Switching Method Research Articles

A 0.6-V 12-bit Set-and-Down SAR ADC With a DAC-Based Bypass Window Switching Method

This paper proposes a digital-to-analog-converter-based (DAC-based) bypass window switching method for the successive-approximation register analog-to-digital converter (SAR ADC). The proposed method defines the size of the bypass window by switching the designated capacitor in the DAC capacitor array to achieve low power for a small input amplitude. If the input falls within the window, some switching phases can be skipped to save power consumption. Since this switching method only utilizes the existing DAC capacitor array and a few additional digital circuits for window definition, it can be employed in SAR ADC architectures with a variable input common-mode voltage during conversion operation, such as set-and-down SAR ADCs. The operation of the proposed bypass window switching is verified with a 12-bit set-and-down SAR ADC fabricated in TSMC 0.18 lm CMOS process. At the sampling rate of 50 kHz, the total power consumption is 1.54 from a 0.6-V supply with a 760-mVpp 24.95-kHz input. The power consumption with a 20-mVpp input that all falls in the window can be significantly reduced to 0.49 . The measured signal-to-noise and distortion ratio and spurious-free dynamic range with 760-mVpp 24.95-kHz input and 50-kS/s sampling rate are 62.67 and 82.44 dB, respectively, resulting in the effective number of bits of 10.12. Based on the power consumption of 1.54, the Walden figure of merit is 27.7 fJ/conversion-step.

Sensorless model predictive control based on I‐f integrated sliding mode observer for surface permanent magnet synchronous motor

SummaryDue to the limited fast dynamic response of the dual proportional‐integral (PI) control strategy in sensorless speed control, a novel composite control strategy is proposed for sensorless control of the full speed range of the surface‐mounted permanent magnet synchronous motor. This strategy combines dual closed‐loop model predictive control (MPC) with a sliding mode observer (SMO) and a constant current‐frequency ratio (I‐f). The I‐f control scheme is employed in the low‐speed range, while the SMO is utilized for motor speed and rotor position estimation in the medium and high‐speed ranges, enabling the dual‐loop MPC. Furthermore, a new smooth switching method is proposed for transitioning between the two control methods. In addition, the MPC outer loop parameters were thoroughly analyzed and optimized for better dynamic performance of sensorless control. The steady‐state performance of this control strategy is compared to PI control and improved the dynamic responsiveness of the system. Experiments have verified the feasibility of this strategy. Under the control of the MPC outer loop, the steady‐state speed fluctuation of the motor is within 10 r/min. Compared to PI control, the motor settling time was reduced by 17% and 60% during the start‐up phase and after a sudden speed change, respectively.

Soft Switching for MOSFET and IGBT Based Hybrid DC-DC Boost Converter

In this study, a hybrid DC-DC boost converter was proposed for high voltage gain. The proposed converter was analyzed and designed. The active soft switching method was applied to proposed converter to reduce the losses due to hard switching. While the main switch of proposed converter is turning off, the main switch current is zero during voltage transition and in the opposite case, the main switch voltage is zero during current transition. Thus, power losses for both states of the main switch were minimized. The simulation for MOSFET and IGBT based hybrid DC-DC boost converter with active soft switching were obtained for different loads.

Enhancing Metaheuristic Optimization: A Novel Nature-Inspired Hybrid Approach Incorporating Selected Pseudorandom Number Generators

In this paper, a hybrid nature-inspired metaheuristic algorithm based on the Genetic Algorithm and the African Buffalo Optimization is proposed. The hybrid approach adaptively switches between the Genetic Algorithm and the African Buffalo Optimization during the optimization process, leveraging their respective strengths to improve performance. To improve randomness, the hybrid approach uses two high-quality pseudorandom number generators—the 64-bit and 32-bit versions of the SIMD-Oriented Fast Mersenne Twister. The effectiveness of the hybrid algorithm is evaluated on the NP-hard Container Relocation Problem, focusing on a test set of restricted Container Relocation Problems with higher complexity. The results show that the hybrid algorithm outperforms the individual Genetic Algorithm and the African Buffalo Optimization, which use standard pseudorandom number generators. The adaptive switch method allows the algorithm to adapt to different optimization problems and mitigate problems such as premature convergence and local optima. Moreover, the importance of pseudorandom number generator selection in metaheuristic algorithms is highlighted, as it directly affects the optimization results. The use of powerful pseudorandom number generators reduces the probability of premature convergence and local optima, leading to better optimization results. Overall, the research demonstrates the potential of hybrid metaheuristic approaches for solving complex optimization problems, which makes them relevant for scientific research and practical applications.

