Additional Switching Research Articles

A Novel Nonsingular Fast Fixed‐Time Sliding Mode Control and Its Application to Satellite Attitude Control

ABSTRACTIn this paper, a Lyapunov‐like sufficient condition for the fast fixed‐time stability of autonomous systems is proposed. The proposed fast fixed‐time stability theorem ensures a smaller upper bound on the convergence time than the existing fixed‐time stability theorems. The fixed‐time sliding mode controls require switching from the fixed‐time sliding surface to the general sliding surface in the vicinity of the origin to avoid non‐differentiability at that point. It is demonstrated that the switching method converges the system states either to a residual set around the equilibrium point or directly to the equilibrium point, depending on the tuning parameter settings. To address this issue, a new nonsingular sliding surface is proposed based on the fast fixed‐time stability theorem. This approach ensures singularity‐free convergence of the system states to the equilibrium point without additional switching logic for the sliding surfaces or any constraints on tuning parameters. Furthermore, a novel continuous adaptive fast fixed‐time sliding mode control (AFFTSMC) law is proposed for attitude control of a satellite in the presence of the satellite inertia uncertainty and unknown upper‐bounded external disturbance torques. The proposed AFFTSMC law ensures chattering‐free and singularity‐free satellite attitude control. Simulation results are presented for both rest‐to‐rest and tracking attitude maneuvers of a satellite, demonstrating the superiority of the proposed controller.

Nonlinear Bifunctional Memristor for Reprogrammable Programmable Read-Only Memory (PROM) Applications

In current von Neumann computing systems, tremendously separate processing and memory units are involved. However, data movement is costly in terms of time and energy, and this problem is aggravated by the recent explosive growth in highly data-centric applications related to artificial intelligence (AI) on the hardware, especially performance and reliability [1-3]. Sneak path current (SPC) is an inevitable problem in large memory array, deteriorating the read/write margin of crossbar configuration, where the leakage current from neighboring cells results in operation errors. The 1T-1R or 1S-1R configuration with good SPC suppressing ability is proposed for most emerging memory technologies, while with significant cost and fabrication complexity (Fig. 1). To reduce the SPC with cost efficiency, nonlinear self-rectified memory with thin film stacking fabrication is presented as the highly scalable non-volatile memory for storage and computing configurations (Fig. 1). Meanwhile, the one-time fusing state is implemented with hybrid function in nonlinear memristor, as “reprogrammable programmable-read-only memory (PROM)” for future security applications.On the pristine state of devices, electroforming processes were conducted as followed with the first RESET process. The self-selectivity (i.e. nonlinearity) of three various structures was stabilized after 30-cycle seasoning. Nonlinearity (NL) is defined as ratio of the LRS current at Vread divided by the LRS current at 1/3Vread. The greater SPC immunity of 1R-only self-rectified memory is demonstrated with the higher the NL. The NL modulated with the SET compliance current limit (CCL) is shown in Fig. 2 (a), where the NL of HfOx/SiOx stacked devices (i.e. H4S9, H11S2) is optimized with CCL of 1 mA and 2 mA, respectively. That is, the H4S9 shows improved energy efficiency as compared to H11S2 devices. The I-V characteristics of H11S2 under three various ambient conditions (i.e. nitrogen, vacuum, and RT) depicts the memory window (MW) shrinks under the nitrogen and vacuum (Fig. 2 (b)), which is suggested as resulting from the reduction of oxygen vacancies. Noted the NL reduces with the ambient changes in both reading polarities (Fig. 2 (c)), where the switching voltages reduces under the vacuum (~10-3 torr). Unlike the single layer SiOx which should be operated under vacuum/nitrogen condition, bilayer self-rectified memory performed well under the RT ambient [4]. Figure 3 shows the transfer curves for a single layer of SiOx, single layer of HfOx, and bilayer device. With the high dielectric layer insertion (i.e. HfOx), the current under voltage larger than -1 V has ~0.5 order of magnitude higher than single layer low dielectric layer. This is thought to be suggested that the high-k layer provides higher current distribution under higher voltage, and remains the same with bilayer when voltage is less than 1 V [4-5]. With the high-k/low-k configurations for selectorless memristor devices, the graphite and graphite oxide are also studied as stacked with HfOx (6 nm). Noted the HfOx/RuOx stacked devices are fabricated as the reference for investigating the reprogrammable PROM memory (Fig. 4 a-b). The dielectric fusing occurs in the graphite-based nonlinear memristor with the functional write-erase cycles before finalized the fuse state (I <10-9 A) under the voltage around -2.4 ~-2.8 V (Fig 4 c-d). The fusing voltage is independent of the high-k/low-k stacking, but only correlated to the thickness of effective dielectrics. This could be beneficial for realizing the hybrid functional memristor in OTP applications, according to the margin to modulate the stack configuration whereas fixed the fusing voltage.In this work, the bilayer self-rectified memristors have been realized in the bilayer stacked structures for suppressing the sneak path current without an additional switch device integration. The ambient response and switching gap determination, and defect distribution has been investigated. Nonlinear bifunctional memristor with low voltage dielectric fusing operation is presented for reprogrammable PROM Applications as the future features for security applications.

