Voltage Control Research Articles

Wide-Adaptable Uninterrupted Power Supply System for Neutral Sections of ERs With Event-Triggered Flexible Power and Voltage Control

Wide-Adaptable Uninterrupted Power Supply System for Neutral Sections of ERs With Event-Triggered Flexible Power and Voltage Control

Single-phase five level modified neutral point clamped grid connected inverter topology with front-end chopper control of DC-link capacitor voltages

Single-phase five level modified neutral point clamped grid connected inverter topology with front-end chopper control of DC-link capacitor voltages

Comparative analysis of two static var compensator models in voltage control of transmission network

The static var compensator (SVC) is a member of the family of flexible alternating current transmission systems controllers used in power system engineering to manage specific transmission network characteristics to enhance the performance of the transmission networks and thus increase the networks’ reliability. Power system engineers typically find it difficult to choose which SVC model to implement for simulations. This research aims to address this issue by conducting a comparative examination of two key SVC models on a transmission network. The two models of SVC variable shunt susceptance and firing angle were mathematically modeled and methodically included into the Newton-Raphson power flow algorithm for the network power flow solution. The IEEE 30-bus network was adopted as the test case, and the method was implemented in the MATLAB/Simulink environment. The network performance metric utilized was the voltage profile of the network. The two SVC models were successful in enhancing the network's performance; however, the variable shunt susceptance model was computationally faster than the firing angle model, as revealed by the simulation results. Therefore, among the two SVC models, the variable shunt susceptance model may be taken into account for simulation to enhance the performance of the transmission networks.

An Ultrafast and Low-Invasive Short-Circuit Current Limiting Method by Gate Voltage Control for SiC MOSFETs With Kelvin-Source

An Ultrafast and Low-Invasive Short-Circuit Current Limiting Method by Gate Voltage Control for SiC MOSFETs With Kelvin-Source

Low cost pulsed electric field generator using DC-DC boost converter and capacitor diode voltage multiplier

Traditional high-voltage pulse generators, like Marx generators often face challenges related to efficiency and complexity. In this paper, a solid-state multi-module high-voltage pulse generator that integrates capacitor-diode voltage multipliers (CDVM) with DC-DC boost converters and closed-loop voltage control is proposed to overcome these challenges. The system achieves high output voltage by coupling the pulsed output voltages of individual low-voltage DC sources in series across each module. The proposed design was modeled using MATLAB, and experimental testing was conducted on a single stage. Comparative analyses between timedomain parameters, proportional-integral (PI), and fractional order proportional integral derivative (FOPID) controllers were performed. Both MATLAB simulations and experimental validations demonstrate the effectiveness of this approach. The rise time, peak time, settling time, and steady-state error are all improved using an FOPID controller, decreasing from 0.32 to 0.31 seconds, 0.42 to 0.35 seconds, and 3.15 to 2.20 seconds, respectively. These findings indicate that a closed-loop FOPID controller enhances time-domain performance parameters more effectively than a PI controller for a two-stage DC-DC voltage multiplier.

Fuel recycling feedback control via real-time boron powder injection in EAST with full metal wall

Abstract A feedback control of fuel recycling via real-time boron powder injection, addressing the issue of continuously increasing recycling in long-pulse plasma discharges, has been successfully developed and implemented on EAST tokamak. The feedback control system includes four main parts: the impurity powder dropper (IPD), a diagnostic system measuring fuel recycling level represented by Dα emission, a plasma control system (PCS) implementing the Proportional Integral Derivative (PID) algorithm, and a signal converter connecting the IPD and PCS. Based on this control system, both active control and feedback control experiments have recently been performed on EAST with a full metal wall. The experimental results show that the fuel recycling can be gradually reduced to lower level as PCS control voltage increases. In the feedback control experiments, it is also observed that the Dα emission is reduced to the level below the target Dα value by adjusting boron injection flow rate, indicating successful implementation of the fuel recycling feedback control on EAST. This technique provides a new method for fuel recycling control of long pulse and high parameter plasma operations in future fusion devices.

Structural Model and Characteristics of a Nanopiezoactuator for Nanoresearch

The structural model, static and dynamic characteristics of a nanopiezoactuator for nanoresearch are received from the piezoelasticity equation and the differential equation of a nanopiezoactuator. A nanopiezoactuator is a piezomechanical device for converting electrical energy into mechanical energy and for actuating mechanisms, systems in nanodisplacement diapason or controlling them by inverse piezoeffect. In the work uses method of applied mathematical physics. A nanopiezoactuator for alignment and positioning with a nanometric error, compensation of temperature and gravitational deformations, spatial movement in nanoresearch, nanotechnology, microelectronics, nanobiotechnology, scanning microscopy, astronomy, adaptive optics, large compound telescope, deformation mirror of telescope, mechatronics and robotics, medical equipment for microsurgical eyesoperations. The schemes, functions and characteristics a nanopiezoactuator are obtained from its structural model by method of applied mathematical physics. The structural model of the transverse piezoactuator is obtained for the voltage control. The characteristics of the transverse piezoactuator are received. Piezoceramic from PbZr1-xTixO3 (PZT) lead zirconate titanate is widely used in a nanopiezoactuators for its reliability, high accuracy, simple control. The characteristics of the PZT transverse actuator are determined.

