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Bipolar gradual resistive switching was investigated in ITO/InGaZnO/ITO resistive switching devices. Controlled intrinsic oxygen vacancy formation inside the switching layer enabled the establishment of a stable multilevel memory state, allowing for RESET voltage control and non-degradable data endurance. The ITO/InGaZnO interface governs the migration of oxygen ions and redox reactions within the switching layer. Voltage–stress-induced electron trapping and oxygen vacancy formation were observed before conductive filament electroforming. This device mimicked biological synapses, demonstrating short- and long-term potentiation and depression through electrical pulse sequences. Modulation of post-synaptic currents and pulse frequency-dependent short-term potentiation were successfully emulated in the InGaZnO-based artificial synapse. The ITO/InGaZnO/ITO memristor exhibited spike–amplitude-dependent plasticity, spike–rate-dependent plasticity, and potentiation–depression synaptic learning with low energy consumption, making it a promising candidate for large-scale integration. [ABSTRACT FROM AUTHOR]

Real‐time acquisition of microgrid (MG) operation data and remote control play a crucial role in the safe and stable operation of MG. A design scheme of monitoring system is proposed for the wind/photovoltaic/energy storage islanded direct current MG. The core controllers used in direct current MG system are programmable logic controller and digital signal processor. The monitoring system mainly adopts Ethernet communication, together with serial port communication mode Recommend Standard 232 (RS232) and Recommended Standard 485 (RS485) communication modes. A heterogeneous networking is built with controllers and data display instruments. Different monitoring interfaces are designed, the important information can be real‐time detected, collected and displayed. The multi‐energy and multi‐load dispatching operation control are realized according to scheduling operation plan. The parameters of the inverter can be adjusted, and the output voltage waveform and sinusoidal pulse width modulation waveform of the inverter can be measured. The communication of the proposed monitoring system is reliable, flexible and expandable, and easy to realize remote operation control. Moreover, the detection and control functions can be extended further. Through experiments, the effective control and monitoring of the designed monitoring system is verified, and the intelligent management is realized. [ABSTRACT FROM AUTHOR]

Finite control set model predictive control (FCS‐MPC) has gained widespread application in permanent magnet synchronous motor (PMSM) drives, especially for the operations below the base speed. In this paper, a novel voltage feedback‐based flux‐weakening control scheme is proposed to enable FCS‐MPC to extend its operation above the base speed. In this method, an extended state observer (ESO)‐based ultra‐local model is employed as the prediction model to reduce parameter dependence. To realize flux‐weakening operation, PMSM's steady‐state voltage drop is estimated using the information from ultra‐local model. And the magnitude of steady‐state voltage drop is then used as the feedback variable to reconstruct a novel voltage control loop. The output of voltage controller automatically modifies the d‐axis current reference when motor operates above the base‐speed. With the help of voltage control loop, a smooth and automatic flux‐weakening operation can be achieved without requiring the motor parameters. The proposed method is verified experimentally under various speed and load conditions. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The hybrid cascaded high‐voltage direct‐current (HC‐HVDC) links are recently introduced for ultra‐high voltage bulky power transmissions. However, as wind power becomes more prevalent, the grid is gradually weakened and will face voltage stability issues. This paper proposes a coordinated reactive power control strategy for HC‐HVDC links to enhance the voltage stability of AC bus. Firstly, the impact of HC‐HVDC on the static voltage stability of the AC bus is studied by the voltage sensitivity coefficient. Then, the limitation of reactive power capability of modular multilevel converter in the HC structure is identified. Based on the analysis results, a coordinated reactive power control strategy based on adaptive voltage droop is proposed. In the strategy, the DC voltage ratio is regulated according to the fluctuation degree of the AC bus voltage to adjust the reactive power of HC‐HVDC, which realized the dynamic voltage support for the AC bus. Finally, electromagnetic simulations in power systems computer aided design (PSCAD)/electromagnetic transients including DC (EMTDC) are performed, and the results validate the theoretical findings and the effectiveness of the control strategy. [ABSTRACT FROM AUTHOR]

Transition‐metal dichalcogenides (TMDs), as atomically thin semiconductors, have shown immense promise for next‐generation electronics due to their high mobility and potential for creating van der Waals heterostructures. However, precise control of the threshold voltage (Vth) in field‐effect transistors (FETs) remains a significant challenge, impeding the development of 2D material circuits with tailored electronic functions. Herein, a graphene‐assisted one‐step van der Waals integration technique is presented for fabricating multi‐threshold 2D functional circuits. Graphene's unique property of having a surface without dangling bonds is utilized as an intermediary layer, allowing for the transfer of electrodes with various work functions and high‐κ dielectric layers onto 2D channel materials in a single step. This technique has successfully produced Al‐gated MoS2 FETs with a Vth of −0.2 V and Au‐gated MoS2 FETs with a Vth of 1.9 V. This precision enables the development of functional devices such as rail‐to‐rail inverters with large noise margins. Furthermore, more complex multi‐threshold 2D circuits are achieved, including basic logic gates (NOT, NAND, NOR), six‐transistor static random‐access memory (6T‐SRAM), and ring oscillators (RO). This work showcases a scalable and effective strategy for threshold voltage engineering in 2D material‐based circuits, paving the way for sophisticated electronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Dielectric elastomers (DE), renowned for their lightweight, rapid response, high energy density, and efficient conversion, have garnered significant attention in the realm of avian flight bionics. However, a lack of understanding of the mechanical principles underlying flapping wing biomimetics has hindered accurate simulations of actual bird flight postures. To address this, a stiffness-variable DE-based wing (DEW) has been designed, inspired by the characteristics of seagulls, to mimic the wing deformations across different bird flight phases. The evolution of the DEW's deformation is modeled based on the differential equation describing the bending curve of a DE cantilever beam. By applying different voltage cycles, three continuous avian flight postures have been replicated: takeoff, cruising, and hovering. The simulation results demonstrate that the stiffness-variable DEW effectively mimics the wing deformations observed in birds during different flight postures, closely resembling real-world flight conditions. This study has the potential to serve as an important reference for exploring changes in bird flight behavior, thereby advancing the application of DE materials in the field of soft robotics. [ABSTRACT FROM AUTHOR]

