was found that the stator current waveform becomes purely sinusoidal with a reduction in the harmonic distortion rate to 11.77%.

A novel Switching Unscented Kalman Filter method for remaining useful life prediction of rolling bearing

A new Switching Unscented Kalman Filter (SUKF) algorithm is proposed. The corresponding state-space models for each kind of bearing operation state are established, and the UKF algorithm is incorporated into the Bayesian estimation method to calculate the probability of each state at every time and determine the most probable state. The prediction of Remaining Useful Life (RUL) can be carried out once the accelerated degradation stage is detected. In order to make the filtering results of Condition Monitoring (CM) data smoother and avoid misjudgment of status when the degradation speed is negative, the measurement error parameter is selected as the standard deviation of CM data in the degradation stage. The proposed method is applied into the bearing CM data from Intelligent System Maintenance Center of University of Cincinnati. Besides, it is also compared with the traditional Switching Kalman Filter (SKF) algorithm. The results show the effectiveness of the proposed method.

Psychometric proprieties of a color-shape version of the switch task

The impact of concussions on an individual's cognitive functioning has become a growing health concern over the past several years; however, the search for sensitive tests persists. The task-switching paradigm is known to be sensitive to various medical conditions, including concussion. Accordingly, we developed 2 versions of the color-shape switch task. Three different costs are computed from the raw scores: global switch cost, which is thought to be a measure of global cognitive control; local switch cost, which is believed to be a measure of cognitive flexibility; and working memory cost. The aim of this study was to evaluate psychometric characteristics of these costs. An ANOVA revealed a main effect of sex on local latency switch cost, with females exhibiting longer latencies than males, p = 0.05. No main effect of sex was observed on any other switch costs. Moreover, no main effect of experimenter or version of the task was observed. Local switch cost was significantly correlated with trails 4 and 5 of the Comprehensive Trail Making Test (rs > 0.21, ps < 0.04). No other significant correlation between costs and established neuropsychological tests was observed, indicating low convergent validity. The intraclass correlation coefficient estimates ranged from 0.23 to 0.77, suggesting low-to-moderate 1-week test-retest reliability. Results indicated a low switch costs; convergent validity. Moreover, results show that the traditionally computed switch costs are less reliable than the primary outcomes (i.e., reaction time and accuracy). Researchers and clinicians should rely on primary variables from the task-switching paradigm rather than computing the traditional switch costs to increase the psychometric properties of the tasks which is critical to advances in theoretical models of executive functions and evaluations of clinical populations.

Evaluation of Operating Margin and Switching Probability of Voltage- Controlled Magnetic Anisotropy Magnetic Tunnel Junctions

Voltage-controlled magnetic anisotropy (VCMA) has attracted great attention as it allows faster switching and lower energy consumption compared to traditional spin-transfer torque-based magnetization switching. In this paper, we evaluate the operating margin and switching probability of VCMA-based magnetic tunnel junctions using realistic material and device parameters. For this paper, we developed a physics-based SPICE model that incorporates various VCMA parameters such as VCMA coefficient, energy barrier, time constant, and external magnetic field. Switching probability of a VCMA device was obtained by running Monte Carlo simulations including thermal fluctuation effects. A design space exploration was performed using the proposed simulation framework. The highest switching probabilities we were able to achieve were 94.9%, 84.8%, and 53.5%, for VCMA coefficient values of 33, 105, and 290 fJ · V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> · m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , respectively. Our study shows that for VCMA devices to become viable, their switching probability must be improved significantly either through new physics or material innovation.