The NanoSIMS-HR: The Next Generation of High Spatial Resolution Dynamic SIMS.

The high lateral resolution and sensitivity of the NanoSIMS 50 and 50L series of dynamic SIMS instruments have enabled numerous scientific advances over the past 25 years. Here, we report on the NanoSIMS-HR, the first major upgrade to the series, and analytical tests in a suite of sample types, including an aluminum sample containing silicon crystals, microalgae, and plant roots colonized with a symbiotic fungus. Significant improvements have been made in the Cs+ ion source, high voltage (HV) control, stage reproducibility, and other aspects of the instrument that affect performance. The modified design of the NanoSIMS-HR thermal-ionization Cs+ source enables a 5 pA primary ion beam to be focused into a 100 nm spot, a ∼2.5-fold increase compared to Cs+ sources on previous instruments (∼2 pA at 100 nm). The brightness of the new Cs+ source enables an ultimate lateral resolution as high as 30 nm and improved detection limits for a given analysis area. Sample stage movement accuracy is higher than 500 nm, enabling many-fold higher throughput automated analyses. With the new HV control, the primary ion beam impact energy can be reduced from 16 to 2 keV, which enables higher depth resolution during depth profiling (a 2-fold improvement), albeit with a 5-fold decrease in lateral resolution. In the NanoSIMS-HR, the secondary ion column and detection system are identical to those used in the previous series, and the isotopic analysis performance is as precise as in previous NanoSIMS instruments.

Impact of Advanced Thyristor Controlled Series Capacitor on Load Frequency Control and Automatic Voltage Regulator Dual Area System with Interval Type-2 Fuzzy Sets-PID Usage

A major priority for practicing engineers in an electric power system is preserving the stability of frequency and voltage levels. Any change in these two factors will impact the efficiency and lifespan of the machines connected to the power supply. Therefore, this paper provides a control approach utilizing the Interval Type-2 Fuzzy Sets- Proportional Integral Derivative (IT2FSs-PID) controller and Advanced Thyristor Controlled Series Capacitor (ATCSC) with a combined Load Frequency Control-Automatic Voltage Regulator (LFC-AVR). Several inspections were implemented to demonstrate the controller’s strength, including various disturbances in the power system. The LFC-AVR was studied using two different dynamic models, referred to as open and closed loops on the Generation Rate Constraint (GRC) forms. A comparison was made using different techniques from the literature using the same model. Before using the approach, the frequency deviation of area-1 had a very large settling time value, which was caused by system instability. However, after implementing the approach, this value decreased to 4.9236 s. Finally, an additional ATCSC was added to the proposed model to observe its effect on the power system. The simulation was implemented using MATLAB/SIMULINK tools.

Improvement of EME accuracy based on an equivalent voltage acquisition method and corresponding voltage compensation strategy

AbstractIt is a known cost‐effective method to employ a DSP‐based electric machine emulator (EME) for motor control unit testing, this paper introduces a novel approach to enhance the emulator's accuracy. The inaccuracies caused by terminal voltage sampling errors in the motor control unit and voltage distortions in the inverter are addressed in this paper. An advanced equivalent voltage acquisition technique, which samples the duty cycle‐amplitude of the inverter's terminal voltage, is developed. Leveraging the acquired equivalent voltage data, a novel voltage compensation strategy that providing more accuracy in EME performance is proposed. The mathematical foundation of the EME is established using Kirchhoff's voltage and current laws. These findings are independently validated through simulations and experiments. The results provide robust evidence that the proposed equivalent voltage acquisition and compensation strategies can enhance the accuracy of the EME.