The "infinitesimal phase response curve" (PRC) is a common tool used to analyze phase resetting in the natural sciences in general and neuroscience in particular. We make the observation that the PRC with respect to a coordinate v actually depends on the choice of other coordinates. As a consequence, a complete delay embedding reconstruction of the dynamics using v which would allow phase to be computed still does not allow the v PRC to be computed. We give a coordinate-free definition of the PRC making this observation obvious. This leads to an experimental protocol: first collect an appropriate ensemble of measurements by intermittently controlling neuron voltage. Then, for any suitable current carrier dynamic postulated, we show how the ensemble can be used to compute the voltage PRC with that current carrier. The approach extends to many oscillators measured and controlled through a subset of their coordinates. [ABSTRACT FROM AUTHOR]

This paper proposes a cost-effective and reliable circuit configuration for active power decoupling in dual-inverter-fed open-end winding motor systems. Compared to separately installed active power decoupling circuits, the proposed configuration and control method that utilizes mode switches minimizes the number of components and prevents lifetime imbalance of the inverters by alternating their use every cycle while maintaining low voltage ripple. Junction temperature analysis of the power devices further indicates this approach can prevent lifetime imbalance and rapid aging of the dual-inverter system, resulting in enhanced overall system reliability. The effectiveness of the proposed configuration and control method is validated through a MATLAB/Simulink model and experimental tests using a digital signal processor. [ABSTRACT FROM AUTHOR]

This paper proposes a fast dynamic DC-link voltage control strategy for dual three-phase permanent-magnet-assisted synchronous reluctance starter/generator (DTP-PMa-SRS/G) system. First, the model of a DTP-PMa-SRS/G is analyzed considering its asymmetric structure. A power balance strategy is adopted to solve the coupling problem between two sets of windings. Then the power model of the starter/generator system is analyzed considering the disturbance caused by inherent parameter uncertainty and external load variation. To improve the dynamic response performance of the DC-link voltage, an integral terminal sliding-mode DC-link voltage controller (ITSMVC) with an extended state observer (ESO) is proposed. The system stability is verified by Lyapunov theory. A simple parameter design method for the proposed ESO-ITSMVC is adopted to ensure satisfactory performance. Finally, a comparison of experimental results with the conventional ITSMVC, the active-disturbance rejection controller (ADRC), and the disturbance observer-ITSMVC (DO-ITSMVC) is carried out. The superior DC-link voltage dynamic response performance of the proposed method is verified. [ABSTRACT FROM AUTHOR]

Summary: This paper presents the development of a single‐phase voltage source inverter (VSI) of 3.5KW, applied to grid‐connected photovoltaic systems (GCPS). The proposed system has a boost interface converter connected to a full bridge inverter with an LCL filter. Each block that constitutes the proposed GCPS is described in detail, containing the specifications of the solar modules, the design of the power circuit components, the mathematical modeling, and the control design of the converters. The presentation of the Volt‐VAR Control (VVC) highlights the contribution of this work, where it is implemented with the intention of the inverter to supply/consume reactive power, in order to minimize voltage variations at the point of common coupling (PCC). To validate the inverter operation with VVC, three cases are presented, encompassing grid voltage and irradiance variations, and load steps. Through the PCC voltage profiles, currents, and power supplied/consumed, the means to demonstrate the effectiveness of the proposed control is shown. The results obtained through the PSIM simulations and verified by Typhoon Hardware in the Loop (HIL) model, showed the regulation of grid voltage levels for all established conditions. [ABSTRACT FROM AUTHOR]

This article presents an experimental study that evaluated droop control strategies in DC microgrids with parallel-connected converters. In a decentralized control scheme, it is critical to ensure voltage regulation and load sharing in each converter to maintain a stable operation. Two scenarios are considered: the first involves two converters operating in parallel as voltage mode control, a conventional method discussed in the literature. In the second scenario, a less commonly used method is presented, in which one converter operates in voltage mode control and another operates in current mode control. The proposed decentralized control method is experimentally validated in a DC microgrid using parallel-connected lithium-ion batteries and converters. Load sharing results are examined under conditions with equal droop coefficients, demonstrating equivalent outcomes for specific load steps in both scenarios. However, in the case of different droop coefficients, the alternative method proves to be highly satisfactory, particularly for a broader range of load variations. The results confirm the efficacy of the control method in load sharing and voltage regulation among each converter, as well as the equivalence of control between both scenarios. [ABSTRACT FROM AUTHOR]

This paper utilizes the optimized composite neural network (OCNN)-Hammerstein model to directly identify the dynamic inverse hysteresis effect, employing it as a feedforward controller to compensate for the rate-dependent and amplitude-dependent dynamic hysteresis of the piezoelectric actuator. The OCNN-Hammerstein model consists of an optimized composite neural network and an auto-regressive exogenous model in series. The OCNN comprises convolutional neural network layer and radial basis function neural network layer, with its hyperparameters optimized using a modified grey wolf optimizer algorithm. Compared to the existing dynamic Prandtl-Ishlinskii-Hammerstein and dynamic Bouc-Wen-Hammerstein models in the literature, the feedforward controller based on the proposed model in this paper demonstrates superior performance, with an RSME below 0.45 μm and a 74.5% reduction in relative hysteresis at the condition of 300 Hz and maximum amplitude. The feedforward controller exhibits universality across all amplitude ranges and within the 50–300 Hz frequency range, while also providing predictive compensation for dynamic hysteresis at 300–400 Hz. The feedforward controller based on the OCNN-Hammerstein model in this paper provides a crucial methodology for open-loop control of piezoelectric actuators. [ABSTRACT FROM AUTHOR]

