Bidirectional Control Research Articles

A Bidirectional Control Regenerative Braking Strategy for EV Applications- A Review

In this paper, Review on bi-directional DC/DC buck-boost converter with dual control strategy during regenerative braking is used for a two-wheeler application. To reduce the harmful emissions from automobiles and massive surges in fuel prices, automotive electric vehicles are an effective alternate solution. In this paper, a cascaded bi-directional DC/DC buck-boost converter with dual control strategy during regenerative braking is used for a two-wheeler application. The dual control strategy with the cascaded converter is used to increase the average power stored during the braking period and to reduce the vehicle’s stopping time. The converter with the proposed control strategy used in this work has made it possible to charge the battery even when the back emf of the machine is less than the battery voltage. A fuzzy logic control strategy is used to consider the non-linear factors like SOC, speed of the vehicle and the required brake force. This is done in order to make the system more reliable and realistic. implementing the dual control strategy, the average power stored by the battery is increased by 2.5 times and the vehicle comes to halt faster in comparison with the existing control strategy. The versatility of the strategy is shown by examining three different scenarios during the regenerative braking process

Successful modulation of temporoparietal junction activity and stimulus-driven attention by fNIRS-based neurofeedback—A randomized controlled proof-of-concept study

Abstract The right temporoparietal junction (rTPJ) is a core hub in neural networks associated with reorienting of attention and social cognition. However, it remains unknown whether participants can learn to actively modulate their rTPJ activity via neurofeedback. Here, we explored the feasibility of functional near-infrared spectroscopy (fNIRS)-based neurofeedback in modulating rTPJ activity and its effect on rTPJ functions such as reorienting of attention and visual perspective taking. In a bidirectional regulation control group design, 50 healthy participants were reinforced to either up- or downregulate rTPJ activation over 4 days of training. Both groups showed an increase in rTPJ activity right from the beginning of the training but only the upregulation group maintained this effect, while the downregulation group showed a decline from the initial rTPJ activation. This suggests a learning effect in the downregulation exclusively, making it challenging to draw definitive conclusions about the effectiveness of rTPJ upregulation training. However, we observed group-specific effects on the behavioral level. We found a significant group x time interaction effect in the performance of the reorienting of attention task and group-specific changes, with decreased reaction times (RTs) in the upregulation group and increased RTs in the downregulation group across all conditions after the neurofeedback training. Those with low baseline performance showed greater improvements. In the perspective-taking task, however, only time effects were observed that were non-group-specific. These findings demonstrate that fNIRS-based neurofeedback is a feasible method to modulate rTPJ functions with preliminary evidence of neurophysiologically specific effects, thus paving the way for future applications of non-invasive rTPJ modulation in neuropsychiatric disorders.

Bidirectional Control With Fitting Model-Based Synchronous Rectification and Input Ripple Current Feedforward for SiC Bidirectional CLLC EV Charger

Conventional CLLC Synchronous Rectification (SR) typically adopts detection circuits to sense the high frequency signals. It can hardly be used in the high voltage SiC applications directly as it is sensitive to high dv/dt and may cause false operation. A bidirectional control is proposed for the SiC CLLC charger to achieve the SR function and mitigate the input ripple current. Considering the switching frequency and load, the SR on-time is calculated by the proposed three-order fitting model with low calculation source and high immunity to high dv/dt. Moreover, an input ripple current feedforward control is proposed in the discharging mode, which adds the extracted double line-frequency ripple current to the bus voltage reference. It not only achieves low SR conduction loss, but also reduces the input ripple current largely in the discharge. A 6.6-kW SiC bidirectional CLLC charger was built. Compared to the conventional SR, the CLLC efficiency of proposed SR improves 0.28% at 6.6 kW in the charge. In the discharge, the reduction of CLLC input ripple current at the double line-frequency is up to 91%. The overall charging and discharging efficiencies are 95.4% and 96.1% at full load, respectively.