2D α‐In2Se3 Flakes for High Frequency Tunable and Switchable Film Bulk Acoustic Wave Resonators

AbstractTunable and switchable film bulk acoustic resonators (FBARs) with the capability of dynamically adjusting their resonant frequencies hold significant promise for advanced multi‐band radio frequency (RF) communication systems. However, tunable and switchable FBARs based on conventional thin ferroelectric materials face several challenges in meeting the demands of advanced RF applications. Specifically, submicron‐thick ferroelectric materials suffer from degradation in piezoelectric performance due to the strong scattering of acoustic waves caused by surface defects, as well as the inconsistency in crystal orientation. Recent advances in 2D ferroelectric materials create new opportunities for high‐performance tunable and switchable FBARs. Here, the first batch of FBAR chips based on 2D α‐In2Se3 flakes is reported. The α‐In2Se3‐based FBARs are normally under the on‐state and possess a small off‐voltage of −4 V. A tuning range of 26 MHz is achieved with a control voltage from −2 to 4 V at the resonant frequency of 8.6 GHz. To the best of the author's knowledge, this is the first batch of tunable FBARs that can function beyond the sub‐6 GHz band. This work demonstrates for the first time that 2D ferroelectric materials are very promising for high‐frequency tunable and switchable FBARs.

Modeling and Active Vibration Control of Flexible Robotic Arm and Its Application in Agricultural Water Conservancy Field

In order to improve the modeling and active vibration control effectiveness of flexible manipulators, this paper combines big data technology to study the modeling and active control of flexible manipulators. In addition, this article decouples the dynamic model of the flexible joint manipulator based on voltage control method, redefines the control input of the system as the voltage of the joint motor, and uses a nonlinear state observer to control the flexible link manipulator. The control strategy proposed in this article is based on a nonlinear state observer, combined with input-output control, to achieve tracking of joint angular displacement in a flexible linkage manipulator. Through experimental research, it can be seen that the big data based modeling and active vibration control research system for flexible robotic arms proposed in this paper can effectively improve the motion control effect of flexible robotic arms.

A decoupling strategy for average value control and ripple suppression of capacitor voltages in modular multilevel converters based on notch filters

AbstractModular multilevel converters (MMC) have become an emerging hotspot in the field of medium‐voltage drives. A major challenge is the large voltage ripple of sub‐module capacitors at low rotor speeds with high torque. Therefore, it is necessary to achieve ripple suppression while maintaining the average values of the capacitor voltages at their reference. However, the average value control and ripple suppression of the capacitor voltages have a coupling effect during the circulating current control loop, which reduces the performance. This paper proposes a decoupling strategy based on notch filters (NF). First, the coupling problem existing in the traditional control strategy is analysed by theoretical analysis and simulation. Then, the principle and parameter design method of the improved decoupling strategy are introduced. Finally, the performance of the decoupling strategy is experimentally verified using a small prototype.

A Modified Control Strategy for Three-Phase Four-Switch Active Power Filters Based on Fundamental Positive Sequence Extraction

Three-phase four-switch active power filters (APFs) have attracted attention due to their low amount of semiconductors and low cost. The traditional control strategy of three-phase four-switch APFs usually includes phase-locked loops (PLLs) and rotating coordinate transformation for harmonic detection, resulting in complicated calculations and increased computation. In this paper, a modified control strategy for three-phase four-switch APFs based on fundamental positive sequence extraction is proposed, eliminating PLLs and rotating coordinate transformation with trigonometric calculations. Harmonic extraction is based on the fundamental positive sequence extraction method, while non-locked phase loop coordinate transformation is proposed to eliminate trigonometric calculations. Quasi-PR control is adopted for current tracking, and DC voltage control is designed to suppress voltage imbalance between the two split capacitors on the DC side. The space vector pulse width modulation (SVPWM) method is modified for a reduced-switch APF topology. The proposed control strategy guarantees excellent harmonic compensation: harmonic currents are significantly suppressed when the APFs are working, the THD of the source current decreases to 3.86%, the bus voltage fluctuation on the DC side is small, the voltage remains stable, and the computational complexity is reduced. Finally, a simulation and an experimental hardware platform are established to validate the feasibility and performance of the proposed control strategy. The experimental results show that it has good performance in suppressing harmonics and improving power quality.

Virtual Generator to Replace Backup Diesel GenSets Using Backstepping Controlled NPC Multilevel Converter in Islanded Microgrids with Renewable Energy Sources

This work presents an islanded microgrid energy system that uses backstepping control applied to neutral point clamped (NPC) multilevel converters coupled with batteries to behave as virtual generators, able to absorb surplus renewable energy, therefore increasing the penetration of renewable energy sources. Additionally, on a charged battery the virtual generator allows turning-off the backup diesel generator set (GenSet). Aside from improving energy efficiency, the battery-connected multilevel converter aims to regulate frequency, improves power quality, and keeps the microgrid operational in the event of a GenSet failure. The backstepping controlled NPC multilevel converter emulates a virtual generator injecting power to perform as the primary and secondary microgrid frequency controller. Additionally, AC voltage control is implemented, which enables running the islanded microgrid only with multilevel converters, supplied by the battery while integrating solar and wind energy sources. Energy demand and renewable energy forecasts are used to manage the battery state-of-charge. Simulation results, obtained from switched and phasor models show that energy storage and the backstepping frequency control enables the compensation of power fluctuations from renewable energy sources. Furthermore, in the event of the main GenSet failure, the controlled virtual generator keeps the microgrid running for a few minutes, until another GenSet is ready to supply the microgrid. Therefore, the microgrid integration of the battery-connected multilevel converter results in a significant boost in energy efficiency by allowing the disconnection of the backup GenSet.