Digitalization enables the automation required to operate modern cyber-physical energy systems (CPESs), leading to a shift from hierarchical to organic systems. However, digitalization increases the number of factors affecting the state of a CPES (e.g., software bugs and cyber threats). In addition to established factors like functional correctness, others like security become relevant but are yet to be integrated into an operational viewpoint, i.e., a holistic perspective on the system state. Trust in organic computing is an approach to gain a holistic view of the state of systems. It consists of several facets (e.g., functional correctness, security, and reliability), which can be used to assess the state of CPES. Therefore, a trust assessment on all levels can contribute to a coherent state assessment. This article focuses on the trust in ICT-enabled grid services in a CPES. These are essential for operating the CPES, and their performance relies on various data aspects like availability, timeliness, and correctness. This article proposes to assess the trust in involved components and data to estimate data correctness, which is crucial for grid services. The assessment is presented considering two exemplary grid services, namely state estimation and coordinated voltage control. Furthermore, the interpretation of different trust facets is also discussed. [ABSTRACT FROM AUTHOR]

The virtual synchronous generator (VSG) technology has been proposed to address the problem of system frequency and active power oscillation caused by grid-connected new energy power sources. However, the traditional voltage-current double-closed-loop control used in VSG has the disadvantages of poor disturbance immunity and insufficient dynamic response. In light of the issues above, a virtual synchronous generator voltage outer-loop control strategy based on improved linear autonomous disturbance rejection control (ILADRC) is put forth for consideration. Firstly, an improved first-order linear self-immunity control structure is established for the characteristics of the voltage outer loop; then, the effects of two key control parameters-observer bandwidth ω0 and controller bandwidth ωc on the control system are analyzed, and the key parameters of ILADRC are optimally tuned online using improved gray wolf optimizer-radial basis function (IGWO-RBF) neural network. A simulation model is developed using MATLAB to simulate, analyze, and compare the method introduced in this paper. Simulations are performed with the traditional control strategy for comparison, and the results demonstrate that the proposed control method offers superior anti-interference performance. It effectively addresses power and frequency oscillation issues and enhances the stability of the VSG during grid-connected operation. [ABSTRACT FROM AUTHOR]

This research focuses on the importance of maintaining generator output voltage stabilization using automatic voltage regulator (AVR), especially in dealing with load impacts and environmental changes. Through the implementation of internet of things (IoT), this system can be controlled and monitored remotely, enabling real-time monitoring without physical presence at the generator location. The main objective of this research is to increase energy efficiency by optimizing generator operation. System development methods include design, prototyping and testing stages. Test results show that the automatic voltage regulator is effective in maintaining a stable output voltage of around 220 V, even though the current varies according to the existing load. The power produced ranges from 23 to 670 W, with a power factor between 0.7 and 1. Despite a slight voltage drop to 217 V, the power factor increases to 0.93. The system uses NodeMCU to send data to Blynk and Google Spreadsheets servers, as well as servo motors and PZEM-004T sensors for control and monitoring. Overall, this research shows that the internet of things-based automatic voltage regulator system is effective in maintaining stability and increasing generator operational efficiency, with the ability to manage voltage, current, power, and power factor efficiently. [ABSTRACT FROM AUTHOR]

A wide band trans-impedance amplifier (WBTIA) with tunable bandwidth for near infra-red spectroscopy (NIRS) bio-medical applications is presented in this research article. The first stage of the proposed WBTIA is implemented by a modified inverter-cascode (InvCas) trans-impedance amplifier (TIA) with series and shunt inductive peaking for the bandwidth extension and a common-source amplifier as a second stage for gain boosting. Bandwidth tuning is achieved by a novel tuning mechanism with a fixed capacitor and tunable metal-oxide-semiconductor (MOS) capacitor with a control voltage. The fixed capacitor provides a coarse-grain bandwidth tuning whereas the tunable MOS capacitors are used for finegrain bandwidth tuning. The WBTIA is designed in 45 nm technology and it achieved a maximum trans-impedance gain (TIG) of 84.91 dBO and 354.81 MHz bandwidth. The proposed WBTIA consumes 41.24 µW power from 1 V supply voltage. The input referred current noise at 100 MHz is 169 fA/sqrt (Hz) and the output noise voltage is 69.8 pV/sqrt (Hz). [ABSTRACT FROM AUTHOR]

To realize high‐power inductive power transfer (IPT) for fast charging of electric vehicles (EVs), an input‐series output‐parallel (ISOP) multi‐channel IPT system is analysed in this paper, and an output control strategy based on single neuron controller is proposed to improve the stability of the system. Firstly, the steady‐state operating conditions of ISOP‐IPT system is analysed based on different compensation networks which shows that the constant‐voltage‐output compensation networks are more suitable for the proposed circuit structure. Then, to improve the voltage equalization between channels, an open‐loop control method combining parameter design and phase‐shift control is proposed against different coil misalignments. At the same time, based on the single neuron controller, the system output closed‐loop control is realized without the need of accurate system modelling. Finally, a three‐channel ISOP‐IPT experimental system was constructed, which operated stably at 2.9 kW with a power efficiency of 93.38%. The system closed‐loop control with control time of 22 ms is realized. The voltage equalization control offset is less than 1%. [ABSTRACT FROM AUTHOR]

