Control Pulse Research Articles

Model predictive controlled pulse current battery charging with power electronic switches thru advanced semiconductor material in DC-DC converter

The pulse charging method is one of the fastest charging methodologies for batteries like lithium ion batteries, which are used in electric vehicle applications. This pulse charging methodology leads to fast charging and has higher energy efficiencies. The aim of the paper is to present an overview of the DC-DC battery charger with a model predective (MP) controller. A MP controller is one that predicts the behaviour of the system with a finite time window. The controlled inputs were generated by the MP controller to have optimal operation with respect to predicted value. The process of prediction and generation of controlled input gets repeated after several intervals of time and whenever the DC voltage is greater than the rated voltage of the battery, the charging circuit is disconnected. The modelling of a closed loop pulse current rechargeable battery converter using a PI controller and an MP controller is the subject of this paper. The goal is to increase output power while lowering steady-state error where the same got reduced to 1.05 V (MP controller) from 2.12 V (PI controller). Similarily, rise, settling and peak times are, 0.21, 0.45 and 0.30 secs respectively in system with MP controller. The results demonstrate the model predictive regulated closed loop pulse current rechargeable battery converter's higher performance. Charging a battery also relies on the performance and efficiency of the power electronic switching devices, which in turn rely on the material qualities. These switches are often made of silicon. Due to improved material technology and a desire for higher performance, wide band-gap semiconductors are used in switching devices. This paper also discusses the semiconductor material used to manufacture the power electronic switches that are cast-off in the DC-DC Converter.

An elitist control scheme for power flow management in smart grid system: a hybrid optimization scheme

ABSTRACT In this manuscript, an elitist power flow management (PFM) scheme of PV/FC/battery/SCAP in smart grid (SG) system is proposed. The proposed structure has photovoltaic (PV) generator (Maximum Power Point Tracking (MPPT) and power limitation mode), battery storage, fuel cell (FC), and super capacitor (SCAP). The proposed method is the consolidation of binary adaptation of ant lion optimizer (BALO) and squirrel search optimizer (SSO), and hence it is known BALSO method. Here, BALO is generated the inverter control pulses depends on power transfer an assortments among source and load side. The formulation of multiobjective function in terms of available source power through grid required generated active with reactive power variety. Here, SSO is utilized to obtain that online control pulse using power flow varieties. Moreover, a power flow management method as per the global state of charge (SOC) of energy storage and load demand is proposed. Finally, the BALSO system is performed on MATLAB/Simulink work site. The efficiency of the BALSO system is analyzed through other existing systems. The elapsed time with proposed and existing technique is evaluated.

Strategy of state transfer for open quantum systems by no-knowledge feedback control: Via reverse engineering

It has long been interest to control the transfer of population between specified quantum states and protect the coherence of the system at the same time. In this paper, we investigate a scheme to improve the strategy of state transfer for open quantum systems using no-knowledge measurement-based feedback control and reverse engineering. In order to ensure that the system can process information effectively, we first design the control pulse in advance from the perspective of population and coherence and then verify it through numerical simulations. The research results show that, based on the designed control pulse, we can indeed drive the system from any initial state to the desired target state, and the coherence of the system can be effectively protected during the state transition.

Laboratory Investigation of Impact of Slickwater Composition on Multiphase Permeability Evolution in Tight Sandstones

