Статті в журналах: "On-state voltage"

1

Mohammed, Jamal Abdul-Kareem, Sahar R. Al-Sakini, and Arkan Ahmed Hussein. "Assessment of disturbed voltage supply effects on steady-state performance of an induction motor." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 3 (June 1, 2020): 2259. http://dx.doi.org/10.11591/ijece.v10i3.pp2259-2270.

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An electric power system is usually exposed to unequal and variable loads across its three phases, which leads to voltage unbalance and variation, making the three-phase voltages asymmetrical in nature at the distribution end. This problem is clearly evident in Iraq country, particularly with regard to the fluctuating voltage levels of electricity distribution during peak hours. Providing a three-phase motor with asymmetric voltages is badly affecting its working performance. Estimating the performance of this motor at steady-state under different conditions of voltage disturbances is investigated in this paper through Matlab simulation using Symmetrical component approach. The motor performance represented by active and reactive input powers, output put power, developed torque, power losses, efficiency and power factor is analyzed under full load conditions. Also, the steady-state power losses- and torque-slip characteristics at certain degrees of voltage unbalance have been calculated and plotted

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2

Kuo, Ting-Tzu, Ying-Chung Chen, Ting-Chang Chang, Mao-Chou Tai, Yu-Xuan Wang, Kuan-Hsu Chen, Yu-Shan Lin, et al. "Analysis of abnormal threshold voltage shift induced by surface donor state in GaN HEMT on SiC substrate." Applied Physics Letters 120, no. 23 (June 6, 2022): 233505. http://dx.doi.org/10.1063/5.0090133.

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This study investigates the recovery behavior of GaN high-electron mobility transistors on SiC substrates under different hot-carrier stress conditions. The threshold voltage shifts positively due to hot electron trapping at the buffer layer under hot-carrier stress. However, the recovery between semi-on (Vt < VG < 0 V) hot-carrier stress and on-state (VG > 0 V) carrier stress is significantly different. This phenomenon is systematically discussed in terms of the applied gate voltage under stress condition, which affects the occupation of the surface donor states. After applying a semi-on hot-carrier stress, the threshold voltage continues to shift positively after relaxing the applied voltage. In contrast, the threshold voltage exponentially recovers after applying an on-state hot-carrier stress. Silvaco technology computer aided design (TCAD) simulation was performed to verify the effect of the surface donor state on the threshold voltages. Since switching between on-state and off-state in RF-applications includes both conditions, we suggest that the surface donor states are crucial to determine the failure of devices.

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3

Lebedev, V., V. Zhukov, and A. Yablokov. "Analysing the thermal state of voltage transformer based on resistive voltage divider." IOP Conference Series: Materials Science and Engineering 93 (October 13, 2015): 012020. http://dx.doi.org/10.1088/1757-899x/93/1/012020.

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4

Deng, Yaping, Lu Wang, Hao Jia, Xiaohui Zhang, and Xiangqian Tong. "A Deep Learning Method Based on Bidirectional WaveNet for Voltage Sag State Estimation via Limited Monitors in Power System." Energies 15, no. 6 (March 21, 2022): 2273. http://dx.doi.org/10.3390/en15062273.

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Voltage sag state estimation on the basis of a limited number of installed monitors is essential to dividing the responsibility for the voltage sag and taking corresponding measurements for improvement in voltage quality. Therefore, a deep learning methodology via bidirectional WaveNet for the voltage sag state estimation is proposed in this paper. The presented method can simultaneously estimate voltage sag state at non-monitored buses via limited monitors. Especially, the proposed deep learning method using the bidirectional WaveNet is designed to explore the long-term and long-range temporal dependencies in both the forward and backward directions. In this way, only by using original measured voltages through monitors, high accuracy for voltage sag state estimation can be achieved without restructured or redesign of the raw monitored data. An excellent advantage of the presented algorithm is that it can be implemented without system parameters or operating conditions or any other prior information. The presented methodology was verified by the IEEE 30-bus benchmark system. The experimental results illustrated that the accuracy of the voltage sag state estimation results was over 99.83%. Furthermore, a comparison among different models, including the bidirectional GRU-based model, one-way WaveNet-based model, and bidirectional WaveNet-based model, was also conducted. The results illustrated that the proposed bidirectional WaveNet-based model achieved the highest accuracy and quickest convergence speed.

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5

Kong, Qingyi, Mingxing Du, Ziwei Ouyang, Kexin Wei, and William Hurley. "A Model of the On-State Voltage across IGBT Modules Based on Physical Structure and Conduction Mechanisms." Energies 12, no. 5 (March 5, 2019): 851. http://dx.doi.org/10.3390/en12050851.

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The on-state voltage is an important electrical parameter of insulated gate bipolar transistor (IGBT) modules. Due to limits in instrumentation and methods, it is difficult to ensure accurate measurements of the on-state voltage in practical working conditions. Based on the physical structure and conduction mechanism of the IGBT module, this paper models the on-state voltage and gives a detailed method for extracting the on-state voltage. Experiments not only demonstrate the feasibility of the on-state voltage separation method but also suggest a method for measuring and extracting the model parameters. Furthermore, on-state voltage measurements and simulation results certified the accuracy of this method.

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6

Lian, Han. "The State Monitoring Method of Electronic Voltage Transformer Based on L-M Algorithm." Journal of Advanced Computational Intelligence and Intelligent Informatics 23, no. 3 (May 20, 2019): 385–89. http://dx.doi.org/10.20965/jaciii.2019.p0385.

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In the traditional method of monitoring the state of electronic voltage transformer, there are problems of large monitoring error and weak robustness. Therefore, a new state monitoring method of electronic voltage transformer based on L-M algorithm is proposed. The relationship between input voltage and output voltage of capacitor voltage divider in electronic voltage transformer is obtained by using Laplasse transform. The transfer function model of electronic voltage transformer is constructed based on the relationship result and L-M algorithm. The transfer function model is used to analyze the frequency characteristics of the electronic voltage transformer and the range of normal measurement frequency, and then the partial pressure ratio of the electronic voltage transformer under the high frequency condition is derived. On this basis, by calculating the over voltage amplitude on the two sides of acquisition card in the electronic voltage transformer, the capacitance value between the two adjacent coaxial cylindrical cylinders of the capacitance divider in the electronic voltage transformer is obtained, thus the monitoring of the state of the electronic voltage transformer is completed. The experimental results show that the proposed method has low detection error and strong robustness, and can effectively improve the reliability of electronic voltage transformer.

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7

Golub, Irina, and Evgeny Boloev. "Methods of linear and nonlinear state estimation of distribution network." E3S Web of Conferences 58 (2018): 03010. http://dx.doi.org/10.1051/e3sconf/20185803010.

