• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.2014-2020
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• 2017

A compact current model applicable to both single-gate (SG) and double-gate (DG) tunneling field-effect transistors (TFETs) is presented. The model is based on Kane's band-to-band tunneling (BTBT) model. In this model, the well-known and previously-reported quasi-2-D solution of Poisson's equation is used for the surface potential and length of the tunneling path in the tunneling region. An analytical tunneling current expression is derived from expressions of derivatives of local electric field and surface potential with respect to tunneling direction. The previously reported correction factor with three fitting parameters, compensating for superlinear onset and saturation current with drain voltage, is used. Simulation results of the proposed TFET model are compared with those from a technology computer-aided-design (TCAD) simulator, and good agreement in all operational bias is demonstrated. The proposed SG/DG-TFET model is developed with Verilog-A for circuit simulation. A TFET inverter is simulated with the Verilog-A SG/DG-TFET model in the circuit simulator; the model exhibits typical inverter characteristics, thereby confirming its effectiveness.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.266-269
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• 1999

Several power factor correction(PFC) circuits are presented to achieve high PF electronic ballast for both voltage-fed and current-fed electronic ballast. The proposed PFC circuits use valley-fill(VF) type DC-link stages modified from the conventional VF circuit to adopt the charge pumping method for PFC operations during the valley intervals. In voltage-fed ballast, charge pump capacitors are connected with the resonant capacitors. In current-fed type, the charge pump capacitors are connected with the additional secondary-side of the power transformer. The measured PF and THD are higher than 0.99 and 15% for all proposed PFC circuits. The lamp current CF is also acceptable in the proposed circuits. The proposed circuit is suitable for implementing cost-effective electronic ballast.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.93-97
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• 2011

In this paper, we discuss design considerations for an n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) with a lateral asymmetric channel (LAC) doping profile. We employed a 0.35 ${\mu}M$ standard complementary MOSFET process for fabrication of the devices. The gates to the LAC doping overlap lengths were 0.5, 1.0, and 1.5 ${\mu}M$. The drain current ($I_{ON}$), transconductance ($g_m$), substrate current ($I_{SUB}$), drain to source leakage current ($I_{OFF}$), and channel-hot-electron (CHE) reliability characteristics were taken into account for optimum device design. The LAC devices with shorter overlap lengths demonstrated improved $I_{ON}$ and $g_m$ characteristics. On the other hand, the LAC devices with longer overlap lengths demonstrated improved CHE degradation and $I_{OFF}$ characteristics.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.1-8
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• 2018

A problem exists in the conventional transportation cart applications, in which an external power supply with mechanical contact connection (bus bar connection) is required to drive the motor. Therefore, continuous effort for maintenance is required, aside from the expensive bus bar connector. To solve this problem, a self-electricity-generated transportation cart system without bus bar has recently been introduced. In this system, a battery needs to store the power of the generated wheel, and a boost converter, which converts the low battery voltage to high bus voltage to drive the motor inverter, is necessary. However, since the instantaneous large current required for starting the motor is supplied from the battery, a battery with large size and volume should be adopted to withstand this large current. In this study, a boost converter that can supply a large instantaneous current by using super Capacitor string is proposed. The proposed converter can be realized with a small size and volume compared with the conventional battery-fed boost converter. Operational principles, analysis, and design of the proposed converter are presented, and experimental results are provided to validate the proposed converter.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.11
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• pp.717-723
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• 1999

The transient characteristics of grounding systems play a major role in the protection of power equipments, electronic circuits and info-communication facilities against surges which arise from lightning or ground faults. Electronic devices are very weak against lightning surges injected from grounding systems and can be damaged. The malfunction and damage of electronic circuits bring about bad operation performances, a lot of economical losses, and etc. Therefore, in order to obtain the effective protection measure of electronic devices from overvoltages and lightning surges, the analysis of the transient grounding impedances in essential. One of this work is to examine the transient behaviors of grounding impedances under steplike currents for various grounding systems. And the other of this work is to evaluate the transient behaviors of a grid with rods under impulse currents and to investigate the effect of grounding lead wire. Transient grounding impedances of a grid with rods under impulse current waves have been measured as a parameter of the length of the grounding leads. Z-t, Z-i and V-i curves of transient grounding impedance under impulse current waveforms have been measured and analyzed. It was found that the grounding impedance gives the inductive, resistive and capacitive aspects under steplike current. Transient grounding impedance characteristics were very different with shapes, geometries of ground electrodes. Also, they were dependent on the waveform and magnitude of impulse current.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.515-522
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• 1999

