Artykuły w czasopismach: „CURRENT CONTROL SCHEMES”

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Limongi, L., R. Bojoi, G. Griva i A. Tenconi. "Digital current-control schemes". IEEE Industrial Electronics Magazine 3, nr 1 (marzec 2009): 20–31. http://dx.doi.org/10.1109/mie.2009.931894.

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Fujita, Hideaki, Hiroshi Yamashita i Hirofumi Akagi. "Control and Performance of Digital Current-Control Schemes". Journal of the Japan Institute of Power Electronics 29, nr 1 (2003): 93–100. http://dx.doi.org/10.5416/jipe2003.29.1_93.

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Yuan, Jie, Dingdou Wen i Yang Zhang. "Model Predictive Current Control Strategy with Reduced Computation Burden". Mathematical Problems in Engineering 2021 (4.02.2021): 1–10. http://dx.doi.org/10.1155/2021/6677543.

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In this paper, three model predictive current control (MPCC) schemes for permanent magnet synchronous motors (PMSM) are studied. The first control scheme is the traditional optimal duty cycle model predictive current control (ODC-MPCC). In this scheme, according to the principle of minimizing the cost function, the optimal voltage vector is selected from the six basic voltage vectors which are optimized simultaneously with the duty, and then, the optimal voltage vector and its duty are applied to the inverter. In order to reduce the computational burden of ODC-MPCC, a second control scheme is proposed. This scheme optimizes the voltage vector control set, reducing the number of candidate voltage vectors from 6 to 2. Finally, according to the principle of minimizing the cost function, the optimal voltage vector is found from the two voltage vectors, and the optimal voltage vector and its duty cycle are applied to the inverter. In addition, in order to further improve the steady-state performance, another vector selection method is introduced. In the combination of voltage vectors, the third control scheme extends the combination of voltage vectors in the second control scheme. The simulation results show that the second control scheme not only reduces the computational burden of the first control scheme but also obtains steady-state performance and dynamic performance equivalent to the first control scheme. The third control scheme obtains better steady-state performance without significantly increasing the computational burden and has dynamic performance comparable to the first and second control schemes.

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Azab, Mohamed. "Comparative Study of BLDC Motor Drives with Different Approaches: FCS-Model Predictive Control and Hysteresis Current Control". World Electric Vehicle Journal 13, nr 7 (24.06.2022): 112. http://dx.doi.org/10.3390/wevj13070112.

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The control techniques of the brushless DC (BLDC) motor have gained a large amount of interest in recent years, with their use being implemented in order to achieve a high-performance drive, including quick transient response and high-quality waveforms at the steady state. This paper provides a comparative study between three control schemes of BLDC motors: the direct power control scheme using a finite control set model predictive control (FCS-MPC) approach, the stator current controlled scheme using an FCS-MPC approach, and the stator current controlled scheme using ON–OFF hysteresis current controllers. The three systems were studied and investigated under the same operating conditions. The comparative study included investigating the performance of the BLDC drive in both steady state and transient operations. Qualitative and quantitative analyses were performed on the results obtained with each control scheme. The obtained results demonstrate the validity and effectiveness of the three investigated schemes in controlling the motor speed to the desired value under sudden load changes and achieving satisfactory quick transient responses. However, the results indicate the superiority of the direct power control scheme using an FCS-MPC approach over the others in terms of its minimum torque ripple, lowest torque and speed pulsations, minimum active and reactive power ripples, and high-quality waveforms of the stator currents drawn by the motor with minimum THD.

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Abubakar, Muhammad, Herwig Renner i Robert Schürhuber. "Development of A Novel Control Scheme for Grid-Following Converter under Asymmetrical Faults". Energies 16, nr 3 (25.01.2023): 1276. http://dx.doi.org/10.3390/en16031276.

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With the increasing penetration of converter-based power sources into the power system, the performance of the converter has become a key factor for enhancing grid reliability, especially during asymmetrical faults. To meet the low voltage ride-through requirements, the converter should feed the reactive power to the grid for voltage support while ensuring the maximum current limitation for the converter’s safety. For such injections, the grid codes are defined. This paper presents a novel and simplified reference current generation scheme to fulfill the requirement of recent grid codes, ensure the current limit of the converter and confirm better utilization of the converter’s current capacity during asymmetrical faults. Moreover, it also discusses the new sequence extraction scheme based on the delay sample method in the stationary reference frame and the control modifications for the negative sequence current injection. The proposed scheme was tested for different priority injection schemes. Its performance was also compared with other control schemes. Detailed simulation studies, in MATLAB/Simulink, were presented to confirm the performance of the proposed scheme under different faulty conditions. The results confirmed the supremacy of the proposed scheme over the available schemes for better utilization of the converter’s current capacity during asymmetrical faults. It also ensured the peak current limitation of the converter while fulfilling the recent grid code requirements. Moreover, the results showed that the new scheme has 10% more current capacity compared to the other schemes due to better incorporation of the angle between the positive and negative phase sequences of the voltage.

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Hawkins, Nicholas, Bhagyashri Bhagwat i Michael L. McIntyre. "Nonlinear Current-Mode Control of SCIG Wind Turbines". Energies 14, nr 1 (24.12.2020): 55. http://dx.doi.org/10.3390/en14010055.

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In this paper, a nonlinear controller is proposed to manage the rotational speed of a full-variable Squirrel Cage Induction Generator wind turbine. This control scheme improves upon tractional vector controllers by removing the need for a rotor flux observer. Additionally, the proposed controller manages the performance through turbulent wind conditions by accounting for unmeasurable wind torque dynamics. This model-based approach utilizes a current-based control in place of traditional voltage-mode control and is validated using a Lyapunov-based stability analysis. The proposed scheme is compared to a linear vector controller through simulation results. These results demonstrate that the proposed controller is far more robust to wind turbulence than traditional control schemes.

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Javed, Khalid, Ruben De Croo, Lieven Vandevelde i Frederik De Belie. "Circulating Current Control in Interleaved and Parallel Connected Power Converters". Machines 11, nr 9 (1.09.2023): 878. http://dx.doi.org/10.3390/machines11090878.

