Electromechanical Switches Research Articles

Qualitative performance improvement of a hybrid power supply at the DC common coupling point using a neuro-fuzzy method

Continuity of power supply service in production industries is of crucial importance, given the severity imposed in these sectors. A poor power supply leads to underproduction or degradation of equipment sensitive to electrical variations. A direct consequence of this is loss of earnings for industry. To ensure continuity of service for industrial power supplies, at least one secondary power source must be available. However, the switching system between sources may not be spontaneous due to the presence of electromechanical switches. The solution to this problem is to use electronic converters for control. The aim of this work is to enhance the parameters of an industrial photovoltaic-grid hybrid power supply to ensure uninterrupted power supply and balance between energy supply and demand. The sources are coupled to the DC bus via electronic converters. The photovoltaic system and the inverter are assumed to be unknown, and only the load terminal voltage is accessible and measurable. To address the lack of mathematical model of the system, we propose a mechanism that combines a fuzzy logic (FLC) centred mechanism with a radial basis function (RBF) neural network for the studied case. The FLC self-determines the image of the compensation power to be extracted through the current to the secondary energy source, ensuring continuity of service and balance between supply and demand. The FLC mechanism self-adjust the parameters of the RBF neural network and coordinates the energy at the DC link. The results obtained in the Matlab/Simulink environment are compared with the fuzzy logic and proportional integral (PI) control method. The quality of the results show that the proposed method is excellent compared with FLC and PI control. It improves response time between 24.223% and 82.9% for PI and between 22.292% and 63.694% for FLC. It guarantees an improvement in the mean square error on PI of between 5.865% and 57.994%, and on FLC of between 1.582% and 29.683%. The proposed method guarantees a high rationing coefficient, helping to maintain the balance between supply and demand, ensure continuity of service for the power supply, and improve the accuracy and self-compensation of the energy to be supplied, both qualitatively and quantitatively.

Kirigami beyond tension: Expanding Kirigami's versatility via shear actuation

The potential of Kirigami-based metamaterials as versatile platforms in applications where shape-morphability is desired is presently well established. Interestingly, in-plane loading under simple tension has been the predominant actuation-of-choice, with other fundamental loadings (e.g., shear, torsion) being largely overlooked. In this work, we explore the instability landscape of a simple Kirigami motif under in-plane shear loading and demonstrate how the incorporation of shear actuation effectively augments both the design and output space of Kirigami-based metamaterials. The nonlinear response of Kirigami under shear is first elucidated parametrically via nonlinear Finite Element Analysis on a subset of geometrically asymmetric motifs. The interplay between cut layout and the bidirectional nature of in-plane shear enables a variegated bifurcation landscape that includes unusual inversions and sharp kinks in the bifurcation curves. The numerical analysis is complemented with experimental validation of the out-of-plane bifurcation curves of several cases of interest by means of shadow moiré and laser displacement sensing. Together with the experimental validation, a proof-of-concept demonstration of the applicability of Kirigami-shear metamaterials as multistate electro-mechanical switches is presented. Overall, our findings add a new dimension to an already rich design space, thus opening a vista of opportunities for multimodal programmable structures, particularly appealing in sensing and actuation applications.

Energy Efficiency Improvement in Reconfigurable Photovoltaic Systems: An Evaluation of Team Systems

The main objective of this work is to evaluate the energy efficiency improvement obtained in grid-connected photovoltaic systems based on a dynamic reconfiguration strategy. The MIX and team reconfigurable photovoltaic system topologies have been considered since both minimize the operation of the inverters in low-load conditions. A numerical method is used to analyze the energy flows within the photovoltaic system, with a specific focus on the plant-oriented configuration. In this work, MIX systems are only presented briefly, while team reconfigurable photovoltaic systems are analyzed in more detail. This is because team systems can be implemented using conventional commercial inverters, electromechanical switches to redirect power flows, and a simple digital controller (as based on the Arduino platforms). The energy supplied to the grid by two grid-connected photovoltaic systems will be evaluated: one based on a classic non-reconfigurable strategy and another based on the team strategy. The measurement of the energy generated by these two systems, tested under various irradiance levels (emulating different climatic conditions), shows that reconfigurable systems always exhibit greater energy efficiency. However, this energy improvement can only be considered substantial in certain situations.