Energy Management and Charging Portfolio Analysis for Future Battery Powered Harbor Vessels

This paper intends to provide key insights to the marine designers and port authorities for adapting battery-operated zero emission electric harbor vessels (ZEE-HVs) and plan the resources for charging infrastructure. The present study is a cumulatively coordinated analysis of various significant aspects concerning the adaptation of ZEE-HVs for short-endurance commercial maritime operations. The sizing of onboard battery energy systems (OBES) is discussed for different short-endurance ZEE-HVs by considering the speed-resistance characteristics of the hull and open-water characteristics of the propeller without limiting their operations for specific load profiles/operating cycles. Charging portfolio selection is critical for a marine vessel as the OBES size is several times higher than a regular electric vehicle's battery. Hence charging portfolio selection criteria are presented to select a suitable battery charging protocol for each ZEE-HV as per the OBES ratings and available idle times on a typical day. Since the port is a commercial spot, uncertainty in resource planning leads to penalties and loss of goodwill. Therefore, Monte Carlo-based iterative analytical method is adopted to forecast the ZEE-HVs' maximum possible charging power demand on a typical day. By the load forecast data, optimal sizing of the load peak shaving battery (LPSB) was performed to limit load fluctuations at the port grid. The synergy of ZEE-HVs with LPSB and bi-directional charge-discharge controller is pivotal for effectively administering the seaport shore charging facility, which is demonstrated for a typical energy management cycle.

Research on the control strategy of interlinking converters for photovoltaic storage hybrid microgrid

This article mainly solves the problem of accurate power distribution and stable running in the photovoltaic storage hybrid microgrid and studies different control strategies of the interlinking converter connected to the AC-DC subnet under on-grid and off-grid conditions. The relationship between DC-side voltage, active power and active current is analyzed in the on-grid, and the DC voltage stability is supported by using a closed-loop voltage and current; in the off-grid mode, an improved bidirectional sag control method based on unitization processing is adopted, in which the power to be transmitted by the converter is differed from the actual value as the reference input of the current loop on the traditional double sag control, which can coordinate the power transmission between subgrids more precisely; And the action threshold is designed for the problem of repeated switching of converter operating modes. The results of simulation show that the converter able effectively to judge the magnitude and power direction in both parallel and off-grid operation modes, which ensures the normal operation of the important loads inside the subnets on both sides, thus verifying the feasibility of the control method.

A grid voltage perturbations based bidirectional impedance uniform control for grid‐connected DC/AC converter

AbstractFor bidirectional grid‐connected DC/AC converters, the power flow variation substantially alters the system stability, and especially severs under heavy load. Towards this problem, this paper proposes a novel impedance uniform control method to eliminate the stability degradation under power flow variations, which is achieved by reshaping the converter negative incremental impedance to resistive in the stability fragile mode. The d‐axis voltage perturbation is extracted to dynamically modify the active power current reference. Hence, the system bidirectional damping performance can be simultaneously improved by this dedicated design. Without switching control modes or sacrificing dynamic performance, the grid‐connected converter system can maintain satisfied stability under bidirectional power flow variations. Finally, the effectiveness of the proposed control method has been validated by both simulations and experiments.

Synthesis and Characterization of Photoswitchable Dithienylethene-Based Chiral Bisoxazoline Compounds with Bidirectional Visible-Light Control.

In this paper, we have successfully synthesized dithienylethene-based chiral bisoxazoline ligands with bidirectional photoswitching capabilities under visible light irradiation and proposed a strategy for adjusting the conjugation system length in sensitizer groups. The detailed experimental procedures and the characterization data are presented in the main text and the Supporting Information. Despite their moderate photoswitching rates, these ligands provide a promising approach towards developing fully visible light-responsive chiral catalysts.

Motion In-Betweening with Phase Manifolds

This paper introduces a novel data-driven motion in-betweening system to reach target poses of characters by making use of phases variables learned by a Periodic Autoencoder. Our approach utilizes a mixture-of-experts neural network model, in which the phases cluster movements in both space and time with different expert weights. Each generated set of weights then produces a sequence of poses in an autoregressive manner between the current and target state of the character. In addition, to satisfy poses which are manually modified by the animators or where certain end effectors serve as constraints to be reached by the animation, a learned bi-directional control scheme is implemented to satisfy such constraints. The results demonstrate that using phases for motion in-betweening tasks sharpen the interpolated movements, and furthermore stabilizes the learning process. Moreover, using phases for motion in-betweening tasks can also synthesize more challenging movements beyond locomotion behaviors. Additionally, style control is enabled between given target keyframes. Our proposed framework can compete with popular state-of-the-art methods for motion in-betweening in terms of motion quality and generalization, especially in the existence of long transition durations. Our framework contributes to faster prototyping workflows for creating animated character sequences, which is of enormous interest for the game and film industry.

Programmable Control of Nanoliter Droplet Arrays using Membrane Displacement Traps.