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This article analyzes circulating current control in single-phase power electronic converters, focusing on two different topologies: interleaved and parallel configurations. The study involves a bridgeless interleaving topology with two boost converters for increased efficiency. A parallel connection is also examined for monitoring line current, circulating currents, and power factor control. The article widely explains all current loops, including Common Mode Circulating Currents (CMCC) in the bridgeless interleaved topology and Differential Mode Circulating Currents (DMCC) in parallel-connected interleaved power converters. The proposed control scheme employs voltage and current control loops for output voltage and line current control and introduces CMCC and DMCC compensators to eliminate all types of circulating currents. An efficient Power Factor Correction (PFC) and output voltage control method is presented in this article. The effectiveness of the proposed schemes is validated through comparisons with modern control systems. The results are verified using Simulink/MATLAB and experimental setups with TI Instruments Piccolo prototypes and C2000 (TMS320F28035 microcontroller MCU) microcontrollers in parallel configurations.

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Grcar, Bojan, Gorazd Stumberger, Anton Hofer i Peter Cafuta. "IM Torque Control Schemes Based on Stator Current Vector". IEEE Transactions on Industrial Electronics 61, nr 1 (styczeń 2014): 126–38. http://dx.doi.org/10.1109/tie.2013.2247016.

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Moin, Parviz, i Thomas Bewley. "Feedback Control of Turbulence". Applied Mechanics Reviews 47, nr 6S (1.06.1994): S3—S13. http://dx.doi.org/10.1115/1.3124438.

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A brief review of current approaches to active feedback control of the fluctuations arising in turbulent flows is presented, emphasizing the mathematical techniques involved. Active feedback control schemes are categorized and compared by examining the extent to which they are based on the governing flow equations. These schemes are broken down into the following categories: adaptive schemes, schemes based on heuristic physical arguments, schemes based on a dynamical systems approach, and schemes based on optimal control theory applied directly to the Navier-Stokes equations. Recent advances in methods of implementing small scale flow control ideas are also reviewed.

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Peng, Jingyao, i Ming Yao. "Overview of Predictive Control Technology for Permanent Magnet Synchronous Motor Systems". Applied Sciences 13, nr 10 (19.05.2023): 6255. http://dx.doi.org/10.3390/app13106255.

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Permanent magnet synchronous motors (PMSMs) are commonly used in the automation industry. With the speedy development of digital system processors, predictive control as a modern control scheme has been applied to improve the dynamic performance and work efficiency of PMSMs. This paper provides an overview of the research status of PMSM-based predictive control strategies. The deficiencies of the three most popular predictive schemes, deadbeat predictive control, finite-control-set model predictive control, and continuous-control-set model predictive control, and existing improvement strategies such as delay compensation schemes, robust control schemes, and multi-vector control schemes, are summarized. Finally, current technological trends are discussed, emphasizing future research directions for predictive control in PMSM drive systems.

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Kasai, Kazuhiko, i Yoji Ooki. "Current Status of Japanese Passive Control Technology Using Various Damping Materials". Key Engineering Materials 319 (wrzesień 2006): 197–208. http://dx.doi.org/10.4028/www.scientific.net/kem.319.197.

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Due to the recent earthquakes in the U.S. and Japan, many modern buildings ceased functioning and required costly structural and nonstructural repairs, although they successfully protected the lives of the occupants. Because of these, most major buildings constructed after the earthquakes utilize either passive-control scheme or base-isolation scheme in order to better protect the building and its contents. This paper addresses current status of passive control technology being implemented in Japan. Four major groups of dampers and their basic mechanisms are discussed. Three groups of frames are explained, referring to different connection schemes and deformation lags between the frame and damper. A unified approach to assess effectiveness of various dampers and frames will be presented.

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Li, Guang Lei, Shu Min Sun, Yan Cheng, Hong Bo Li i Shuai Yuan. "Research on Optimization Control Strategy for Limiting Short-Circuit Current Based on Fuzzy Quantitative Control". Applied Mechanics and Materials 214 (listopad 2012): 527–30. http://dx.doi.org/10.4028/www.scientific.net/amm.214.527.

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To decrease short-circuit current, adjusting the power network operation by breaking transmission lines is the most economic and convenient measure. For large power grid, breaking transmission lines has thousands of combinations, so it's very difficult to find the best combination in a short time. Firstly, this paper formulated the sensitivity relationship between transmission line outage and impedance change. Then preliminary combinations schemes of transmission line outage were selected according to the sensitivity. Index values of factors were given using the fuzzy control evaluation. Finally, this paper determined optimal scheme from maximum priority and accomplished the accessorial intelligent optimize system of limiting short-circuit current. The rapidity and rapidity of the proposed control strategy was verified by calculating the actual power grid.

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Hussein, Hussein A., Ali J. Mahdi i Thamir M. Abdul-Wahhab. "Current-Control Inverter Schemes for a Grid-Connected PV Generator". IOP Conference Series: Materials Science and Engineering 1105, nr 1 (1.06.2021): 012018. http://dx.doi.org/10.1088/1757-899x/1105/1/012018.

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Shi, Jie, i Xiangzheng Xu. "A Robust Control Scheme for Dynamic Voltage Restorer with Current Limiting Capability". Sustainability 14, nr 24 (14.12.2022): 16752. http://dx.doi.org/10.3390/su142416752.

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In this paper, a second order sliding mode control scheme is utilized for outer voltage loop of a three-phase fault current limiter-based dynamic voltage restorer (FCL-DVR) instead of a conventional proportional integral/proportional resonance (PI/PR) controller. The new control strategy improves the dynamic performance of the FCL-DVR against voltage distortion. Furthermore, by using the proposed robustness controller, the FCL-DVR can smoothly switch between the FCL and DVR operation modes. Compared with other existing control schemes, the proposed control strategy for the FCL mode can still work well under a large fault current. The MATLAB/Simulink simulation results demonstrate that the proposed control strategy is robust to voltage harmonics, sag and swell. They also show that the proposed control scheme can effectively limit the fault current in different scenarios.