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The paper proposes a new approach to the problem of state estimation of a low voltage distribution network by the measurements coming from smart meters. The problem of nonlinear state estimation based on the measurements of nodal powers and voltages is solved by the method of simple iteration which minimizes the quadratic function of the residues with and without the consideration of the constraint on the zero currents in the transit nodes. The same algorithms are proposed to use for linear state estimation based on the measurements of nodal currents and voltages. The effectiveness of the proposed methods for linear and nonlinear state estimation is illustrated on the 33 nodes three-phase four-wire low-voltage network.

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8

Popovic, Dragan, and Milos Stojkovic. "An efficient generator voltages control method for improvement of voltage-reactive states in transmission network." Facta universitatis - series: Electronics and Energetics 21, no. 2 (2008): 221–32. http://dx.doi.org/10.2298/fuee0802221p.

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This paper presents an efficient generator voltage control method for improvement of voltage-reactive states in transmission networks. This method enables fast and sufficiently accurate definition of generator voltages to realize the favorable voltage-reactive states. In peak load state, this generator voltage control is made to improve the economic operation, e.g. to reduce the active and reactive power losses or to enlarge the reactive reserve of generators. In minimum load state, this voltage control is made to reduce the generator under-excitation states, or to make the favorable redistribution of those under-excitation states. The verification of method proposed is made in context of steady-state and dynamic simulation models, on the examples of realized and perspective states of Serbian transmission network, in own wide environment. .

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9

Costa Nascimento, Priscila, Michel Girotto de Oliveira, and José Carlos M. Vieira. "Investigation on Using Low Voltage Automatic Regulation to Minimize the Impacts of Charging Plug-in Electric Vehicles in Distribution Systems." Renewable Energy and Power Quality Journal 19 (September 2021): 85–90. http://dx.doi.org/10.24084/repqj19.222.

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The growth of micro and mini distributed generation and, more recently, the use of electric energy storage systems and the incentives for electric mobility are important examples of the transformations that distribution networks have been going through. In this context, this paper firstly presents the impacts of uncoordinated plug-in electric vehicles (PEVs) charging in a real Brazilian distribution system. Four scenarios were elaborated with different PEVs penetration levels and the results show increased voltage unbalance, system losses, and violations of the steady-state voltage limits, even in the presence of an automatic voltage regulator installed in the medium voltage network. Then, as the main contribution, the potential usage of automatic voltage regulation at the low voltage network was investigated to minimize the negative impacts of uncontrolled PEV charging on distribution system steady-state operation. It is important to highlight that this is not a common practice of utilities in Brazil. The obtained results showed that regulating the voltage at the low voltage side could be an effective solution to keep the voltages within statutory limits.

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10

Horrigan, Frank T., and Richard W. Aldrich. "Coupling between Voltage Sensor Activation, Ca2+ Binding and Channel Opening in Large Conductance (BK) Potassium Channels." Journal of General Physiology 120, no. 3 (August 26, 2002): 267–305. http://dx.doi.org/10.1085/jgp.20028605.

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To determine how intracellular Ca2+ and membrane voltage regulate the gating of large conductance Ca2+-activated K+ (BK) channels, we examined the steady-state and kinetic properties of mSlo1 ionic and gating currents in the presence and absence of Ca2+ over a wide range of voltage. The activation of unliganded mSlo1 channels can be accounted for by allosteric coupling between voltage sensor activation and the closed (C) to open (O) conformational change (Horrigan, F.T., and R.W. Aldrich. 1999. J. Gen. Physiol. 114:305–336; Horrigan, F.T., J. Cui, and R.W. Aldrich. 1999. J. Gen. Physiol. 114:277–304). In 0 Ca2+, the steady-state gating charge-voltage (QSS-V) relationship is shallower and shifted to more negative voltages than the conductance-voltage (GK-V) relationship. Calcium alters the relationship between Q-V and G-V, shifting both to more negative voltages such that they almost superimpose in 70 μM Ca2+. This change reflects a differential effect of Ca2+ on voltage sensor activation and channel opening. Ca2+ has only a small effect on the fast component of ON gating current, indicating that Ca2+ binding has little effect on voltage sensor activation when channels are closed. In contrast, open probability measured at very negative voltages (less than −80 mV) increases more than 1,000-fold in 70 μM Ca2+, demonstrating that Ca2+ increases the C-O equilibrium constant under conditions where voltage sensors are not activated. Thus, Ca2+ binding and voltage sensor activation act almost independently, to enhance channel opening. This dual-allosteric mechanism can reproduce the steady-state behavior of mSlo1 over a wide range of conditions, with the assumption that activation of individual Ca2+ sensors or voltage sensors additively affect the energy of the C-O transition and that a weak interaction between Ca2+ sensors and voltage sensors occurs independent of channel opening. By contrast, macroscopic IK kinetics indicate that Ca2+ and voltage dependencies of C-O transition rates are complex, leading us to propose that the C-O conformational change may be described by a complex energy landscape.

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11

Sosnina, Elena, Aleksey Kralin, Anatoly Asabin, and Evgeny Kryukov. "Medium-Voltage Distribution Network Parameter Optimization Using a Thyristor Voltage Regulator." Energies 15, no. 15 (August 8, 2022): 5756. http://dx.doi.org/10.3390/en15155756.

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The article is devoted to the study of steady-state conditions of a distribution network containing a thyristor voltage regulator. The thyristor voltage regulator (TVR) is a new controlled semiconductor device developed at Nizhny Novgorod State Technical University n.a. R.E. Alekseev (NNSTU). The TVR allows the optimization of the parameters of 6–20 kV distribution networks (currents and voltages) by voltage regulation. An analytical calculation of electromagnetic processes of a distribution network with the TVR has been carried out. The verification of the obtained results has been made using a computer simulation. The dependences of the current and power on additional voltage introduced by the TVR under different voltage regulation modes have been obtained. It has been shown that the use of the TVR enables optimal flow distribution to be ensured over the power transmission lines in proportion to their transfer capability when changing load power and its power factor.

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12

Nguyen, Phuong T., Ian H. Kimball, Kenneth S. Eum, Bruce E. Cohen, Jon T. Sack, and Vladimir Yarov-Yarovoy. "Understanding the State Dependence of Voltage Sensor Toxin Action on Voltage Gated Sodium Channels." Biophysical Journal 108, no. 2 (January 2015): 574a. http://dx.doi.org/10.1016/j.bpj.2014.11.3139.

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13

Guacci, Mattia, Dominik Bortis, and Johann W. Kolar. "On-State Voltage Measurement of Fast Switching Power Semiconductors." CPSS Transactions on Power Electronics and Applications 3, no. 2 (June 2018): 163–76. http://dx.doi.org/10.24295/cpsstpea.2018.00016.