This paper emphasizes the significance of implementing an effective control system to enhance the performance of a three-stage DC–DC buck converter (TDDC). Herein, we present the development of an observer controller (OC) for TDDC, where average modeling of the DC–DC converter was employed alongside an observer algorithm for the OC. The primary focus is on the adoption of an observation topology aimed at enhancing system responsiveness under various conditions, including variable input voltages, reference voltage changes, load fluctuations, integration with photovoltaics, and battery charging. This approach ensures improved stability and performance, addressing the dynamic challenges inherent in such systems. A comparative analysis was conducted on two distinct control topologies for the proposed TDDC system, namely proportional–integral (PI) and advanced OC. Simulink software was used to model and simulate the proposed system. The results demonstrate lower rising and settling times of the TDDC for the OC and PI implementations, respectively. Additionally, the system with the OC eliminates 20% of the overshoot, while the system with OC minimizes the output voltage oscillations from 13% to 2% compared to the PI system. The OC was integrated into the TDDC to enhance system stability and improve the control loops, particularly the third loop. These improvements make the TDDC with OC suitable for application to renewable energy systems, microgrids, telecommunication networks, and electric vehicles, where precise control and stability are essential. [ABSTRACT FROM AUTHOR]

The integration of large‐scale distributed power sources increases the voltage fluctuation in AC/DC hybrid distribution network (AD‐HDN). Power electronics devices such as photovoltaic (PV) inverters, soft open point (SOP), and voltage source converters (VSCs) can be utilized for voltage/var control (VVC) to alleviate the risk of voltage fluctuation and violation. This paper proposes a distributed optimal VVC method in power electronics dominated AD‐HDN. Firstly, the reactive power and voltage characteristics of PV inverters, SOP, and VSCs are analysed, and an optimal VVC optimization model for AD‐HDN to minimize node voltage deviation, PV curtailment, and network loss is proposed. Then, the second‐order cone (SOC) relaxation technique is used to re‐formulate the model into a convex optimization model. A distributed optimal VVC framework based on the alternating direction method of multipliers (ADMM) is constructed. Based on the residual balance principle and relaxation technique, an accelerated ADMM method is further proposed to solve the proposed model. Finally, case studies are conducted on the IEEE 33‐node and 85‐node systems to verify the superiority and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

A large scale of distributed photovoltaics is accessed through a low voltage distribution network in a single‐phase or two‐phase, which causes three‐phase unbalance and over‐voltage problems. These problems can be solved by using a voltage source converter to realize AC/DC interconnection and flexible power transfer between lines. How to utilize the characteristics of voltage source converters to optimize the power qualities, and fully promote distributed PV systems consumption in low voltage distribution network is an important research point. This paper proposes a power regulation model of VSC. The goal of this model is to adjust and optimize over‐voltage and three‐phase unbalance problems. By constructing a voltage‐power sensitivity calculation model for a three‐phase four‐wire system and integrating different control modes and adjustment capabilities of voltage source converters, a control strategy based on voltage source converters is proposed to address three‐phase unbalance and over‐voltage issues. Finally, the simulation results demonstrate the effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

The energy storage adjustment strategy of source and load storage in a DC microgrid is very important to the economic benefits of a power grid. Therefore, a multi-timescale energy storage optimization method for direct current (DC) microgrid source-load storage based on a virtual bus voltage control is studied. It uses a virtual damping compensation strategy to control the stability of virtual bus voltage and establishes a virtual energy storage model by combining different types of distributed capability units. The design of an optimization process for upper-level daily energy storage has the objective function of maximizing the economic benefits of microgrids to cope with unplanned fluctuations in power. A real-time energy-adjustment scheme for the lower level is introduced, and a real-time energy-adjustment scheme based on virtual energy storage for the short-term partition of the source-load storage is designed to improve the reliability of microgrid operations. The experiment shows that, in response to the constant amplitude oscillation of the power grid after a sudden increase in power, this method introduces a virtual damping compensation strategy at 20 s, which can stabilize the virtual bus voltage. From 00:00 to 09:00, the battery power remains at around 4 MW, and from 12:00 to 21:00, the battery exits the discharge state. The economic benefits from applying this method are significantly higher than before. This method can effectively adjust the source-load energy storage in real time. During peak electricity price periods, the SOC value of supercapacitors is below 0.4, and during normal electricity price periods, the SOC value of supercapacitors can reach up to 1.0, which can make the state of the charge value of supercapacitors meet economic requirements. [ABSTRACT FROM AUTHOR]

To address the issue of uncertainty in the occurrence time of voltage sags in power grids, which affects power quality, a voltage state prediction method based on LSTM neural networks is proposed for predicting voltage states. For the problem of quickly and accurately compensating for voltage sags, a DVR system based on a new approach law of sliding mode variable structure control is proposed, which significantly reduces chattering, improves response speed, and enhances the robustness of the system. The stability of the system is proven based on Lyapunov stability theory. Simulation experiments are conducted to analyze the voltage state prediction effect based on the LSTM neural network and the compensation effect of the novel reaching law of sliding mode variable structure control under different levels of voltage sag, validating the effectiveness and correctness of the proposed solution. [ABSTRACT FROM AUTHOR]

In order to solve the problem of voltage fluctuation caused by the grid integration of wind power cluster, a multitime scale reactive power and voltage optimal regulation method based on model predictive control (MPC) is proposed in this paper. In the day‐ahead stage, the reduction of network active power loss is mainly achieved through the regulation of discrete reactive power compensation devices and generator units, focusing on the economic operation of the power system. In the intraday stage, considering the rapid response characteristics of continuous reactive power compensation devices, the optimal regulation aiming to minimize voltage control deviation is carried out under 15‐ and 5‐min time scale based on the MPC algorithm with the adjustment of continuous reactive power compensation devices. In the feedback correction stage, a fast calculation method considering reactive power partitioning is adopted instead of solving the 5‐min optimization model for 288 periods, avoiding excessive adjustment of reactive compensation devices. While effectively improving voltage fluctuations caused by wind power prediction deviation, it also alleviated the computational and communication burden on the system. Finally, the effectiveness of the proposed regulation method in this paper is verified with the improved IEEE‐39 test case. [ABSTRACT FROM AUTHOR]