Multiple satellite and ground clock sources‐based high‐precision time synchronization and lossless switching for distribution power system

AbstractPrecise energy management in distribution power system requires high‐precision time synchronization among large‐scale deployed devices. Multiple clock sources‐based time synchronization possesses advantages of reliability, high precision, and robustness, but still faces several challenges such as coupling between time synchronization error and delay, as well as different timescales between clock source and clock weight optimization. In this paper, a multi‐clock source time synchronization model is constructed and a problem is formulated to minimize the synchronization error and delay through jointly optimizing large‐timescale clock source selection and small‐timescale weight selection. A reinforcement learning‐based multi‐timescale multi‐clock source time synchronization algorithm named RL‐M2 is proposed to solve the formulated problem from a learning perspective. Besides, a lossless switching method is proposed to address the switching problem for multiple clock sources. Simulation results demonstrate the superior performance of RL‐M2 and the lossless switching method in time synchronization delay and error.

Застосування методу парирування відмов датчиків при управлінні роботою малорозмірного авіадвигуна

The subject of the research is the application of the method of parrying sensor failures - one of the modern progressive approaches to ensuring the smooth and efficient operation of complex automatic control systems. This article is devoted to the application of this method in the control of a small-sized aircraft engine, which is an actual solution for the development of the aviation industry. The purpose of this study is to choose the optimal method for parrying sensor failures of a small-sized aircraft engine by analyzing existing methods and choosing engine parameters that should be used for parrying. Tasks. Consider the main methods of countering sensor failure and justify the choice of the most effective one. To state the main principles of the method of replacing the parameter value at all stages of the development of the control unit for the operation of a small-sized aircraft engine and to carry out an analysis of the disadvantages and advantages of such an approach. Consider algorithms for identifying and countering sensor failures for the engine management system. Analyze the simulation of individual parameters of a small-sized aircraft engine and propose parameters that should be replaced in the event of sensor failure. Research methods. Comparative analysis of methods of parrying sensor failures and models for simulating the parameters of small-sized aircraft engines with adjacent ones. The results. The method for replacing the parameter value with an adjacent one, switching to a backup value, redundancy, and the use of backup data sources are analyzed. Among the parrying methods, the two most optimal ones are selected (the method of replacing the value of the failed sensor parameter with an adjacent parameter and the method of switching to a backup value) and their work algorithms are described. The advantages are increased reliability and efficiency of engine operation, prevention of information loss, adaptability, and improved diagnostics. Among the shortcomings, the existence of risks of erroneous measurements, complex settings, accuracy limitations, dependence on other parameters, cost and complexity of the system are highlighted. Using the example of the ECU-35 unit developed by JSC "Element", the model of replacing the engine rotor speed parameter using the current temperature of the gases behind the turbine, taking into account the calibration of the measurement channel, was described. Conclusions (scientific and practical novelty). It was found that the application of the method of identification and parrying of sensor failures ensured the smooth operation of the control system when individual sensors failed. Thanks to the method for parrying sensor failures, it was possible to achieve a significant improvement in the performance of a small-sized aircraft engine.

Switching quantum reference frames in the N-body problem and the absence of global relational perspectives

Given the importance of quantum reference frames (QRFs) to both quantum and gravitational physics, it is pertinent to develop a systematic method for switching between the descriptions of physics relative to different choices of QRFs, which is valid in both fields. Here we continue with such a unifying approach, begun in [Quantum 4, 225 (2020)], whose key ingredient is a symmetry principle, which enforces physics to be relational. Thanks to gauge related redundancies, this leads to a perspective-neutral structure which contains all frame choices at once and via which frame perspectives can be consistently switched. Formulated in the language of constrained systems, the perspective-neutral structure is the constraint surface classically and the gauge invariant Hilbert space in the Dirac quantized theory. By contrast, a perspective relative to a specific frame corresponds to a gauge choice and the associated reduced phase and Hilbert space. QRF changes thus amount to a gauge transformation. We show that they take the form of `quantum coordinate changes'. We illustrate this in a general mechanical model, namely the relational N-body problem in 3D space with rotational and translational symmetry. This model is especially interesting because it features the Gribov problem so that globally valid gauge fixing conditions, and hence relational frame perspectives, are absent. The constraint surface is topologically non-trivial and foliated by 3-, 5- and 6-dimensional gauge orbits, where the lower dimensional orbits are a set of measure zero. The N-body problem also does not admit globally valid canonically conjugate pairs of Dirac observables. These challenges notwithstanding, we exhibit how one can construct the QRF transformations for the 3-body problem. Our construction also sheds new light on the generic inequivalence of Dirac and reduced quantization through its interplay with QRF perspectives.