Summary Fracturing fluid filtrate that leaks off during injection is imbibed by strong capillary forces present in low-permeability sandstones and may severely reduce the effective gas permeability during cleanup and post-fracture production. This work aims to investigate the role fracturing fluid filtrate from slickwater has on rock-fluid and fluid-fluid interactions and to quantify the resulting multiphase permeability evolution during imbibition and drainage of the filtrate by means of specialized core laboratory techniques. Three suites of experiments were conducted. In the first suite of experiments, a fluid leakoff test was conducted on selected core samples to determine the extent of polymer invasion and leakoff characteristics. In the second suite, multigas relative permeability measurements were conducted on sandstone plugs saturated with fracturing fluid filtrate. A combination of controlled fluid evaporation and pulse decay permeability technique was used to measure liquid and gas effective permeabilities for both drainage and imbibition cycles. These experiments aim to capture dynamic permeability evolution during invasion and cleanup of fracturing fluid (slickwater). The final suite of experiments consists of adsorption flow tests to investigate, identify, and quantify possible mechanisms for adsorption of the polymeric molecules of friction reducers present in the fluid filtrate to the pore walls of the rock sample. Imbibition tests and observations of contact angles were conducted to validate possible wettability changes. Results from multiphase permeability flow tests show an irreversible reduction in endpoint brine permeability and relative permeability with increasing concentration of friction reducer. Our results also show that effective gas permeability during drainage/cleanup of the imbibed slickwater fluid is controlled to a large degree by trapped gas saturation than by changes in interfacial tension. Adsorption flow tests identified adsorption of polymeric molecules of the friction reducer present in the fluid to the pore walls of the rock. The adsorption friction reducer increases the wettability of the rock surface and results in the reduction of liquid relative permeability. The originality of this work is to diagnose formation damage mechanisms from laboratory experiments that adequately capture multiphase permeability evolution specific to a slickwater fluid system, during imbibition and cleanup. This will be useful in optimizing fracturing fluid selection.

Performance analysis of an optical TDM transmission link considering fiber dispersion and demultiplexer crosstalk

This paper outlines the performance evaluation of high speed optical time division multiplexed (OTDM) system considering the effect of fiber dispersion and the impairments of nonlinear optical loop mirror (NOLM) used as a demultiplexer. The system performance gets deteriorated by the channel crosstalk and the relative intensity noise (RIN) of the NOLM. Our investigation demonstrates that the system is penalized in terms of power penalty significantly when the intrinsic crosstalk becomes higher than −25 dB. The power coupling ratio must be within the range of 0.47–0.53 in order to maintain the intrinsic crosstalk within −25 dB level. Our analysis also indicates that the system suffers more power penalty with the increasing number of demultiplexing channel and the amount of pulse walk-off between signal and control pulse. Apart from channel crosstalk the system performance is also investigated taking into account the effect of intensity fluctuation of the demultiplexed signal which is called RIN of the NOLM. The system suffers from significant power penalty for the value of such noise higher than 10−5. It is also reported that the power penalty is significant when the chromatic dispersion index becomes higher than 0.30.

Quantum optimal control for pure-state preparation using one initial state

This paper presents a framework for solving the pure-state preparation problem using numerical optimal control. As an example, we consider the case where a number of qubits are dispersively coupled to a readout cavity. We model open system quantum dynamics using the Markovian Lindblad master equation driven by external control pulses. The main result of this paper develops a basis of density matrices (a parameterization) where each basis element is a density matrix by itself. Utilizing a specific objective function, we show how an ensemble of the basis elements can be used as a single initial state throughout the optimization process—independent of the system dimension. We apply the general framework to the specific application of ground-state reset of one and two qubits coupled to a readout cavity.

Deep reinforcement learning for universal quantum state preparation via dynamic pulse control

Accurate and efficient preparation of quantum state is a core issue in building a quantum computer. In this paper, we investigate how to prepare a certain single- or two-qubit target state from arbitrary initial states in semiconductor double quantum dots with only a few discrete control pulses by leveraging the deep reinforcement learning. Our method is based on the training of the network over numerous preparing tasks. The results show that once the network is well trained, it works for any initial states in the continuous Hilbert space. Thus repeated training for new preparation tasks is avoided. Our scheme outperforms the traditional optimization approaches based on gradient with both the higher efficiency and the preparation quality in discrete control space. Moreover, we find that the control trajectories designed by our scheme are robust against stochastic fluctuations within certain thresholds, such as the charge and nuclear noises.

