높은 전력밀도를 갖는 500 kHz 고주파 LLC 컨버터의 설계와 구현

박화평(Hwa-Pyeong Park),정지훈(Jee-Hoon Jung) 전력전자학회 2015 전력전자학회 논문지 Vol.20 No.1

In order to decrease the size of a switch mode power supply, high switching frequency can be an efficient way to reduce the size of passive components in the converter. In this paper, a 500-kHz high-frequency LLC resonant converter is proposed with an accurate design method of magnetizing inductance, as well as the relationship between the switching frequency and the size of the passive components. Simulation and experimental results are presented to verify the proposed methods and equations, including the temperature data of each passive and active device of the converter. Using those results, dominant power losses in the prototype converter under 500-kHz high-frequency operation are investigated, compared with the results from a 100-kHz converter. In addition, operating waveforms and power conversion efficiency will be shown to obtain design considerations for the high switching frequency LLC resonant converter.

Integrated Magnetics를 적용한 고속 스위칭 및 고전력밀도 3 레벨 LLC 공진형 컨버터

남경훈,박철완,배지훈,지상근,류동균,최흥균,한상규 전력전자학회 2017 전력전자학회 논문지 Vol.22 No.6

This paper proposes a three-level LLC resonant converter using integrated magnetics (IM). Given that the switch voltage stress of the proposed converter is guaranteed to be half of the input voltage, the switching losses can be greatly reduced, thereby benefitting the high-frequency operation. To reduce the volume of reactive components such as transformers, high-frequency driving and planar core are applied. However, two resonant inductors and one transformer are required because of the three-level structure and the limited leakage inductance of the planar transformer for the resonant operation. Therefore, the effect of volume reduction is not very large. In order to solve these drawbacks, this paper proposes a new IM that integrates all magnetic elements used in the proposed three-level resonant converter by using the magnetizing inductor as a resonant inductor. The experimental results are presented by conducting a theoretical analysis of a prototype with 350 W to 800 kHz.

Design and Implementation of High Switching Frequency LLC Resonant Converter for High Power Density

Hwa-Pyeong Park,Hyun-Jun Choi,Jee-Hoon Jung 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

To improve the power density of switch-mode power supplies, high switching frequency operation is an effective method to make the size of passive components small. The new design methodology of magnetizing inductance for zero voltage switching condition, and the size reduction of passive components should be proposed for 500 kHz high switching frequency operation. To verify the proposed methodology, the simulation and experimental results which include power conversion efficiency, and temperature of each passive and active component will be presented. Using those results, dominant power losses will be investigated according to the comparison of 100 kHz and 500 kHz operations. In addition, the small-sized output capacitor which has small output capacitance, and small effective series resistance induces the unstable operation problem. To analyze these control issue, the frequency response of small signal will be discussed to design the optimal feedback loop compensator for high switching frequency LLC resonant converter.

Modeling and Feedback Control of LLC Resonant Converters at High Switching Frequency

박화평,정지훈 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

The high-switching-frequency operation of power converters can achieve high power density through size reduction of passive components, such as capacitors, inductors, and transformers. However, a small-output capacitor that has small capacitance and low effective series resistance changes the small-signal model of the converter power stage. Such a capacitor can make the converter unstable by increasing the crossover frequency in the transfer function of the small-signal model. In this paper, the design and implementation of a high-frequency LLC resonant converter are presented to verify the power density enhancement achieved by decreasing the size of passive components. The effect of small output capacitance is analyzed for stability by using a proper small-signal model of the LLC resonant converter. Finally, proper design methods of a feedback compensator are proposed to obtain a sufficient phase margin in the Bode plot of the loop gain of the converter for stable operation at 500 kHz switching frequency. A theoretical approach using MATLAB, a simulation approach using PSIM, and experimental results are presented to show the validity of the proposed analysis and design methods with 100 and 500 kHz prototype converters.

설계 시간 가속화를 위한 NSGA-II 알고리즘 기반 LLC 공진형 컨버터용 고주파 변압기 최적 설계 기법

차명준,박수성,전선호,김래영 대한전기학회 2024 전기학회논문지 Vol.73 No.1

This paper proposes an optimal design method to minimize the volume and losses of the frequency converter for achieving high efficiency and high density in LLC resonant converters. Specifically, we focus on reducing the volume and losses of the high-frequency transformer, utilizing the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) for this purpose. The proposed method, in contrast to global search methods exploring all possibilities, efficiently acquires Pareto Set values using NSGA-II, thereby reducing design time. The design process was conducted using Matlab, and the results obtained from applying the algorithm were compared with those from global search in terms of design time and accuracy. Additionally, the optimal design points were validated through experimentation.