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14

Reddy, P. Chow. "Fuzzy Logic Control on Solid State Servo Voltage Stabilizer." International Journal for Research in Applied Science and Engineering Technology 7, no. 9 (September 30, 2019): 1027–33. http://dx.doi.org/10.22214/ijraset.2019.9147.

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15

AJJARAPU, VENKATARAMANA, and SRINIVASU BATTULA. "EFFECT OF LOAD MODELING ON STEADY STATE VOLTAGE STABILITY." Electric Machines & Power Systems 23, no. 5 (September 1995): 501–14. http://dx.doi.org/10.1080/07313569508955639.

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16

He, Yong Song, Xiao Sheng Wu, Fu Zheng, Wen Yuan Chen, Wei Ping Zhang, Feng Cui, and Wu Liu. "Study on Driving Technology of Piezoelectric Solid-State Micro Gyroscope." Applied Mechanics and Materials 278-280 (January 2013): 817–20. http://dx.doi.org/10.4028/www.scientific.net/amm.278-280.817.

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In order to compensate the noise brought by piezoelectric gyroscope or external environment and track the resonance frequency, Closed Loop Driving Circuit (CLDC) of piezoelectric solid-state micro gyroscope is proposted in the paper which will stabilize the driving voltage value and keep the resonance frequency tracked. CLDC mainly contains Phase Lock Loop (PLL) circuit, Automatic Gain Circuit (AGC). Experimental results show that the fluctuation of reference voltage is within ±7mv, while the fluctuation of reference voltage in Open Loop Driving Circuit (OLDC) without noise compensation is ±23mv. The frequency of CLDC drifts within 0.03 kHz with the resonance frequency of 357.9 kHz while the OLDC can’t track any drifting.

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17

Liu, Yanjuan, Dezhen Jia, and Junpeng Fang. "On-State Voltage Drop Analytical Model for 4H-SiC Trench IGBTs." Crystals 12, no. 5 (April 22, 2022): 582. http://dx.doi.org/10.3390/cryst12050582.

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In this paper, a model for the forward voltage drop in a 4H-SiC trench IGBT is developed. The analytical model is based on the 4H-SiC trench MOSFET voltage model and the hole-carrier concentration profile in the N-drift region for a conventional 4H-SiC trench IGBT. Moreover, an on-state voltage drop analytical model is validated using a 2D numerical simulation, and the simulation results demonstrate that there is good agreement between the ATLAS simulation data and analytic solutions.

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18

Popova, Natalya, Lyudmila Erygina, Elena Nikonenko, and Mazhin Skakov. "Influence of electrolytic plasma nitriding mode on structural phase state of pearlitic steel." MATEC Web of Conferences 143 (2018): 03004. http://dx.doi.org/10.1051/matecconf/201814303004.

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The paper describes results of studies of phase transitions in structural phase state occurring in the type 0.34C-1Cr-1Ni-1Mo-Fe steel under electrolytic plasma nitriding in nitrogen-containing water solution. The nitriding voltages considered in the given study were 550 and 600 V. The research was conducted by means of X-ray diffraction electron microscopy. The specimens were studied in two states : 1) before modification (original state) and 2) after nitriding in the surface layer of the specimen. The study was conducted on thin foils. It was found that nitriding lead to significant changes in the structure of steel, namely in its phase composition and in the number of existing phases. In the original state the structure of steel was given as lamellar pearlite, ferritic carbide mix and fragmented ferrite. After 550 V nitriding it was lath martensite, plates of α-phase, with colonies of thin parallel plates of γ-phase and coarse grains of α-phase, containing γ-phase grains which were different in size and shape and were various-directional. Increase in nitriding voltage up to 600 V lead to change in the structure given as a lamellar non-fragmented pearlite and fragmented ferrite. The original state was marked by presence of particles of M3C cementite, after nitriding irrespective of the voltage it had the particles of M3C alloyed cementite, Fe3Mo3N nitride and Cr2C0.61N0.39 carbonitride. The sizes, volume fractions and locations of particles were dependent on nitriding voltage.

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19

Liu, Chih Yi, Yu Chen Li, Chun Hung Lai, and Shih Kun Liu. "Influence of SiO₂ Layer on Resistive Switching Properties of SiO₂/Cu_XO Stack Structure." Materials Science Forum 687 (June 2011): 106–11. http://dx.doi.org/10.4028/www.scientific.net/msf.687.106.

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CuxO and SiO2thin films were deposited using a radio-frequency magnetron sputter on Pt/Ti/SiO2/Si substrates to form SiO2/CuxO/Pt and CuxO/Pt structures. The current-voltage characteristics were measured by DC voltage sweeping using a tungsten (W) probe. The two structures needed a large voltage to initiate the first resistive switching; this sweep was called the forming process. Afterwards, the resistances of the two structures could be switched reversibly between the low-resistance-state (LRS) and high-resistance-state (HRS) by applying a DC voltage. The conduction mechanisms of the LRS and the HRS were dominated by Ohmic conduction. Structures with non-destructive readout characteristics and long retention time were suitable for use in non-volatile memory. The difference between resistive switching in W-probe/SiO2/CuxO/Pt and W-probe/CuxO/Pt structures was investigated. The additional SiO2layer decreased the switching voltages and currents; this should be due to the presence of pinholes within the SiO2layer. The influence of SiO2thickness on the resistive switching characteristics was also investigated. The switching voltages and currents, except the forming voltage, decreased as the thickness of SiO2decreased. The conducting filament model with a thermochemical reaction was suggested to best explain the resistive switching behavior that was observed.

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20

Zhang, Huaqin, Jichao Hong, Zhezhe Wang, and Guodong Wu. "State-Partial Accurate Voltage Fault Prognosis for Lithium-Ion Batteries Based on Self-Attention Networks." Energies 15, no. 22 (November 12, 2022): 8458. http://dx.doi.org/10.3390/en15228458.

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Multiple faults in new energy vehicle batteries can be diagnosed using voltage. To find voltage fault information in advance and reduce battery safety risk, a state-partitioned voltage fault prognosis method based on the self-attention network is proposed. The voltage data are divided into three parts with typical characteristics according to the charging voltage curve trends under different charge states. Subsequently, a voltage prediction model based on the self-attention network is trained separately with each part of the data. The voltage fault prognosis is realized using the threshold method. The effectiveness of the method is verified using real operating data of electric vehicles (EVs). The effects of different batch sizes and window sizes on model training are analyzed, and the optimized hyperparameters are used to train the voltage prediction model. The average error of predicted voltage is less than 2 mV. Finally, the superiority and robustness of the method are verified.