A unique droplet microfluidic technology enabling programmable deterministic control over complex droplet operations is presented. The platform provides software control over user-defined combinations of droplet generation, capture, ejection, sorting, splitting, and merging sequences to enable the design of flexible assays employing nanoliter-scale fluid volumes. The system integrates a computer vision system with an array of membrane displacement traps capable of performing selected unit operations with automated feedback control. Sequences of individual droplet handling steps are defined through a robust Python-based scripting language. Bidirectional flow control within the microfluidic chips is provided using an H-bridge channel topology, allowing droplets to be transported to arbitrary trap locations within the array for increased operational flexibility. By enabling automated software control over all droplet operations, the system significantly expands the potential of droplet microfluidics for diverse biological and biochemical applications by combining the functionality of robotic liquid handling with the advantages of droplet-based fluid manipulation.

Bidirectional Position Control of a Prismatic joint for Motorized Single Link Robotic Arm Using Adaptive Super- Twisting Sliding Mode Control

Bidirectional Position Control of a Prismatic joint for Motorized Single Link Robotic Arm Using Adaptive Super- Twisting Sliding Mode Control

Bidirectional motion characteristics of resonant inertial impact rotating piezoelectric motor based on self-clamping structure

A new working principle for multimodal excitation of a resonant bidirectional rotary inertial impact piezoelectric motor with a self-clamping structure was developed based on previous research on piezoelectric motors. Unlike previous piezoelectric motors that relied on single harmonic waves for unidirectional rotation, in this motor, we can simply change the driving signal characteristics of the motor without changing the structure of the piezoelectric motor to excite multiple vibration modes, thereby achieving rotation in both directions. Compared with other bidirectional resonant motors, the structure and control signal are simpler. The finite element simulation software COMSOL5.5 was used to simulate the working mode of the motor, and the results were in good agreement with the final experiment. During the experiments, the optimal operating frequency of the motor prototype was 900 Hz. The maximum output speed of the motor prototype was 3.9 rad/s, the maximum output torque was 15 N mm, and the maximum resolution was 0.248° under the conditions of 240 Vp-p voltage, 900 Hz frequency, and 7.8 N mm preload torque.

Strain-Driven Bidirectional Spin Orientation Control in Epitaxial High Entropy Oxide Films.

High entropy oxides (HEOs), based on the incorporation of multiple-principal cations into the crystal lattice, offer the possibility to explore previously inaccessible oxide compositions and unconventional properties. Here it is demonstrated that despite the chemical complexity of HEOs external stimuli, such as epitaxial strain, can selectively stabilize certain magneto-electronic states. Epitaxial (Co0.2 Cr0.2 Fe0.2 Mn0.2 Ni0.2 )3 O4 -HEO thin films are grown in three different strain states: tensile, compressive, and relaxed. A unique coexistence of rocksalt and spinel-HEO phases, which are fully coherent with no detectable chemical segregation, is revealed by transmission electron microscopy. This dual-phase coexistence appears as a universal phenomenon in (Co0.2 Cr0.2 Fe0.2 Mn0.2 Ni0.2 )3 O4 epitaxial films. Prominent changes in the magnetic anisotropy and domain structure highlight the strain-induced bidirectional control of magnetic properties in HEOs. When the films are relaxed, their magnetization behavior is isotropic, similar to that of bulk materials. However, under tensile strain, the hardness of the out-of-plane (OOP) axis increases significantly. On the other hand, compressive straining results in an easy OOP magnetization and a maze-like magnetic domain structure, indicating the perpendicular magnetic anisotropy. Generally, this study emphasizes the adaptability of the high entropy design strategy, which, when combined with coherent strain engineering, opens additional prospects for fine-tuning properties in oxides.

An SOC-Based Bidirectional Virtual DC Machine Control for Energy Storage Systems in Offshore Isolated Island DC Microgrids

In order to achieve the state of charge (SOC) balance of distributed energy storage systems (ESSs) in offshore isolated island DC microgrids and enhance the inertia and damping characteristics of DC microgrids, an SOC-based bidirectional virtual DC machine (VDCM) control is presented. The control proposed has the following three improvements. Firstly, the improved VDCM control removes the power loop and torque loop on the basis of ensuring inertia and damping characteristics. Secondly, the inertia time constant and damping constant, which are related to the bus voltage difference and the change rate of bus voltage difference, are introduced to improve bus voltage dynamic performance. The proposed method overcomes the shortcoming in that traditional VDCM control cannot adaptively suppress bus voltage oscillation according to the bus voltage fluctuation amplitude. Thirdly, an improved SOC-based VDCM virtual armature resistance (VAR) is proposed to achieve rapid SOC balance. The improved SOC-based VDCM VAR is an SOC-related function added to the initial VAR. This enables the proposed VAR to have a certain adaptive ability, which can adjust the energy absorbed or released by energy storage units according to the SOC state. Compared with other controls, the control proposed takes less time to achieve SOC balance. Finally, the effectiveness and superiority of the scheme are proven by simulation cases.