Research on transmission and coupling characteristics of multi-frequency pressure fluctuation of high pressure common rail fuel system

To analyze the coupling characteristics of system-level fuel supply and injection and the mechanism of multi-frequency pressure fluctuations affecting system stability, a prediction model of the high-pressure common rail system was established. The effects of common rail pressure, control pulse width and engine speed on pressure fluctuations were analyzed. Simultaneously, the influence of different hydraulic components such as pumps, rails, and injectors on pressure fluctuations was analyzed by employing hydraulic decoupling method. The influence of pressure fluctuations caused by fuel supply characteristics of pump, filtering effect of rail and fuel injection characteristics of injector on the entire system was studied. The result demonstrates that adjusting target rail pressure and control pulse width alters the fuel supply ability and fuel injection level respectively. During the fluctuation process, the pressure fluctuation overshoot is about 7.7%, and the steady state fluctuation is about ± 1.5%. The adjustment of engine speed influences the overall trend of pressure fluctuations apparently. Additionally, the pressure fluctuations in the system are mainly induced by the coupling of high and low frequency pressure waves. Among them, low-frequency fluctuations everywhere are highly consistent, whereas high-frequency fluctuations are affected significantly by working properties of hydraulic components. Through decoupling analysis, it is illustrated that the fuel pump fluctuations affect the entire fluctuation trend to a great extent. The volume of common rail pipe has an effect on the fluctuation degree and filtering capability. The transient motions of fuel inlet valve, fuel delivery valve and needle valve are the main source of high-frequency fluctuations.

Effect of Pulse Duration and Direction on Plasticity Induced by 5 Hz Repetitive Transcranial Magnetic Stimulation in Correlation With Neuronal Depolarization.

Introduction: High frequency repetitive transcranial magnetic stimulation applied to the motor cortex causes an increase in the amplitude of motor evoked potentials (MEPs) that persists after stimulation. Here, we focus on the aftereffects generated by high frequency controllable pulse TMS (cTMS) with different directions, intensities, and pulse durations.Objectives: To investigate the influence of pulse duration, direction, and amplitude in correlation to induced depolarization on the excitatory plastic aftereffects of 5 Hz repetitive transcranial magnetic stimulation (rTMS) using bidirectional cTMS pulses.Methods: We stimulated the hand motor cortex with 5 Hz rTMS applying 1,200 bidirectional pulses with the main component durations of 80, 100, and 120 μs using a controllable pulse stimulator TMS (cTMS). Fourteen healthy subjects were investigated in nine sessions with 80% resting motor threshold (RMT) for posterior-anterior (PA) and 80 and 90% RMT anterior-posterior (AP) induced current direction. We used a model approximating neuronal membranes as a linear first order low-pass filter to estimate the strength–duration time constant and to simulate the membrane polarization produced by each waveform.Results: PA and AP 5 Hz rTMS at 80% RMT produced no significant excitation. An exploratory analysis indicated that 90% RMT AP stimulation with 100 and 120 μs pulses but not 80 μs pulses led to significant excitation. We found a positive correlation between the plastic outcome of each session and the simulated peak neural membrane depolarization for time constants >100 μs. This correlation was strongest for neural elements that are depolarized by the main phase of the AP pulse, suggesting the effects were dependent on pulse direction.Conclusions: Among the tested conditions, only 5 Hz rTMS with higher intensity and wider pulses appeared to produce excitatory aftereffects. This correlated with the greater depolarization of neural elements with time constants slower than the directly activated neural elements responsible for producing the motor output (e.g., somatic or dendritic membrane).Significance: Higher intensities and wider pulses seem to be more efficient in inducing excitation. If confirmed, this observation could lead to better results in future clinical studies performed with wider pulses.

Actively tunable photonic crystal-based switch via plasmon-analog of index enhancement

We propose a miniaturized photonic switch, which utilizes (recently discovered) plasmon analog of index enhancement. An index is tuned via a control (auxiliary) pulse. The operation principle of the proposed device, composed of a few layers of nanorod dimers, is different than the conventional photonic switches. In the proposed device, a stop band is created at the desired frequency determined by the control pulse frequency. Calculated modulation depths are quite large, and response time is determined by the plasmon lifetime. The method we propose here is based on linear operation that requires low power and has very small foot-print that satisfies the major needs to be the choice of a switching scheme for integrated optics.