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21

Wang, Caroline K., Shawn M. Lamothe, Alice W. Wang, Runying Y. Yang, and Harley T. Kurata. "Pore- and voltage sensor–targeted KCNQ openers have distinct state-dependent actions." Journal of General Physiology 150, no. 12 (October 29, 2018): 1722–34. http://dx.doi.org/10.1085/jgp.201812070.

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Ion channels encoded by KCNQ2-5 generate a prominent K+ conductance in the central nervous system, referred to as the M current, which is controlled by membrane voltage and PIP2. The KCNQ2-5 voltage-gated potassium channels are targeted by a variety of activating compounds that cause negative shifts in the voltage dependence of activation. The underlying pharmacology of these effects is of growing interest because of possible clinical applications. Recent studies have revealed multiple binding sites and mechanisms of action of KCNQ activators. For example, retigabine targets the pore domain, but several compounds have been shown to influence the voltage-sensing domain. An important unexplored feature of these compounds is the influence of channel gating on drug binding or effects. In the present study, we compare the state-dependent actions of retigabine and ICA-069673 (ICA73, a voltage sensor–targeted activator). We assess drug binding to preopen states by applying drugs to homomeric KCNQ2 channels at different holding voltages, demonstrating little or no association of ICA73 with resting states. Using rapid solution switching, we also demonstrate that the rate of onset of ICA73 correlates with the voltage dependence of channel activation. Retigabine actions differ significantly, with prominent drug effects seen at very negative holding voltages and distinct voltage dependences of drug binding versus channel activation. Using similar approaches, we investigate the mechanistic basis for attenuation of ICA73 actions by the voltage-sensing domain mutation KCNQ2[A181P]. Our findings demonstrate different state-dependent actions of pore- versus voltage sensor–targeted KCNQ channel activators, which highlight that subtypes of this drug class operate with distinct mechanisms.

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22

Alias, Nurul Ezaila, Anil Kumar, Takuya Saraya, and Toshiro Hiramoto. "Threshold voltage shifts and their variability behaviors in p-channel FETs by high voltage on-state and off-state stress." Japanese Journal of Applied Physics 53, no. 8S1 (July 3, 2014): 08LC01. http://dx.doi.org/10.7567/jjap.53.08lc01.

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23

Horrigan, Frank T., and Zhongming Ma. "Mg2+ Enhances Voltage Sensor/Gate Coupling in BK Channels." Journal of General Physiology 131, no. 1 (December 31, 2007): 13–32. http://dx.doi.org/10.1085/jgp.200709877.

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BK (Slo1) potassium channels are activated by millimolar intracellular Mg2+ as well as micromolar Ca2+ and membrane depolarization. Mg2+ and Ca2+ act in an approximately additive manner at different binding sites to shift the conductance–voltage (GK-V) relation, suggesting that these ligands might work through functionally similar but independent mechanisms. However, we find that the mechanism of Mg2+ action is highly dependent on voltage sensor activation and therefore differs fundamentally from that of Ca2+. Evidence that Ca2+ acts independently of voltage sensor activation includes an ability to increase open probability (PO) at extreme negative voltages where voltage sensors are in the resting state; 2 μM Ca2+ increases PO more than 15-fold at −120 mV. However 10 mM Mg2+, which has an effect on the GK-V relation similar to 2 μM Ca2+, has no detectable effect on PO when voltage sensors are in the resting state. Gating currents are only slightly altered by Mg2+ when channels are closed, indicating that Mg2+ does not act merely to promote voltage sensor activation. Indeed, channel opening is facilitated in a voltage-independent manner by Mg2+ in a mutant (R210C) whose voltage sensors are constitutively activated. Thus, 10 mM Mg2+ increases PO only when voltage sensors are activated, effectively strengthening the allosteric coupling of voltage sensor activation to channel opening. Increasing Mg2+ from 10 to 100 mM, to occupy very low affinity binding sites, has additional effects on gating that more closely resemble those of Ca2+. The effects of Mg2+ on steady-state activation and IK kinetics are discussed in terms of an allosteric gating scheme and the state-dependent interactions between Mg2+ and voltage sensor that may underlie this mechanism.

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24

Veleba, Jan, and Tomáš Nestorovič. "On Steady-State Voltage Stability Analysis Performance in MATLAB Environment." International Journal of Energy 15 (November 21, 2021): 73–79. http://dx.doi.org/10.46300/91010.2021.15.11.

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Nowadays, electric power systems have been often operated close to their limits due to increased electric power consumptions, vast installments of renewable power sources and deliberated power market policies. This poses a serious threat to stable network operation and control. Therefore, voltage stability is currently one of key topics worldwide for preventing related black-out and islanding scenarios. In this paper, modelling and simulations of steady-state voltage stability problems in MATLAB environment are performed using author-developed computational tool implementing both conventional and more advanced numerical approaches. Their performance is compared with Simulink-based library Power System Analysis Toolbox (PSAT) in terms of solution accuracy, CPU time, and possible limitations. Their use for both real-time and off-line monitoring and assessment of system's voltage stability are also discussed.

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25

Lin, Peng, Peng Jin, Jichao Hong, and Zhenpo Wang. "Battery voltage and state of power prediction based on an improved novel polarization voltage model." Energy Reports 6 (November 2020): 2299–308. http://dx.doi.org/10.1016/j.egyr.2020.08.014.

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26

Lee, Seung Min, Hyun Jun Jang, and Jong Tae Park. "Comparative Study on Off-State Breakdown Characteristics in Nanowire Junctionless and Inversion Mode Multiple Gate MOSFET." Advanced Materials Research 684 (April 2013): 295–98. http://dx.doi.org/10.4028/www.scientific.net/amr.684.295.

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A comparative study on off-state breakdown characteristics in nanowire JL and IM multiple gate MOSFETs has been performed for different gate bias voltages and fin widths. In order to understand the drain breakdown mechanism with different transistor structures, the device was simulated using the 3-dimensional ATLAS software. The band-to-band tunneling current and the gate-induced-drain-leakage current trigger the off-state breakdown in JL transistor and IM transistor, respectively. From experiment and simulation, the off-state breakdown voltage is lower in JL transistor than in IM transistor. As the gate is biased more negatively, the off-state breakdown voltages are increased in JL and IM transistors.

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27

Yun, Chun-gi, and Younghoon Cho. "Active Hybrid Solid State Transformer Based on Multi-Level Converter Using SiC MOSFET." Energies 12, no. 1 (December 26, 2018): 66. http://dx.doi.org/10.3390/en12010066.