Mechanism of time-delay feedback control of suspension damping with an annular vibration-absorbing structure

With the aim of enhancing both the ride comfort and the safety of the vehicle, we propose a new type of suspension with an annular vibration-absorbing structure, and establish a 3-DOF 1/4 vehicle model. The structure parameters and time-delay feedback control parameters are determined by particle swarm optimization algorithms, which take the root mean values of body acceleration, suspension dynamic deflection, and tire dynamic displacement as their optimization objectives. We analyze the stability of the suspension control system to ensure the stability of the time-delay control system through the Routh-Hurwitz stability criterion, characteristic root method, and stability switching method. Then, we compare and analyze the response characteristics of conventional suspension, new suspension without time-delay feedback control, and new suspension with time-delay feedback control under simple harmonic excitation and random excitation. The results show that the new suspension with time-delay feedback control has a significant damping effect on the body under the premise of ensuring the stability of the system.

Adaptive sliding mode controller based on fuzzy rules for a typical excavator electro-hydraulic position control system

In order to improve the trajectory tracking accuracy and robustness of a typical heavy electro-hydraulic position system, a fuzzy adaptive sliding mode controller is proposed. A potential-like function is introduced to design a new sliding surface with non-linear integral term. An adaptive controller is designed to approximate the equivalent controller in sliding mode control. Stability of the controller is demonstrated by Lyapunov method, and the chattering phenomenon caused by the nonlinear switching term is reduced by using the fuzzy switching method, 25 fuzzy rules are given to adjust the sliding mode switching controller. Simulations with sinusoidal, ramp and step signals, and experiments with leveling operation at different speeds are carried out. The proposed controller can follow the reference trajectory quickly and smoothly, and has certain anti-interference ability. Compared with the traditional sliding mode controller, the proposed controller has small tracking error, fast response and good tracking performances.

Downlink massive full dimension-multiple input multiple output downlink beamforming analysis at 3.5 GHz using coordinated ON-OFF switching

<p><span lang="EN-US">The long-term evolution and advancement (LTE-A) of the 5G wireless network depends critically on energy consumption. Many existing solutions focus on limiting power constraints and consequently system coverage. So, improving the antenna array elements of the base station (BS) can solve this issue. In this paper, introduce a coordinated ON-OFF switching method in the massive full dimensional multiple input multiple output (massive-FD-MIMO) system. It enhances the radiation pattern of the antenna array element by adjusting the angular power spectra at the BS. By the way, it allows to select the minimum number of antennas for effective beamforming toward specific user equipment’s (UEs). In this context, part of antenna element should be active mode and remining should be sleep mode at the time of signal beamforming. The multipath spatial profiles are decided the beamforming frequency band with minimize energy consumption. As part of the method, we used a conjugated beamforming with power optimization scheme to determine the individual antenna potential and fading channel condition, power optimization is performed. This method quality of service, reliability, energy consumption and data rate can all be evaluated by experimenting with different-sized antenna arrays such as 16×16, 32×32, 64×64 and 128×128.</span></p>

Comparison of Methods for Determining Harmonic Distortion Contributions Using the IEEE Benchmark Test System

The growing use of nonlinear devices has raised the harmonic levels in power systems. A challenging power quality problem is determining how much each installation contributes to the harmonic voltages measured at a point of common coupling so that the costs of mitigation solutions can be fairly divided. Currently, there is still no practical worldwide established method to solve this problem. The IEEE PES Task Force on Harmonic Modeling and Simulation developed a Benchmark Test System to support this line of research. Therefore, this study uses the IEEE PES Benchmark to evaluate and compare harmonic contribution determination (HCD) methods. To do so, this Benchmark Test System was implemented in MATLAB/Simulink and used to test five HCD methods proposed in the literature under different network operating cases, including cases with background distortions and resonance. The methods are the Voltage Harmonic Vector Method, the IEC Method, the Dominant Impedance Method, the Capacitor Switching Method, and the Harmonic Current Injection Method. It has been found that the HCD methods generally led to similar contribution percentages, proving the convergence of the methodologies. In addition, an analysis of the methods' sensitivity to input measurement errors was done.