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Garrido, Izaskun, Aitor J. Garrido, Jesús A. Romero, Edorta Carrascal, Goretti Sevillano-Berasategui i Oscar Barambones. "Low EffortLiNuclear Fusion Plasma Control Using Model Predictive Control Laws". Mathematical Problems in Engineering 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/527420.

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One of the main problems of fusion energy is to achieve longer pulse duration by avoiding the premature reaction decay due to plasma instabilities. The control of the plasma inductance arises as an essential tool for the successful operation of tokamak fusion reactors in order to overcome stability issues as well as the new challenges specific to advanced scenarios operation. In this sense, given that advanced tokamaks will suffer from limited power available from noninductive current drive actuators, the transformer primary coil could assist in reducing the power requirements of the noninductive current drive sources needed for current profile control. Therefore, tokamak operation may benefit from advanced control laws beyond the traditionally used PID schemes by reducing instabilities while guaranteeing the tokamak integrity. In this paper, a novel model predictive control (MPC) scheme has been developed and successfully employed to optimize both current and internal inductance of the plasma, which influences the L-H transition timing, the density peaking, and pedestal pressure. Results show that the internal inductance and current profiles can be adequately controlled while maintaining the minimal control action required in tokamak operation.

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Pidikiti, Tripura, i Tulasi Ram Das G. "Modelling and simulation of ZDC controlled PMSG based wind energy conversion system". International Journal of Engineering & Technology 7, nr 1.8 (9.02.2018): 46. http://dx.doi.org/10.14419/ijet.v7i1.8.9449.

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This paper presents the comparison of dynamic performance and steady state operation of PMSG wind energy conversion systems with two modulation techniques. Voltage oriented control (VOC) is used for grid-connected converter along with sinusoidal pulse width modulation (SPWM) and Space Vector Modulation (SVM) schemes. The generator is controlled by using zero d- axis current (ZDC) control scheme along with optimal torque control (OTC). Performance comparison with two pulse width modulation schemes through simulation results are presented for 2MW/ 690V/ 9.75Hz Non-Salient Pole PMSG using MATLAB/SIMULINK.

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Jayasawal, Kishan, i Khagendra Thapa. "An Enhanced Low Voltage Ride-Through Control Scheme of a DIFG based WTG Using Crowbar and Braking Chopper". Journal of the Institute of Engineering 16, nr 1 (12.04.2021): 61–67. http://dx.doi.org/10.3126/jie.v16i1.36537.

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The grid codes define low voltage ride-through (LVRT) as capability of wind turbine generator (WTG) to support the grid voltage by injecting reactive power and suppress the rise of DC-link voltage and inrush rotor current in the rotor side converter (RSC) of the doubly fed induction generator (DFIG) during a fault. Moreover, the rotor current increases significantly during severe disturbances if any protection schemes are not employed. Therefore, the protection schemes must be used to avoid the damage to the converter during a fault. This paper proposes an enhanced LVRT control scheme of a DFIG employing a crowbar in the RSC side and braking chopper across the DC-link capacitor. The DFIG is highly delicate to grid voltage fluctuation during a fault because the DFIG is directly linked to the grid via stator. During severe fault the crowbar regulates the rotor current within an acceptable range and the braking chopper discharges the DC-link capacitor via resistor within a safe limit. The proposed LVRT control scheme is performed for a 2.4-MW DFIG using a MATLAB/SIMULINK simulator. The results delineate that the proposed control scheme is able to rapidly decrease the rotor current and repress the escalation in DC-link voltage during a grid fault.

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Chong, Zhi Lin, Shuo Huang, Amitava Mukherjee i Jun Yang. "Performance comparisons of distribution-free Shewhart-type Lepage and Cucconi schemes in monitoring complex process distributions". Transactions of the Institute of Measurement and Control 42, nr 14 (2.07.2020): 2787–811. http://dx.doi.org/10.1177/0142331220932466.

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In recent years, researchers introduced several distribution-free schemes for simultaneously monitoring the location and scale parameters of distribution in the literature related to process monitoring and control. To this end, the Shewhart-Lepage (SL) and Shewhart-Cucconi (SC) schemes are two fundamental distribution-free schemes. These schemes are primarily designed to monitor the location-scale family of densities. In practice, apart from the location and scale parameters, we often encounter the presence of a shape (or skewness) parameter. In this article, we investigate the performance of the SL and SC schemes in monitoring such models. We consider some skewed distributions in the location-scale family with one or two additional parameters, some three-parameter time-to-event processes, such as three-parameter Weibull and Gamma, which are very common in various measurement and control literature. First, we present the in-control performance of the two competing schemes and then carry out a comprehensive out-of-control performance study by considering different combinations of shifts. Several recent investigations showed that the SC scheme performs just as well or better than the SL scheme in joint monitoring of the location and scale parameters for a large number of process distributions. The current study shows that in the presence of an additional parameter, especially when the shift in the shape parameter is substantial, the SL scheme is better; for a small change in shape, the SC scheme is more competitive. In general, the SL scheme performs better in monitoring the three-parameter distributions for time-to-event processes. Finally, a real application and some concluding remarks are presented.

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Abedinzadeh, Taher, i Sajjad Tohidi. "A comprehensive sensorless control of DFIG-based wind turbines". COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 35, nr 1 (4.01.2016): 27–43. http://dx.doi.org/10.1108/compel-09-2014-0236.

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Purpose – The purpose of this paper is to present an improved approach for estimation of the rotor position and speed of doubly fed induction generator, which can be used in vector control and direct torque control (DTC) schemes. Design/methodology/approach – Some novel equations are developed for calculation of the rotor position and rotor speed. Such equations do not need to the value of stator flux linkage and just, measured values of the stator voltage and currents as well as rotor current are required to be known. Findings – The simulation results verify the satisfactory steady-state and dynamic performance of proposed approach with both the vector control and DTC schemes. The results show that the proposed estimation approach benefits from the starting on the fly, robustness against the variations of the most of the stator and rotor parameters and immunity against the noise. Originality/value – The proposed estimation approach is novel and the outcome of the research of authors. It is simple and effective and, no approximation is made in the calculations. The simulation results demonstrate that the proposed scheme can be successfully implemented in various control strategies, e.g. DTC and vector control.