Out of The Box, Onto the Screen: Insights from an OOBE Study of the Xbox Adaptive Controller

This study investigates the Out-of-Box Experience (OOBE) of the Xbox Adaptive Controller and Logitech Gaming Kit, focusing on users with varying levels of disability and gaming experience. Fifteen participants were recruited from a university population and had varying levels of gaming and disability experienced. The study observed participants’ interactions with the packaging, instructions, and setup process for both the controller and the switch kit. The Xbox Adaptive Controller received positive feedback for its easy-to-open packaging, aesthetically pleasing design, and a relatively easy setup and use process. However, weaknesses included a lack of clear information on functionalities of additional switches, difficulties with cable management, and unclear instructions with a reliance on diagrams Incorporating individuals with diverse gaming backgrounds and experience with disability throughout the design process can help identify challenges and opportunities for a wider range of users.

Syntax drives default language selection in bilingual connected speech production.

The present study investigated the role of syntactic processing in driving bilingual language selection. In two experiments, 120 English-dominant Spanish-English bilinguals read aloud 18 paragraphs with language switches. In Experiment 1a, each paragraph included eight switch words on function targets (four that repeated in every paragraph), and Experiment 1b was a replication with eight additional switches on content words in each paragraph. Both experiments had three conditions: (a) normal, (b) noun-swapped (in which nouns within consecutive sentences were swapped), and (c) random (in which words in each sentence were reordered randomly). In both experiments bilinguals produced intrusion errors, automatically translating language switch words by mistake, especially on function words (e.g., saying the day and stay awake instead of the day y stay awake). Intrusion rates did not vary across experiments even though switch rate was doubled in Experiment 1b relative to Experiment 1a. Bilinguals produced the most intrusions in normal paragraphs, slightly but significantly fewer intrusions in noun-swapped paragraphs, and a dramatic drop in intrusion rates in the random condition, even though the random condition elicited the most within-language errors. Bilinguals also demonstrated a common signature of inhibitory control in the form of reversed language dominance effects, which did not vary significantly across paragraph types. Finally, intrusions increased with switch word predictability (surprisal), but significant differences between conditions remained when controlling for predictability. These results demonstrate that bilingual language selection is driven by syntactic processing, which operates independently from other language control mechanisms, such as inhibition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A Non-Linear Control Technique for Single Phase qZSI

Quasi-Z-source inverters, or qZSIs, are a common type of inverter used in transformer-less systems because they can boost or buck input voltage without a requirement for a DC- DC converter. A transformer is not necessary for the qZSI's single-stage conversion to operate as a grid-tie converter. In transformer-less designs common mode current is the major problem, though, because there is no galvanic isolation. To reduce the common mode current, this article offers controlling the qZSI using a modified pulse width modulation (PWM) approach two additional semiconductor switches. The developed methodology provides a practical means of integrating solar photovoltaic systems into the grid. what the recommended topology's attributes should be: 1)It uses the phase-leg shoot through to boost the direct current and voltage to required level by eliminating the need for a second dc-dc converter. 2) Freewheeling is achieved while removing PWM deadtime by employing extra linked switches.

