Control Circuitry Research Articles

Optimized sensor charge controller for bus voltage stabilization in hybrid battery-supercapacitor fed islanded microgrid system

This paper proposes a novel Energy Storage Device (ESD) charge controller for integrating multiple hybrid ESD (battery-supercapacitor) stacks within the DC microgrids. A low-cum-medium power islanded DC microgrid system, consisting of Distributed Energy Resources (DERs), loads and isolated/non-isolated multiple hybrid ESDs is configured for this purpose. The hybrid ESDs tackle the source-load and DC bus voltage fluctuations smoothly, while multiple ESDs foster system redundancy. As opposed to conventional ESD controllers where sensory requirements increase proportionally with the number of ESDs converters connected, the proposed algorithm uses just one voltage sensor placed at the DC link bus. The Power Management Strategy (PMS) is designed accordingly, considering the system power flow status and State of Charge (SOC) of each ESD. The minimum use of sensors leads to simplified control circuitry, better system stability (less control error tuners required), ease of hardware implementation and makes system economical for market outreach. The viability of the proposed ESD controller for multiple hybrid isolated/non-isolated ESDs converter has been tested through the simulation platform during the transient conditions. The power exchange between different ESDs in factors of 1:1 and 1:2 is verified. The DC link voltage is stabilized with the ripple factor of <1.0 %. For experimental verification, scaled-down laboratory prototype of DC microgrid (≈ 0.25 to 0.5 kW) is made and tested in ESD charging-discharging modes. A fast transient response slope of up to 2.0 kW/s. is tested using the proposed controller on the experimental platform. Since the proposed controller is less computation intensive, a low-cost microcontroller serves the purpose.

A 2D-Programmable and Scalable Reconfigurable Intelligent Surface Remotely Controlled via Digital Infrared Code

Reconfigurable intelligent surfaces (RISs) are promising and relatively low-cost tools for improving signal propagation in wireless communications. A RIS assists a base station (BS) in optimizing the channel and maximizing its capacity by dynamically manipulating the reflected field. Typically, RISs are based on dynamically reconfigurable reflectarrays (RAs), i.e., 2-D arrays of passive patch antennas, individually switchable between two or more reflection phases. The spatial resolution of provided reflected field patterns is governed by the aperture dimensions and the number of patches to meet the requirements of different communication scenarios and environments. Here, we demonstrate a 1 bit RIS for 5 GHz Wi-Fi band made by assembling together multiple independently operating and structurally detached building blocks all powered by the same DC source. Each block contains four separately phase-switchable patch antennas with varactor diodes and a common microcontroller extracting digital control commands from modulated infrared light illuminating the entire RIS. Such distributed light-sensitive controllers grant the possibility of scaling the aperture by adding or removing blocks without redesigning any control circuitry. Moreover, in the proposed RIS a full 2-D phase encoding capability is achieved along with a robust remote infrared control.

Inductor Based Active Cell Equalization for Ultracapacitor Energy Storages

Ultracapacitors, known for their high power density and long cycle life, are widely used in various applications. However, when ultracapacitor cells are connected in series, voltage imbalances can occur, limiting overall energy storage capacity and system performance. This paper presents an investigation into inductor-based active cell equalization techniques for ultracapacitor energy storage systems. The proposed approach utilizes inductors, switching devices, and control circuitry to efficiently balance cell voltages. By monitoring cell voltages and activating switching devices when predetermined thresholds are exceeded, energy is transferred from higher voltage cells to inductors during the charging phase. In the subsequent discharging phase, the stored energy is released, equalizing the cell voltages. This iterative process continues until voltage balance is achieved. Inductor-based active cell equalization offers advantages such as rapid voltage equalization, wide voltage range operation, and electrical isolation between cells. However, challenges include system complexity, cost, and losses introduced by switching devices. Ongoing research focuses on optimizing design and control strategies to improve energy efficiency and address these challenges. The proposed technique shows promise in maximizing energy storage capacity and enhancing the performance and lifespan of ultracapacitor systems. This circuit could balance the capacity of the ultracapacitor in 2.3 seconds with a voltage ripple of 0.0038 V (0.18 %). Further advancements are expected to promote the widespread adoption of inductor-based active cell equalization in diverse applications. (Abstract)

A microfluidics vapor-membrane-valve generated by laser irradiation on carbon nanocoils.