Temperature Dependent Performance of a Conduction-Cooled Jc(B) Transformer- Rectifier Flux Pump

Transformer-rectifier flux pumps provide an elegant solution for high current generation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&gt;$</tex-math></inline-formula> 1 kA) in superconducting magnets. By using step-down transformers and superconducting switches they can charge magnets with minimal heat-load between the external and cryogenic components. High temperature superconductors' type-II superconductivity enables a range of different switching approaches. It was recently shown that a switching approach based on reducing the critical current with an applied DC magnetic field - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c(B)</i> switching - is feasible. The efficiencies of this switching method are an attractive option for a conduction-cooled system where cooling power is limited. In this work we present the first conduction-cooled transformer-rectifier driven by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c(B)</i> switching where we successfully charge a magnet up to its critical current of 115 A whilst monitoring various component temperatures. We explore the parameter space of applied current and switch temperature to establish the effects on the charging time and maximum current.

Design and implementation of capacitor array as DC converters for electrical lighting in limited area

The widely used DC-DC converters are inductor-based DC-DC converters and inductors along with combustion. The use of inductors can lead to large power losses, as well as heavy components in real terms. The proposed converter warning array aims to increase the voltage with a large increase ratio through a switching configuration process. This switching method is very simple and uses two pulses that are opposite each other so that the array converter can work optimally, whose function is to adjust the arrangement in a parallel arrangement to a series arrangement. The advantage of using a device is that it makes DC-based DC conversion lightweight and easy to implement. Tests have been carried out on 5 hanger arrays with a power of 80 W and 65 W, and the data from the test results show that the voltage increase ratio reaches 81.5 % or 4.08 times the input voltage, which indicates that the array converter warning is able to increase the input voltage according to the number of the arrays.

Practical Approaches for the Yeast Saccharomyces cerevisiae Genome Modification.

The yeast S. cerevisiae is a unique genetic object for which a wide range of relatively simple, inexpensive, and non-time-consuming methods have been developed that allow the performing of a wide variety of genome modifications. Among the latter, one can mention point mutations, disruptions and deletions of particular genes and regions of chromosomes, insertion of cassettes for the expression of heterologous genes, targeted chromosomal rearrangements such as translocations and inversions, directed changes in the karyotype (loss or duplication of particular chromosomes, changes in the level of ploidy), mating-type changes, etc. Classical yeast genome manipulations have been advanced with CRISPR/Cas9 technology in recent years that allow for the generation of multiple simultaneous changes in the yeast genome. In this review we discuss practical applications of both the classical yeast genome modification methods as well as CRISPR/Cas9 technology. In addition, we review methods for ploidy changes, including aneuploid generation, methods for mating type switching and directed DSB. Combined with a description of useful selective markers and transformation techniques, this work represents a nearly complete guide to yeast genome modification.

Evaluation of Low-Loss Polymer Switches for Multinuclear MRI/S.

Implementation of multinuclear MRI/S as a diagnostic tool in clinical settings faces many challenges. One of those challenges is the development of highly sensitive multinuclear RF coils. Current multi-tuning techniques incorporate lossy components that impact the highest achievable SNR for at least one of the coil frequencies. As a result, optimization of multinuclear coil designs continues to be a priority for RF hardware engineers. To address this challenge, a new frequency switching technology that incorporates stimuli-responsive polymer materials was explored. Q measurements were used as a comparison metric between single-tuned, a standard switching network, and the proposed switching technology. The Q losses measured in the new switching method remained below 38% when compared to single-tuned coils. These results are consistent with low loss values reported using traditional switching networks. Furthermore, preliminary testing indicates that there is potential for improvement. These results establish the new technology as a promising alternative to traditional switching techniques.Clinical Relevance- A low loss multi-tuning technique for MRI radiofrequency coils has the potential of improving the study and diagnosis of disease.