A soft switching non‐isolated bidirectional DC–DC converter with improved voltage conversion ratio and minimum number of switches

AbstractA soft switching non‐isolated bidirectional DC–DC converter with an improved voltage conversion ratio without any additional auxiliary switch is presented in this paper. In the proposed converter, improved step‐up/step‐down gain conversion is achieved by employing the coupled inductors method. Also, the auxiliary circuit provides soft switching conditions for all the semiconductor elements, regardless of the power flow direction and without any extra voltage stress. The other switch helps provide soft switching conditions for the main switch. Moreover, the switch used for providing soft switching conditions operates as a synchronous rectifier as well. The additional circuit added to attain soft switching is composed of an inductor, coupled with the converter's main inductor, and two auxiliary diodes. The auxiliary diodes benefit from zero‐current‐switching conditions. Fully soft switching conditions for all semiconductor devices, removing the reverse recovery problem, and a low number of components have led to mitigating switching losses and improving efficiency. Detailed operating principles and a theoretical analysis of the proposed converter are presented. Also, the experimental results of a 220 W prototype circuit are provided to confirm the validity of the proposed topology.

Model predictive control for single-phase cascaded H-bridge photovoltaic inverter system considering common-mode voltage suppression

In this article, a model predictive control (MPC) with common-mode voltage (CMV) suppression is proposed for single-phase cascaded H-bridge (CHB) inverters, which can also simultaneously achieve control objectives of grid-connected current tracking, voltages balancing of different H-bridge submodules on the DC-side and switching frequency reduction. To suppress high-frequency components of the common-mode voltage without additional switching devices, the algorithm proposed designs the predicted and reference values of the CMV and incorporates them in the cost function. At the same time, the capacitor voltages balancing control is integrated in the calculation of the optimal modulation function of the H-bridge, which reduces the complexity of control effectively. Besides, switching times of the MOSFETs are compared in two cycles. The cost function is constructed to represent comprehensive effect of the control. Finally, an experiment is performed on the hardware-in-the-loop experimental platform. The experimental results show that the proposed algorithm can offer a better voltage THD and reduce the times of switch action by nearly half while maintaining high-precision current tracking and maximum power point of photovoltaic modules, which alleviate the potential electromagnetic interference and cabling problem.

Self-Adaptive Resonance Technology for Wireless Power Transfer Systems to Eliminate Impedance Mismatches

Impedance mismatching can severely decrease the power transmission capacity or even invalid the control logic of wireless power transfer (WPT) systems. To eliminate the impedance mismatch caused by various factors, such as resonant parameter drift, coupling structure misalignment and control strategy, a self-adaptive mistuning correction circuit and corresponding parameter design rules are proposed to ensure the WPT system consistently operates under resonant state, accompanying the optimal power transfer ability. Moreover, a reactive compensation circuit that can create an auxiliary voltage source by the absorbed reactive power that is introduced by impedance mismatching is designed. This source can generate a new current on the coil to bring the mismatched input current back to the resonant state, according to the current superposition principle. Unlike passive impedance network that require high parameter precision and active impedance matching strategies equipped with detection and control circuits, the proposed approach can self-adaptively eliminate either undesired capacitive or inductive reactance with two additional switches and an energy-storage capacitor, improving impedance adjusting rate and providing better system robustness. The simulations and experiments are in good agreement with the theoretical analysis. This study has potential applications in harsh environments where the system impedance and coupling strength are continuously disturbed.

A Cascaded H-Bridge Multilevel Inverter with DC Cells Input Fault Tolerance Capability Based on PSC-PWM Control

Multilevel inverters have proven their efficiency in generating better AC voltage outputs. This functional quality is mainly due to the use of multi-source DC inputs. Despite the fact that this type of topology is generally reliable, switching faults caused by the complete loss of a switching component or DC input cell may still occur. Such incident may inflict heavy impacts to the conversion chain resulting in a permanent damage to the switching cells or the connected load. This article presents a dynamic switching control strategy capable of tolerating DC cells open-circuit input faults in basic symmetric Cascaded H-bridge multilevel inverter architectures. The proposed topology uses a control scheme to overcome the switching cells’ fault by adapting the configured level of conversion and bypassing the flawed unit with no additional switching components. Furthermore, the proposed control strategy is capable of reversing back the inverter configuration to its original functional state after the disappearance of the faut. This research article answers the need for a theorical study of a fault tolerant Cascaded H-Bridge multilevel inverter where the short circuit’s fault types are bypassed by Pulse width modulation alteration only.

