• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2010년도 하계학술대회 논문집
• /
• pp.470-471
• /
• 2010

In this paper, the coupled inductor with three branches in two interleaved converter are analyzed to effectively suppress the high frequency circulating current since the circulating current controller cannot mitigate the high frequency circulating current. As a result, the novel averaged model including the coupled inductor with zero sequence components is developed for reducing the low and high frequency circulating current simultaneously.

• Journal of Electrical Engineering and Technology
• /
• 제8권5호
• /
• pp.1086-1095
• /
• 2013

The main issue of parallel three-phase boost converters is reduction of the low- and high frequency circulating currents. Most present technologies concentrate on low frequency circulating current because the circulating current controller cannot mitigate the high frequency circulating current. In this paper, analytical approach of three-phase coupled inductor applied to parallel system becomes an important objective to effectively reduce the low- and high frequency circulating currents. The characteristics of three-phase coupled inductor based on a structure and voltage equations are mathematically derived. The modified voltage equations are then applied to parallel three-phase boost converters to develop averaged models in stationary coordinates and rotating coordinates. Based on the averaged modeling approach, design of the circulating current controller is presented. Simulation and experimental results demonstrate the effectiveness of the analysis and modeling for the parallel three-phase boost converters using three-phase coupled inductor.

• 한국진공학회지
• /
• 제8권4A호
• /
• pp.461-464
• /
• 1999

Planar type thin film inductors have a potential for the application of miniaturized DC-DC converters. For those high current applications, the magnetic film with high current capability is required. The current capability of magnetic films is mainly determined from high saturation magnetization (4$\piM_s$) as well as large anisotropy field $(H_k)$. We fabricated a double rectangular spiral thin film inductor which consist of magnetic layer, coil and insulator. Highest inductance values as well as best frequency characteristics can be obtained from 5 MHz and quality factor exhibit about 7.

• Journal of Power Electronics
• /
• 제4권2호
• /
• pp.87-95
• /
• 2004

A new fast-response high-current clamp DC-DC converter circuit design is presented that will meet the requirements and features of the new generation of microprocessors and digital systems. The clamp in the proposed converter amplifies the current in case of severe load changes and is able to produce high slew rate of output current and capability to keep constant the output voltage. This proposed high-current clamp technique is theoretically loss less, low cost and easy to implement with simple control scheme. This is modified from a basic buck topology by replacing the output inductor with two magnetically coupled inductors. Inductors are difference in inductance, one has large inductance and other has small inductance. The inductor with small inductance will take over the output inductor during fast load transient. It speedup the output current slew rate and reduce the output voltage drop in the case of heavy burden load changes.

• Journal of Power Electronics
• /
• 제13권1호
• /
• pp.9-19
• /
• 2013

In this paper, a ripple input current embedded switched-inductor Z-source inverter (rESL-ZSI) and a continuous input current embedded switched-inductor Z-source inverter (cESL-ZSI) are proposed by inserting two dc sources into the switched-inductor cells. The proposed inverters provide a high boost voltage inversion ability, a lower voltage stress across the active switching devices, a continuous input current and a reduced voltage stress on the capacitors. In addition, they can suppress the startup inrush current, which otherwise might destroy the devices. This paper presents the operating principles, analysis, and simulation results, and compares them to the conventional switched-inductor Z-source inverter. In order to verify the performance of the proposed converters, a laboratory prototype was constructed with 60 $V_{dc}$ input to test both configurations.

• Journal of Power Electronics
• /
• 제16권4호
• /
• pp.1277-1287
• /
• 2016

This study proposes a novel isolated high step-up galvanic converter, which is suitable for renewable energy applications and integrates a boost converter, a coupled inductor, a charge pump capacitor cell, and an LC snubber. The proposed converter comprises an input inductor and thus features a continuous input current, which extends the life of the renewable energy chip. Furthermore, the proposed converter can achieve a high voltage gain without an extremely large duty cycle and turn ratio of the coupled inductor by using the charge pump capacitor cell. The leakage inductance energy can be recycled to the output capacitor of the boost converter via the LC snubber and then transferred to the output load. As a result, the voltage spike can be suppressed to a low voltage level. Finally, the basic operating principles and experimental results are provided to verify the effectiveness of the proposed converter.