Design Considerations of Resonant Network and Transformer Magnetics for High Frequency LLC Resonant Converter

Hwa-Pyeong Park,Younggon Ryu,Ki Jin Han,Jee-Hoon Jung 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.2

This paper proposes the design considerations of resonant network and transformer magnetics for 500 kHz high switching frequency LLC resonant converter. The high power density can be effectively achieved by adopting high switching frequency which allows small size passive components in the converter. The design methodology of magnetizing inductance is derived for zero voltage switching (ZVS) condition, and the design methodology of the transformer and output capacitance is derived to achieve high power density at high operating frequency. Moreover, the structure of transformer is analyzed to obtain the proper inductance value for high switching operation. To verify the proposed design methodology, simulation and experimental results will be presented including temperature of passive and active components, and power conversion efficiency to evaluate dominant power loss. In addition, the validity of magnetics design will be evaluated with operating waveforms of the prototype converter.

Design Considerations of Resonant Network and Transformer Magnetics for High Frequency LLC Resonant Converter

Park, Hwa-Pyeong,Ryu, Younggon,Han, Ki Jin,Jung, Jee-Hoon The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.2

This paper proposes the design considerations of resonant network and transformer magnetics for 500 kHz high switching frequency LLC resonant converter. The high power density can be effectively achieved by adopting high switching frequency which allows small size passive components in the converter. The design methodology of magnetizing inductance is derived for zero voltage switching (ZVS) condition, and the design methodology of the transformer and output capacitance is derived to achieve high power density at high operating frequency. Moreover, the structure of transformer is analyzed to obtain the proper inductance value for high switching operation. To verify the proposed design methodology, simulation and experimental results will be presented including temperature of passive and active components, and power conversion efficiency to evaluate dominant power loss. In addition, the validity of magnetics design will be evaluated with operating waveforms of the prototype converter.

Modeling and Feedback Control of LLC Resonant Converters at High Switching Frequency

Hwa-Pyeong Park,Jee-Hoon Jung 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

The high-switching-frequency operation of power converters can achieve high power density through size reduction of passive components, such as capacitors, inductors, and transformers. However, a small-output capacitor that has small capacitance and low effective series resistance changes the small-signal model of the converter power stage. Such a capacitor can make the converter unstable by increasing the crossover frequency in the transfer function of the small-signal model. In this paper, the design and implementation of a high-frequency LLC resonant converter are presented to verify the power density enhancement achieved by decreasing the size of passive components. The effect of small output capacitance is analyzed for stability by using a proper small-signal model of the LLC resonant converter. Finally, proper design methods of a feedback compensator are proposed to obtain a sufficient phase margin in the Bode plot of the loop gain of the converter for stable operation at 500 kHz switching frequency. A theoretical approach using MATLAB, a simulation approach using PSIM, and experimental results are presented to show the validity of the proposed analysis and design methods with 100 and 500 kHz prototype converters.

Modeling and Feedback Control of LLC Resonant Converters at High Switching Frequency

Park, Hwa-Pyeong,Jung, Jee-Hoon The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

The high-switching-frequency operation of power converters can achieve high power density through size reduction of passive components, such as capacitors, inductors, and transformers. However, a small-output capacitor that has small capacitance and low effective series resistance changes the small-signal model of the converter power stage. Such a capacitor can make the converter unstable by increasing the crossover frequency in the transfer function of the small-signal model. In this paper, the design and implementation of a high-frequency LLC resonant converter are presented to verify the power density enhancement achieved by decreasing the size of passive components. The effect of small output capacitance is analyzed for stability by using a proper small-signal model of the LLC resonant converter. Finally, proper design methods of a feedback compensator are proposed to obtain a sufficient phase margin in the Bode plot of the loop gain of the converter for stable operation at 500 kHz switching frequency. A theoretical approach using MATLAB, a simulation approach using PSIM, and experimental results are presented to show the validity of the proposed analysis and design methods with 100 and 500 kHz prototype converters.

Analysis and Design of Novel High-Frequency Integrated Transformer with Adjusting Leakage Inductance for LLC Resonant Converter

Park Su-Seong,Park Jae-Hee,Park Hae-Chan,Kim Rae-Young 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

Adjusting the leakage inductance to approximate the initial design value is important for obtaining the desired output voltage range for an LLC resonant converter with an integrated transformer. To date, various integrated transformer structures and design techniques have been explored to adjust leakage inductance; however, they often require additional devices or complex winding structures, making it difcult to apply them to normal winding-type transformers. This study presents a new integrated transformer structure based on a winding-type transformer that allows to adjust the leakage inductance without additional devices through segments where primary and secondary windings are completely separated or partially overlapped. The proposed integrated transformer structure is manufactured using design techniques that consider not only efciency and power density, but also reliability factors such as magnetic fux and temperature. The proposed structure and design techniques are validated through fnite element analysis simulations and experiments with a 10 kW LLC resonant converter, which confrms the exact design value of the leakage inductance and ensures resonant operation, resulting in a highly efcient resonant converter.