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As the types of loads have been diversified and demand has increased, conventional distribution transformers are difficult to maintain the constant voltage against voltage drop along with distance, grid voltage swell/sag, and various loads. Also, it is hard to control the power flow when connecting renewable energy sources. Active hybrid solid state transformer (AHSST) is application to keep the voltage and power quality. AHSST is a system that combines conventional distribution transformer and converter. Accordingly, it can be applied directly to distribution infrastructure and it has both the advantages of solid state transformer (SST) and conventional transformer. AHSST is capable of active voltage and current control and power factor control. It has a simpler structure than SST and it can perform the same performance with the lower rating converter. This paper presents two stage AHSST system based on multi-level converter. The converter is composed of the back-to-back converter using silicon carbide (SiC) metal-oxide semiconductor field effect transistor (MOSFET). Proposed system has a wider voltage and power flow control range, lower filter size, and simpler control sequence than existing AHSST systems. The performance of the proposed system was verified by prototype system experiments.

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Khediri, Abdelkrim, Abbasia Talbi, Abdelatif Jaouad, Hassan Maher, and Ali Soltani. "Impact of III-Nitride/Si Interface Preconditioning on Breakdown Voltage in GaN-on-Silicon HEMT." Micromachines 12, no. 11 (October 21, 2021): 1284. http://dx.doi.org/10.3390/mi12111284.

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In this paper, an AIGaN/GaN metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT) device is realized. The device shows normal ON characteristics with a maximum current of 570 mA/mm at a gate-to-source voltage of 3 V, an on-state resistance of 7.3 Ω·mm and breakdown voltage of 500 V. The device has been modeled using numerical simulations to reproduce output and transfer characteristics. We identify, via experimental results and TCAD simulations, the main physical mechanisms responsible for the premature breakdown. The contribution of the AlN/Silicon substrate interface to the premature off-state breakdown is pointed out. Vertical leakage in lateral GaN devices significantly contributes to the off-state breakdown at high blocking voltages. The parasitic current path leads to premature breakdown before the appearance of avalanche or dielectric breakdown. A comparative study between a MOS-HEMT GaN on a silicon substrate with and without a SiNx interlayer at the AlN/Silicon substrate interface is presented here. We show that it is possible to increase the breakdown voltages of the fabricated transistors on a silicon substrate using SiNx interlayer.

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He, Guofeng, Shicheng Zheng, Yanfei Dong, Guojiao Li, and Wenjie Zhang. "Model Predictive Voltage Control of Uninterruptible Power Supply Based on Extended-State Observer." Energies 15, no. 15 (July 28, 2022): 5489. http://dx.doi.org/10.3390/en15155489.

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Finite-set model predictive controls have been widely used in inverter control because of the flexible target control and no need of a modulation unit. However, the mismatching of prediction model parameters produces prediction errors, resulting in a significant decline in the performance of finite-set model predictive controls. Aiming at the problem of model parameter mismatch, an extended-state observer was proposed to accurately estimate the disturbance of the system in this paper, and the obtained disturbance value was added to a finite-set model predictive control controller to compensate for the prediction error and achieve parameter robustness. By constructing a prediction model of the inverter output voltage in αβ coordinates, all the possible output voltage values were predicted by using different voltage vectors and system measurement values. A set of voltage vectors that minimized the cost function was selected, and its corresponding switching state was applied to the inverter in the next sampling period to achieve control of the output voltage quality. Both the simulation and experimental results showed that the finite-set model predictive voltage control method based on the extended-state observer can estimate the total disturbance quickly and accurately, suppress the influence of capacitance parameter disturbance, and improve the control effect of an inverter.

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Zhao, Zhennan, Shanlu Zhang, Lei Li, Shengfang Fan, and Cheng Wang. "Digital Implementation of LCC Resonant Converters for X-ray Generator with Optimal Trajectory Startup Control." World Electric Vehicle Journal 13, no. 5 (April 19, 2022): 71. http://dx.doi.org/10.3390/wevj13050071.

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High voltage LCC resonant converters have been widely used in X-ray imaging systems in automobile nondestructive testing (NDT) applications. Low ripple voltage waveforms with fast-rising time under no-overshoot response are required for safety in such applications. The optimal state trajectory control (OTC) based on the state plane model is one of the most effective control methods to optimize transient response. Dynamic variations of the resonant voltages/currents are described as corresponding trajectories on the state plane. The transient relations can be determined by evaluating the geometric relationships of the trajectories. However, the LCC resonant converter has more state variables, resulting in more complex calculations that make the state trajectory control challenging. Furthermore, the startup duration is the most demanding process of the state trajectory control. In this paper, a digital implementation based on a hybrid controller built in a field-programmable gate array (FPGA) is proposed for LCC resonant converters with optimal trajectory startup control. A coordinated linear compensator is employed to control the switching frequency during steady-state conditions, hence eliminating the steady-state error. The experimental results were conducted on a 140-kV/42-kW LCC resonant converter for an X-ray generator. It achieves a short rising time of output voltage with no additional current or voltage stress in the resonant tank during startup compared to the conventional digital implementation control.

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31

Milojković, Jelena, Vančo Litovski, and Simon Le Blond. "Low-Voltage Circuit Breakers Based on WBG Solid-State Devices." Journal of Circuits, Systems and Computers 27, no. 02 (September 11, 2017): 1850020. http://dx.doi.org/10.1142/s0218126618500202.

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Conventional circuit breakers suffer from two main deficiencies: they are slow to operate and develop an electrical arc. These may be overcome by using solid-state switches which in turn introduce other problems, most significantly power dissipated while in the on-state. Nevertheless, a number of solid-state devices are candidates for implementation as low-voltage circuit breakers and there are several options based on the semiconductor material that may function as high-power switches. This paper presents a unique, extensive and systematic evaluation of these options. Voltage-controlled devices are selected due to the simplicity of the controlling circuit and their resilience to [Formula: see text]/[Formula: see text]-induced switching. Properties of fully solid-state circuit breakers are established and systematic comparisons are made among switches built of silicon and other wide bandgap (WBG) devices such as SiC MOS and GaN HEMT transistors. Using SPICE simulation it is shown that solid-state circuit breakers (SSCBs) based on WBG devices exhibit superior characteristics compared with silicon devices, with faster switching and higher voltage and current ratings. Hybrid circuit breakers, combining both conventional and solid-state switches, are discussed too and a new design circuit is simulated and compared to both conventional and fully solid-state designs.

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32

Chen, Shiying, Shengchang Ji, Liang Pan, Chenshuo Liu, and Lingyu Zhu. "An ON-State Voltage Calculation Scheme of MMC Submodule IGBT." IEEE Transactions on Power Electronics 34, no. 8 (August 2019): 7996–8007. http://dx.doi.org/10.1109/tpel.2018.2879995.