A triple‐LC‐based DC/DC converter with wide input voltage gain in both under‐resonance and over‐resonance frequency regions

AbstractIn recent years, wide voltage range DC/DC converters have been widely used in telecom power, solar generation and electric vehicle charger applications. Based on this, a new multi‐resonant converter with wide input voltage is proposed here. Compared with the traditional LLC converter, the proposed converter can maintain the output voltage within a narrow frequency regulation range in both under‐resonance and over‐resonance areas. Thus, a wide voltage range can be realized without additional switch components or complex control strategies. The topology and the corresponding working principle of the proposed converter are introduced. In addition, the equivalent model by considering the fundamental wave is established and the influence of the resonance parameters on the voltage gain characteristic is analysed in detail. With these considerations, the resonance parameters are designed. Finally, a 500 W experiment platform is established to verify the effectiveness and feasibility of the proposed converter.

Modeling and control of a new multi-port converter for hybrid energy system integration

This research introduces a new topology called the quasi-Z-source integrated isolated multiport bidirectional resonant DC-DC converter. The aim is to achieve cost-effective and efficient multi-directional power flow between photovoltaic (PV), battery/supercapacitor, and DC loads. The proposed topology ensures uninterrupted power supply to the loads and supports reverse power transfer through its bidirectional power flow capability. By combining quasi z-source and H-bridge resonant converters with an existing switch, a four-port converter is achieved without the need for separate converters or additional switches. The high-gain quasi z-source converter reduces the required voltage ratings of the battery and supercapacitor packs while enabling the utilization of a high-frequency transformer (HFT) with a low turns ratio. Isolation between the ports is achieved using a secondary center-tapped HFT equipped with a controlled full-wave rectifier on the secondary side, allowing bidirectional power flow. A power flow management system and corresponding control scheme are proposed to optimize the system's performance. The proposed system's performance is evaluated under various operating conditions, demonstrating its effectiveness in power flow management and overall efficiency. The results confirm the feasibility and effectiveness of the proposed system.

Investigation of a power factor correction converter utilizing SEPIC topology with input current switching

The single-ended primary-inductor converter (SEPIC) is a popular converter topology that can be employed in diverse application fields where the needed output voltage is greater or lesser than the input voltage. The non-inverted output voltage of a SEPIC converter provides additional advantages when compared to a buck-boost or Ćuk converter. Furthermore, the position of the capacitor in the SEPIC converter provides inherent isolation and circuit safety. One drawback in the conventional bridge-diode SEPIC AC-DC converter is the lack of controllability which can be overcome by adding extra active switch(es) or by replacing the passive diode(s) with active switch(es). However, introducing more active switches increases the control complexity and may increase the requirement for additional driver circuits. To address this trade-off, this article proposes a single-phase AC to DC modified SEPIC converter with input current-switching capability without adding any extra active switch(es). The existing active switch of the DC-DC SEPIC converter was shifted towards the input side and thus no additional switch has been introduced. This allows the option of input-current switching without any additional complexity in the control or driver circuit. The circuit topology, principles of operation, and ideal voltage gain equations for the suggested circuit have been derived and included in this research work. The proposed circuit has been simulated in both open-loop conditions and closed-loop control with varying duty cycles and output load. Results from the simulation show that the proposed converter provides better efficiency (∼90 %) and lower total harmonic distortion (THD) (10 %) for varying duty cycles when compared to a conventional converter. The converter also shows good dynamic response. A low-power 15V hardware prototype has been built to experimentally validate the performance of the proposed converter. Experimental results illustrate that the suggested converter can improve the power factor by up to 0.968 while operating at an efficiency above 75 %. This converter topology can be suitable for applications where high output voltage gain, high power factor, and lower THD are needed without isolation requirements.

An improved nested 3-phase 5-level MLI design with optimized output voltage and total harmonic distortion

Multilevel Inverters (MLIs) have advanced progressively and demonstrated enormous capacity in power electronics. To provide a 5-level voltage output with a 3-phase full-bridge arrangement and an additional bi-directional switch, a dc voltage input was split by two capacitors. This setup has two issues namely the output voltage limiting the magnitude of the input supply voltage and the voltage disparity between the isolating capacitors. This study suggests an improved nested 3-phase 5-level MLI design with a voltage level and total harmonic distortion (THD) that are both optimized. The suggested arrangement has the features of a lower proportion of passive elements and separated DC sources as it is constructed with a cascade linking of nested two-level cells (NTCs). The suggested unit cell was found to produce a 9-level output voltage (line) by producing a 5-level output voltage (phase) with a peak value that is double the level of the input voltage. The output voltage increasing the capacity of the suggested circuit is its prominent advantage, and the efficacy of the suggested design is 95% and validated by the simulated resultsKeywords: Multilevel Inverters (MLIs), Total harmonic distortion (THD), Voltage level.