To enhance the dynamic performance and robustness of the voltage control system of islanded microgrid inverters, a new control strategy combining integral sliding mode (ISM) control and composite nonlinear feedback (CNF) control is proposed. In ISM control, firstly, a new reaching law is designed to improve movement quality in the reaching phase by improving the power term and introducing the inverse tangent function. Then, to improve disturbance observation accuracy, a variable gain extended state observer is designed by improving the regulation mechanism of the state variables according to deviation control. Using the idea of variable damping, linear and nonlinear feedback are combined into CNF control. Specifically, linear feedback provides a small damping ratio for faster system response, while nonlinear feedback increases the damping ratio to improve steady‐state performance. Simulation results show that the integral sliding mode‐composite nonlinear feedback (ISM‐CNF) control strategy cam balances convergence speed and chattering better and achieves higher steady‐state accuracy than conventional strategies. Moreover, ISM‐CNF control has better robustness to reference voltage variations and disturbances caused by sudden load changes. Therefore, the ISM‐CNF control strategy can accomplish voltage control of islanded microgrid inverters quickly and steadily, effectively suppressing system disturbances and enhancing stability and power quality. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper introduces a distributed control approach for optimizing the operation of islanded DC microgrids (µGs), accounting for cyber delays and network failures. Initially, an integrated network emulation platform is utilized to calculate realistic cyber delays for islanded DC µGs employing IEC 61850 communication standard. To address the instability issues arising from cyber delays, the Artstein-Kwon-Pearson reduction technique is employed to convert the system with cyber delays into one without delays. The Subsequently, a consensus-based generation-cost optimization algorithm is designed for maintaining the economic operation of the µG. This algorithm efficiently equalizes the incremental costs (ICs) of all distributed generators (DGs) in a fully distributed manner, while adhering to the DGs capacity limits. Additionally, a fully distributed voltage regulation control is developed to stabilize µG average voltage, ensuring the balance between generation and demand. The efficacy of the formulated control technique is substantiated through diverse case studies, thereby underscoring its superior operational performance. [ABSTRACT FROM AUTHOR]

This paper investigates the application of fractional proportional–resonant controllers within the voltage control loop of grid-forming inverters. The use of such controllers introduces an additional degree of freedom, enabling greater flexibility in manipulating frequency trajectories. This flexibility can be harnessed to improve tracking error and enhance disturbance rejection, particularly in applications requiring precise voltage regulation. The paper conducts a conceptual stability analysis of ideal fractional proportional–resonant controllers using the Nyquist criterion. A tuning procedure based on robustness criteria for the proposed controller is also addressed. This tuning strategy is used to compare different controllers under the same conditions. In addition, a sensitivity analysis is provided, comparing the performance of fractional proportional–resonant controllers with traditional proportional–resonant controllers equipped with harmonic compensation. The controller's formulation and performance are validated through simulations and tested with a 20 kVA inverter under high non-linear loads. Compared to classical control approaches, the fractional tuning parameter enhances tracking performance, reduces phase delay, and improves disturbance rejection. These improvements are achieved with a controller designed to minimise computational demands in terms of memory usage and execution time. [ABSTRACT FROM AUTHOR]

The transient stability control for disturbances in microgrids based on a lithium-ion battery–supercapacitor hybrid energy storage system (HESS) is a challenging problem, which not only involves needing to maintain stability under a dynamic load and changing external conditions but also involves dealing with the energy exchange between the battery and the supercapacitor, the dynamic change of the charging and discharging process and other factors. This paper focuses on the bus voltage control of HESS under load mutations and system uncertainty disturbances. A BP Neural Network-based Active Disturbance Rejection Controller (BP-ADRC) is proposed within the traditional voltage-current dual-loop control framework, leveraging uncertainty quantification. Firstly, system uncertainties are quantified using system-identification tools based on measurable information. Subsequently, an Extended State Observer (ESO) is designed to estimate the total system disturbance based on the quantified information. Thirdly, an adaptive BP Neural Network-based Active Disturbance Rejection Controller is studied to achieve transient stability control of disturbances. Robust controllers, PID controllers and second-order linear Active Disturbance Rejection Controllers are employed as benchmark strategies to design simulation experiments. Simulation results indicate that, compared to other benchmark strategies, the BP-ADRC controller based on uncertainty quantification exhibits superior tracking and disturbance-rejection performance in transient stability control within microgrids of hybrid energy storage systems. [ABSTRACT FROM AUTHOR]

This paper proposes novel multi-energy inertia support for simultaneous frequency and voltage control of an isolated hybrid power system (IHPS). Multi-energy storage (gas inertia – hydrogen storage, thermal inertia – solar thermal storage, hydro inertia – gravity hydro storage, chemical inertia – battery energy storage) supported by demand side management (DSM) for simultaneous voltage and frequency regulation and backed by biodiesel generators, are the essential elements of IHPS. A novel control strategy of concurrent virtual droop control, virtual damping control, virtual inertia control, and virtual negative inertia control is proposed to utilise multiple inertia sources and to improve LFC and AVR performance effectively. The effective coordination of inertia sources in eradicating oscillations in IHPS, is aided by a developed cascaded proportional integral-tilt-integral-sliding mode (PI-TISMC) controller. The performance of PI-TISMC is compared with PID, PI-PID, and PI-SMC controllers. A maiden attempt has been done by training five diverse classes of optimization techniques to optimize the parameters of controllers in the present work. The results are evaluated in MATLAB and it is evident from the results that the performance of frequency control is improved by 6.5%, 7.8% and 3.4 s (over shoot, undershoot, and settling time). The performance of frequency control is improved by 6.5%, 7.8% and 3.4 s (over shoot, undershoot, and settling time). Similarly, the performance of voltage control is improved by 6.7%, 4.8% and 2.3 s (over shoot, undershoot, and settling time) by employing developed PI-TISMC controller and proposed concurrent inertia control. The combination exhibits superior performance in minimizing oscillations in IHPS due to variations in loading and solar insolation. [ABSTRACT FROM AUTHOR]

