Earticle

본 논문은 Buck-Boost DC-DC 변환기를 이용하여 다중 대역으로 존재하는 RF 신호를 수집하여 에너지를 생성하는 에너지 수집시스템에 대하여 소개한다. 수집된 전기에너지를 사용하는 부하의 저항이 지속적으로 변하는 환경에서는 부하 저항이 변하여도DC-DC 변환기의 입력저항이 변하지 않는 Buck-Boost DC-DC 변환기를 사용하였다. 입력으로 들어오는 RF 신호의 주파수 대역이다양하므로 다중대역을 다 처리 할 수 있도록 정류기를 대역별로 설계하고 정류기 앞에 각 대역별로 매칭 회로를 추가하였다. 크기가매우 작은 RF 신호를 효과적으로 수집하기 위한 정류기를 위하여 각 대역에서 수집하여 발생시킨 전압을 계속 누적하여 축적하는방법을 고안하여 매우 작은 크기의 입력 신호에도 일정한 전압이 출력되게끔 회로를 설계하였다. 입력이 –20 dBm의 크기를 가진RF 신호에도 출력 효율이 20% 정도까지 낼 수 있음을 확인하였다

This paper introduces an energy harvesting system that generates energy by collecting multi-band RF signals using buck-boost DC-DC converter. In an environment where the resistance of load using the collected electric energy is constantly changing, a buck-boost DC-DC converter is used in which the input resistance of the DC-DC converter does not change even if the load resistance changes. Since the frequency band of the input RF signal varies, the rectifier is designed for each band so that multiple bands can be processed, and a matching circuit is added to each band in front of the rectifier. For a rectifier to collect very small RF signals, a circuit is designed so that a constant voltage is obtained according to a very small input signal by devising a method of continuously accumulating the voltages collected and generated in each band. It is confirmed that the output efficiency can reach up to 20% even for the RF signal having the input of -20 dBm.

본 논문에서는 함정용 ICCP(Impressed Current Cathodic Protection) 정류기에 적용되어 온 구역 단위 대표 전위 기반 제어 구조의 공간 분해능 및 제어 단위 한계를 분석하고, 이를 개선하기 위한 채널 단위 독립 제어 기반 분산 제어 아키텍처를 제안한다. 제안 구조는 기준전극–양극 쌍을 최소 제어 단위로 정의하고, 기준전위 수집–제 어 연산–전류 출력 경로를 분리하여 채널별 병렬 제어 루프가 독립적으로 동작하도록 설계되었다. 제안 구조의 타 당성은 고객 요구사항에 기반한 합/부 판정 체계를 통해 검증하였으며, 실환경에서 반복 재현이 어려운 전위 비대칭 및 국부 외란 조건을 HIL 기반 시험 환경으로 구성하여 구조적 독립성과 제어 동작 특성을 확인하였다. 본 연구는 기존 구조 대비 수치적 성능 비교가 아니라, 제어 단위 재정의를 통한 분산 제어 아키텍처의 설계 타당성을 구조적 으로 입증하였다는 점에서 의의를 가진다.

This paper analyzes the spatial resolution and control-unit limitations of the conventional zonebased representative potential control structure applied to naval ICCP rectifiers and proposes a channel-level independent distributed control architecture to address these limitations. In the proposed structure, each reference electrode–anode pair is defined as a minimal control unit, and the processes of potential acquisition, control computation, and current output are logically separated to enable parallel and independent control loops for each channel. The validity of the proposed architecture is verified through a requirement-based pass/fail evaluation framework. A hardwarein- the-loop (HIL) test environment was constructed to emulate asymmetric potential distributions and localized disturbance conditions that are difficult to reproduce in real operational environments. Experimental results confirm the structural independence and operational characteristics of the channel-level control loops. Rather than focusing on numerical performance optimization against the conventional structure, this study demonstrates the structural design validity of a distributed control architecture achieved through the redefinition of the control unit.

기존의 NEDSCR 소자는 매우 낮은 스냅백 홀딩전압과 낮은 온-저항을 가져 정상적인 동작 동안 래치업을 초래하므로 ESD 보호소 자로 사용하는데 어려움이 있었다. 본 연구에서는 NEDSCR 소자의 시뮬레이션 및 TLP 테스트를 통해 이러한 단점들을 극복할 수 있는 새로운 방법을 제안하였다. 매우 우수한 ESD 보호 성능과 높은 래치업 면역 특성을 구현하기 위해 N+ 소오스 확산영역을 둘러싸는 P형의 CPS 이온주입공정을 추가함으로써 NEDSCR 소자의 스냅백 홀딩전압과 온 저항을 증가시켜 정전기 보호 성능을 개선시킬 수 있는 것으로 입증되었다.