Approximations in Transmon Simulation

Classical simulations of time-dependent quantum systems are widely used in quantum control research. In particular, these simulations are commonly used to host iterative optimal control algorithms. This is convenient for algorithms that are too onerous to run in the loop with current-day quantum hardware, as well as for researchers without consistent access to hardware. However, if the model used to represent the system is not selected carefully, an optimised control protocol may be rendered futile when applied to hardware. We present a series of models, ordered in a hierarchy of progressive approximation, which appear in quantum control literature. The validity of each model is characterised experimentally by designing and benchmarking control protocols for an IBMQ cloud quantum device. This result demonstrates error amplification induced by the application of a first-order perturbative approximation. Furthermore, the emergence of errors that cannot be corrected by simple amplitude scaling of control pulses is demonstrated in simulation, due to an underlying mistreatment of noncomputational dynamics. Finally, an evaluation of simulated control dynamics reveals that despite the substantial variance in numerical predictions across the proposed models, the complexity of discovering local optimal control protocols appears invariant in the simple control scheme setting.

The challenge in measuring low-permeability materials: a comparison of different approaches

Abstract. The German repository site selection procedure calls for a radioactive waste containment zone with a low-permeability host rock (kf<10-10 m s−1, StandAG §23, 5) and long-term sealing by barrier materials (EndlSiAnfV, 2020; ESK, 2019). The potential host rocks, clay and rock salt, as well as the considered barrier materials, bentonite and compacted crushed salt, show permeability in the range of kf∼10-16 m s−1 (K∼10-21 m2). These low values suggest that advective flow is as slow as diffusive mass flux. Measuring such low permeability with adequate accuracy challenges measurement setups and respective error evaluation. Methodologies. Several low-permeability measurements are carried out by transient tests, e.g. by monitoring controlled fluid pressure changes in: (1) pressure decay and (2) oscillating pulse tests. The first method (1) deviates permeability from the time needed to compensate pressure differences through the sample. The latter (2) monitors phase shift and amplitude attenuation of controlled pressure pulses passing through the sample. Any permeability measurement needs to be post-processed, e.g. for: (1) material-intrinsic controls (saturation state, storativity, the fluids' compressibility, etc.), (2) environmental controls (temperature, confining pressures, etc.) and (3) theoretical considerations (Klinkenberg correction, multi-phase wetting angles, etc.). Salts. A porosity-permeability relation was found down to K=10-19 m2 (e.g., Popp et al., 2007). Testing fluids were NaCl brine, oils, He and N2 as a fluid. As a matter of current research, a critical, low-permeability value might be associated with the so-called “percolation threshold” that defines the minimal requirements for an interconnected pore system (e.g., DAEF, 2016). Clays. A major challenge is the long duration of sample saturation (up to several months) and pressure equilibration (often days), as well as precise, temperature-compensated measuring and the determination of the samples' storativity (e.g., Winhausen et al., 2021). Testing fluids are commonly designed mixtures mimicking the rocks' pore waters. Geotechnical barrier materials. The permeability testing performed is similar to that of salt and clays mentioned above. However, both barrier materials, crushed salt and bentonite, have significant permeability early after emplacement. This is beneficial, as it allows the outflow of unwanted canister corrosion gases. Eventually, the permeability drops by orders of magnitude and the barriers become tight seals in the long-term. Here, identifying the gas entry/breakthrough pressure has been valuable (e.g., Rothfuchs et al., 2007). Figure 1 shows a preliminary sensitivity analysis as an example of pressure decay measurements. It suggests that the pressure equilibration term (c), and hence the test duration, is most sensitive to the calculation of low permeability. However, the large variation of (representative) material and environmental controls make permeability measurements complex. This workshop aims to encourage discussions on uncertainty and sensitivity of the influencing controls, such that it may lead to a “best-practice” guide for permeability measurements.