Due to the use of multi winding high-frequency isolation transformers in the three port isolated bidirectional DC–DC converter to achieve port isolation and power transmission, there is a power coupling problem between each port. This article proposes a Model Prediction Control (MPC) strategy to address this issue. Considering the control objectives for each port of the Triple Active Bridge (TAB) DC–DC converter, a discrete predictive model of the TAB converter is established based on phase-shifting modulation and average model. The MPC problem is solved optimally and a predictive controller is designed with control accuracy to achieve decoupling control effect between each port. And the traditional single voltage closed-loop control, diagonal matrix decoupling control, and model predictive control proposed in this paper are compared through simulation. Finally, a TAB converter experimental platform is built based on the DSP control chip TMS320F28335. The experimental results are verified the effectiveness and superiority of the proposed method, as well as its faster dynamic characteristics and power decoupling ability between each port. [ABSTRACT FROM AUTHOR]

The stability and reliability of modern power systems, especially those with several renewable energy sources, strongly rely on load frequency control (LFC) and automatic voltage regulation (AVR) for frequency and voltage control under inconstant load demands. In this study, a new cascade tilt integral derivative-fractional order proportional tilt integral derivative (TID-FOPTID) controller is presented that is polished through the salp swarm algorithm (SSA) for LFC of a multi-area power system with AVR in all control areas. The system integrates capacitive energy storage (CES) and deals with governor dead-band and generation rate constraint nonlinear effects in a thermal-hydro-gas three-area multi-source power system (TAMSPS). The analysis of results, due to the SSA-based TID-FOPTID controller compared to TID-FOTID and TID-FOTID + 1 shows a positive outcome. Integrating CES brings additional improvement in the system performance, the overshoot/undershoot, and settling time are minimized. Finally, the sensitivity analysis reveals that the suggested controller will be effective and reliable for enhancing the frequency stability of the complex power system with a high RES integration level. [ABSTRACT FROM AUTHOR]

The active power control of photovoltaic (PV) inverters without energy storage can flatten the fluctuating power and support the voltage amplitude and frequency of the grid. When operated in grid‐forming voltage‐control mode, because the PV power can change rapidly and widely, the PV inverter needs to track the power commands quickly and precisely. Traditionally, this goal is achieved with the estimation of PV power curve or PI‐based multiple‐loop feedback control, where flexibility, availability and accuracy are not satisfactory. Therefore, a CC/VC‐based power tracking (CVPT) method is proposed, which only uses single‐loop in control. The proposed method does not need to tune multiple loops and can respond faster, which is important for grid‐forming voltage control. Furthermore, the different operating modes due to the limitation of PV maximum power are analysed, and a mode switch method is proposed. Simulation and experimental results demonstrate that the PV inverter can cope with power disturbances from both the power and grid sides and maintain the quality of grid voltage. [ABSTRACT FROM AUTHOR]

Finite control set model predictive control (FCS‐MPC) has been widely used in the control of three‐phase voltage source converter (VSC), but its control performance declines sharply at low sampling frequencies. This paper proposes an optimal control set expansion method with slip window selection and online parameter modification to improve the performance and robustness of FCS‐MPC. First, the performance of different control set expansion methods is compared. Then, an optimal control set expansion method that carries 12 virtual vectors is proposed. Last, a slip window selection strategy and an online parameter modification algorithm are proposed to reduce the computational burden and improve the controller's robustness respectively. Experimental result show that the proposed method significantly improves the control accuracy and carries good robustness and anti‐disturbance ability. Compared with existing typical MPC strategies, the proposed method obtains better current quality with lower switching frequency and requires less calculation. Moreover, the design of the proposed method is simple and there is no weighting factor to be tuned, which increases the method's practicality. [ABSTRACT FROM AUTHOR]

This article presents the measurement verification of a novel strategy for inrush current reduction in an unloaded three-phase Dy transformer. The strategy combines appropriate pre-magnetization of transformer cores with an original control switching system using initial phase values of the supply voltage as control variables. Measurements were recorded for primary voltages and currents as well as secondary voltages during transient states at start-up under no-load conditions. Various inrush scenarios were examined across the full angular spectrum of initial phase angles, both polarities, and in regard to different pre-magnetization current values. A detailed analysis of the inrush currents was performed using proprietary automated software based on the recorded data. A comparative study with a nonlinear mathematical model of the transformer was also conducted. Additionally, key technical aspects of the designed system for implementing the proposed pre-magnetization strategy with controlled voltage energization are discussed. [ABSTRACT FROM AUTHOR]

The increasing number of distributed generators (DGs) leads to the frequent occurrence of voltage violations in distribution networks. The soft open point (SOP) can adjust the transmission power between feeders, leading to the evolution of traditional distribution networks into flexible distribution networks (FDN). The problem of voltage violations can be effectively tackled with the flexible control of SOPs. However, the centralized control method for SOP may make it difficult to achieve real-time control due to the limitations of communication. In this paper, a distributed voltage control method is proposed for FDN with SOPs based on the multi-agent deep reinforcement learning (MADRL) method. Firstly, a distributed voltage control framework is proposed, in which the updating algorithm of the intelligent agent of MADRL is expounded considering experience sharing. Then, a Markov decision process for multi-area SOP coordinated voltage control is proposed, where the control areas are divided based on electrical distance. Finally, an IEEE 33-node test system and a practical system in Taiwan are used to verify the effectiveness of the proposed method. It shows that the proposed multi-area SOP coordinated control method can achieve real-time control while ensuring a better control effect. [ABSTRACT FROM AUTHOR]