We have investigated a micro vapor membrane valve (MVMV) for closing the microfluidic channels by laser irradiation on carbon nanocoils (CNCs) attached to the inner wall of the microchannels. The microchannel with MVMVs was found to exhibit a "closed" state without the supply of laser energy, which is explained on the basis of the theory of heat and mass transfer. Multiple MVMVs for sealing the channels can be generated in sequence and exist simultaneously at different irradiation sites, independently. The significant advantages of the MVMV generated by the laser irradiation on CNCs are the elimination of extrinsic energy required to maintain the microfluidic channel "closed" state and the simplification of the structure integrated into the microfluidic channels and fluid control circuitries. The CNC-based MVMV is a powerful tool for the investigations of the functions of microchannel switching and sealing on microfluidic chips in biomedicine, chemical analysis and other fields. The study of MVMVs will have great significance for biochemical and cytological analysis.

Enhancing voltage regulation using 5‐level TCHB based DVR in radial secondary distribution feeder system

SummaryThe voltage quality issues shows the significant effect on the performance of radial secondary distribution feeder. This paper aims to enhance the voltage regulation of radial secondary distribution feeder system using 5‐level TCHB inverter based dynamic voltage restorer. Series voltage drop is the major factor causes poor voltage regulation. A 5‐level TCHB inverter based DVR is used to inject the same amount of voltage dropped by series impedance. The DVR injects voltage with proper magnitude, phase and frequency with the proposed single phase PLL based SRF control circuitry. This enhances the voltage regulation by maintaining the load voltage at its rated value. Both the simulation and hardware results shows the enhancement of voltage regulation with mitigation using DVR.

Printable and flexible photodetectors via scalable fabrication for reading applications

Printing techniques have been widely adopted in the fabrication of flexible electronic components. However, its application is still limited in complex control and communication circuitry due to the low performance and low fabrication uniformity amongst printed devices, compared to conventional electronics. Thus, the electronic systems in real-world applications are hybrid integrations of printed and conventional electronics. Here we demonstrate a low-cost, low-complexity, fully-printable flexible photodetector that can withstand over 100 1 mm-radius bending cycles using a simple and scalable two-step fabrication process. The prototypes are implemented in an augmented book system to automatically detect the ambient light through optical apertures on paper of a printed book, and then transmit the information to an adjunct device. This technique demonstrates the utility of low-cost materials and processes for robust large area sensing applications and could act as a gateway to pertinent multimedia information.

Stabilization of hESCs in two distinct substates along the continuum of pluripotency.

A detailed understanding of the developmental substates of human pluripotent stem cells (hPSCs) is needed to optimize their use in cell therapy and for modeling early development. Genetic instability and risk of tumorigenicity of primed hPSCs are well documented, but a systematic isogenic comparison between substates has not been performed. We derived four hESC lines in naive human stem cell medium (NHSM) and generated isogenic pairs of NHSM and primed cultures. Through phenotypic, transcriptomic, and methylation profiling, we identified changes that arose during the transition to a primed substate. Although early NHSM cultures displayed naive characteristics, including greater proliferation and clonogenic potential compared with primed cultures, they drifted toward a more primed-like substate over time, including accumulation of genetic abnormalities. Overall, we show that transcriptomic and epigenomic profiling can be used to place human pluripotent cultures along a developmental continuum and may inform their utility for clinical and research applications.

Integrated Stress Sensors for Humidity Performance Drift Analysis and Compensation in Inertial Measurement Units

Microelectromechanical devices are known to be sensitive to ambient humidity. This is especially true for devices in moisture sensitive plastic packages such as consumer targeted inertial measurement units. Stress and deformation based effects are shown to be a main contributor to humidity related effects such as performance and offset drifts. This paper shows that stress sensing units embedded in the mechanically coupled electronic control circuitry can be utilized to detect and compensate stress based humidity performance drifts of plastic packaged inertial measurement units. Next to the utilized stress sensor cells themselves a compensation approach is presented, that corrects the humidity based scale factor drift of a MEMS angular rate sensor while a humidity load is applied. This is achieved by finding a symbolic compensation function, which predicts the moisture induced scale factor drift, based only on the stress values within the electronic control circuitry, utilizing genetic symbolic regression. It is demonstrated that, using stress sensors, the humidity induced scale factor drift of two different gyroscope core types can be reduced by a factor of 3, which holds true for parts coming from separate assembly lots. [2022-0013]

Operant conditioning of stochastic chemical reaction networks.

