• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.280-283
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• 2004

This paper discribes the design concept, fabrication process and measuring result of 2.5kV Gate Commutated Thyristor devices. Integrated gate commutated thyristors(IGCTs) is the new power semiconductor device used for high power inverter, converter, static var compensator(SVC) etc. Most of the ordinary GTOs(gate turn-off thyristors) are designed as non-punch-through(NPT) concept; i.e. the electric field is reduced to zero within the N-base region. In this paper, we propose transparent anode structure for fast turn-off characteristics. And also, to reach high breakdown voltage, we used 2-stage bevel structure. Bevel angle is very important for high power devices, such as thyristor structure devices. For cathode topology, we designed 430 cathode fingers. Each finger has designed $200{\mu}m$ width and $2600{\mu}m$ length. The breakdown voltage between cathode and anode contact of this fabricated GCT device is 2,715V.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1088-1096
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• 2017

Load variations on a distribution line result in voltage fluctuations at the point of common coupling (PCC). In order to keep the magnitude of the PCC voltage constant at its rated value and obtain zero voltage regulation (ZVR), a D-STATCOM is installed for voltage correction. Moreover, the ZVR mode of a D-STATCOM can also be used to balance the source current during unbalanced loading. For medium voltage and high power applications, a D-STATCOM is realized by the cascaded H-bridge topology. In the ZVR mode, the D-STATCOM may draw unbalanced current and in this process is required to handle different phase powers leading to deviations in the cluster voltages. Zero sequence voltage needs to be injected for ZVR mode, which creates circulating power among the phases of the D-STATCOM. The computed zero sequence voltage and the individual DC capacitor balancing controller help the DC cluster voltage follow the reference voltage. The effectiveness of the control scheme is verified by modeling the system in MATLAB/SIMULINK. The obtained simulations are further validated by the experimental results using a dSPACE DS1106 and five-level D-STATCOM experimental set up.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1175-1186
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• 2020

In this study, the problem is analyzed, and methods of improvement are presented. For evaluating the performance of the proposed EGT sensor, a complex environment test equipment has been developed to test both high temperature and vibration conditions at the same time. This equipment evaluates the accuracy and response time of the EGT sensor. In the results of the comparison test of the complex environment test equipment of heat and vibration, the existing sensor showed a carbonization problem, and the proposed sensor showed no problem. Therefore, it is expected that the improved EGT sensor will be able to be applied to various industrial fields, including gas turbines for power generation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.17-23
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• 2020

This paper proposes a simulation model using an equivalent circuit for the development of an MMC system. The MMC has been chosen as the most suitable topology for high voltage power transmission, such as a voltage-type HVDC, and it has dozens to hundreds of sub-modules in the form of a half-bridge or full-bridge connected in series. A simulation study is essential for the development of an MMC algorithm. On the other hand, it is virtually impossible to construct and implement MMC simulation models, including hundreds or thousands of switching devices. Therefore, this paper presents an MMC equivalent model, which is easily expandable and implemented by modeling the dynamic characteristics. The voltage and current equation of the equivalent circuit was calculated using the direction of the arm current and switching signal. The model was implemented on Matlab/Simulink. In this paper, to show the validity of the model developed using Matlab/Simulink, the simulation results of a five-level MMC using the real switching element and the proposed equivalent model are shown. The validity of the proposed model was verified by showing that the current and voltage waveform in the two models match each other.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.203-205
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Journal of Power Electronics
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• v.16 no.3
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• pp.1110-1121
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• 2016