This paper presents a fuzzy sliding mode control method for voltage control of islanded AC/DC hybrid microgrid. The T‐S fuzzy model is utilized to approximate initial non‐linear dynamic model of the microgrid. The fuzzy rules and membership functions are designed according to the coupling relationship between AC part and DC part. To reduce the influence of external disturbance and cyber‐attacks, an integral sliding mode controller is considered. Furthermore, a sufficient condition is proposed with H∞${H}_\infty $ attenuation performance to ensure the asymptotic stability of sliding motion. The set of gain matrices can be acquired via solving the linear matrix inequalities deduced from the Lyapunov stability analysis. The reachability to the proposed sliding mode surface can be guaranteed via switching control law based on a Lyapunov function. In addition, to eliminate chattering performance of the sliding mode control theory, the fuzzy logic controller is designed to optimize the switching region in boundary layers of saturation functions. Finally, the simulation results for the islanded AC/DC hybrid microgrid are implemented to verify the robustness and effectiveness of the designed fuzzy sliding mode control method. [ABSTRACT FROM AUTHOR]

In this paper, a single-phase five-level active neutral-point-clamped with coupled inductors (ANPC-CI) rectifier topology is studied to meet the needs of efficient and reliable power electronic converters. A sliding mode model predictive power control method is proposed to achieve high-efficiency energy conversion, precise voltage control, and low harmonic distortion. By analyzing the working states, establishing a mathematical model and introducing the theory of instantaneous power, the outer loop sliding mode power control and the inner loop model predictive power control algorithms are designed. When compared with traditional PI-DPC algorithm, this algorithm avoids the tedious setting of parameters, reduces input power fluctuations, and improves the system dynamic response speed. The superiority of the sliding mode model predictive power control is verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the rapid development of 5G base station construction, significant energy storage is installed to ensure stable communication. However, these storage resources often remain idle, leading to inefficiency. To enhance the utilization of base station energy storage (BSES), this paper proposes a co-regulation method for distribution network (DN) voltage control, enabling BSES participation in grid interactions. In this paper, firstly, an energy consumption prediction model based on long and short-term memory neural network (LSTM) is established to accurately predict the daily load changes of base stations. Secondly, a BSES aggregation model is constructed by using the power feasible domain maximal inner approximation method and Minkowski summation to evaluate the charging and discharging potential and adjustable capacity of BSES clusters. Subsequently, a BSES demand assessment and optimal scheduling model for low voltage regulation in DN is developed. This model optimizes the charging and discharging strategies of BSES to alleviate low voltage problems in DN. Finally, the simulation results effectively verify the feasibility of the proposed optimal scheduling method of BSES for voltage regulation in DN. [ABSTRACT FROM AUTHOR]

The principles of multi-level output voltage control of an autonomous power supply system implemented on the basis of a three-phase constant speed self-excited induction generator with a regulated source of reactive power connected to the stator terminals and containing both a multi-modular electronic power converter and excitation capacitors are proposed. To regulate the voltage of the specified system, a stator voltage oriented vector control algorithm has been developed. Using the developed dynamic simulation model, numerical investigations of electromechanical processes in the system supplying RL-load of the local consumers were carried out to verify the effectiveness of the proposed principles of voltage control and the proposed vector control algorithm of the generator. The main advantages of applying multi-module electronic power converters in autonomous power supply systems using a self-excited induction generator with a short circuited rotor winding and an electronic power converter connected to the stator terminals for reactive power control are noted. References 10, figures 3, table 1. [ABSTRACT FROM AUTHOR]

The scale factor of thermal sensitivity serves as a crucial performance metric for micro-electromechanical system (MEMS) gyroscopes, and is commonly employed to assess the temperature stability of inertial sensors. To improve the temperature stability of the scale factor of MEMS gyroscopes, a self-compensation method is proposed. This is achieved by integrating the primary and secondary relevant parameters of the scale factor using the partial least squares regression (PLSR) algorithm. In this paper, a scale factor prediction model is presented. The model indicates that the resonant frequency and demodulation phase angle are the primary correlation terms of the scale factor, while the drive control voltage and quadrature feedback voltage are the secondary correlation terms of the scale factor. By employing a weighted fusion of correlated terms through PLSR, the scale factor for temperature sensitivity is markedly enhanced by leveraging the predicted results to compensate for the output. The results indicate that the maximum error of the predicted scale factor is 0.124% within the temperature range of −40 °C to 60 °C, and the temperature sensitivity of the scale factor decreases from 6180 ppm/°C to 9.39 ppm/°C. [ABSTRACT FROM AUTHOR]

With the increasing market demands for wearable and portable electronic devices, binary metal oxides (BMOs) with a remarkable capacity and good structure stability have been considered as a promising candidate for fabricating coplanar micro-supercapacitors (CMSCs), serving as the power source. However, the current fabrication methods for BMO microelectrodes are complex, which greatly hinder their further development and application in BMO CMSCs. Herein, the one-step fabrication of 2.5D CuMoOx-based CMSCs (CuMoCMSCs) has been realized by numerically controlled electric discharge machining (NCEDM) for the first time. In addition, the controllable capacity of CuMoCMSCs has been achieved by adjusting the NCEDM-machining voltage. The CuMoCMSCs machined by a machining voltage of 60 V (CuMoCMSCs60) showed the best performance. The fabricated CuMoCMSCs60 with binary metal oxides could operate at an ultra-high scanning rate of 10 V s−1, and gained a capacity of 40.3 mF cm−2 (1.1 mA cm−2), which is more than 4 times higher than that of MoOx-based CMSCs (MoCMSCs60) with a single metal oxide. This is because CuMoOx BMOs materials overcome the poor electroconductivity problem of the MoOx single metal oxide. This one-step and numerically controlled fabrication technique developed in this research opens a new vision for preparing BMO materials, BMO microelectrodes, and BMO microdevices in an environmental, automatic, and intelligent way. [ABSTRACT FROM AUTHOR]