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To, Hoang-Linh, Thuyen Minh Thi i Won-Joo Hwang. "Cascade Probability Control to Mitigate Bufferbloat under Multiple Real-World TCP Stacks". Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/628583.

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Persistently full buffer problem, commonly known as bufferbloat, causes unnecessary additional latency and throughput degradation whenever congestion happens in Internet. Several proposed queue management schemes, with the debloat mission, are almost based on the modification of one-loop feedback control where the instability and bad transient behavior are still big challenges. In this paper, we present a cascade probability control scheme using margin optimal method to address such challenges under different kinds of real-world TCP stacks. Simulation results guarantee the measured round trip time tracking to a low value of delay (e.g., ≈180 ms under TCP Reno, and ≈130 ms under TCP Cubic) and ≈50% delay reduction in comparison to current deployed queue management schemes in network devices.

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Mu, Weilei, Yuxue Wang, Hailiang Sun i Guijie Liu. "Double-Loop Sliding Mode Controller with An Ocean Current Observer for the Trajectory Tracking of ROV". Journal of Marine Science and Engineering 9, nr 9 (13.09.2021): 1000. http://dx.doi.org/10.3390/jmse9091000.

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To solve the trajectory tracking problem of insufficient response and the large tracking error of remotely operated vehicles (ROVs) under the interference of large ocean currents, this paper proposes a double-loop sliding mode controller with an ocean current observer. The designed controller consisted of an outer-loop controller (the position controller) and an inner-loop controller (the velocity controller): the outer controller was designed by the position error, and a reference velocity was created for the inner loop to achieve accurate positioning and attitude tracking. The reference control input was treated as a new target to design the inner-loop controller, enabling the ROV to achieve accurate reference velocity tracking. Based on the theoretical idea of active disturbance rejection control, a kinematic equation-based ocean current observer was designed to estimate and compensate for large unknown currents to ensure accurate trajectory tracking performance under large currents. The simulation results proved that the double-loop sliding-mode control scheme with an ocean current observer always showed good tracking performance, demonstrating the excellent control performance and high robustness of the scheme. Compared with the high-complexity control schemes such as neural network-based PID control or fuzzy sliding mode control, it effectively improves the robustness to ocean current disturbances without increasing the computational effort excessively, and is more practical in ROV systems with limited computational power.

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Cortes-Vega, David, Hussain Alazki i Jose Luis Rullan-Lara. "Current Sensorless MPPT Control for PV Systems Based on Robust Observer". Applied Sciences 12, nr 9 (26.04.2022): 4360. http://dx.doi.org/10.3390/app12094360.

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Photovoltaic (PV) systems are among the most used alternatives for electrical power generation from renewable sources. To ensure that PV systems make the most of the available solar energy, maximum power point tracking (MPPT) schemes must be implemented, which usually require voltage and current sensors to track the PV power. This paper presents the design of a robust observer using the Attractive Ellipsoid Method to achieve a precise estimation of PV current under parametric uncertainty and output perturbations. The application of such an observer enables the PV generation system to operate in a current sensorless mode, which reduces the overall cost of the system and enhances its reliability. The convergence of the observer is guaranteed by solving an optimization problem which generates the optimal gains using Linear Matrix Inequalities (LMI). To prove the effectiveness of the proposed sensorless scheme, simulations are performed in Matlab under test profiles based on the EN50530 standard and parameter uncertainty conditions, obtaining an accurate estimation which is used for MPPT operation.

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Cortes-Vega, David, Hussain Alazki i Jose Luis Rullan-Lara. "Current Sensorless MPPT Control for PV Systems Based on Robust Observer". Applied Sciences 12, nr 9 (26.04.2022): 4360. http://dx.doi.org/10.3390/app12094360.

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Photovoltaic (PV) systems are among the most used alternatives for electrical power generation from renewable sources. To ensure that PV systems make the most of the available solar energy, maximum power point tracking (MPPT) schemes must be implemented, which usually require voltage and current sensors to track the PV power. This paper presents the design of a robust observer using the Attractive Ellipsoid Method to achieve a precise estimation of PV current under parametric uncertainty and output perturbations. The application of such an observer enables the PV generation system to operate in a current sensorless mode, which reduces the overall cost of the system and enhances its reliability. The convergence of the observer is guaranteed by solving an optimization problem which generates the optimal gains using Linear Matrix Inequalities (LMI). To prove the effectiveness of the proposed sensorless scheme, simulations are performed in Matlab under test profiles based on the EN50530 standard and parameter uncertainty conditions, obtaining an accurate estimation which is used for MPPT operation.

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Routray, Abhinandan, i Sung-Ho Hur. "Leakage Current Mitigation of Photovoltaic System Using Optimized Predictive Control for Improved Efficiency". Applied Sciences 12, nr 2 (10.01.2022): 643. http://dx.doi.org/10.3390/app12020643.

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This paper proposes an optimized predictive control strategy to mitigate the potential leakage current of grid-tied photovoltaic (PV) systems to improve the lifespans of PV modules. In this work, the PV system is controlled with an optimized predictive control algorithm that selects the switching voltage vectors intelligently to reduce the number of computational burdens. Thus, it improves the dynamic performance of the overall system. This is achieved through a specific cost function that minimizes the change in common-mode voltage generated by the parasitic capacitance of PV modules. The proposed controller does not require any additional modulation schemes. Normalization techniques and weighting factors are incorporated to obtain improved results. The steady state and dynamic performance of the proposed control scheme is validated in this work through simulations and a 600 W experimental laboratory prototype.

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Chakkirala, Sudhakarababu, i Mummadi Veerachary. "Stability Analysis of Fixed and Variable Frequency Digital Predictive Current Control Schemes". IEEJ Transactions on Industry Applications 127, nr 12 (2007): 1205–14. http://dx.doi.org/10.1541/ieejias.127.1205.