Analysis and Treatment of Typical Problems of GIS Circuit Breaker

With the development and progress of society, the demand for electric energy is increasing day by day. The number of hydropower stations has increased dramatically. In the large-scale hydropower stations and substations currently under construction, GIS high-voltage switch stations have gradually replaced traditional high-voltage switch stations due to their advantages of arc extinguishing and insulation performance, low floor space and high reliability. The GIS breaker body and the operating mechanism of the GIS breaker, or other components of the GIS switch station, are subject to various reasons such as design, manufacture, installation, commissioning, operation and maintenance. Frequently, the GIS breaker leaks, the circuit breaker refuses to move, the operating mechanism cannot store energy normally, and the closing time is not easy to measure. These phenomena pose a serious threat to the safe and stable operation of the power system. Such typical phenomena of GIS circuit breakers deserve our consideration of inquiry, analysis and summary. Find the root cause of the failure and propose the most effective improvement. This paper proposes and solves several typical faults during the installation, commissioning, operation and maintenance of GIS circuit breakers. Provide reference for the fault analysis and processing of GIS circuit breakers in the future.

A Kind of New Designing Method About High Speed Optcial Network Auto Protect Switch System

In this paper, we research and develop a new type of optical fiber based on high-speed switching FPGA routing automatic protection switching device, its innovative USES high-speed electronic SWITCH high-speed exchange of FPGA design, will be 0 to 10 g digital optical signal photoelectric conversion amplification and rearrangement of the equipment selected by the high speed switching FPGA SWITCH protection, can for any important 0 to 10 g optical signal circuit after transformation (1 + 1) send after protect rearrangement of amplification, adopt concurrent optimization of transmission mode, automatic selection of high quality circuit signal in the microsecond time complete electrical SWITCH (far superior to the traditional common optical SWITCH SWITCH time), based on the development of commercial products for the national grid ehv transmission network users with high reliability, high performance of 0 to 10 g optical signal transmission channel protection. If there is no insertion loss, does not affect the original light path, also used in long-distance optical network transmission protection system in the west and subvert the traditional light path switching apparatus for at least 2 ~ 5 DBM large insertion loss. It overcomes the disadvantage of the traditional optical switch protection device.

Predictive DTC Strategy With Fault-Tolerant Function for Six-Phase and Three-Phase PMSM Series-Connected Drive System

On the one hand, with the use of direct torque control (DTC) for a six-phase permanent magnet synchronous motor (PMSM) and a three-phase PMSM series-connected system supplied by a six-phase inverter, it is possible to realize fast torque control for two PMSMs. On the other hand, because the number of inverter output voltage vectors (VVs) is increased to 64, it is difficult to divide sectors for traditional switching table DTC (ST-DTC). Furthermore, it is difficult to choose an optimal switching vector to reduce torque and flux ripples of two PMSMs in ST-DTC. A predictive control strategy of torque and stator flux is introduced into a two-PMSM series-connection DTC system, including winding fault, in this paper. Based on the principle of minimum errors of torque and stator flux amplitude and minimum zero-sequence current, an optimal VV is predicted. In order to realize uninterrupted torque control before and after open-phase fault, open-phase winding flux is considered in stator flux, and the inverter VV considering open-phase voltage is constructed in an open-phase control strategy. The experimental results show that the steady-state torque and stator flux ripples of a series-connected drive system are greatly reduced, and the drive system can operate without interruption from failure-free to failure operation.

On Per-Phase Topology Control and Switching in Emerging Distribution Systems

This paper presents a new concept and approach for topology control and switching in distribution systems by extending the traditional circuit switching to laterals and single-phase loads. Voltage unbalance and other key performance indicators including voltage magnitudes, line loading, and energy losses are used to characterize and demonstrate the technical value of optimizing system topology on a per-phase basis in response to feeder conditions. The near-optimal per-phase topology control is defined as a series of hierarchical optimization problems. The proposed approach is applied to IEEE 13-bus and 123-bus test systems for demonstration, which included the impact of integrating electric vehicles (EVs) in the test circuit. It is concluded that the proposed approach can be effectively leveraged to improve voltage profiles with electric vehicles, the extent of which depends on the performance of the base case without EVs.