Several power factor correction(PFC) circuits are presented to achieve high PF electronic ballast for both v voltage-fed and current-f,어 ek'Ctronic ballast. The proposed PFC circuits use valley-fil[(VF) type DClink s stages modified from the conventional VF circuit to adopt the charge pumping method for PFC operations d during the valley intervals. In voltage-fed ballast, charge pump capacitors are connected with the resonant c capaCltor In current-fed type, the charge pump capacitors are connc'Ctc'Cl with the additional second따y-side of t the power transformer. The measured PF is higher than 0.99 and THD is about 10% for all proposed PFC c circuits. The lamp current CF is also acceptable in the proposed circuits. The proposed circuit is suitable for i implementing cost longrightarroweffective electronic ballast.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.2
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• pp.96-105
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• 2021

Large-scale power converters consist of series or parallel module combinations. In these modular converter systems, the interleaving technique can be applied to improve capacitor reliability by reducing the ripple of the I/O current in which each module operates as a phase difference. However, when applying the interleaving technique for conventional three-level boost converters, the short-circuit period of the converter can be an obstacle. Such problem is caused by the absence of a low-level inductor of the conventional three-level boost converter. To solve this problem, a three-level boost converter with a low-level inductor is proposed and analyzed to enable interleaved operation. In the proposed circuit, the current ripple of the output capacitor depends on the neutral point connections between the modules. In this study, the ripple current is analyzed by the neutral point connections of the three-level boost converter that has a low-level inductor, and the effectiveness of the proposed circuit is proven by simulation and experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.191-195
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• 2015

Inside the existing superconducting cables, the superconducting wire carries a loss-free current, and the cable former (the stranded copper wire) bypasses the fault current to prevent damage and loss of the superconducting cable when the fault current is applied. The fault-current-limiting-type superconducting cable proposed in this paper usually carries a steady current; but in a fault state, the cable generates self-resistance that makes the fault current lower than a certain width. That is, the superconducting cable that transmitted only a low voltage and a large capacity power repetitively limits the fault current, as does a superconducting current limiter. To complete this structure, it is essential to investigate the mutual resistance relationship between the superconducting wires after applying a fault current. Therefore, in this paper, one kinds of superconducting wires (a wire without a stabilization layer) were connected parallel 4 tapes, respectively; and after applying a fault current, the current, voltage, resistance and thermal stability of the HTS thin-film wires were examined.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.147-147
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• 2009

Every year respect a countermeasure establishment the electric leakage detection system and electric leakage investigation work are becoming enforcement line plentifully in about the electric leakage accident which is increasing, measuring in compliance with a most ground connection voltage and an image electric current mainly is become accomplished, inputs a pulsation group signal in the line and detects a signal change between the line a method which there is. In order to investigate the quality in compliance with an electric leakage electric current from the electric leakage area after conferring the electric leakage environment in compliance with a flooding when the electric leakage electric current exists in the surface, it investigated the electric leakage electric current quality from the electric current distribution and flooded districts from the present paper.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.5
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• pp.351-356
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• 2018

Commonly, a live-line alarm can be used to measure the electric field strength of a high-voltage system to calculate its current, but it is hard to detect the electric field of shielded cables or concealed structures, such as underground distribution cables. Current sensors can detect the magnetic field in a single core wire, but they cannot determine the magnetic field about a double-core wire because the currents flow in opposite directions. Therefore, it is very difficult to detect certain current problems, such as a fault current in an extension line comprised of a double line. In this paper, to ultimately develop a sensor that can detect the current regardless of line conditions, we used a simulation to determine the concentration of the magnetic field dependent on the distribution of the external magnetic field and the path of each line's core.