아크 용접기 DC-DC 컨버터용 10kW급 평면 변압기의 설계 및 분석

김종수,유재곤 대한전기학회 2022 전기학회논문지 Vol.71 No.12

In this paper, a design method for a 10kW planar transformer is presented. The problems and design considerations when applying a planar transformer to a 10kW arc welder are described. We present a design technique considering power density, heat generation, and efficiency, which are important elements of a planar transformer. In addition, in order to verify the validity of the design, general winding transformers, winding type planar transformers, and printed circuit board type planar transformers are designed, respectively, and finite element method (FEM) simulations and experiments are performed for efficiency and heat generation. As a result of the experiment based on the proposed planar transformer, it is confirmed that the rated system efficiency is improved by 2.1%, the power density by 204%, and the transformer temperature by 28.3℃ compared to the normal winding transformer designed under the same conditions.

300W 평면 변압기적용 포워드 컨버터

김은수,최선호,박진영 전력전자학회 2004 전력전자학회 논문지 Vol.9 No.6

In this paper, the design and implementation of a high power(300W) forward converter using a planar transformer is presented. The overall size and volume of the converter is decreased by replacing a planar transformer in stead of using a conventional winding transformer. Due to the decreased size and volume, power density of the applied forward converter is increased. Also, in this paper, the 300W ZVS forward converter with active clamp snubber circuit is compared to the 300W hard switching forward converter. 이 논문에서는 Planar transformer를 적용한 300W급 포워드 컨버터에 대한 설계와 실험결과를 소개한다. 컨버터의 전체적인 크기와 체적은 일반적인 권선형 변압기 대신 Planar transformer를 적용함으로써 감소하였고 크기와 체적의 감소로 포워드 컨버터의 전력밀도가 증가하였다. 또한, Single Switch 포워드 컨버터 와 Active Clamp ZVS 포워드 컨버터를 비교연구 하였다.

Novel central‑tapped planar transformer structure with natural current‑sharing for LLC resonant converters

Cheng Gu,Qinsong Qian,Dalin Xu,Tianhao Tan 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.9

Planar transformers have been widely used in isolated power supplies. However, with a large current density, the parallel windings usually cannot share the current evenly. This uneven current-sharing may cause additional winding losses, and damage the performance of the power converter. In this paper, a novel central-tapped planar transformer structure is proposed. Regardless of whether it is in the first half cycle or the second half cycle, the proposed twelve-layer transformer can be simplified as four three-layer transformers connected in parallel. Moreover, there is a “shielding layer” between adjacent three-layer transformers. In addition, the proposed transformer structure is optimized with a symmetrical layer arrangement, and the skin effect and proximity effect can be further reduced. Simulation and experimental tests indicate that the optimized planar transformer can stably provide 476.1 W of output power at a frequency of 1.25 MHz. The peak efficiency of the optimized transformer is up to 99.2%, and there is no obvious hot spot on the PCB board. It is noteworthy that the temperature difference in the secondary windings is less than 5 °C, which means the current-sharing in the secondary windings works well.

Crescent-shaped Input Type 원형압전변압기의 특성 연구

정성수,박태곤,Jeong, Seong-Su,Park, Tae-Gone 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.7

This paper presents a new disk-type piezoelectric transformer. The input side of the transformer has a crescent-shaped electrode and the output side has a focused poling direction. The piezoelectric transformers operated in each transformer's resonance vibration mode. The electrodes and poling directions on commercially available piezoelectric ceramic disks were designed so that the planar or shear mode coupling factor $(k_p\;k_{15})$ becomes effective rather than the transverse mode coupling factor $(k_{31})$. ANSYS finite element code was used to analyze transformer behavior and to optimize electrode and poling configurations. The voltage step-up ratio of the proposed transformer has been markedly improved in comparison with that of the equivalent rectangular(Rosen) type. A single layer prototype transformer, $20\sim30mm$ in diameter and $1.0\sim3.5mm$ thick, was fabricated, such as step-up ratio, power transformation efficiency, and temperature were measured. While the transformer was driving a Cold Cathode Fluorescent Lamp(CCFL), the temperature field of the transformer was also observed.

고전력밀도 OBC를 위한 6.6kW Planar 변압기의 머신러닝 기반 최적 설계

노은총,박수미,김길동,손정우,이승환 전력전자학회 2024 전력전자학회 논문지 Vol.29 No.1

This paper proposes an optimal design process for a planar transformer for on-board charger(OBC). As it is difficult to mathematically model the high-frequency copper loss of the transformer, conventional design processes tend to have large errors in designing the transformers. In this paper, geometric parameters of a shell-type planar transformer are identified, and FEA simulations are completed to obtain the copper loss of various shapes of the shell-type planar transformers. Regression models for the copper loss are determined using the simulation results and the machine learning technique. From the regression model, optimal high-frequency transformer designs and Pareto front(in terms of transformer 2-dimensional area and loss) are obtained using NSGA-II. In the Pareto front, a design was selected as a desired optimal, and the selected design was verified by FEA simulation. The simulated copper loss of the selected design matched very well, thus demonstrating the validity of the proposed design process.