An FPGA-based balancing of capacitor voltage for multi-level inverter

ABSTRACT This paper introduces a novel cascaded multilevel inverter circuit configuration aimed at generating a five-level load voltage using a single DC source and a capacitor. In this inverter configuration, an additional switch is added to the charging circuit which helps to charge the capacitor from the DC source. Additionally, an inductor is incorporated to mitigate the substantial charging current during capacitor charging operation. A level-shifted pulse width modulation (LS-PWM) technique is implemented to generate gate pulses for both inverter and charging switches. The capacitor gets charged when an extra switch is enabled and discharged when it is connected to a load. Analysis of charging and discharging of capacitor is described thoroughly in this paper. Each operational mode of the inverter is thoroughly analysed. Furthermore, the proposed five-level inverter setup is designed, and its control logic is implemented using FPGA platform. Subsequently, simulation and experimental investigations are conducted under varied loads and different modulation indices to evaluate the efficacy of the proposed inverter configuration and the respective results are presented.

Comparison of Magnetostrictive-Actuated Semi-Active Control Methods Based on Synchronized Switching

Three distinct synchronized switching circuits based on a magnetostrictive actuator are compared in this paper to examine their control mechanisms and circuit characteristics. These circuits include a semi-active shunt circuit, a semi-active current inversion and amplification circuit, and a semi-active automatic current inversion and amplification circuit. Each circuit type employs an additional electronic switch. The synchronized switching method enables the rational control of the circuit current generated by the magnetostrictive actuator to fulfill any desired control strategy. Simulation and experimental results on a 10-bay truss structure reveal that the three circuits can effectively adjust the polarity of the induced current as needed. The three circuits are then compared to thoroughly analyze their unique characteristics and explain their respective advantages and dis-advantages. Using the comparison results, various options available for control circuit design are demonstrated.

Switching between foods is reliably associated with intake across eating events in children

Emerging evidence suggests switching between foods during an eating event is positively associated with intake. However, it is unclear whether switching is a stable behavior that predicts consumption across multiple eating events. The current study explored whether switching is consistent within children and reliably associated with intake across varied eating events. We analyzed data from 88 (45 F), 7–8-year-old children without obesity participating in a 7-visit prospective cohort study (ClinicalTrials.gov NCT03341247). Amount consumed and energy intake were measured at 4 separate meals of foods that varied by portion sizes served. Meals included macaroni and cheese, chicken nuggets, broccoli, and grapes (all 0.7–2.5 kcal/g). Children's intake was also assessed during 2 eating in the absence of hunger (EAH) paradigms separated by ≥ 1 year. The EAH paradigm included 9 sweet and savory snack foods (all 1.9–5.7 kcal/g). All eating events were video-recorded and switching was assessed by counting the number of times a child shifted between different food items. Results demonstrated that switching was reliably associated with intake at both the meals and the EAH paradigms (ps < 0.01). Specifically, at meals each additional switch was associated with 11.7 ± 1.3 kcal (7.7 ± 0.8 g) more consumed, and during EAH each additional switch was associated with 8.1 ± 2.1 kcal (2.1 ± 0.5 g) more consumed. Switching behavior was also moderately consistent across meals (ICC = 0.70) and EAH paradigms (ICC = 0.50). However, switching at meals was not related to switching at EAH paradigms. This study demonstrates the consistency of switching behavior and its reliable association with intake across eating events, highlighting its potential to contribute to chronic overconsumption and childhood obesity.