Analysis of Active Spectrum Handoff Effect Based on Cooperative Spectrum Prediction

In the cognitive radio network environment, because the sub-user opportunistic use of “spectrum hole” to communicate, resulting in the inevitable uninterrupted system for spectrum switching, and frequent spectral switching system performance significantly reduced. In this paper, an active spectrum switching method based on improved cooperative spectrum prediction is proposed based on the existing active spectrum switching based on single user prediction. This method can effectively improve the performance of spectrum switching by introducing the cooperative prediction module into the frame structure and the idea of dividing the frame structure frequency domain. Based on the experimental simulation, it is proved that the performance of the method is improved compared with the traditional single-user prediction active spectrum switching method and the periodic spectrum sensing switching method, the average switching delay, channel switching frequency and collision rate and other performance indicators have been effectively improved.

Stability Analysis for a Type of Multiswitching System with Parallel Structure

This paper proposes a new type of multiswitching system and a subsystems-group as a basic switching unit that obeys the law. Unlike traditional switching systems, the system selects multiple subsystems instead of one on each time interval. Thus, a framework of parallel structure organizes the subsystems as a group. A multiswitched system is widely used in engineering for modelling and control; this system reflects the actual industrial dynamical process. Thus, the stability of the system is studied. Assuming that these continuous and discrete-time subsystems are Hurwitz and Schur stable, the subsystems-groups matrices commute each other based on the subsystems matrices pairwise commutative. Then, the multiswitched system is exponentially stable under arbitrary switching, and there exists a common Lyapunov function for these subsystems. The main result is extended to a parallel-like structure; therefore, some stability results are gained under some reasonable assumption. At last, a numeral example is given to illustrate the structure and the stability of this system.

Crossing Classified and Corrected Fewest Switches Surface Hopping.

In the traditional fewest switches surface hopping (FSSH), trivial crossings between uncoupled or weakly coupled states have highly peaked nonadiabatic couplings and thus are difficult to deal with in the preferred, adiabatic representation. Here, we classify surface crossings into four general types and propose a parameter-free crossing corrected FSSH (CC-FSSH) algorithm, which could treat multiple trivial crossings within a time interval. As examples, Holstein Hamiltonians with different parameters are adopted to mimic electron dynamics in tens to hundreds of molecules, which suffer from severe trivial crossing problems. Using existed surface hopping approaches as references, we show that CC-FSSH exhibits significantly fast time interval convergence and weak system size dependence. In all cases, a reliable description is achieved with a large time interval of 1 fs. With a simple formalism and the ability to describe complex surface crossings, CC-FSSH could potentially simulate general nonadiabatic dynamics in nanoscale materials with a high efficiency.

Electrochromic-Tuned Plasmonics for Photothermal Sterile Window

Electrochromic materials are widely used in smart windows. An ideal future electrochromic window would be able to control visible light transmission, tune building's heat conversion of near-infrared (NIR) solar radiation, and reduce attacks by microorganisms. To date, most of the reports have primarily focused on visible-light transmission modulation using electrochromic materials. Herein, we report the fabrication of an electrochromic-photothermal film by integrating electrochromic WO3 with plasmonic Au nanostructures and demonstrate its adjustability during optical transmission and photothermal conversion of visible and NIR lights. The localized surface plasmon resonance (LSPR) of Au nanostructures and the broadband nonradiative plasmon decay are proposed to be tunable using both the electric field and the WO3 substrate. Further enhanced photothermal conversion is achieved in colored state, which is attributed to coupling of traditional visible-band optical switching with NIR-LSPR extinction. The resulted electrochromic-photothermal film can also effectively reduce the numbers of attacking microorganisms, thus promising for use as a sterile smart window for advanced applications.

An Improved P-DPC for A New Inverter Based on MLD Model

Building an accurate mathematical model for inverter is the key to achieving a precise control. Contrasted to the traditional switching function model of power electronic circuits, this paper built the mixed logical dynamic(MLD) model for a new inverter, and the MLD model was used as a prediction model, then a predictive direct power control(P-DPC) method was researched for the new inverter. A symmetrical 4+4 voltage vector sequence was employed to obtain constant switching frequency and lower THD of output voltage, the action time of vector sequence was calculated by minimizing objective function. The feasibility and effectiveness were proved by simulations.