Discrete space-time processing in multifunctional radar systems

In radar systems, all basic tasks, from signal detection to their recognition, are solved under conditions of a priori uncertainty arising, among other things, due to natural or organized interference. The task of maintaining a balance between the speed of the information-measuring and control system and the detail of the assessment of the phase coordinates of targets is of particular relevance in modern on-board multifunctional radar systems of fighter aircraft. In such systems, all basic tasks are solved with strict restrictions on space-time resources. The purpose of the work is to analyze the options for reviewing the airspace that provide the solution of basic tasks in multifunctional radar systems with restrictions on the permissible time of observation of targets and taking into account electronic countermeasures. Based on the analysis performed using performance indicators that ensure the noise immunity of multifunctional radar systems, rational variants of a discrete space-time survey for active phased antenna arrays are proposed. In modern antennas with electromechanical scanning, two space viewing modes are used – continuous direction-finding mode and on-pass tracking. In the continuous direction-finding mode, the detail of the phase coordinate estimates is realized only for a single target, but the secrecy of the actions of the multifunctional radar system is not ensured. In the pass-through tracking mode, a high level of detail is provided for assessing the phase coordinates of targets and the noise immunity of multifunctional radar systems. Therefore, in this mode, it is advisable to evaluate only the noise immunity of multifunctional radar systems against the background of natural interference. The greatest detail of estimates of the phase coordinates of targets and noise immunity are achieved in multifunctional radar systems with active phased antenna arrays, the element base of which allows for a fast discrete space-time overview when all parameters of the electromagnetic wave change, including its polarization, according to pseudo-random laws. The use of modern onboard time standards with stability up to 〖10〗^(-18) in combination with high-speed electromechanical switches will significantly increase the detail of the evaluation of the phase coordinates of targets and noise immunity, including during group actions of aircraft. The proposed review options relate to a new priority scientific and technical direction  correction of techniques (principles, methods and algorithms) for the construction of avionics using technological advances in the development of the element base of active phased antenna arrays.

Comparative Study of Different High Voltage Switches Used in Pulsed High Voltage Application

High-voltage switches play a crucial role in pulsed power applications, where the efficient and reliable control of highvoltage pulses is required. This study aims to compare different types of high-voltage switches commonly used in pulsed power systems including electromechanical switches, vacuum switches, gas-filled switches, triggered spark gaps and solidstate switches. The comparison study focuses on key performance parameters such as voltage handling capability, current carrying capacity, turn-on time, and repetition rates are considered to provide a comprehensive study and analysis of the switch’s suitability for different pulsed power applications. Gas-filled switches such as spark gaps, thyratrons and ignitrons have been used in pulsed power systems due to their high voltage handling capability and low switching losses. However, they suffer from a limited lifetime and require maintenance and periodic replacement. Solid-state switches, i.e. Silicon-Controlled Rectifiers (SCRs), Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) offer advantages in terms of longevity, reliability, and reduced maintenance. However, they have limitations in high-voltage applications and exhibit higher switching losses. The findings of this comparison study will assist researchers, engineers, and system designers in selecting the most appropriate high-voltage switch for pulsed power applications, considering the specific requirements and constraints of the system. This will ultimately contribute to the advancement and optimization of pulsed power technologies across a wide range of scientific, industrial, and strategic applications.

Transient Arc Characteristic of a Commutation Switch Utilizing High Velocity Contact Separation

Commutation circuits are commonly used for low on state resistance and high current interruption capability if this can not be achieved by a single device or single current switching path. In case of fault detection, a very fast commutation of the current from the low-impedance main current path into the parallel high-current interrupting path is necessary. For single usage applications a low-cost approach is the utilization of a pyrotechnical switch in the low-impedance path. Compared to other electromechanical switches, those switches provide very high velocity of contact separation and thus a fast arc voltage rise with short commutation times. Here, measurements of the contact movement of a pyrotechnical switch were carried out using optical high speed imaging and an arc elongation up to 100ms−1 was calculated. From this, transient arc characteristics were measured in a simplified commutation network during the period until current zero in the low-impedance main current path.