A Compensated Peak Current Mode Control PWM for Primary-Side Controlled Flyback Converters

In this paper, a feedback compensator (FBC) and a Feedforward compensator (FFC) are proposed to construct a novel compensated peak current mode control pulse width modulation (CPC-PWM) for primary-side controlled flyback converters. Using the proposed FBC, the PWM duty cycle of an abnormal operating flyback converter would be descended to limit the output current for reducing power dissipation. Using the proposed FFC, the effect of delay time would be descended to reduce the over-flow current for increasing the current accuracy. In this paper, the operating principle and mathematical model are described and analyzed. Then, the component values are well designed to satisfy the electrical specifications. Finally, a prototype is designed and realized to access system performance. The experimental results show that the proposed CPC-PWM can validate in a wide input voltage range and output short conditions, which also has good current accuracy and reduces power dissipation by about 68%.

Efficient Biexciton State Preparation in a Semiconductor Quantum Dot‐Metallic Nanoparticle Hybrid Structure Using Transitionless Quantum Driving

AbstractHow to efficiently prepare the biexciton state in a semiconductor quantum dot placed in the vicinity of a metal nanoparticle is investigated, with control pulses calculated using shortcuts to adiabaticity and specificaly transitionless quantum driving. The quantum dot is considered to be initialized in its ground state. It is numerically demonstrated that the proposed scheme can generate biexciton population values close to unity, for a broad span of interparticle distances and small to moderate values of the biexciton binding energy, when using short laser pulses. It is also shown that these results are robust for small errors in the nanoparticle placement. When the interparticle distance is decreased or the duration of the applied pulses is increased, the population transfer to the biexciton state is reduced. The reason is that for shorter distances the nonlinear terms in the density matrix equation, arising due to exciton‐plasmon interaction, become stronger, while for longer pulses the influence of these unwanted terms is prolonged. Similarly, the fidelity is also reduced for larger values of the biexciton binding energy and longer pulses. This work may be exploited in research fields like quantum information processing and high speed nanoswitches, where a key procedure is the efficient biexciton state preparation in quantum dots.

Optimal control pulses establishment for the power flow management in hybrid renewable energy sources using BCRFA controller

These works are introduced to avoid electrical problems in literary works. An intelligent hybrid control technique for optimal power flow management (OPFM) in grid-associated hybrid renewable energy sources (HRES) with energy storage is proposed in this dissertation. For stabilizing power fluctuations, the intelligent controller is proposed. The proposed intelligent controller is joint performance of Big Bang-Big Crunch (BB-BC) and random forest algorithm known as BCRFA controller. In the proposed controller, the BB-BC method reproduces the evaluation process to establish the exact control signals (ECS) system depending on power variations with source, load side. With this appropriate control, HRES can significantly improve the dynamic safety of the power system. Finally, the proposed system is executed on MATLAB/Simulink work site. The efficiency of the BCRFA system compares the existing system. The result of the comparison reveals that HRES power flow using the proposed system is direct efficiently compared with the existing systems. The efficiency of the various techniques and the proposed technique has been analysed in three case studies. In Case 1, the PV, wind, battery and FC gives the efficiency using proposed technique is 95.3617%, 99.1235%, 98.1264% and 99.4677%. In Case 2, the photovoltaic (PV), wind, battery and fuel cell (FC) give the efficiency using the proposed technique is 91.4365%, 93.6537%, 98.5151% and 97.1562%. In Case 3, the PV, wind, battery and FC give the efficiency using the proposed technique is 92.5479%, 91.2369%, 97.5631% and 90.1245%.

Floquet Prethermalization with Lifetime Exceeding 90s in a Bulk Hyperpolarized Solid.