Adaptive Control Approach-Based Isolated Microgrid System with Alleviating Power Quality Problems

In this article, a dual third-order generalized integrator-based phase-locked loop (DTOGI-PLL) and an additional degree of freedom-based frequency locked loop (ADF-FLL) control approaches are utilized on a voltage source converter (VSC) to control an isolated microgrid system under different operating conditions. The proposed adaptive approaches provide a fast dynamic response with a precise estimation of frequency, phase angle, and fundamental load current component compared to that of the TOGI-PLL and least mean square (LMS) algorithms. An ADF-FLL allows closed-loop poles to perform more optimally, resulting in faster dynamic performance without compromising filtering capability. Moreover, the proposed adaptive approaches with VSC provide power support, load leveling, harmonic eliminations, and enhance the isolated microgrid’s overall power quality during dynamics in load and energy sources. A solar PV (SPV) array with perturb & observe (P&O) MPPT control is interfaced at the DC link of a bidirectional controller (BDC) to draw maximum solar power. Through dc-link voltage control, the BDC with energy storage system (ESS) ensures the appropriate power flow and power equilibrium between energy sources and load. The Simulation and test results show the dynamic performance of the isolated microgrid is examined under different operational scenarios.

MicroRNA-335-5p suppresses voltage-gated sodium channel expression and may be a target for seizure control

There remains an urgent need for new therapies for treatment-resistant epilepsy. Sodium channel blockers are effective for seizure control in common forms of epilepsy, but loss of sodium channel function underlies some genetic forms of epilepsy. Approaches that provide bidirectional control of sodium channel expression are needed. MicroRNAs (miRNA) are small noncoding RNAs which negatively regulate gene expression. Here we show that genome-wide miRNA screening of hippocampal tissue from a rat epilepsy model, mice treated with the antiseizure medicine cannabidiol, and plasma from patients with treatment-resistant epilepsy, converge on a single target-miR-335-5p. Pathway analysis on predicted and validated miR-335-5p targets identified multiple voltage-gated sodium channels (VGSCs). Intracerebroventricular injection of antisense oligonucleotides against miR-335-5p resulted in upregulation of Scn1a, Scn2a, and Scn3a in the mouse brain and an increased action potential rising phase and greater excitability of hippocampal pyramidal neurons in brain slice recordings, consistent with VGSCs as functional targets of miR-335-5p. Blocking miR-335-5p also increased voltage-gated sodium currents and SCN1A, SCN2A, and SCN3A expression in human induced pluripotent stem cell-derived neurons. Inhibition of miR-335-5p increased susceptibility to tonic-clonic seizures in the pentylenetetrazol seizure model, whereas adeno-associated virus 9-mediated overexpression of miR-335-5p reduced seizure severity and improved survival. These studies suggest modulation of miR-335-5p may be a means to regulate VGSCs and affect neuronal excitability and seizures. Changes to miR-335-5p may reflect compensatory mechanisms to control excitability and could provide biomarker or therapeutic strategies for different types of treatment-resistant epilepsy.

Optimized Control of a Hybrid Water Pumping System Integrated with Solar Photovoltaic and Battery Storage: Towards Sustainable and Green Water-Power Supply

This article presents the modeling and optimization control of a hybrid water pumping system utilizing a brushless DC motor. The system incorporates battery storage and a solar photovoltaic array to achieve efficient water pumping. The solar array serves as the primary power source, supplying energy to the water pump for full-volume water surrender. During unfavorable weather conditions or when the photovoltaic array is unable to meet the power demands of the water pump, the battery discharges only at night or during inadequate solar conditions. Additionally, the photovoltaic array can charge the battery on its own when water distribution is not necessary, negating the need for external power sources. A bi-directional charge control mechanism is employed to facilitate automatic switching between the operating modes of the battery, utilizing a buck-boost DC–DC converter. The study incorporates a control system with loops for battery control and DC voltage control within the bidirectional converter. The water cycle algorithm adjusts four control parameters by minimizing an objective function based on tracking errors. The water cycle optimization is compared to other methods based on overshoot and settling time values to evaluate its performance, showcasing its effectiveness in analyzing the results.