Adapting one's behavior to environmental conditions and past experience is a key trait of living systems. In the biological world, there is evidence for adaptive behaviors such as learning even in naturally occurring, non-neural, single-celled organisms. In the bioengineered world, advances in synthetic cell engineering and biorobotics have created the possibility of implementing lifelike systems engineered from the bottom up. This will require the development of programmable control circuitry for such biomimetic systems that is capable of realizing such non-trivial and adaptive behavior, including modification of subsequent behavior in response to environmental feedback. To this end, we report the design of novel stochastic chemical reaction networks capable of probabilistic decision-making in response to stimuli. We show that a simple chemical reaction network motif can be tuned to produce arbitrary decision probabilities when choosing between two or more responses to a stimulus signal. We further show that simple feedback mechanisms from the environment can modify these probabilities over time, enabling the system to adapt its behavior dynamically in response to positive or negative reinforcement based on its decisions. This system thus acts as a form of operant conditioning of the chemical circuit, in the sense that feedback provided based on decisions taken by the circuit form the basis of the learning process. Our work thus demonstrates that simple chemical systems can be used to implement lifelike behavior in engineered biomimetic systems.

Dynamic control of eye-head gaze shifts by a spiking neural network model of the superior colliculus.

To reorient gaze (the eye's direction in space) towards a target is an overdetermined problem, as infinitely many combinations of eye- and head movements can specify the same gaze-displacement vector. Yet, behavioral measurements show that the primate gaze-control system selects a specific contribution of eye- and head movements to the saccade, which depends on the initial eye-in-head orientation. Single-unit recordings in the primate superior colliculus (SC) during head-unrestrained gaze shifts have further suggested that cells may encode the instantaneous trajectory of a desired straight gaze path in a feedforward way by the total cumulative number of spikes in the neural population, and that the instantaneous gaze kinematics are thus determined by the neural firing rates. The recordings also indicated that the latter is modulated by the initial eye position. We recently proposed a conceptual model that accounts for many of the observed properties of eye-head gaze shifts and on the potential role of the SC in gaze control. Here, we extend and test the model by incorporating a spiking neural network of the SC motor map, the output of which drives the eye-head motor control circuitry by linear cumulative summation of individual spike effects of each recruited SC neuron. We propose a simple neural mechanism on SC cells that explains the modulatory influence of feedback from an initial eye-in-head position signal on their spiking activity. The same signal also determines the onset delay of the head movement with respect to the eye. Moreover, the downstream eye- and head burst generators were taken to be linear, as our earlier work had indicated that much of the non-linear main-sequence kinematics of saccadic eye movements may be due to neural encoding at the collicular level, rather than at the brainstem. We investigate how the spiking activity of the SC population drives gaze to the intended target location within a dynamic local gaze-velocity feedback circuit that yields realistic eye- and head-movement kinematics and dynamic SC gaze-movement fields.

Fault Tolerant Power Supply for Aircraft Store Interface

This paper brings out the design of a fault-tolerant power supply unit for the aircraft-store interface. This switched mode power supply provides multiple 30 V regulated and isolated DC outputs required for pre-launch preparations and auto-launch operations of avionic sub-systems in a store. 3Ø-115V-400Hz-AC supply as well as 27V-DC supply are available from a fighter aircraft for powering up of any store. Power (wattage) output from 27V/10A DC is inadequate to power up various onboard avionic sub-systems in guided stores involving seekers and other avionics. Hence, it is planned to convert available high power 3Ø-115V-400Hz-AC supply for applications requiring higher wattages (of the order of 500 watts or more). This power supply provides multiple output options of 30V regulated and isolated DC supply with multiple input supplies from Aircraft, viz. 3Ø-115V-400Hz-AC, 1Ø-115V-400Hz-AC and 27V DC. One of the outputs provided is with hold-up capacitors, to cater for any input power interruptions as per requirements of MIL-STD-704F and GOST-19705-89 standards. This power supply is a ready-to-connect device and essentially consists of housing, components of DC to DC conversions, EMI/EMC filters, solid state power controllers, control switches, and control circuitry for monitoring signals.