An electrostatic discharge (ESD) protection device, so called, N-type extended drain silicon controlled rectifier (NEDSCR) device, was analyzed for high voltage I/O applications. A conventional NEDSCR device shows typical SCR-like characteristics with extremely low snapback holding voltage. This may cause latch-up problem during normal operation. However, a modified NEDSCR device with proper junction/channel engineering using counter pocket source (CPS) ion implantation demonstrates itself with both the excellent ESD protection performance and the high latch-up immunity. Since the CPS implant technique does not change avalanche breakdown voltage, this methodology does not reduce available operation voltage and is applicable regardless of the operation voltage.

PPS 구조를 갖는 N형 실리콘 제어 정류기 소자에서 부분웰 구조가 정전기 보호 성능에 미치는 영향을 고찰하였다. 종래의 NSCR표준소자는 온-상태 저항, 스냅백 홀딩 전압 및 열적 브레이크다운 전압이 너무 낮아 정전기 보호소자의 필요조건을 만족시키지못해 적용이 어려웠으나, 본 연구에서 제안하는 부분웰 구조를 갖도록 변형 설계된 NSCR-PPS 소자는 안정한 정전기보호 성능을나타내어 고전압 동작용 마이크로 칩의 정전기보호 소자로 적용 가능함을 확인하였다.

Electrostatic Discharge(ESD) protection performance of PPS(PMOS pass structure) embedded N-type silicon controlledrectifier(NSCR_PPS) device with different partial p-well(PPW) structure was discussed for high voltage I/O applications. Aconventional NSCR_PPS standard device shows typical SCR-like characteristics with low on-resistance, low snapbackholding voltage and low thermal breakdown voltage, which may cause latch-up problem during normal operation. However,our proposed NSCR_PPS devices with modified PPW demonstrate the stable ESD protection performance with high latch-upimmunity.

The accumulator battery test requests its system converter to output excellent charging/discharging current. According to special request, PWM converter with current mode control is analyzed and designed in this paper. Morever, a loop-locked control strategy is put forward based on dq coordinate conversion to SVPWM converters in the power accumulator battery testing system. low ripple and fast response testing current in a wide adjustable range is achieved, and high power factor is obtained. Considering resonance of LC filter, the passive damping is designed, which is based on the series resistance of capacitor. Simulation results verify the feasibility and validity of this strategy.

This article is a study on the analysis of harmonics reductions and load voltage control for Vienna Rectifier (VR) with help of the Triplen Harmonic Injection (THJ) and the proportional integral controller (PIC). The sinusoidal PWM is the easiest modulation technique for AC-DC rectifiers to comprehend; however, it is not capable of entirely using the accessible DC bus source voltage. In order to enhance the load voltage regulation and harmonics reductions of the VR, PIC and THJ PWM methods are developed. The performances of the designed PWM methods as well as the PIC are validated at different operating conditions by developing models using MATLAB/Simulink as well as real experimental models. Simulation and experimental results are presented to show the effectiveness of the designed control methods.

The artificial intelligence techniques are widely applied to many works of engineering. This paper presents the application of the artificial intelligence techniques to identify the AC-DC power system parameters. The DC-link filters are normally included in such power systems. For some applications, accurate DC-link filter parameters are very important for the system analysis and design. According to the measurement errors and a large variation in a capacitor value, the parameter identification is needed to provide the accurate parameters. Therefore, the paper presents the identification of DC-link filter parameters using the adaptive tabu search technique and the genetic algorithm. The experimental results from the testing rig and the averaging model of the system are used in the searching process. The identification results show that the accurate DC-link filter parameters including line parameters on the AC side can be easily obtained via the proposed method. Moreover, the resulting parameters are very useful for a stability analysis of the power electronic systems due to a constant power load.