Electromechanical Switching of a C60 Chain in a Nanogap

Electromechanical switching in fullerene C60 nanochains, introduced in the device as a C60 pyrrolidine tris-acid (CPTA) film, was realized in nanogap electrodes with ∼20 nm separation. Unlike microscale C60 channels, a conductive C60 chain spontaneously formed in the nanogap without electron beam irradiation. The initial current flow was likely due to electron hopping through the CPTA molecules. A higher voltage generated a nonlinear current and caused a rapid current step to drastically generate a large current flow. A further high current generated a sudden current reduction recognized as the negative differential resistance, suggesting a resistance state change from a low state to a high state. At the high-resistance state, a step-like current increase changed the nanochain conduction to the low-resistance state. The high- to low-resistance state switching was reproducible, and a sequential input voltage executed a binary resistance switching operation at room temperature. From the switching voltage and current values, the switching energy for the C60 chain in the nanogap was estimated to be approximately several milliwatts, most probably caused by the polymerization and depolymerization of the conductive C60 chain.

Design and Validation of a MVDC Isolated Active Voltage Injection Based HCB

A MVDC Hybrid Circuit Breaker (HCB) is proposed in this paper that consists of an electro-mechanical switch (EMS) in series with a Voltage Injector Building Block (VIBB). The VIBB-HCB does not employ any semiconductor devices in the main DC line. The VIBB utilizes an E-core-based integrated magnetic structure for injection purpose. The core is unbiased during normal operation, which does not affect system response or add more inductance in the main DC line. Further, the injection circuit is isolated from the main circuit. Hence, any surge or fault current does not impact the injection circuit. The injection circuit comprises a SiC-based full bridge auxiliary converter, which provides fast (μs range) bidirectional fault clearing capability. Moreover, the EMS is opened under zero voltage and zero current, which increases EMS reliability and lifetime. Lastly, the design does not require bulky high rating energy absorption components such varistors due to miniscule post-fault interruption residual energy. A detailed design procedure is derived and validated through Finite Element Analysis using ANSYS Maxwell Transient solver. This is followed by experimental verification on a scaled down hardware prototype.

Optimal hybrid multiplexed AC-DC-AC power converters

The flexibility of multi-terminal AC-DC-AC converters connected in distribution networks can be increased by changing the sizes of the individual AC-DC converter stages and connecting the AC side of those converters to electromechanical switches (multiplexers) to allow reconfiguration within the network. The combinations of real powers that can be transferred by such a design can be described using a capability chart. In this work, it is proposed that the area of these capability charts is a meaningful metric for describing the flexibility of such a device. These capability chart areas are calculated in closed form for a three-terminal AC-DC-AC device consisting of three AC-DC converters of arbitrary sizes, allowing the optimal AC-DC converter sizing to be determined to maximise this area. It is shown that this optimal design yields a capability chart area that is 64% larger than the equivalent area from a conventional equally-sized AC-DC-AC converter. Converters which are optimal in other senses are discussed, such as a design with 10% increased per-feeder real power transfer, albeit with an 8% area reduction. It is concluded that the capability chart area is an intuitive and informative approach for describing the increased flexibility of multiplexed AC-DC-AC converters.

Design of Hybrid Electromechanical Switch for Automatic Voltage Control of on Load Tap Changer Transformer

Design of Hybrid Electromechanical Switch for Automatic Voltage Control of on Load Tap Changer Transformer

All-Liquid Reconfigurable Electronics Using Jammed MXene Interfaces.

Rigid, solid-state components represent the current paradigm for electronic systems, but they lack post-production reconfigurability and pose ever-increasing challenges to efficient end-of-life recycling. Liquid electronics may overcome these limitations by offering flexible in-the-field redesign and separation at end-of-life via simple liquid phase chemistries. Up to now, preliminary work on liquid electronics has focused on liquid metal components, but these devices still require an encapsulating polymer and typically use alloys of rare elements like indium. Here, using the self-assembly of jammed 2D titanium carbide (Ti3 C2 Tx ) MXene nanoparticles at liquid-liquid interfaces, "all-liquid" electrically conductive sheets, wires, and simple functional devices are described including electromechanical switches and photodetectors. These assemblies combine the high conductivity of MXene nanosheets with the controllable form and reconfigurability of structured liquids. Such configurations can have applications not only in electronics, but also in catalysis and microfluidics, especially in systems where the product and substrate have affinity for solvents of differing polarity.