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Liang, Gan Jia, Zhang Hong Xia i Zhao Jin. "Fuzzy Logic based Current Control Schemes for Vector-controlled Asynchronous Motor Drives". Information Technology Journal 9, nr 7 (15.09.2010): 1495–99. http://dx.doi.org/10.3923/itj.2010.1495.1499.

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Rathore, Anurag S., Somesh Mishra, Saxena Nikita i Priyanka Priyanka. "Bioprocess Control: Current Progress and Future Perspectives". Life 11, nr 6 (13.06.2021): 557. http://dx.doi.org/10.3390/life11060557.

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Typical bioprocess comprises of different unit operations wherein a near optimal environment is required for cells to grow, divide, and synthesize the desired product. However, bioprocess control caters to unique challenges that arise due to non-linearity, variability, and complexity of biotech processes. This article presents a review of modern control strategies employed in bioprocessing. Conventional control strategies (open loop, closed loop) along with modern control schemes such as fuzzy logic, model predictive control, adaptive control and neural network-based control are illustrated, and their effectiveness is highlighted. Furthermore, it is elucidated that bioprocess control is more than just automation, and includes aspects such as system architecture, software applications, hardware, and interfaces, all of which are optimized and compiled as per demand. This needs to be accomplished while keeping process requirement, production cost, market value of product, regulatory constraints, and data acquisition requirements in our purview. This article aims to offer an overview of the current best practices in bioprocess control, monitoring, and automation.

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Adel, Mohamed, i Tarek Kandil. "Assessment of Direct and Indirect Current Control Techniques Applied to Active Power Filters". Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) 13, nr 8 (3.12.2020): 1256–65. http://dx.doi.org/10.2174/2352096513999200710143353.

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Background: In this paper, an assessment of active power filter (APF) performance is presented under direct and indirect current control schemes through on-line compensation theory. Methods: Conventional Direct Current Control (DCC) measures both load current and filter current beside source and DC-link voltages, while Indirect Current Control (ICC) measures only source current beside voltage measurements. Both DCC and ICC control algorithms are implemented using 80C196KC low-cost microcontroller. Results: The performance parameters of APF are compared under two methods, and it is assigned that ICC gives a better performance with lower cost due to reduced number of sensors. The DC-link output voltage is controlled through simple PI-controller, and the PWM switching signals required by APF power circuit is obtained by hysteresis current controller. Conclusion: The comparative simulation and experimental results exhibit that performance of APF due to ICC scheme is superior than DCC one.

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Lei, Jiaxing, Chaofan Wei i Shuang Feng. "Input Disturbance Suppression for Unidirectional Matrix Converter with a Stability-Enhancing Modulation Scheme". Energies 12, nr 13 (8.07.2019): 2625. http://dx.doi.org/10.3390/en12132625.

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This paper proposes an input voltage disturbance suppression control strategy for the unidirectional matrix converter (UMC) with a new modulation scheme enhancing the stability. In the new scheme, the modulation index is directly, rather than reversely, proportional to the instantaneous amplitude of input filter capacitor voltages. Contrary to traditional schemes, the stability of the UMC with this new scheme is even better with the increase of the transferred active power, which is particularly suitable for applications with sinusoidal and balanced input conditions. As to the disturbed input conditions, the new scheme could introduce low-frequency harmonics into output currents. To address this issue, a feedback control strategy of output current amplitude is further proposed to eliminate the additional harmonics. Stability analysis of a UMC with the proposed modulation scheme and feedback control strategy is presented. Experimental results have verified the validity of the proposed control solution.

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Sun, Zhenxing, Shihua Li, Jiegao Wang, Xinghua Zhang i Xiaohui Mo. "Adaptive composite control method of permanent magnet synchronous motor systems". Transactions of the Institute of Measurement and Control 40, nr 11 (21.09.2017): 3345–57. http://dx.doi.org/10.1177/0142331217719956.

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With the development of digital signal processes, the relative differences of PMSM single loop in control periods between the speed loop and current loops are becoming smaller or even vanishing. Therefore, cascade control schemes seem to be unnecessary. In addition, considering the effects of disturbances and the variety of moments of inertia, this paper proposes a scheme using an adaptive non-cascade control method to design the controller, which merges speed loop and q-axis current loop into one single loop. First, an extended state observer (ESO) is employed to estimate the disturbances of the system. The estimated value is used in the feedforward compensation design to improve the capability of system anti-disturbance. Then, considering the performance degradation caused by inertia change, an adaptive control scheme is developed. By using inertia identification technology, the feedforward compensation gain can be tuned automatically according to the identification value. Several groups of simulations and experiments are carried out and the results demonstrate the effectiveness of the proposed scheme.

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Zhou, Sizhan, Yan Zhang, Zeng Liu, Jinjun Liu i Linyuan Zhou. "Implementation of Cross-Coupling Terms in Proportional-Resonant Current Control Schemes for Improving Current Tracking Performance". IEEE Transactions on Power Electronics 36, nr 11 (listopad 2021): 13248–60. http://dx.doi.org/10.1109/tpel.2021.3080131.

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Yang, Xiaodong, Aijia Chen, Zhisong Wang i Shudong Li. "Cloud Storage Data Access Control Scheme Based on Blockchain and Attribute-Based Encryption". Security and Communication Networks 2022 (11.05.2022): 1–12. http://dx.doi.org/10.1155/2022/2204832.

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Cloud storage is a popular model of the application in various fields, and the security of storage data and access permission have been widely considered. Attribute-based encryption (ABE) provides fine-grained user access control and ensures data confidentiality. However, current ABE access control schemes rely on trusted cloud servers and provide a low level of security. To solve these problems of traditional encryption schemes, we propose a blockchain-based and ABE cloud storage data access control scheme. In this article, blockchain and smart contract technology are the core elements to ensure data integrity and build a decentralized verification method for outsourcing results. This application can minimize the reliance on servers in the cloud environment. Based on the ciphertext-policy ABE algorithm, the proposed scheme supports a hidden access policy to avoid the risk of privacy leakage. In addition, we adopt outsourcing technology and predetected decryption algorithms to reduce the computational overhead of local and outsourced servers. Security analysis and performance evaluation show that our proposed scheme has high computational efficiency and satisfies the condition of indistinguishability under the chosen-ciphertext attacks.