This paper proposes a high power full-bridge DC-DC converter, using a center-tapped transformer and a full-wave type rectifier. The proposed converter realizes unipolar primary voltage switching, using the unipolar pulse-width modulation (PWM) technique. Also, the proposed converter reduces the freewheeling conduction loss, using the unipolar PWM technique and a resonant circuit, composed of a clamp capacitor and resonant inductor in the primary, and thus achieves high efficiency. However, because the proposed converter uses only a full-bridge circuit, center-tapped transformer, and full-wave type rectifier, the structure of the proposed converter is simple. In this paper, the operational principle of the proposed converter is described in detail, and a design example of a proposed converter prototype is shown. Finally, experimental results of the prototype are shown, to verify the feasibility of the proposed converter.

본 논문에서는 입력전류를 센싱 받지 않아도 역률 보상을 하는 새로운 단일단 브리지리스 AC-DC컨버터를 제안한다. 제안하는 컨버터의 스위치는 전구간에서 ZVS(Zero Voltage Switching) 턴 온을 성취하며, 다이오드는 전구간에서 ZCS(Zero Current Switching) 턴 오프를 성취한다. 제안하는 컨버터의 넓은 범위의 출력전압 제어와 간단한 전력 제어를 위해 SDAB(Semi-Dual Active Bridge)기반의 모듈레이션 기법을 적용하였다. 1kW급 50kHz의 스위칭 주파수를 갖는 시작품을 통해 본 논문의 타당성을 검증하였다.

실리콘카바이드 소자는 넓은 밴드갭을 갖는 물질로서 많은 주목을 받아왔다. 특히 4H-SiC 쇼트키 배리어 다이오드는 빠른 스위칭 속도와 낮은 순방향 전압강하의 특성으로 인해 널리 사용되고 있다. 그러나 쇼트키 배리어 다이오드의 낮은 신뢰성으로 인한 문제로 대안인 Super Barrier Rectifier(SBR)가 연구되었다. 본 논문은 4H-SiC trench-type accumulation super barrier rectifier(TASBR)를 분석하고 제안한다. 2D 시뮬레이션을 통해 본 구조는 심각한 역방향 저지전압의 감소와 누설전류의 증가가 없는 동시에 순방향 전압 강하는 21.06% 향상됨을 확인 할 수 있었다. 이러한 새로운 정류기 구조를 이용하면 전력손실이 적은 애플리케이션을 기대할 수 있다.

SiC devices have drawn much attentions for its wide band gap material properties. Especially 4H-SiC Schottky barrier diode is widely used for its rapid switching speed and low forward voltage drop. However, the low reliability of Schottky barrier diode has many problems that Super Barrier Rectifier(SBR) was researched for alternative. makes 4H-SiC trench-type accumulation super barrier rectifier(TASBR) is analyzed and proposed in this paper. We could verified that forward voltage drop was improved 21.06% without severe degradation of reverse breakdown voltage and leakage current based on the results from 2-D numerical simulations. With this novel rectifier structure, we can expect application with less power loss.

This paper suggests a high performance lateral super barrier rectifier (Lateral SBR) device which has the advantages of both Schottky diode and pn junction, that is, low forward voltage and low leakage current, respectively. Advantage of the proposed lateral SBR is that it can be easily implemented and integrated in current BCD platform. As a result of simulation using TCAD, BVdss = 48 V, $V_F=0.38V$ @ $I_F=35mA$, T_j = $150^{\circ}C$ were obtained with very low leakage current characteristic of 3.25 uA.

본 논문에서는 전력반도체 소자의 재료로써 주목받고 있는 탄화규소 기반의 Trench MOS Barrier Schottky(TMBS)의 순방향 및 역방향 특성을 개선시키기 위한 구조를 제안한다. 순방향 전압강하와 역방향 항복전압을 개선시키기 위하여 사다리꼴 mesa 구조와 trench sidewall의 길이를 조절하는 기법을 사용하는 4H-SiC TMBS 정류기를 제안하고 있다. 제안된 구조는 사다리꼴 mesa 구조를 적용하여 trench sidewall에 경사를 줌으로써 1508V의 역방향 항복전압을 얻었다. 이것은 기존의 4H-SiC TMBS 정류기에 비하여 역방향 항복전압을 11% 개선시켰음을 나타낸다. 또한 trench sidewall 상단의 길이를 조절하여 순방향 전류 $200A/cm^2$에 대하여 12% 감소된 1.6V의 순방향 전압강하를 얻었다. 제안된 소자는 Silvaco사의 T-CAD를 사용하여 전기적 특성을 분석하였다.