A Wireless DC Motor Drive Using LCCC-CCL Compensated Network With Bidirectional Motion Capability

This paper proposes an LCCC and CCL compensated wireless servo motor control circuitry utilizing the merits of fundamental and third harmonic. With this circuitry, the motor side needs no additional power supply and controller, which significantly reduces the difficulty of maintenance. Besides, benefiting from the proposing of CCL compensating topology and utilizing of the self-driven circuitry, the secondary operates in fully resonant state and the motor direction control H-bridge is self-driven by the LC frequency selecting circuitry (FSC). Moreover, compared with the conventional motor control circuitry, because of the use of fundamental and third harmonic, the power equalization becomes significantly easier, and zero voltage switch (ZVS) can be realized at the same time; Besides, motion direction control of the motor is simpler with only a single pole double throw (SPDT) at the transmitter side. In addition, system resource consumption is reduced compared with conventional motor drive topologies. In this paper, an 180W prototype is built for experimental verification, and the result shows a good power equalization capability and a transfer efficiency reaching up to 90% at the distance of 10cm.

Detection of VOCs and Nitrogen Containing Gaseous Molecules By Utilizing Carbon Nanotubes (CNTs) As Sensing Materials

Carbon nanomaterials are increasingly attractive as potential candidates to make new generation of sensors due to their unique nanostructures that grant their promising electrical, chemical, and physical properties. Among the group of carbon materials, carbon nanotube (CNT) is one of the most encouraging materials because of its features of high surface-to-volume ratio and unique electronic structure. These features enable CNTs the potential to become a highly sensitive sensing material. Since our project aims on detecting bio-marks from human breath, of which the concentrations are extremely low, the nature of our sensor R&D becomes extremely challenging. Consequently, using CNTs as the sensing materials ought to be our obvious choice at this stage. This choice of carbonous materials as sensing media is also on the hope to simplify the sensor’s instability problems in our R&D effort because carbon itself is very chemically inert toward many chemicals.This presentation will serve as a report of the preliminary results from a lab experiment setting to detect several human breath related bio-marks. Sensors were chemiresistive typed and constructed through drop casting on interdigitated sensor circuit. Each sensor chip contains 8 sensor pixels, and the test bed can host maximum of 16 sensor chips simultaneously. In other words, our sensor testing chamber can embed up to 128 sensors at the same time. We then performed the sensor testing against several gases. As expected, the application of nanotechnology in using CNTs enabled us to approach high sensitivity towards to several gaseous analytes, ranging from sub-ppb to sub-ppm. Noticed that, the previous study from our lab revealed that the sensitivity of sensors could be promoted by illuminations of UV light.1 It was approved that the detection limit of nitric oxides is about 27 ppm, providing reliable and stable sensitivity. To simplify the sensor fabrication and miniaturization as well as to reduce power consumption of final sensor units, in this work, we employed an external thermal power to improve the reversibility of the sensors. Two external 375W IR bulbs were used as the heating source in this setting. A dimmer and temperature control circuitry were integrated to maintain the intended operating temperatures. Moreover, we employed our test protocols and methods by functionalizing the CNTs with carboxylic group, besides utilizing the pristine CNTs. It was resulted that this sensor array was able to detect various gaseous species, including NH3, Isoprene, acetone, etc., with relatively high sensitivity.The existence of surfactants in the CNT sensing layer lowered the conductivity of sensor pixels by a great magnitude and resulted in much reduced sensors’ sensitivities. Therefore, removing surfactants in the CNT solution was made, which dramatically improved the sensors’ electric conductivities and boosted sensors’ sensitivities. However, CNT solutions with diluted surfactants destabilize the CNTs’ aqueous suspension, and lead to the non-uniform CNTs layers. The sensor pixels fabricated by using this surfactant deficient CNTs resulted in the formation of CNT bundles or clusters. The gathering of CNTs in a non-uniform fashion could dramatically reduce the sensor’s sensitivity because the bundles would short the interdigitated circuit and disable the CNTs’ sensing capability in most other area of the sensor film. We, therefore, increased the amount of surfactant in the CNT solutions. The sensors fabricated with excess amount of surfactant exhibited highly electric resistance or even non-conductance with very low or no sensitivity. A simple washing process was then developed to wash out the surfactant, which partially resolved the non-uniformity problem. The method to completely prevent the CNT bundles from formation in sensor film is in progress.In conclusion, we developed a gas sensor array that can detect various VOCs and certain nitrogen containing gas molecules with an extremely high or reasonably high sensitivities. Through applying pristine, modified CNTs or mixtures of both into sensor fabrication, the sensing properties were enhanced under an external heating source in comparison with illumination of UV light. The best sensitivity of the sensors is achieved by removing the surfactants in the sensing films. The application of external thermal energy to help on sensors’ performance gets approved. The benefit of using thermal energy vs. UV light is also discussed. G. Chen, T. M. Paronyan, E. M. Pigos, and A. R. Harutyunyan, Scientific Reports 2, 343 (2012).