Fault-tolerant control for sensor faults affecting an electromechanical railway track switch

A fault-tolerant control scheme (FTCS) was developed for a novel mechatronic track switch for the first time. The FTCS was first developed and tested on a simulation model of the system, before being applied to an experimental actuation system in the laboratory. Both the simulation and experimental results show that this FTCS works as expected and allows the switch to continue operating as desired under sensor failure, preventing damage to the switch.

Special Considerations of the Developmentof the Contact System of the Microwave Switch with the Frequency Range up to 18 GHz

The paper describes the development results and the construction of the high frequency contact system of the electromechanical microwave switch with the frequency range up to 18 GHz. The S-parameter measurement suggests that the achieved results are in line with the best in class competitive devices. The construction features the radially cut support beads, which enable simple and low-cost coaxial connector design that takes advantage of the monolithic center conductor design. The effects of the size of the radial cut on the effective dielectric parameters are researched using the quarter wavelength resonator method. The presented results of the research allow the accounting of the cut size on the microwave parameters of the switch. The presented construction of the developed resonator allows the coaxial support bead dielectric parameters control, implemented in the manufacturing process of the switch.

Run-to-Run Adaptive Nonlinear Feedforward Control of Electromechanical Switching Devices

Feedforward control can greatly improve the response time and control accuracy of any mechatronic system. However, in order to compensate for the effects of modeling errors or disturbances, it is imperative that this type of control works in conjunction with some form of feedback. In this paper, we present a new adaptive feedforward control scheme for electromechanical systems in which real-time measurements or estimates of the position and its derivatives are not technically or economically feasible. This is the case, for example, of commercial electromechanical switching devices such as solenoid actuators. Our proposal consists of two blocks: on the one hand, a feedforward controller based on differential flatness theory; on the other, an iterative adaptation law that exploits the repetitive operation of these devices to modify the controller parameters cycle by cycle. As shown, this law can be fed with any available measurement of the system, with the only requirement that it can be processed and converted into an indicator of the performance of any given operation. Simulated and experimental results show that our proposal is effective in dealing with a long-standing control problem in electromechanics: the soft-landing control of electromechanical switching devices.

Visualization and Characterization of Cumulative Arc Erosion Behavior Using 2-D Microscopic Images

The electrical arc erosion behavior extremely limits the lifespan of electromechanical switching devices. Observation of the gradual evolution of arc erosion is highly beneficial for to understand the arc ignition and the contact degradation. In this article, the erosion of contact materials is simulated and visualized in situ with the recorded 2-D microscopic images. A novel method for erosion area identification is proposed with the combination of difference image method and mathematical morphology operations. The variation in erosion area as a function of switching current cycles is demonstrated, and the center of erosion zone that migrates continuously during the endurance experiment is determined. Finally, not only three types of arc erosion regimes (centralized arc erosion, separated arc erosion, and commutated arc erosion) are revealed, but also the associated occurrence probabilities during 1000 cycles are provided.

Research on Composite Braking Mode Switching Strategy Based on Fuzzy Algorithm

AbstractAiming at the cruising range of electric vehicles, this paper proposes a control strategy for electric vehicle electromechanical composite braking mode switching based on motor braking force correction. The braking force of the motor is adjusted by factors such as braking intensity to improve the braking energy recovery, and the braking force distribution curve is designed considering the braking energy and braking safety and stability. The research results show the braking time, braking torque, and battery charge. The peak value of discharge current has been improved, and the braking energy recovery efficiency has increased by 9.17% and 3.32% respectively under different working conditions. Under different braking modes with an initial speed of 30 km h−1, the braking energy recovered by the battery has increased by 16.04 , 3.89, 9.63 kJ, the braking time and braking distance are also shorter, which highlights the superiority of this control strategy.