This manuscript investigates the transformative shift in electricity generation and distribution towards distributed power networks, particularly microgrids, amid escalating energy demand and environmental concerns. Emphasizing a pioneering technoeconomic conservation voltage reduction–based demand response approach, the study integrates conservation voltage reduction as a controllable demand response method within distributed power networks, highlighting the developed droop control method for effective regulation. Conservation voltage reduction, a no‐cost procedure for minimizing loss, is applied to reduce voltage during peak periods to conserve power, decrease active and reactive power losses through precise load modeling, and enhance consumption efficiency. The most significant challenge of this project is the simultaneous use of conservation voltage reduction with the uncertainties of distributed generation sources, resulting to reduce losses and ultimately lower operating costs, a topic not previously studied in existing literature. The contributions include introducing a novel approach based on droop control to manage resources and presenting a detailed control strategy tailored to distributed power networks for improving voltage stability with minimal costs. Importantly, the proposed method demonstrates superior accuracy, achieving up to an 18% improvement over existing methods. This research contributes to comprehensive solutions for optimizing energy consumption, enhancing grid stability, and adapting to the evolving distributed power systems landscape. [ABSTRACT FROM AUTHOR]

ABSTRACT The unidirectional multilevel rectifier has immense potential in high‐power medium‐voltage industrial applications. This paper proposes a multiobjective control method based on the combination of optimal‐vector‐pair modulated model predictive control (OVP‐M2PC) and a phase‐shifted modulation strategy for a unidirectional five‐level rectifier. This strategy takes both of the inductor current tracking and capacitor voltage balancing as the control objectives. First, an optimal vector pair is determined based on the AC‐side current variation rate, and then, through combining the calculated action duration of OVP with carrier phase‐shifted modulation, inductor current tracking is achieved. Second, capacitor voltage balancing control is carried out by compensating for the duty cycles which also decouples the input current tracking and output capacitor voltage balance control. Compared with traditional FCS‐MPC, under the proposed control strategy, complex cost function calculation and weighting factor tuning are not required, which much reduced computational burden. Multiobjective control is achieved with better performance in both steady‐state and dynamic conditions. The superiority of the proposed strategy over traditional FCS‐MPC are validated through simulations and hardware experiments. [ABSTRACT FROM AUTHOR]

Commercial off‐the‐shelf (OTS) photovoltaic systems coupled with battery energy storage units (PV‐BES) are typically designed to increase household self‐consumption, neglecting their potential for voltage regulation in low voltage distribution networks (LVDNs). This work proposes an enhanced sensitivity‐based combined (ESC) control method for voltage regulation, using BES control as level 1 and reactive power compensation as level 2. A centralized controller manages charging/discharging intervals, while local inverters handle real‐time power rates and reactive power, ensuring effective LVDN voltage regulation. The BES set points are obtained concerning the measured local bus voltage and according to enhanced sensitivity coefficients. The enhancement algorithm ensures that the full capacity of BES is utilized and that there is adequate capacity during charging and discharging time intervals. The proposed method, tested on 8‐bus and 116‐bus LV test feeders, outperforms OTS and an adaptive decentralized (AD) control method by completely preventing overvoltage issues, minimizing various changes in the direction of BES power, and reducing voltage deviation without significantly affecting consumers' grid dependency. [ABSTRACT FROM AUTHOR]

This article aims to investigate different dc‐bus voltage balancing control modes for a modular HVDC drive train applied to offshore wind energy. The modular structure discussed consists of a stacked polyphase bridge converter connected to the modules of a segmented generator. Three voltage control modes are analysed: non‐voltage balancing, voltage balancing allowing overcurrent, and voltage balancing with power derating. Assembly imperfections and operation differences can cause parametric deviations across modules leading to generation unbalance. When operating with voltage balancing with power derating, none has ac overcurrent or dc overvoltage. However, when the turbine is already operating at nominal power, a reduction in total power is required for this to occur. On the other hand, non‐voltage balancing or voltage balancing allowing overcurrent could bring more generated power to the system as the optimal output power allows dc overvoltage or ac overcurrent in some of the modules, respectively. Therefore, there is a trade‐off between efficiency and oversizing the system's components. A sensitivity analysis is performed to identify the expected dc‐bus voltage deviation. Experimental results in a low‐power prototype validate the voltage balancing control modes and a case study demonstrates the impact on energy yield in an offshore wind turbine. [ABSTRACT FROM AUTHOR]

Aiming to improve the voltage distribution and realize the proportional sharing of active and reactive power in the distribution network (DN), this article proposes a distributed optimal control strategy based on the grouping cooperation mechanism of the distributed generation (DG). The proposed strategy integrates the local information of the DG and the global information of the DN. Considering the high resistance/reactance ratio of DN, distributed optimization control strategies for node voltage control and active power management are developed with the consensus variable of active utilization rate. And distributed strategy for reactive power management is proposed with a consensus variable of reactive utilization rate. The convergence of the distributed control system for each group is proved. The validity and robustness of the proposed strategy are verified by several simulations in the IEEE 33‐bus system. [ABSTRACT FROM AUTHOR]

The point of common coupling (PCC) voltage feedforward control strategy can effectively reduce the startup inrush current and improve the anti‐interference ability of the LCL‐type converters, which is widely used in the renewable energy converters control field. With the high penetration of the new energy, the increase of grid impedance leads to the weakening of the grid. Under weak grid conditions, the PCC voltage feedforward control strategy will generate an additional feedback loop of grid‐side current, which has a great impact on the stability of the system. In this paper, the damping characteristic of the PCC voltage feedforward control strategy and the effect on the open loop characteristic of the system have been deeply analyzed. An improved PCC voltage feedforward control strategy based on a proportional plus band‐pass filter is proposed, which can effectively improve the phase margin and achieve active damping under weak grid conditions, therefore, the robustness of the converters can be effectively improved. A three‐phase LCL‐type AC/DC converter platform is built and comparative experiments are carried out to verify the effectiveness of the proposed algorithm. The experimental results are consistent with the theoretical analysis. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]