Non-Assembly 3D-Printed Walking Mechanism Utilising a Hexapod Gait

Small inspection robots can allow for the exploration of environments and the collection of data from dangerous or difficult to access areas. These robots can be custom built for specific tasks, but the design and assembly process for this can be costly, both in money and time. The use of 3D Printing in creating Non-Assembly mechanisms can assist in saving time and resources by reducing the number of different components required and removing the necessity for complex assembly tasks. This paper introduces a robot to explore the capabilities of this approach, by iterating on a previous example of a robot with Non-Assembly mechanisms. This explores how altering the size, mechanism type and accompanying control circuitry can affect the efficiency of the practice. Through developing on previous knowledge, this new walking robot improves on the previous iteration by creating a more robust and reliable system, more capable of effectively exploring challenging environments accurately, while still using practices designed to save on cost and production time.

Circuit Proposal of a Latching Current Limiter for Space Applications Based on a SiC N-MOSFET

Latching current limiters (LCLs) provide individual overcurrent protection to payloads protecting the satellite power bus. Under an overload, they limit the maximum current for a certain time. After this time, if the failure persists, the LCL isolates it from the power bus. The keystone of the LCLs is the current-limiting transistor. In traditional LCL designs, P-MOSFETs are used as the main current-limiting device. However, in this work, a complete LCL based on N-MOSFETs is presented. This change involves a complete redesign of the control circuitry of the LCL architecture. The use of silicon carbide (SiC) is explored to assess the possibility of operating at higher voltages and potentially at higher temperatures. This article shows a complete LCL design based on a SiC N-MOSFET. The design is tested implementing a class 10 LCL (10 A as nominal current) for a bus voltage of 100 V, a limitation current of 12 A, and a limitation time (trip-OFF time) of 1.5 ms.

TGFβ superfamily signaling regulates the state of human stem cell pluripotency and capacity to create well-structured telencephalic organoids.

SummaryTelencephalic organoids generated from human pluripotent stem cells (hPSCs) are a promising system for studying the distinct features of the developing human brain and the underlying causes of many neurological disorders. While organoid technology is steadily advancing, many challenges remain, including potential batch-to-batch and cell-line-to-cell-line variability, and structural inconsistency. Here, we demonstrate that a major contributor to cortical organoid quality is the way hPSCs are maintained prior to differentiation. Optimal results were achieved using particular fibroblast-feeder-supported hPSCs rather than feeder-independent cells, differences that were reflected in their transcriptomic states at the outset. Feeder-supported hPSCs displayed activation of diverse transforming growth factor β (TGFβ) superfamily signaling pathways and increased expression of genes connected to naive pluripotency. We further identified combinations of TGFβ-related growth factors that are necessary and together sufficient to impart broad telencephalic organoid competency to feeder-free hPSCs and enhance the formation of well-structured brain tissues suitable for disease modeling.