We report the observation of long-lived Floquet prethermal states in a bulk solid composed of dipolar-coupled ^{13}C nuclei in diamond at room temperature. For precessing nuclear spins prepared in an initial transverse state, we demonstrate pulsed spin-lock Floquet control that prevents their decay over multiple-minute-long periods. We observe Floquet prethermal lifetimes T_{2}^{'}≈90.9 s, extended >60 000-fold over the nuclear free induction decay times. The spins themselves are continuously interrogated for ∼10 min, corresponding to the application of ≈5.8×10^{6} control pulses. The ^{13}C nuclei are optically hyperpolarized by lattice nitrogen vacancy centers; the combination of hyperpolarization and continuous spin readout yields significant signal-to-noise ratio in the measurements. This allows probing the Floquet thermalization dynamics with unprecedented clarity. We identify four characteristic regimes of the thermalization process, discerning short-time transient processes leading to the prethermal plateau and long-time system heating toward infinite temperature. This Letter points to new opportunities possible via Floquet control in networks of dilute, randomly distributed, low-sensitivity nuclei. In particular, the combination of minutes-long prethermal lifetimes and continuous spin interrogation opens avenues for quantum sensors constructed from hyperpolarized Floquet prethermal nuclei.

An efficient hybrid tunicate swarm algorithm and radial basis function searching technique for maximum power point tracking in wind energy conversion system

Purpose The purpose of this paper is to track the maximal power of wind energy conversion system (WECS) and enhance the search capability for WECS maximum power point tracking (MPPT). Design/methodology/approach The hybrid technique is the combination of tunicate swarm algorithm (TSA) and radial basis function neural network. Findings TSA gets input parameters from the rectifier outputs such as rectifier direct current (DC) voltage, DC current and time. From the input parameters, it enhances the reduced fault power of rectifier and generates training data set based on the MPPT conditions. The training data set is used in radial basis function. During the execution time, it produces the rectifier reference DC side voltage that is converted to control pulses of inverter switches. Originality/value Finally, the proposed method is executed in MATLAB/Simulink site, and the performance is compared with different existing methods like particle swarm optimization algorithm and hill climb searching technique. Then the output illustrates the performance of the proposed method and confirms its capability to solve issues.

Double-Frequency-Shift Acousto-Optic Modulator with Controllable Pulse Pair Frequency Difference

A scheme for controlling the frequency difference of output pulse pair with double frequency shift loops is proposed. The frequency shift system includes two loop elements of 20 and 200 MHz. The first one carries out a single selective positive frequency shift of 1–20 MHz, and the second one can satisfy a single fixed positive frequency shift of 200 MHz. The reverse cascade technology of two acousto-optic crystals is introduced to solve the limitation of the small frequency shift of crystal size. A multichannel synchronization signal completes the time domain control of each acousto-optic modulator. Finally, the frequency shift difference of the output pulse pair ranges of 0–2 GHz, and the frequency shift accuracy is 5 MHz.

Parametrized Hamiltonian simulation using quantum optimal control

Analog quantum simulation offers a hardware-specific approach to studying quantum dynamics, but mapping a model Hamiltonian onto the available device parameters requires matching the hardware dynamics. We introduce a paradigm for quantum Hamiltonian simulation that leverages digital decomposition techniques and optimal control to perform analog simulation. We validate this approach by constructing the optimal analog controls for a superconducting transmon device to emulate the dynamics of an extended Bose-Hubbard model. We demonstrate the role of control time, digital error, and pulse complexity, and we explore the accuracy and robustness of these controls. We conclude by discussing the opportunity for implementing this paradigm in near-term quantum devices.

Semiclassical control theory of coherent anti-Stokes Raman scattering maximizing vibrational coherence for remote detection

A semiclassical theory that describes the generation of a coherent anti-Stokes Raman scattering (CARS) signal is presented that maximizes vibrational coherence in a mode predetermined by the pump, the Stokes, and the probe chirped pulse trains and takes into account the field propagation effects in a cloud of molecules. The buildup of the anti-Stokes signal, which may be used as a molecular signature in the backward CARS signal, is demonstrated numerically. The theory is based on the solution of the coupled Maxwell's and Liouville--von Neumann equations and focuses on the quantum effects induced in the target molecules by the control pulse trains. A deep convolutional neural network technique is implemented to evaluate time-dependent phase characteristics of the control fields. The effect of decoherence induced by spontaneous decay and collisional dephasing is examined.