Enhanced Grid Frequency and DC-Link Voltage Regulation in Hybrid AC/DC Microgrids Through Bidirectional Virtual Inertia Support

AC mains frequency and dc-link voltage are two of the most important parameters that determine the stability of hybrid ac/dc microgrids. Frequency and voltage deviations beyond the acceptable threshold can lead to unscheduled load curtailments, cascading failures, or even power system blackouts. To enhance the stability of hybrid ac/dc microgrids, this paper proposes a hybrid microgrid with bidirectional virtual inertia support, where virtual inertia is introduced to slow down dc voltage and ac frequency changes, thus enhancing system stability. The proposed approach allows significant reductions in voltage and frequency fluctuations. With a standard hybrid microgrid configuration, inertia is delivered to both ac and dc subgrids via the change of bi-directional interlinking converter control. Specifically, the bidirectional interlinking converter uses the dc voltage of the dc grid and ac frequency of the ac grid as inputs through a proportional integral (PI) controller and regulates the active power between two sub grids so that inertia and other supportive functions are implemented. To validate the merits of the proposed approach, experimental results are provided. According to experimental results, the frequency nadir, rate-of-change-of-frequency (RoCoF), and dc bus voltage deviation can be improved by the proposed strategy of bidirectional virtual inertia support in the hybrid ac/dc microgrid.

Bidirectional Monitoring and Control Technology of Solar Photovoltaic Module Using Power Frame

Bidirectional Monitoring and Control Technology of Solar Photovoltaic Module Using Power Frame

Assessing attention and impulsivity in the variable stimulus duration and variable intertrial interval rodent continuous performance test schedules using noradrenaline receptor antagonists in female C57BL/6JRj mice

RationaleNoradrenergic dysfunction is associated with disorders of impulsivity and inattention. The rodent continuous performance test (rCPT) quantifies changes in attention and impulsivity.ObjectiveTo use NA receptor antagonists to examine the roles of NA on attention and impulsivity behaviours measured in the rCPT variable stimulus duration (vSD) and the variable intertrial interval (vITI) schedules.MethodsTwo cohorts of 36 female C57BL/6JRj mice were examined separately in the rCPT vSD and vITI schedules. Both cohorts received antagonists of the following adrenoceptors: α1 (doxazosin, DOX: 1.0, 3.0, 10.0 mg/kg), α2 (yohimbine, YOH: 0.1, 0.3, 1.0 mg/kg), and β1/2 (propranolol, PRO: 1.0, 3.0, 10.0 mg/kg) in consecutive balanced Latin square designs with flanking reference measurements. The antagonists were subsequently examined for effects on locomotor activity.ResultsDOX showed similar effects in both schedules, improving discriminability and accuracy, and reducing responding and impulsivity, and DOX also reduced locomotor activity. YOH showed prominent effects in the vSD schedule to increase responding and impulsivity, while impairing discriminability and accuracy. YOH did not affect locomotor activity. PRO increased responding and impulsivity, decreased accuracy, but did not affect discriminability or locomotor activity.ConclusionAntagonism of α2 or β1/2 adrenoceptors caused similar increases in responding and impulsivity and worsened attentional performance, while α1 adrenoceptor antagonism showed the opposite effects. Our results suggest that endogenous NA exerts bidirectional control of most behaviours in the rCPT. The parallel vSD and vITI studies showed a substantial overlap in effects, but also some differences that indicate differing sensitivity towards noradrenergic manipulations.

Multifaceted luminance gain control beyond photoreceptors in Drosophila

Animals navigating in natural environments must handle vast changes in their sensory input. Visual systems, for example, handle changes in luminance at many timescales, from slow changes across the day to rapid changes during active behavior. To maintain luminance-invariant perception, visual systems must adapt their sensitivity to changing luminance at different timescales. We demonstrate that luminance gain control in photoreceptors alone is insufficient to explain luminance invariance at both fast and slow timescales and reveal the algorithms that adjust gain past photoreceptors in the fly eye. We combined imaging and behavioral experiments with computational modeling to show that downstream of photoreceptors, circuitry taking input from the single luminance-sensitive neuron type L3 implements gain control at fast and slow timescales. This computation is bidirectional in that it prevents the underestimation of contrasts in low luminance and overestimation in high luminance. An algorithmic model disentangles these multifaceted contributions and shows that the bidirectional gain control occurs at both timescales. The model implements a nonlinear interaction of luminance and contrast to achieve gain correction at fast timescales and a dark-sensitive channel to improve the detection of dim stimuli at slow timescales. Together, our work demonstrates how a single neuronal channel performs diverse computations to implement gain control at multiple timescales that are together important for navigation in natural environments.