Which Came First? Part II [White Hot

<fig orientation="portrait" position="float" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <graphic orientation="portrait" position="float" xlink:href="rober-3218356.tif"/> </fig> In my previous column, I started by asking which led the way in the advancement of power electronics technology—devices or topologies? I then reviewed the early history of “switched mode power conversion,” given that converters that used electromechanical switches like vibrators were switched mode power. That column ended with a discussion of the developments in power electronics in the 1960s after the first solid state switches started becoming generally available.

Why it is Unfortunate that Linear Machine Learning "Works" so well in Electromechanical Switching of Ferroelectric Thin Films.

Machine learning (ML)is relied on for materials spectroscopy. It is challenging to make ML models fail because statistical correlations can mimic the physics without causality. Here, using a benchmark band-excitation piezoresponse force microscopy polarization spectroscopy (BEPS) dataset the pitfalls of the so-called "better", "faster", and "less-biased" ML of electromechanical switching are demonstrated and overcome. Using a toy and real experimental dataset, it is demonstrated how linear nontemporal ML methods result in physically reasonable embedding (eigenvalues) while producing nonsensical eigenvectors and generated spectra, promoting misleading interpretations. A new method of unsupervised multimodal hyperspectral analysis of BEPS is demonstrated using long-short-term memory (LSTM) β-variational autoencoders (β-VAEs) . By including LSTM neurons, the ordinal nature of ferroelectric switching is considered. To improve the interpretability of the latent space, a variational Kullback-Leibler-divergency regularization is imposed . Finally, regularization scheduling of β as a disentanglement metric is leveraged to reduce user bias. Combining these experiment-inspired modifications enables the automated detection of ferroelectric switching mechanisms, including a complex two-step, three-state one. Ultimately, this work provides a robust ML method for the rapid discovery of electromechanical switching mechanisms in ferroelectrics and is applicable to other multimodal hyperspectral materials spectroscopies.

Rate-dependent ferroelectric switching in barium titanate ceramics from modified PUND experiments

Predicting and controlling the rate-dependent electro-mechanical switching in ferroelectric ceramics is challenging due to our current lack of understanding the underlying domain switching mechanisms at short time scales or high rates. Therefore, we propose an experimental protocol, which is a modification of the so-called Positive Up Negative Down (or PUND) experiment, to probe the rate-dependent competition between domain nucleation, domain growth, and variant selection in barium titanate ceramics as a representative material. Our experiments use a pump electric field pulse to switch the sample from a poled state at electric field rates spanning five orders of magnitude (10−2−102 MV/m⋅s). The remanent microstructures at the end of different pump pulses are probed using a subsequent probe electric field pulse, which is applied at a constant quasistatic rate. Results reveal reduced polarizability at higher electric field rates, indicating reduced domain switching. In addition, this pump-probe experiment shows an increase in domain wall nucleation vs. growth at higher rates. Simultaneous mechanical strain measurements using stereographic digital image correlation indicate a difference in nucleated domain wall variants while switching anti-parallel vs. parallel to the pre-poled direction. The data shows that ferroelastic 90° domain nucleation is preferred in the former case, while ferroelectric 180° nucleation is preferred in the latter. Our study highlights the importance of quantifying microscopic kinetics of domain nucleation, domain wall growth, and the effect of mobile defects in modeling the short-time electro-mechanical response of ferroelectric ceramics.

Flexible radio-frequency micro electro-mechanical switch towards the applications of satellite communications

This paper presents a flexible radio-frequency microelectromechanical system (RF MEMS) switch integrated on cyclo-olefin polymer (COP) substrate using a modified surface MEMS processing technology, which could be used in the 17–19 GHz frequency band of satellite communication. Through systematic simulation analysis, it is found that flexible RF MEMS switch can achieve certain bending radius by miniaturizing the electronic dimension, without degrading the RF performance. It is demonstrated that the RF characteristics of flexible RF MEMS switch with special anchor structural design, fabricated by modified surface MEMS processing, are not sensitive to bending deformation under the curvature of 0 mm−1, 0.05 mm−1, 0.10 mm−1. Furthermore, the range of bending curvature which will affect the RF characteristics is given through systematic simulation. The flexible RF MEMS switch with high process compatibility and stable RF performance is believed to be promising candidates for future microwave communications and other consumer electronics.