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Ghai, Shilpy, Vijay Kumar i Rohit Vaid. "Dynamic Queue Synchronization for Congestion Control Over Wireless Sensor Networks". Journal of Computational and Theoretical Nanoscience 17, nr 6 (1.06.2020): 2562–74. http://dx.doi.org/10.1166/jctn.2020.8931.

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Congestion control over resource constrained sensor network is a critical challenge and it is also quite hard to fulfill the QoS constraints for end users. In this paper, a dynamic queue synchronization (DQS) scheme is introduced that can alter the data rate dynamically as per the current buffer length. Its performance is compared with existing schemes i.e., Dynamic Round Robin (DRR) and Random Early Discard (RED) using different routing protocols i.e., LEACH/PEGASIS/TEEN under various constraints (Throughput/End-to-End Delay/Routing Load/Energy).

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Wei, Lulu, Daofeng Li i Zhiqiang Liu. "Provable Secure Attribute-Based Proxy Signature Over Lattice Small Integer Solution Problem in Random Oracle Model". Electronics 12, nr 7 (30.03.2023): 1619. http://dx.doi.org/10.3390/electronics12071619.

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Current proxy signature schemes are mostly identity-based proxy signatures that distinguish users by identity. This signature method faces some problems, such as identity information leakage and single access control. Attribute-based proxy signature (ABPS) divides the signer’s identity information into a collection of attributes; thus, users’ identity information can be protected and access control can become fine-grained. With the development of quantum computers, the security of signature schemes based on traditional number theory problems is under threat. Therefore, we construct a new attribute-based proxy signature scheme on a lattice that can resist quantum attacks. This scheme has the properties of both attribute-based signatures and proxy signatures, i.e., fine-grained access control and strong undeniability properties. Moreover, based on the small integer solution problem (SIS), our scheme is provably secure in the random oracle model and protects the proxy signer in the adaptive security model.

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Jastrzębski, Rafał P., Alexander Smirnov i Olli Pyrhönen. "Force Controllers for AMB Systems with Position and Current Feedback". Solid State Phenomena 198 (marzec 2013): 495–500. http://dx.doi.org/10.4028/www.scientific.net/ssp.198.495.

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In this paper, the state-of-the-art AMB controller structure, with an outer centralized position control loop with reference currents and inner current control loops, is replaced with an outer control loop with force references and inner flux control loops. The linearization of the force actuators and different control schemes of the centralized outer control for the radial suspension are considered. The operation of the proposed control under a zero bias is verified by simulations. The proposed control solution can achieve a dynamic performance comparable with that of a controller with the classical bias current.

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Shen, Dawei, Wei Yan, Yuhuai Peng, Yanhua Fu i Qingxu Deng. "Congestion Control and Traffic Scheduling for Collaborative Crowdsourcing in SDN Enabled Mobile Wireless Networks". Wireless Communications and Mobile Computing 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/9821946.

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Currently, a number of crowdsourcing-based mobile applications have been implemented in mobile networks and Internet of Things (IoT), targeted at real-time services and recommendation. The frequent information exchanges and data transmissions in collaborative crowdsourcing are heavily injected into the current communication networks, which poses great challenges for Mobile Wireless Networks (MWN). This paper focuses on the traffic scheduling and load balancing problem in software-defined MWN and designs a hybrid routing forwarding scheme as well as a congestion control algorithm to achieve the feasible solution. The traffic scheduling algorithm first sorts the tasks in an ascending order depending on the amount of tasks and then solves it using a greedy scheme. In the proposed congestion control scheme, the traffic assignment is first transformed into a multiknapsack problem, and then the Artificial Fish Swarm Algorithm (AFSA) is utilized to solve this problem. Numerical results on practical network topology reveal that, compared with the traditional schemes, the proposed congestion control and traffic scheduling schemes can achieve load balancing, reduce the probability of network congestion, and improve the network throughput.

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Patel, Hardik, i Ankit Shah. "Boundary-Based Hybrid Control Algorithm for Switched Boost Converter Operating in CCM and DCM". International Journal of Electrical and Electronics Research 11, nr 1 (30.03.2023): 213–21. http://dx.doi.org/10.37391/ijeer.110129.

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It is essential to have enhanced efficiency for the DC-DC converters operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM). This requires a hybrid controller designed using pulse width modulation (PWM) and pulse frequency modulation (PFM) schemes. This paper fixates on a boundary-based hybrid control algorithm for the second-order DC-DC converter - the switched boost converter. The proposed algorithm works in PWM control scheme for CCM operation, whereas DCM operation uses PFM control scheme. The boundary conditions are defined by the load current, output voltage, and switching frequency. Here, an attempt is carried out to have the advantages of both the control schemes. The boost converter is represented by the switched system operating in three modes. Violating transition guards condition orchestrates the switching among these modes. A supervisor detects the CCM and DCM operations, and subsequently switches between PWM and PFM control scheme. Extensive circuit-level simulations are carried out in MATLAB to show the efficacy of the suggested algorithm under the fluctuating line, load, and set-point.

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Patel, Arpitkumar J., i Amit V. Sant. "EV charging station with cascaded low-pass filtering scheme-based control of unified power quality conditioner". Clean Energy 6, nr 5 (1.10.2022): 738–61. http://dx.doi.org/10.1093/ce/zkac052.