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33

Liu, Yan-juan, Ying Wang, Cheng-hao Yu, and Fei-Cao. "4H-SiC trench IGBT with lower on-state voltage drop." Superlattices and Microstructures 103 (March 2017): 56–63. http://dx.doi.org/10.1016/j.spmi.2016.11.036.

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34

Rakpenthai, Chawasak, and Sermsak Uatrongjit. "A new hybrid state estimation based on pseudo-voltage measurements." IEEJ Transactions on Electrical and Electronic Engineering 10 (October 2015): S19—S27. http://dx.doi.org/10.1002/tee.22160.

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35

Rakpenthai, Chawasak, and Sermsak Uatrongjit. "A robust WLAV state estimation based on pseudo‐voltage measurements." IEEJ Transactions on Electrical and Electronic Engineering 15, no. 6 (April 14, 2020): 854–62. http://dx.doi.org/10.1002/tee.23127.

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36

Wang, Xiaozhe, and Hsiao-Dong Chiang. "Numerical investigations on quasi steady-state model for voltage stability." International Transactions on Electrical Energy Systems 24, no. 11 (January 16, 2014): 1586–99. http://dx.doi.org/10.1002/etep.1870.

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37

Popovic, Dragan, and Milos Stojkovic. "Voltage-reactive states on interconnected lines according to the generator voltages control in real-time." Facta universitatis - series: Electronics and Energetics 22, no. 3 (2009): 361–69. http://dx.doi.org/10.2298/fuee0903361p.

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This papers presents the possibility effects of application in real-time an advanced method for fast and sufficiently accurate definition of generator voltages to realize the favorable voltage-reactive states of electric power interconnection. The application in real-time will be realized by use the results of state estimation, which is the part of the new SCADA/EMS system in NDC Elektromreza Srbije. The special part of method developed is the possibility to make the direct connection between the values of generator voltages and voltage-reactive states on interconnected lines. The verification of method proposed is made, on the examples of perspective states of Serbian transmission network, in own wide environment. .

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38

Cao, Peng, Wei Bao, and Jingjing Guo. "An Accurate and Efficient Timing Prediction Framework for Wide Supply Voltage Design Based on Learning Method." Electronics 9, no. 4 (March 30, 2020): 580. http://dx.doi.org/10.3390/electronics9040580.

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The wide voltage design methodology has been widely employed in the state-of-the-art circuit design with the advantage of remarkable power reduction and energy efficiency enhancement. However, the timing verification issue for multiple PVT (process–voltage–temperature) corners rises due to unacceptable analysis effort increase for multiple supply voltage nodes. Moreover, the foundry-provided timing libraries in the traditional STA (static timing analysis) approach are only available for the nominal supply voltage with limited voltage scaling, which cannot support timing verification for low voltages down to near- or sub-threshold voltages. In this paper, a learning-based approach for wide voltage design is proposed where feature engineering is performed to enhance the correlation among PVT corners based on a dilated CNN (convolutional neural network) model, and an ensemble model is utilized with two-layer stacking to improve timing prediction accuracy. The proposed method was verified with a commercial RISC (reduced instruction set computer) core under the supply voltage nodes ranging from 0.5 V to 0.9 V. Experimental results demonstrate that the prediction error is limited by 4.9% and 7.9%, respectively, within and across process corners for various working temperatures, which achieves up to 4.4× and 3.9× precision enhancement compared with related learning-based methods.

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39

Chen, Chaobo, Ying Yang, Binbin Zhang, and Song Gao. "The Diagnostic Method for Open-Circuit Faults in Inverters Based on Extended State Observer." Mathematical Problems in Engineering 2021 (April 26, 2021): 1–11. http://dx.doi.org/10.1155/2021/5526173.

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To reduce the influence of unknown disturbance on open-circuit fault diagnosis of inverters in the motor drive system, an open-circuit fault diagnosis method, which is based on extended state observer, is proposed for inverters. A mixed logic dynamic model of the inverters is established by analyzing the current flow path when the system works normally and there are open-circuit faults. A voltage extended state observer is designed for the mixed logic dynamic model. The open-circuit faults are detected according to the phase voltage residual between the observed voltage and the actual voltage. The position of the faulty switches is determined by querying the voltage residual information table. Finally, the simulation results show that the method can effectively reduce the influence of the unknown interference on the inverter faults diagnosis, improve the fault diagnosis rate, and verify the effectiveness and feasibility of the method.

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40

Thomson, Andrew S., and Brad S. Rothberg. "Voltage-dependent inactivation gating at the selectivity filter of the MthK K+ channel." Journal of General Physiology 136, no. 5 (October 11, 2010): 569–79. http://dx.doi.org/10.1085/jgp.201010507.

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Voltage-dependent K+ channels can undergo a gating process known as C-type inactivation, which involves entry into a nonconducting state through conformational changes near the channel’s selectivity filter. C-type inactivation may involve movements of transmembrane voltage sensor domains, although the mechanisms underlying this form of inactivation may be heterogeneous and are often unclear. Here, we report on a form of voltage-dependent inactivation gating observed in MthK, a prokaryotic K+ channel that lacks a canonical voltage sensor and may thus provide a reduced system to inform on mechanism. In single-channel recordings, we observe that Po decreases with depolarization, with a half-maximal voltage of 96 ± 3 mV. This gating is kinetically distinct from blockade by internal Ca2+ or Ba2+, suggesting that it may arise from an intrinsic inactivation mechanism. Inactivation gating was shifted toward more positive voltages by increasing external [K+] (47 mV per 10-fold increase in [K+]), suggesting that K+ binding at the extracellular side of the channel stabilizes the open-conductive state. The open-conductive state was stabilized by other external cations, and selectivity of the stabilizing site followed the sequence: K+ ≈ Rb+ > Cs+ > Na+ > Li+ ≈ NMG+. Selectivity of the stabilizing site is weaker than that of sites that determine permeability of these ions, suggesting that the site may lie toward the external end of the MthK selectivity filter. We could describe MthK gating over a wide range of positive voltages and external [K+] using kinetic schemes in which the open-conductive state is stabilized by K+ binding to a site that is not deep within the electric field, with the voltage dependence of inactivation arising from both voltage-dependent K+ dissociation and transitions between nonconducting (inactivated) states. These results provide a quantitative working hypothesis for voltage-dependent, K+-sensitive inactivation gating, a property that may be common to other K+ channels.

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41

Sundaresan, Siddarth G., Charles Sturdevant, Madhuri Marripelly, Eric Lieser, and Ranbir Singh. "12.9 kV SiC PiN Diodes with Low On-State Drops and High Carrier Lifetimes." Materials Science Forum 717-720 (May 2012): 949–52. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.949.