In this study, an 4H-SiC Trench MOS Barrier Schottky (TMBS) rectifier which utilizes the trapezoid mesa structure and the upper half of the trench sidewall is proposed to improve the forward voltage drop and reverse blocking voltage concurrently. The proposed 4H-SiC TMBS rectifier reduces the forward voltage drop by 12% compared to the conventional 4H-SiC TMBS rectifier with the tilted sidewall and improves the reverse blocking voltage by 11% with adjusting the length of the upper sidewall. The Silvaco T-CAD was used to analyze the electrical characteristics.

The paper proposes the coupled inductor rectifier of Three Level DC/DC converter CICDR-TL(Coupled Inductor Current Doubler Rectifier-Three Level) achieves Zero Voltage Switching (ZVS) for the switches in a wide load range and Zero Current Switching (ZCS) in a light load range. Advantages and disadvantages of this topology compared to the conventional Center Tapped TL Converter are discussed. Experimental evaluation results obtained on a 27V 60A DC/DC converter prototype for the 1.8kW 40kHz IGBT based experimental circuit.

This paper discusses the design of a high frequency Greinacher voltage multiplier as rectifier; it has a greater conversion efficiency and higher output direct current (DC) voltage at high power compared to a simple halfwave rectifier. Multiple diodes in the Greinacher voltage multiplier with distributed circuits consume excited power to the rectifier equally, thereby increasing the overall power capacity of the rectifier system. The proposed rectifiers are a Greinacher voltage doubler and a Greinacher voltage quadrupler, which consist of only diodes and distributed circuits for high frequency applications. For each rectifier, the RF-to-DC conversion efficiency and output DC voltage for each input power and load resistance are analyzed for the maximum conversion efficiency. The input power with maximum conversion efficiency of the designed Greinacher voltage doubler and quadrupler is 3 and 7 dB higher, respectively;than that of the halfwave rectifier.

A bidirectional-friendly control strategy of three-phase NPC rectifier under unbalanced voltage for advanced traction power supply system (ATPSS) is proposed in this study. Negative-sequence current and DC voltage ripple are restrained effectively with very low total harmonic distortions (THDs) on the basis of predictive current control theory. First, power balance equation containing only positive-sequence voltage of the three-phase grid voltage is derived, and the secondary fluctuation of instantaneous active and reactive powers on the grid side is analyzed and calculated. Second, expression of the DC-side voltage fluctuation is deduced to fix the calculation of P_ref for the optimization of the control system. Third, command current that can achieve bidirectional-friendly control is calculated according to the power expression and the reference voltage value is obtained on the basis of the predictive current control principle. Finally, simulations and experimental results verify the correctness of the theoretical analysis and the effectiveness of the proposed strategy.

In vascular smooth muscle, K⁺ channels, such as voltage-gated K⁺ channels (Kv), inward-rectifier K⁺ channels (Kir), and big-conductance Ca²⁺-activated K⁺ channels (BK_Ca), establish a hyperpolarized membrane potential and counterbalance the depolarizing vasoactive stimuli. Additionally, Kir mediates endothelium-dependent hyperpolarization and the active hyperemia response in various vessels, including the coronary artery. Pulmonary arterial hypertension (PAH) induces right ventricular hypertrophy (RVH), thereby elevating the risk of ischemia and right heart failure. Here, using the whole-cell patch-clamp technique, we compared Kv and Kir current densities (I_Kv and I_Kir) in the left (LCSMCs), right (RCSMCs), and septal branches of coronary smooth muscle cells (SCSMCs) from control and monocrotaline (MCT)-induced PAH rats exhibiting RVH. In control rats, (1) I_Kv was larger in RCSMCs than that in SCSMCs and LCSMCs, (2) I_Kv inactivation occurred at more negative voltages in SCSMCs than those in RCSMCs and LCSMCs, (3) I_Kir was smaller in SCSMCs than that in RCSMCs and LCSMCs, and (4) I_BKCa did not differ between branches. Moreover, in PAH rats, I_Kir and I_Kv decreased in SCSMCs, but not in RCSMCs or LCSMCs, and I_BKCa did not change in any of the branches. These results demonstrated that SCSMC-specific decreases in I_Kv and I_Kir occur in an MCT-induced PAH model, thereby offering insights into the potential pathophysiological implications of coronary blood flow regulation in right heart disease. Furthermore, the relatively smaller I_Kir in SCSMCs suggested a less effective vasodilatory response in the septal region to the moderate increase in extracellular K⁺ concentration under increased activity of the myocardium.