• Journal of Electrical Engineering and Technology
• /
• 제10권3호
• /
• pp.1075-1080
• /
• 2015

A hybrid electric vehicle (HEV) powertrain has more than one energy source including a high-voltage electric battery. However, for a high voltage electric battery, the average current is relatively low for a given power level. Introduced to increase the voltage of a HEV battery, a compact, high-efficiency boost converter, sometimes called a step-up converter, is a dc-dc converter with an output voltage greater than its input voltage. The inductor occupies more than 30% of the total converter volume making it difficult to get high power density. The inductor should have the characteristics of good thermal stability, low weight, low losses and low EMI. In this paper, Mega Flux^® was selected as the core material among potential core candidates. Different structured inductors with Mega Flux^® were fabricated to compare the performance between the conventional air cooled and proposed potting structure. The proposed inductor has reduced the weight by 75% from 8.8kg to 2.18kg and the power density was increased from 15.6W/cc to 56.4W/cc compared with conventional inductor. To optimize the performance of proposed inductor, the potting materials with various thermal conductivities were investigated. Silicone with alumina was chosen as potting materials due to the high thermo-stable properties. The proposed inductors used potting material with thermal conductivities of 0.7W/m·K, 1.0W/m·K and 1.6W/m·K to analyze the thermal performance. Simulations of the proposed inductor were fulfilled in terms of magnetic flux saturation, leakage flux and temperature rise. The temperature rise and power efficiency were measured with the 40kW boost converter. Experimental results show that the proposed inductor reached the temperature saturation of 107℃ in 20 minutes. On the other hand, the temperature of conventional inductor rose by 138℃ without saturation. And the effect of thermal conductivity was verified as the highest thermal conductivity of potting materials leads to the lowest temperature saturations.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2013년도 전력전자학술대회 논문집
• /
• pp.184-185
• /
• 2013

In this paper, design of a variable inductor using MR Fluid Gap is proposed for wide load range efficiency improvement of a bidirectional DC-DC converter. As compared to conventional constant value inductor designed to have negative current for ZVS at heavy load but suffers high losses at light load due to its small inductance, the proposed variable inductor not only have small inductance at high current for ZVS but also it has large inductance at low current to decrease light load losses.

• 조명전기설비학회논문지
• /
• 제24권12호
• /
• pp.9-16
• /
• 2010

In this paper, we have proposed a new dimmable magnetic ballast for HID(High Intensity Discharge) lamps consisted of AC switches to variate inductance value by using Silicon Controlled Rectifiers and the isolated zero current detector on inductor. Conventional dimming ballast has used relays or Solid State Relays in AC switches. However, a relay is difficult to zero current switching, because it has long operating time(10[ms]), and price competitiveness of SSR is very low. The proposed AC switches are suitable to switch at zero inductor current and it is accurately detected by using a opto-coupler. SCR is cheaper than SSR, and it is suitable to switch at zero inductor current because SCR is automatically turned off under holding current at no gate signal. Operating principles, simulation results and experimental results of the proposed ballast are described.

• 조명전기설비학회논문지
• /
• 제16권4호
• /
• pp.15-21
• /
• 2002

본 논문에서는 동적 전류분담 인덕터를 이용한 ZVT 풀 브리지 DC/DC 컨버터의 병렬운전 특성을 해석하였다. 기존의 경우 CT(Current Transformer)를 사용하여 각 단위 컨버터 전류의 크기를 감지하여, 제어회로에서 각 컨버터에 균등한 전류 배분을 하는 방법을 사용하였으나, 본 연구에서는 동적 전류분담 인덕터를 사용함으로써 병렬운전하는 두 대의 풀 브리지 컨버터의 전류분배를 위한 제어회로를 비교적 단순하게 하였다. 동시에 ZVT회로를 이용하여 컨버터의 효율을 향상시켰으며 스위칭소자로서 IGBT를 사용하여 2[㎾]급 시작품을 제작, 50[KHz]에서 실험하였다.