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Sharp avalanche breakdown voltages of 12.9 kV are measured on PiN rectifiers fabricated on 100 µm thick, 3 x 1014 cm-3 doped n- epilayers grown on n+ 4H-SiC substrates. This equates to a record high 129 V/µm for a > 10 kV device. Optimized epilayer, device design and processing of the SiC PiN rectifiers result in a > 60% blocking yield at 10 kV, ultra-low on-state voltage drop and differential on-resistance of 3.75 V and 3.3 mΩ-cm2 at 100 A/cm2 respectively. Open circuit voltage decay (OCVD) measured carrier lifetimes in the range of 2-4 µs are obtained at room temperature, which increase to a record high 14 µs at 225 °C. Excellent stability of the forward bias characteristics within 10 mV is observed for a long-term forward biasing of the PiN rectifiers at 100 A/cm2. A PiN rectifier module consisting of five parallel large area 6.4 mm x 6.4 mm 10 kV PiN rectifiers is connected as a free-wheeling diode with a Si IGBT and 1100 V/100 A switching transients are recorded. Data on the current sharing capability of the PiN rectifiers is also presented.

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42

Guran, Ionuț-Constantin, Adriana Florescu, and Lucian Andrei Perișoară. "A Novel ON-State Resistance Modeling Technique for MOSFET Power Switches." Mathematics 11, no. 1 (December 25, 2022): 72. http://dx.doi.org/10.3390/math11010072.

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Nowadays, electronic circuits’ time to market is essential, with engineers trying to reduce it as much as possible. Due to this, simulation has become the main testing concept used in the electronics domain. In order to perform the simulation of a circuit, a behavioral model must be created. Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are semiconductor devices found in a multitude of electronic circuits, and they are also used as power switches in many applications, such as low-dropout linear voltage regulators, switching regulators, gate drivers, battery management systems, etc. A MOSFETs’ behavior is extremely complex to model, thus, creating high-performance models for these transistors is an imperative condition in order to emulate the exact real behavior of a circuit using them. An essential parameter of MOSFET power switches is the ON-state resistance (RDSON), because it determines the power losses during the ON state. Ideally, the power losses need to be zero. RDSON depends on multiple factors, such as temperature, load current, and gate-to-source voltage. Previous studies in this domain focus on the modeling of the MOSFET only in specific operating points, but do not cover the entire variation range of the parameters, which is critical for some applications. For this reason, in this paper, there was introduced for the first time a novel ON-state resistance modeling technique for MOSFET Power Switches, which solves the entire RDSON dependency on the transistor’s variables stated above. The novel RDSON modeling technique is based on modulating the transistor’s gate-to-source voltage such that the exact RDSON value is obtained in each possible operating point. The method was tested as a real-life example by creating a behavioral model for an N-channel MOSFET transistor and the chosen simulation environment was Oregon, USA, Computer-Aided Design (OrCAD) capture. The results show that the model is able to match the transistor’s RDSON characteristics with a maximum error of 0.8%. This is extremely important for applications in which the temperatures, voltages, and currents vary over a wide range. The new proposed modeling method covers a gap in the behavioral modeling domain, due to the fact that, until now, it was not possible to model the RDSON characteristics in all operating corners.

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43

Seock Lee, Hae, Geon Hee Lee, Byoung Sup Ahn, and Ey Goo Kang. "A Study on the Electric Characteristics of the Trench Gate Field Stop Insulated Gate Bipolar Transistor Through Two-Step Field Stop." Journal of Nanoelectronics and Optoelectronics 16, no. 5 (May 1, 2021): 762–65. http://dx.doi.org/10.1166/jno.2021.3005.

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Insulated gate bipolar transistor (IGBT) element is an electrically conductive device with Bipolar junction transistor (BJT) output and Metal Oxide Silicon Field Effect Transistor (MOSFET) input. The IGBTs is a power semiconductor device that aims for high breakdown voltage, low on-state voltage, fast switching and reliability. This paper is, the experiment was conducted with a two-step field stop, IGBT instead of a traditional one step field stop. In order to minimize the energy loss caused by the trade-off relationship between breakdown voltage and the on-state voltage drop, the experiment was conducted by forming a two-step field stop. Through concentration control between steps, breakdown voltage, On-state Voltage drop and turn off time could be adjusted in detail, and efficient characteristic values could be obtained accordingly. Experiments have confirmed that the On state voltage drop and turn-off time, in particular, can be adjusted by small failure voltage loss upon change in the first stage field stop.

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44

Kang, SeokJu, Jaewoo Kim, Jung-Wook Park, and Seung-Mook Baek. "Reactive Power Management Based on Voltage Sensitivity Analysis of Distribution System with High Penetration of Renewable Energies." Energies 12, no. 8 (April 19, 2019): 1493. http://dx.doi.org/10.3390/en12081493.

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The high penetration of distributed energy resources (DERs) in the distribution system brings new challenges related to voltage variations and reverse power flow. The sudden changes in electric power generation from the DERs due to climate conditions or their internal malfunction might cause high fluctuations in system voltage. To enhance the voltage stability when a disturbance occurs, this paper proposes a new reactive power management method to control each DER based on voltage sensitivity analysis. The voltage variation has the different features in both steady-state and transient conditions. In particular, its transient behavior depends on the type of DERs. Therefore, the particular optimal control for improving the dynamic response of voltage is difficult to apply for all types of DERs. In contrast, the voltage variation in steady-state can be controlled with the reactive power management by the sensitivity analysis between reactive power generation and system voltage. Even though this paper focuses on the reduction of voltage variation in steady-state, the relationship between the voltage variations in steady-state and transient conditions is also analyzed. The effectiveness of the proposed method is verified with several case studies on the practical distribution system in South Korea by using the time-domain simulation based on the PSCAD/EMTDC software. The results show that the proposed reactive power management method can improve the dynamic voltage responses in both steady-state and transient conditions when the distribution system has the high penetration of renewables.

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45

Avdeev, Boris, Aleksei Vyngra, and Sergei Chernyi. "Improving the Electricity Quality by Means of a Single-Phase Solid-State Transformer." Designs 4, no. 3 (September 11, 2020): 35. http://dx.doi.org/10.3390/designs4030035.