Design considerations and applications of a biomedical test bench development kit

Abstract Applications and requirements for biomedical test benches are often quite different, but there is always a need to monitor and usually to control processes. Commercially available development systems can be used to build simple laboratory setups up to industrial systems but are limited with respect to high costs and information for required validation. A test bench development kit is presented which ensures high compatibility for prospective developments, adaptations and embedding of sensors and actuators. The development kit is based on a printed circuit board built around the singleboard computer Raspberry PI. Supporting circuitry for power control, logics and special functions are implemented. Several types of peripheral devices can be connected via two serial bus standards (I2C, or RS-485). Current applications demonstrate the achieved level of automation and process control.

Optrode Array for Simultaneous Optogenetic Modulation and Electrical Neural Recording.

During the last decade, optogenetics has become an essential tool for the investigation of neural signaling due to its unique capability of selective neural modulation or monitoring. As specific types of neuronal cells can be genetically modified to express opsin proteins, optogenetics enables optical stimulation or inhibition of the selected neurons. There have been several technological advances in the optical system for optogenetics. Recently, it was proposed to combine the optical waveguide for light delivery with electrophysiological recording to simultaneously monitor the neural responses to optogenetic stimulation or inhibition. In this study, an implantable optrode array (2x2 optical fibers) was developed with embedded multichannel electrodes. A light-emitting diode (LED) was employed as a light source, and a microfabricated microlens array was integrated to provide sufficient light power at the tip of the optical fibers. The optrode array system comprises the disposable part and the reusable part. The disposable part has optical fibers and electrodes, while the reusable part has the LED and electronic circuitry for light control and neural signal processing. The novel design of the implantable optrode array system is introduced in the accompanying video in addition to the procedure of the optrode implantation surgery, optogenetic light stimulation, and the electrophysiological neural recording. The results of in vivo experiments successfully showed time-locked neural spikes evoked by the light stimuli from hippocampal excitatory neurons of mice.

A Co-Simulation Methodology for the Design of Integrated Silicon Spin Qubits With Their Control/Readout Cryo-CMOS Electronics

Recent years have witnessed a steady growth in the achievable quantum systems due to advancements in qubit technology across several hardware platforms. Currently entering an era of noisy intermediate-scale quantum (NISQ) systems brings additional design challenges. In these systems, each individual qubit is accompanied by a substantial amount of classical CMOS circuitry for qubit instantiation, control and readout, which is to be integrated at the cryo temperature. This work presents a methodology for the co-design and co-simulation of silicon spin qubits in quantum dots, together with their associated cryo-CMOS circuitry, relying on an established spin qubit compact model. In addition, a detailed procedure is proposed for the integration of the model into a classical design flow, which is crucial for the usability of the model in practice. This is illustrated by simulating the readout of a qubit using a complete CMOS readout chip that behaves in a realistic, nonideal way. Bringing the design to a single simulation environment allows for the capture and analysis of effects that otherwise are not possible to simulate when considering the qubits and the cryo-CMOS circuitry separately. This opens up opportunities for more robust design in the future.

The Advancement of Solid-State Transformer Technology and Its Operation and Control with Power Grids: A Review

Solid-state transformer (SST) technology is one of the developing technologies that will be widely used in the future to integrate low-voltage and high-voltage networks with control circuitries and power electronics converters, facilitating renewables integration in smart grid applications. SST technology has crucial key advantageous features, including compact size and weight, low cost, and ease of connection in offshore applications. However, SST technology exhibits a few concerns, such as implementation, protection, economic, and communication compatibility, that need to be addressed. This paper aims to review SST technology with its advanced control schemes and provide future directions for research and development, applications, and prospects. In line with this, highly cited SST technology papers are examined to derive and summarize concerning issues related to its operation and control with further research development of power grids. Moreover, this review discusses the assessment and state-of-the-art technology of SSTs in different applications, focusing on configurations, control circuitry, and their drawbacks and benefits. Numerous issues and challenges of SST technology are explored to identify the existing knowledge gaps and potential future recommendations. All these critical analyses, information, and evaluations would benefit power engineers and researchers in developing and implementing advanced intelligent SST technologies for sustainable energy management in future power systems.