The mathematical model of a three phase PWM converter under the stationary αβ reference frame is deduced and constructed based on a Proportional-Resonant (PR) regulator, which can replace trigonometric function calculation, Park transformation, real-time detection of a Phase Locked Loop and feed-forward decoupling with the proposed accurate calculation of the inductance voltage vector. To avoid the parallel resonance of the LCL topology, the active damping method of the proportional capacitor-current feedback is employed. As to current vector error elimination, an optimized PR controller of the inner current loop is proposed with the zero-pole matching (ZPM) and cancellation method to configure the regulator. The impacts on system's characteristics and stability margin caused by the PR controller and control parameter variations in the inner-current loop are analyzed, and the correlations among active damping feedback coefficient, sampling and transport delay, and system robustness have been established. An equivalent model of the inner current loop is studied via the pole-zero locus along with the pole placement method and frequency response characteristics. Then, the parameter values of the control system are chosen according to their decisive roles and performance indicators. Finally, simulation and experimental results obtained while adopting the proposed method illustrated its feasibility and effectiveness, and the inner current loop achieved zero static error tracking with a good dynamic response and steady-state performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.470-475
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• 2019

This paper deals with a 30kW grid-connected PCS (Power Conversion System) for an Oscillating Water Column (OWC) wave-power generation system. Wave power generation in marine energy is suitable for Korea with the characteristics of a peninsula with three sides facing the sea. In the case of coastal disasters, wave generators can act as a breakwater to reduce damage, and can be integrated with other marine power generation systems to increase efficiency. Wave power generation systems are classified into various types, such as oscillating bodies, OWC, and overtopping according to the operation principle, and they can also be classified into two types according to the installation method: a fixed structure and floating structure. This paper proposes a 30kW grid-connected PCS topology and model for OWC wave power generation that is structurally stable with a turbine and generator that are relatively easy to maintain, and then provide a control method required for grid connection, including DC link voltage control. Simulation verification was performed to verify the proposed PCS.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.63-70
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• 2023

In this work, a capacitive wireless power transfer (C-WPT) system is presented for wireless sensor system (WSS) applications in marine propulsion shafts. For a single Q factor on both sides of the coupling capacitor and reactive power removal from the circuit, a double-sided LCLC converter and transformers topology are designed to drive the rotary C-WPT system for WSS on the shaft. Parallel-connected parallel plate rotating capacitors with a capacitance of 170 pF are designed and implemented for the C-WPT system on a snow rotating shaft. In the experimental results, the C-WPT system achieved a transmission efficiency of 66.67% with 7.8 W output power at 3 mm distance and 1 MHz operating frequency. Therefore, it was proved that the fabricated C-WPT system can supply power to the WSS of the rotating shaft.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.661-668
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• 2024

Based on the topology of the direct-drive permanent magnet synchronous wind power grid-connected system based on the power electronics full-power converter, the wind turbine model and the grid-side inverter model were studied, and the machine-side rectifier control based on current and speed double closed loops was designed. strategy, as well as a grid-side inverter control strategy based on current and voltage double closed loops, implementing a two-level back-to-back double closed-loop full control strategy. A system simulation model was built using Matlab/Simulink, and the operation of the unit was simulated when the wind speed changed step by step. The grid-connected current with the same phase and good sinusoidal nature of the grid voltage was output. The grid-connected system ran stably and efficiently. The simulation results The validity and rationality of the model, as well as the correctness and feasibility of the control strategy were verified.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.4
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• pp.62-68
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• 2010

This work proposes a 10b 100MS/s DAC based on a segmented local matching technique primarily for small chip area. The proposed DAC employing a segmented current-steering structure shows the required high linearity even with the small number of devices and demonstrates a fast settling behavior at resistive loads. The proposed segmented local matching technique reduces the number of current cells to be matched and the size of MOS transistors while a double-cascode topology of current cells achieves a high output impedance even with minimum sized devices. The prototype DAC implemented in a 0.13um CMOS technology occupies a die area of $0.13mm^2$ and drives a $50{\Omega}$ load resistor with a full-scale single output voltage of $1.0V_{p-p}$ at a 3.3V power supply. The measured DNL and INL are within 0.73LSB and 0.76LSB, respectively. The maximum measured SFDR is 58.6dB at a 100MS/s conversion rate.