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The paper describes the use of a single-phase three-stage solid-state transformer in networks with non-sinusoidal voltages in order to improve the quality of electricity. An active-inductive load was chosen as the load. The solid-state transformer was simulated by the Matlab/Simulink software. Its performance was analyzed and the parameters for optimal performance were specified. The voltage and current graphs on the load and their spectral analysis are given. Total harmonic distortion was evaluated for current and voltage. As a comparison, the operation of a classic transformer was simulated. Modeling shows that solid-state transformer copes with improving the quality of electricity better than a classical transformer. In addition to improving the quality of the load current, the solid-state transformer protects the consumer from overvoltage, voltage dips, and other transient phenomena, due to the accumulated supply of electricity in the capacitors of the DC-Bus.

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46

Mayouf, Messaoud. "Control strategy of a standalone variable speed wind energy conversion system based on direct drive permanent magnet synchronous generator." Journal of Renewable Energy and Technology 1, no. 1 (November 11, 2022): 1–8. http://dx.doi.org/10.38208/jret.v1i1.378.

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In this paper, we propose a control strategy for a stand-alone wind energy conversion system (WECS) based on a direct drive permanent magnet synchronous generator (PMSG), loaded on a DC-type charge. In the considered wind-power generating system, the generator provides a DC voltage to the load through a three-phase rectifier, controlled by the Pulse Width Modulation (PWM) technique. The main control strategy target is to maintain the DC voltage insensitive to fast changes in wind speed and load, by offsetting the generator output current with the charge current. The approach adopted in this paper is based on the estimate of the PMSG electromagnetic torque assuming that wind velocity remains quasi-stationary in a steady state. The instant power reference is assessed by the charge controller according to the rated DC bus voltage, using actual electrical measurements as the voltage and current. To achieve adequately the power decoupling, the field-oriented control is used with conventional PI-type regulators to provide direct and quadrature control reference voltages and ensure DC bus voltage regulation. To assess the proposed control strategy efficiency, the simulation model was subjected to different load and wind speed variations. Simulation results performed using the MATLAB Simulink model show high accuracy and strength during steady-state and transient operations.

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47

Dongliang Sun and Qunhua Dong. "Cable Steady-State Ampacity Correction Method based on Multi Physical Field Coupling Algorithm." Electrotehnica, Electronica, Automatica 70, no. 2 (May 15, 2022): 19–27. http://dx.doi.org/10.46904/eea.22.70.2.1108003.

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The difference between the single air laying ampacity test value of medium voltage power cable and the system ampacity of three-phase laying and operation is a common problem in the industry. Based on the TICW-2012 standard, the single cable ampacity of medium voltage single core power cable is tested, and the COMSOL basic simulation model is debugged with the measured ampacity value. On the premise of correct single cable basic simulation model, the system ampacity under three-phase operation under different working conditions is calculated, including triangular laying, plane laying, single circuit and double circuit laying, The difference and correction coefficient between the test current carrying capacity and the of single air laying of medium voltage single core power cable are further analysed. Finally, the analytical formula is derived through the cable ampacity equivalent thermal circuit diagram, and the cable samples are theoretically analysed and calculated. According to the ampacity calculation results of single loop triangular laying and plane laying, the correctness of the simulation results is verified. This study provides a reference basis for the current carrying capacity test and correction of medium voltage power cable in the future, and also provides an effective method for the actual operation state analysis of medium voltage power cable.

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48

Gotovkina, E. E., V. D. Lebedev, G. I. Parfenov, N. N. Smirnov, and V. V. Tyutikov. "A laboratory study of environment and voltage effects on the thermal state of resistive voltage divider." Vestnik IGEU, no. 2 (2019): 5–16. http://dx.doi.org/10.17588/2072-2672.2019.2.005-016.

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Анотація:

There are currently no thermal self-diagnostics systems of instrument transformers operating in real time, as opposed to power ones, and thermal inspections are often carried out according to a maintenance schedule, which affects the reliability of electrical equipment. Therefore, an important task is to create such systems for digital instrument combined current and voltage transformers based on resistive dividers, which determine temperature values at several points, including the most heated element. The aim of this study is to obtain experimental data on the thermal state of a resistive divider exposed to environmental factors and voltage for developing a self-diagnostics system. The results are obtained by physical simulation of thermal conditions of the transformer and its elements in high- and low-voltage climatic chambers. The effects of the following factors of critical importance have been simulated: electric voltage, insolation, temperature and speed of the ambient air. Data processing was performed using the methods of probability theory and mathematical statistics. The time needed for the thermodynamic system to move to a steady heat exchange mode, and also the temperatures on the lower resistors and on the surface of the voltage transformer insulation cover have been determined. It has been established that thermal conditions are more significantly affected by the simulated voltage than by insolation. The study has shown that even in the most severe emergency operating modes, heating in the lower resistor does not exceed the critical value. It has been found that the thermal state of the transformer is significantly influenced by the simulated factors including directional insolation, which is not taken into account in the existing methods of calculating the thermal state of the instrument electrical equipment. The reliability of the obtained results is ensured by the fact that the simulation took into account significant factors. The results of the experiment will be used to develop a thermal self-diagnostics system for the digital transformer, which will improve the reliability of operation of such instrument equipment by allowing the personnel’s to give a rapid response to real-time information about the transformer thermal state.

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49

Kim, Hyeon-Sik, Hyun-Sam Jung, and Seung-Ki Sul. "Discrete-Time Voltage Controller for Voltage Source Converters With LC Filter Based on State-Space Models." IEEE Transactions on Industry Applications 55, no. 1 (January 2019): 529–40. http://dx.doi.org/10.1109/tia.2018.2868552.

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50

Kim, Jun-Seok, and Jung-Min Kwon. "Direct Space Vector Modulation with Novel DC-Link Voltage Balancing Algorithm for Easy Software Implementation of Three-Phase Three-Level Converter." Electronics 9, no. 11 (November 3, 2020): 1841. http://dx.doi.org/10.3390/electronics9111841.

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The present paper proposes a direct space vector modulation and novel balance algorithm for easy software application of three-level converters which operate in three-phase. In the case of the conventional space vector modulation, to get the on-state times of the switches, the dwell times of the three nearest stationary vectors, which are obtained after sector and region selection algorithms, should be rearranged. These processes, therefore, contain diverse conditional statements and complicated calculations such as inverse trigonometric functions and square roots. However, the burden of the software application of the proposed algorithm is greatly reduced by not using the sector selection algorithm, the region selection algorithm, and the on-state time allocation process as the proposed modulation can directly control the switch on-state time. In a three-level topology, it is required to balance top and bottom capacitor voltages because the DC-link voltage is composed of two capacitor voltages; the unbalanced voltage of each DC-link capacitor causes the overvoltage of the switching devices. Thus, the DC-link voltage balancing algorithm is proposed, and it is also very simple and effective without additional circuits because it controls the switch on-state time directly as well. The 5-kW prototype proved the validity of the proposed algorithm with its feasibility.

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