Integrating Multiple Hierarchical Parameters to Achieve the Self-Compensation of Scale Factor in a Micro-Electromechanical System Gyroscope.

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.

Vertical instability prediction and its direction control using a support vector machine in integrated commissioning of JT-60SA solely based on magnetics

Abstract We developed a redundant logic for predicting Vertical Displacement Events (VDEs) using only magnetic diagnostics with a Support Vector Machine (Inoue et al 2022 Nucl. Fusion 62 086007). This logic was experimentally validated in the integrated commissioning of JT-60SA. Triggering of VDEs results in significant asymmetric heat loads on first walls and electromagnetic loads on conducting materials. These concerns are mitigated by a newly proposed direction control for VDEs. We successfully detected VDEs in experiments and controlled their direction by setting the control voltage to zero upon detection, thus guiding VDEs in an intended direction and reducing the risk to the device from unmitigated VDEs in either direction, although completely avoiding VDEs remains the ideal. In the developed predictor, VDEs are predicted using proxies to monitor the controller’s performance with an adaptive voltage allocation scheme (Inoue et al 2021 Nucl. Fusion 61 096009). For future experiments, we plan to extend our approach to monitor more detailed information from the equilibrium controller, including control values of each PID component, which has been shown to enhance the prediction accuracy of VDEs.

Review Paper of Grid-Connected Solar PV Systems With Decoupled Control

This paper presents a decoupled control for grid-connected solar photovoltaic (PV) system. The control framework used in this paper aims not to track the changing maximum power point (MPP) for extracting power at MPP, hence blocking the MPP tracking issue against the effect of solar radiation and temperature. Real power is produced by tracking the control voltage with a zero-dynamics-based controller. A cascaded loop controller with inner loop to regulate the control voltage is incorporated to ensure the produced real power follows the reference power in the presence of power disturbance. The proposed control scheme with the consideration of the inverter's rated voltage shows improved system dynamics. Simulations in various conditions are conducted to prove the effectiveness of the proposed control strategies. CIGRE 13-node benchmark system is used as the case study to evaluate the results of the PV system connected to a more complex power system. It has been shown that the proposed controller allows the total production of the energy under maximum power point conditions and also improves the overall stability of distributed generation connected to the grid. Therefore, it can be implemented to increase the capacity of renewable inverter-based power generation and the power system quality.

A New Third-Order Continuous Sliding Mode Speed and DC-Link Voltage Controllers for a PMSG-based Wind Turbine with Energy Storage System

A New Third-Order Continuous Sliding Mode Speed and DC-Link Voltage Controllers for a PMSG-based Wind Turbine with Energy Storage System

Enhancing load frequency control and automatic voltage regulation in Interconnected power systems using the Walrus optimization algorithm

This paper introduces the Walrus Optimization Algorithm (WaOA) to address load frequency control and automatic voltage regulation in a two-area interconnected power systems. The load frequency control and automatic voltage regulation are critical for maintaining power quality by ensuring stable frequency and voltage levels. The parameters of fractional order Proportional-Integral-Derivative (FO-PID) controller are optimized using WaOA, inspired by the social and foraging behaviors of walruses, which inhabit the arctic and sub-arctic regions. The proposed method demonstrates faster convergence in frequency and voltage regulation and improved tie-line power stabilization compared to recent optimization algorithms such as salp swarm, whale optimization, crayfish optimization, secretary bird optimization, hippopotamus optimization, brown bear optimization, teaching learning optimization, artificial gorilla troop optimization, and wild horse optimization. MATLAB simulations show that the WaOA-tuned FO-PID controller improves frequency regulation by approximately 25%, and exhibits a considerable faster settling time. Bode plot analyses confirm the stability with gain margins of 5.83 dB and 9.61 dB, and phase margins of 10.8 degrees and 28.6 degrees for the two areas respectively. The system modeling and validation in MATLAB showcases the superior performance and reliability of the WaOA-tuned FO-PID controller in enhancing power system stability and quality under step, random step load disturbance, with nonlinearities like GDC and GDB, and system parameter variations.