제안된 평면변압기를 이용한 LLC 공진컨버터

이승민(Seung-Min Lee),김은수(Eun-Soo Kim),정봉근(Bong-Gun Chung),이재삼(Jae-Sam Lee),김유선(Yu-Seon Kim),허동영(Dong-Young Huh) 전력전자학회 2012 전력전자학회 논문지 Vol.17 No.2

In this paper, a new planar transformer with a novel core configuration that can regulate the leakage inductance is proposed and described in detail. In order to design the slim size power system for flat panel TV, Two planar transformers applied to LLC resonant converter are connected in series at primary and in parallel by the center-tap winding at secondary. In this paper, a 300W low profile LLC resonant converter was built and tested to verify the proposed planar transformer.

Design and Modeling of Octagonal Planar Inductor and Transformer in Monolithic Technology for RF Systems

Derkaoui Mokhtaria,Benhadda Yamina,Hamid Azzedine,Temmar Abdelkader 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

This paper presents the design and modeling of planar inductor and transformer for their integration in a Forward converter. The windings are of octagonal spiral planar topology. Basing on Wheeler method, we evaluate the inductance values of planar coils. All parasitic eff ects generated by stacking of diff erent material layers are summarized perfectly in the π-electrical model of both on chip inductor and transformer. The electromagnetic simulation, by using COMSOL Multiphysics 5.3 software, illustrates the distribution of magnetic fi eld lines, the current density and the temperature distribution in our integrated micro coils. To validate the diff erent geometric and electrical parameters values, we have simulated the circuit of the Forward converter containing the π-electrical circuit of on chip integrated inductor and transformer, using the software TINA 9.0.

300 W급 평면 변압기의 설계 및 분석

이해연,김현식,김종령,오영우,김은수,Ustinov Evgeniy 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.5

The forward planar transformer, which had power capacity of 300 W, input voltage of 220 V, output voltage of 15 V, and switching frequency of 300 KHz, was designed and manufactured by using the planar core with large effective area and the flat copper leadframes for miniaturization and high efficiency of the switching mode power supply (SMPS). As well as, a forward converter equipped with the above mentioned planar transformer was manufactured and electromagnetic characteristics were investigated. The numerical value of turns for 1st and 2nd winding were 15 and 2 respectively The self inductance of 1st winding was 1.592 mH, very low leakage inductance of 2.7 $\mu$H, and the coupling factor of 0.928 were obtained at switching frequency of 300 KHz. The high efficiency of 88.62 % for the SMPS equipped with planar transformer was obtained at power capacity of 300 W.

낮은 공통 모드 노이즈를 갖는 인터리빙 평면 변압기 권선기법

정현우,임천용 전력전자학회 2023 전력전자학회 논문지 Vol.28 No.6

Planar transformers that feature low profile, low leakage inductance, and excellent thermal characteristics are widely used to improve the performance of isolated converters in switch-mode power supplies. In the case of a planar transformer, however, the contact area between winding layers is large and distance is close, and thus, parasitic capacitance between windings is extremely large, increasing common mode noise current. In this study, we propose a new transformer winding technique for eliminating common mode noise generated from planar transformers by using an interleaving structure. The proposed transformer winding method is configured by connecting a winding layer with an antiphase to a copper foil layer. The proposed method not only reduces common mode current but also conduction loss due to alternating current winding resistance by enabling a complete interleaving structure without increasing the number of shielding layers.

가변주파수 스위칭 Flyback 컨버터를 이용한 자동차용 고압방전등 안정기의 설계

엄태욱(Tae-Wook Um),김윤호(Yoon-Ho Kim) 한국조명·전기설비학회 2008 조명·전기설비학회논문지 Vol.22 No.4

본 논문은 가변주파수 스위칭 방식의 flyback 컨버터를 이용한 자동차용 35[W]급 고휘도 방전 램프용 전자식 안정기의 고효율 제어시스템을 구현하였다. 또한 안정기 성능, 크기 그리고 효율을 고려하여 planar 변압기를 이용하여 flyback 컨버터를 설계하였다. HID 램프를 자동차에 적용하기 위해 복잡한 과도특성을 제어할 수 있는 매우 복잡한 제어회로와 고효율의 안정기의 제작이 요구되어진다. 제안된 전자식 안정기는 planar 변압기를 사용한 flyback 컨버터, full bridge 인버터와 숭압 정화장치로 구성되어 있으며, flyback 컨버터의 스위칭 주파수는 안정기에 입력 전압의 변화에 따라 제어되도록 설계하였고, planar 변압기를 사용하여, 안정기의 가격과 크기를 크게 절감할 수 있었다. 제안된 시스템에 대한 성능 및 효율은 여러 가지 실험을 통해 확인하였다. This paper presents high efficiency control system of automotive 35W electronic ballast for high intensity discharge(HID) lamp using switching flyback converter with variable frequency, Considering performance, size and efficiency of ballast, the flyback converter is designed with planar transformer in converter stage. HID lamp demands a highly efficient ballast and very complex control circuitry that can control complex transient state for applying to automotive. The proposed electronic ballast system is composed of a flyback converter using planar transformer, a full bridge inverter, and a step up ignitor. In this system, switching frequency of flyback converter is controlled by varying input voltage of HID ballast and the price and the size of HID ballast using planar transformer can be reduced. The performance and efficiency of the proposed system are verified through various the experiment results.