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Abstract This paper proposes a cascaded low-pass filter (CLPF) scheme for the control of a unified power quality conditioner (UPQC) installed for enhancing the power quality of an electric vehicle (EV) charging station. With the incorporation of UPQC, the EV charging station draws sinusoidal currents at unity power factor and the supply voltage is maintained at the nominal value at the charger input. In the CLPF scheme, the α–β components of the load current are individually processed through a cascade connection of two LPFs to determine the corresponding fundamental orthogonal components. Based on thus determined components, the instantaneous and peak value and phase angle of the fundamental positive sequence component (FPSC) of the load current are computed. Similarly, the corresponding quantities related to the load and supply voltages are also computed with the CLPF scheme. With the computations related to the load current and supply voltage, the unit voltage templates (UVTs), power factor and fundamental active component (FAC) of the load current are calculated. For the control of shunt compensation, reference currents are generated based on the FAC of the load current and UVTs. Alternately, the control of series compensation is employed with the help of UVTs and peak amplitude of the FPSC of the load voltage. The performance of CLPF scheme-based extraction is compared with that of the earlier reported schemes through simulation and experimental studies. The performance comparison reveals a faster dynamic and more accurate steady-state response with the proposed scheme. The performance analysis of the proposed CLPF scheme-based control of a UPQC deployed at the EV charging station for different operating conditions demonstrates station operation with requisite reactive power compensation and mitigation of voltage sag/swell, and prevention of propagation of harmonic and unbalanced currents into the grid. This results in increased reliability of charger operation, energy savings and increased efficiency of the distribution network.

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Han, Yang, Pan Shen, Xin Zhao i Josep M. Guerrero. "Control Strategies for Islanded Microgrid Using Enhanced Hierarchical Control Structure With Multiple Current-Loop Damping Schemes". IEEE Transactions on Smart Grid 8, nr 3 (maj 2017): 1139–53. http://dx.doi.org/10.1109/tsg.2015.2477698.

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Lu, Hua Cai, Ming Jiang, Qi Gong Chen i Li Sheng Wei. "Sensorless Position Control of Surface Permanent Magnet Linear Synchronous Motors". Applied Mechanics and Materials 88-89 (sierpień 2011): 165–69. http://dx.doi.org/10.4028/www.scientific.net/amm.88-89.165.

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In this paper, a novel sensorless position control for a surface permanent magnet linear synchronous motor (SPMLSM) is presented. The position and speed of the SPMLSM drive is obtained through a closed loop observer by only measuring phase voltages and currents. Estimation of speed is done using difference between estimates of the current derivatives in the dq frame, which calculated two different ways: first using a high-gain observer, and then using the motor model. Estimation of the mover position is done through integrating the estimation of speed. The proposed scheme works in a closed loop fashion. It enhances the allowable initial position error; can be used without any physical modification; does not rely on motor saliency and requires no knowledge of the load. Results from numerical simulations and practical implementation are presented to validate the proposed schemes.

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41

Premkumar, Manoharan, Kanagarathinam Karthick i Rayichandran Sowmya. "A Review on Solar PV Based Grid Connected Microinverter Control Schemes and Topologies". International Journal of Renewable Energy Development 7, nr 2 (10.07.2018): 171–82. http://dx.doi.org/10.14710/ijred.7.2.171-182.

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From the last decade, there is an increase in the demand of electricity, this will causing depletion in the fossil fuels which results increase in cost. So the focus is shifted to use of renewable energy sources along with the only utility grid but it is not sufficient to supply the power different loads. To overcome these problems, micro-grid (MG) is introduced and it is powered by renewable distributed generation (DG) systems, such as, micro turbines, fuel cells, PV and wind generation due to the limited fossil fuel. Out of the above sources, solar energy provides extraordinary benefits including environmental friendly, surplus availability and low installation cost due to the advanced technology and mass production. The solar grid connected micro inverters gain lot of intention in past few years due to its simple construction, reliability and endurability. Moreover, the grid connected micro inverter has high reliability and it can operate in abnormal conditions also like variations in voltage and current. The micro-inverter has attracted recent market success due to unique features such as lower installation cost, improved energy harvesting, and improved system efficiency. This article gives detailed review on different topologies for grid connected solar PV micro-inverter and suggests the reliable, suitable and efficient topology for micro-inverter.Article History: Received Dec 16th 2017; Received in revised form May 14th 2018; Accepted June 1st 2018; Available onlineHow to Cite This Article: Premkumar, M., Karthick, K and Sowmya, R. (2018) A Review on Solar PV Based Grid Connected Microinverter Control Schemes and Topologies. Int. Journal of Renewable Energy Development, 7(2), 171-182.https://doi.org/10.14710/ijred.7.2.171-182

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Merabet, Adel. "Advanced Control for Electric Drives: Current Challenges and Future Perspectives". Electronics 9, nr 11 (23.10.2020): 1762. http://dx.doi.org/10.3390/electronics9111762.

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In the Special Issue “Advanced Control for Electric Drives”, the objective is to address a variety of issues related to advances in control techniques for electric drives, implementation challenges, and applications in emerging fields such as electric vehicles, unmanned aerial vehicles, maglev trains and motion applications. This issue includes 15 selected and peer-reviewed articles discussing a wide range of topics, where intelligent control, estimation and observation schemes were applied to electric drives for various applications. Different drives were studied such as induction motors, permanent magnet synchronous motors and brushless direct current motors.

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Kuchar, Martin, Petr Palacky, Daniela Perdukova i Martin Sobek. "Compensation of Torque-Producing Stator Current Error for Vector-Controlled Induction Motor Drives". Energies 15, nr 3 (23.01.2022): 815. http://dx.doi.org/10.3390/en15030815.

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This paper presents a detailed analysis of dynamic properties and accuracy issues of the torque-producing stator current control loop for vector-controlled induction motor drives. In this paper, a necessary mathematical description of vector control of an induction motor is shown with respect to the x-axis and y-axis current control in the rotating reference frame. A derivation of a steady-state error for the torque-producing stator current control scheme with and without a decoupling algorithm is described. The presented derivation and dynamic behavior of both these schemes were extensively tested in the MATLAB-SIMULINK software, considering different values for the moment of inertia. This solution was implemented in a DSC-based induction motor drive using a voltage source inverter to obtain experimental results. Moreover, the advantages of using the presented decoupling block for compensation of the problem are discussed at the end of the paper.

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Yoo, Jeong-Un, i Il-Suek Koh. "Comparison of Linear Iteration Schemes to Improve the Convergence of Iterative Physical Optics for an Impedance Scatterer". Journal of Electromagnetic Engineering and Science 23, nr 1 (31.01.2023): 78–80. http://dx.doi.org/10.26866/jees.2023.1.l.12.