Topology, Analysis, and Modulation Strategy of a Fully Controlled Modular Reconfigurable DC Battery Pack With Interconnected Output Ports for Electric Vehicles

Modular battery-integrated converters or so-called dynamically reconfigurable battery packs are expanding into emerging applications. Although they offer many degrees of freedom (DoF), the state of the art focuses on single-output systems and neglects the potential of such systems to generate multiple outputs with minimum added components. This paper investigates the feasibility of a multiport system for various independent loads. The proposed techniques can achieve higher functionality and reduce power conversion stages. Interleaved ports with shared modules can also increase modules’ utilization, avoid redundant power electronics, and reach a better cost-weight trade-off. However, using conventional modulation techniques in particular phase-shifted carrier modulation can be challenging with shared modules among multiple ports, and different control objectives can adversely impact the overall performance. Therefore, this paper analyzes the inherent dynamics of modular batteries and proposes a strategy to decouple the control of multiple ports to simplify power electronics’ complexity and size while improving performance. In addition to the distinct advantages of modular reconfigurable batteries, the proposed concept would not require additional active switches, can operate with a wide range of output voltages, can reduce the size of the filters and transformers, and is extendable to larger setups. Simulation and experiments verify the developed concept.

A Reconfigurable Two-Stage 11 kW DC–DC Resonant Converter for EV Charging With a 150–1000 V Output Voltage Range

In this paper, a reconfigurable two-stage DC/DC resonant topology with a wide output voltage range of 150-1000V is proposed for Electric Vehicle (EV) charging with high efficiency over the entire load range. The proposed topology consists of an LLC resonant converter with dual secondary sides; two interleaved triangular current mode buck converters, and three additional auxiliary switches for reconfiguration. Two possible arrangements of the proposed topology are considered and compared. The analytical model of the topology is developed, which is used for the efficiency estimation of different configurations and the design of the prototype converter. An 11kW hardware demonstrator is built and tested. The maximum measured efficiency of the converter is 97.66%, with a >95% efficiency over the complete 150-1000V range at full power. The proposed two-stage converter achieves the widest output voltage range reported in literature for resonant power converters, thereby capable of charging existing and future EVs very efficiently over any charging cycle.

A Novel Decentralized Frequency Regulation Method of Renewable Energy Stations Based on Minimum Reserve Capacity for Renewable Energy-Dominated Power Systems

In this paper, we propose a novel decentralized frequency regulation method for renewable energy-dominated power systems. First, the system is modularized into unified frequency regulation modules composed of synchronous generators(SGs) and renewable energy stations. Then, based on the aggregation model of the module, a renewable energy station frequency regulation method based on robust control barrier functions(RCBFs) is proposed to ensure that the frequency deviation is limited, and an additional switching control strategy is complemented to avoid the long-term suspension of over-high quasi-steady-state frequency. The proposed method is still applicable under the coordination of multiple renewable energy stations. Each renewable energy station deploys decentralized control based on local information, which can support fast frequency response. The robustness of frequency response time constants of renewable energy stations and frequency dead zone are considered, which makes the control method easy to implement. A module transient frequency stability margin index based on reserve capacity is proposed, which can be used to guide the system planning and operation. Finally, simulation results validate the applicability of the proposed method, demonstrating its efficacy in regulating frequency in renewable energy-dominated power systems.

Programmable Primer Switching for Regulating Enzymatic DNA Circuits.

Developing DNA strand displacement reactions (SDRs) offers crucial technical support for regulating artificial nucleic acid circuits and networks. More recently, enzymatic SDR-based DNA circuits have gained significant attention because of their modular design, high orthogonality signaling, and extremely fast reaction rates. Typical enzymatic SDRs are regulated by relatively long primers (20-30 nucleotides) that hybridize to form stable double-stranded structures, facilitating enzyme-initiated events. Implementing more flexible primer-based enzymatic SDR regulations remains challenging due to the lack of convenient and simple primer control mechanism, which consequently limits the development of enzymatic DNA circuits. In this study, we propose an approach, termed primer switching regulation, that implements programmable and flexible regulations of enzymatic circuits by introducing switchable wires into the enzymatic circuits. We applied this method to generate diverse enzymatic DNA circuits, including cascading, fan-in/fan-out, dual-rail, feed-forward, and feedback functions. Through this method, complex circuit functions can be implemented by just introducing additional switching wires without reconstructing the basic circuit frameworks. The method is experimentally demonstrated to provide flexible and programmable regulations to control enzymatic DNA circuits and has future applications in DNA computing, biosensing, and DNA storage.