Random perfect matchings in regular graphs

AbstractWe prove that in all regular robust expanders , every edge is asymptotically equally likely contained in a uniformly chosen perfect matching . We also show that given any fixed matching or spanning regular graph in , the random variable is approximately Poisson distributed. This in particular confirms a conjecture and a question due to Spiro and Surya, and complements results due to Kahn and Kim who proved that in a regular graph every vertex is asymptotically equally likely contained in a uniformly chosen matching. Our proofs rely on the switching method and the fact that simple random walks mix rapidly in robust expanders.

A versatile switching method for N- or O-alkylation of 2-aminophenols using ionic liquids: Selective access to benzo[1,4]oxazine-2-one and benzo[1,4]oxazine-3-one derivatives

A new method is developed for efficient and chemoselective synthesis of benzo[1,4]oxazineone derivatives. By the choice of an appropriate ionic liquid, the process is directed towards selective O- or N-alkylation to give the desired isomeric structures, as the major product of the reaction. In the presence of choline hydroxide, benzo[1,4]oxazine-3-one derivatives are formed, while by using choline fluoride, the corresponding benzo[1,4]oxazine-2-ones are obtained. The latter pathway would be facilitated for sluggish reactants by in situ use of an alkyl halide.

Unified stability criteria of asynchronous discrete-time impulsive switched delayed systems: bounded admissible edge-dependent average dwell time method

This article investigates input-to-state stability (ISS) problem of asynchronous discrete-time impulsive switched delayed systems, in which switching and impulse may be asynchronous. A novel bounded admissible edge-dependent average dwell time (BAED-ADT) switching signal is designed. Based on this division rule of switching subsystems, we adopt the slow switching method for the stable subsystems and the fast switching method for the unstable subsystems, so that stable subsystems can compensate unstable subsystems. Combined with admissible edge-dependent average impulsive interval (AED-AII) impulsive signal, a new unified ISS stability result is established, which could be applied to impulsive switched systems with an arbitrary combination of unstable and stable subsystems. Without solving the linear matrix inequality, it is allowed to readjust the AED-ADT boundary of the newly proposed stability condition according to the actual impulsive and switching signal. Further, compared with the existing fruits, the new stability condition is an extension and improvement of the previous one, which is less conservative. Several numerical examples are provided to show the validity of the conditions and the advantages of the theoretic results.

Electrophoretic Molecular Communication with Piecewise Constant Electric Field.

This paper studies a novel electrophoretic molecular communication (EMC) framework utilizing a piecewise constant electric field. EMC is a particular type of molecular communication that exploits electric fields to induce the movement of charged particles to enhance communication performance. Our previous work proposed an EMC framework utilizing a time-varying electric field that exponentially changes; however, the field with such a complicated shape might be challenging to be implemented in practice. Thus, this paper proposes a new EMC approach exploiting a piecewise constant electric field that can be readily implemented via, e.g., an on/off switch method. We formulate two optimization problems to design the electric field based on different objectives: minimizing a mean squared error and minimizing a bit interval. The solutions of each, such as optimal on-off timings and corresponding strengths of the constant electric fields, are obtained through the Lagrange multiplier approach and the geometric programming, respectively. The Monte Carlo simulation results verify that the proposed piecewise constant electric field significantly reduces the bit error rate relative to the constant field benchmark while performing less well, but not significantly, than the exponential field benchmark.

A Boiler Feed Pump Speed Control to Reduce Its Own Power Consumption According to Pump Affinity Law

The change in water flow required at the BFP pump at the Barru Power Plant is only regulated by a valve located on the pressure side, causing excess power consumption and its own power consumption. One effort to save energy usage is to make frequency adjustments that refer to the right pressure and water flow. To determine the effect of frequency adjustments on the expected pump pressure, a simulation of frequency inverter modeling is performed using the SPWM switching method based on the pump affinity law using Matlab application software. The simulation results obtained that by adjusting the frequency range of the inverter from 45.5 Hz to 50 Hz and keeping the pump pressure above the minimum limit of 13.2 MPa, the operating power savings of the BFP motor are obtained from 46 kW to 378 kW.