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The conventional iterative physical optics (IPO) method updates the surface current based on the Jacobi iteration scheme, which typically diverges for large objects. To control the convergence property of the IPO method, other iteration schemes, such as Gauss–Seidel and successive over-relaxation, can be used. In this study, we compare the convergence properties of three iteration schemes for scatterings by five scatterers comprising electrically perfect or imperfect conductors modeled with an impedance material. The accuracy of the IPO method is compared with that of the multi-level fast multipole method.

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45

Ledesma, Pablo, i Julio Usaola. "Contribution of Variable-Speed Wind Turbines to Voltage Control". Wind Engineering 26, nr 6 (listopad 2002): 347–58. http://dx.doi.org/10.1260/030952402765173349.

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Variable speed, grid connected, wind turbines open new possibilities for voltage control, because they use electronic converters, which may regulate the reactive power interchange with the grid. This paper proposes two voltage control schemes for variable speed wind turbines with double-fed induction generator. The first scheme acts on the wind-turbine power factor, while the latter acts directly on the converter current. Advantages and drawbacks of both techniques are discussed. Both control techniques have been tested by simulations of a base case, which represent a synchronous generator, a wind farm and a local load, and several disturbances such as the loss of compensator capacitors.

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Nalina, B. S., i V. J. Vijayalakshmi. "Comparison of Current Control Strategies of Shunt Active Power Filter ". Applied Mechanics and Materials 573 (czerwiec 2014): 59–65. http://dx.doi.org/10.4028/www.scientific.net/amm.573.59.

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Nowadays the number of non linear loads in power systems is increasing dramatically. These non linear loads inject harmonic currents and voltage which makes the supply currents non-sinusoidal. These harmonics are eliminated via an active power filter. The reference currents are generated by shunt active filter which is provided to compensate harmonic currents demanded by the load. Different current control strategies are implemented to improve the performance of shunt active power filter. These techniques are useful in making the supply currents sinusoidal. The performance of the current control techniques are different from each other. The %THD can be reduced with the aid of shunt active power filter. In this paper, different current control schemes are analyzed and their outputs are compared to determine the effectiveness. The most effective current controller generates less %THD. The power quality of the system is improved with the reduction of %THD. The different current controllers which are compared in this paper are GA controller and PI-VPI controller.Under analysis, the PI-VPI controller is found to be effective.

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Xu, Zhen Yu, Bing Zhang i Xu Zhang. "Comparison of Feedback Loop Control Schemes for Inverters in Microgrids". Advanced Materials Research 748 (sierpień 2013): 444–48. http://dx.doi.org/10.4028/www.scientific.net/amr.748.444.

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In this paper, two multiple feedback loop control schemes for inverters of distributed generators and energy storage system in a microgrid are described. Both of the droop control method and V/F control method are based on the voltage and the current controllers . A detailed comparison of the simulation results show the advantages and disadvantages of the two methods.

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Li, Zhao, i Shuiyuan Huan. "Multi-Level Attribute-Based Encryption Access Control Scheme for Big Data". MATEC Web of Conferences 173 (2018): 03047. http://dx.doi.org/10.1051/matecconf/201817303047.

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There are many security threats such as data’s confidentiality and privacy protection in the new application scenario of big data processing, and for the problems such as coarse granularity and low sharing capability existing in the current research on big data access control, a new model to support fine-grained access control and flexible attribute change is proposed. Based on CP-ABE method, a multi-level attribute-based encryption scheme is designed to solve fine-grained access control problem. And to solve the problem of attribute revocation, the technique of re-encryption and version number tag is integrated into the scheme. The analysis shows that the proposed scheme can meet the security requirement of access control in big data processing environment, and has an advantage in computational overhead compared with the previous schemes.

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Zhang, Ming, Kaicheng Li, Shunfan He i Jun Wang. "DESIGN AND TEST OF A NEW HIGH-CURRENT ELECTRONIC CURRENT TRANSFORMER WITH A ROGOWSKI COIL". Metrology and Measurement Systems 21, nr 1 (1.03.2014): 121–32. http://dx.doi.org/10.2478/mms-2014-0012.

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Abstract This paper describes the design and test of a new high-current electronic current transformer based on a Rogowski coil. For better performances, electronic current transformers are used to replace conventional electro-magnetic inductive current transformers based on ferromagnetic cores and windings to measure high-current on the high voltage distribution grids. The design of a new high-current electronic current transformer is described in this paper. The principal schemes of the prototype and partial evaluation results are presented. Through relative tests it is known that the prototype has a wide dynamic range and frequency band, and it can allow high accuracy measurements.

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Usama, Muhammad, i Jaehong Kim. "Improved Self-Sensing Speed Control of IPMSM Drive Based on Cascaded Nonlinear Control". Energies 14, nr 8 (15.04.2021): 2205. http://dx.doi.org/10.3390/en14082205.

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This paper presents a nonlinear cascaded control design that has been developed to (1) improve the self-sensing speed control performance of an interior permanent magnet synchronous motor (IPMSM) drive by reducing its speed and torque ripples and its phase current harmonic distortion and (2) attain the maximum torque while utilizing the minimum drive current. The nonlinear cascaded control system consists of two nonlinear controls for the speed and current control loop. A fuzzy logic controller (FLC) is employed for the outer speed control loop to regulate the rotor shaft speed. Model predictive current control (MPCC) is utilized for the inner current control loop to regulate the drive phase currents. The nonlinear equation for the dq reference current is derived to implement the maximum torque per armature (MTPA) control to achieve the maximum torque while using the minimum current values. The model reference adaptive system (MRAS) was employed for the speed self-sensing mechanism. The self-sensing speed control performance of the IPMSM motor drive was compared with that of the traditional cascaded control schemes. The stability of the sensorless mechanism was studied using the pole placement method. The proposed nonlinear cascaded control was verified based on the simulation results. The robustness of the control design was ensured under various loads and in a wide speed range. The dynamic performance of the motor drive is improved while circumventing the need to tune the proportional-integral (PI) controller. The self-sensing speed control performance of the IPMSM drive was enhanced significantly by the designed cascaded control model.

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