• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.1360-1363
• /
• 1997

Development and realizatioin of adaptive Active Noise Cntrol used for quieting transformer nosie are planed to provide workers with comfortable working environment and to attenuate the noise for residents in many noisy areas(power plant, power transformer, GIS transformer etc.).

• 반도체디스플레이기술학회지
• /
• 제21권2호
• /
• pp.95-100
• /
• 2022

In this paper, a power loss analysis technique of a high-frequency transformer of a bidirectional DAB (Dual Active Bridge) converter is reported. To miniaturize the transformer of the dual active bridge converter, a resonant inductor was designed with an air gap included low-coupled rate state core to combine leakage inductor with the resonant inductor which is required for soft-switching. In this paper, leakage inductance and magnetizing inductance, core material, type of winding and winding method are included in the dual active bridge transformer loss analysis process to enable optimal design at the initial design stage. Transformer loss analysis for dual active bridge with a switching frequency of 200 kHz and maximum output of 5 kW was executed, and elements necessary for design based on the number of turns on the primary side were graphed while maintaining the transformer turns ratio and window area. In particular, it was possible to determine the optimal number of turns and thickness of the transformer, and ultimately, the total loss of the transformer could be estimated.

• 전력전자학회논문지
• /
• 제9권6호
• /
• pp.560-567
• /
• 2004

이 논문에서는 Planar transformer를 적용한 30W급 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.

• 소음진동
• /
• 제9권6호
• /
• pp.1137-1144
• /
• 1999

Most of ANC(active noise control) researches are focused on adaptive algorithms, computer simulations and implementations of single-channel system in experimental environments. In this paper, a multi-channel ANC system based on DSP's was developed to obtain global attenuations over wide region and applied to the active control of the humming noise generated by a transformer. The developed ANC system including 24 microphones and 12 spearkers was applied to the real transformer noise reduction problem. Results showed that the control system could successfully control the humming noise over the region of interest.

• 전력전자학회논문지
• /
• 제22권2호
• /
• pp.118-125
• /
• 2017

In this paper, we propose a smart transformer for a smart transformer miniature model, which can replace a 60 [Hz] single-phase transformer installed in an electric vehicle. The proposed smart transformer is lighter than a conventional transformer, can control instantaneous voltage, and can be expected to improve power quality through harmonic compensation. The proposed intelligent transformer consists of an incoming part, an AC/DC converter, and a dual active bridge. Only the incoming part and the AC/DC converter are described in this paper. The proposed intelligent transformer has 75 kVA 3.3 kV input and 750 V DC output, which are verified by simulation and experiment.

• 전기학회논문지
• /
• 제62권12호
• /
• pp.1771-1776
• /
• 2013

Most cases of power transformer failure are caused by physical factors linked to the transient vibrations of multiple 120Hz combinations. In addition, the noise generated in the transformer from this vibration not only directly contributes to the worsening of the work environment but also causes psychological stress, resulting in the worsening of the workers efficiency and of the living environment of the inhabitants around the power plant. Thus, to remedy these problems, the mechanical-excitation forces working on a power transformer were categorized in this study, and the mechanical-damage mechanism was identified through the vibration transfer paths acting on machines or structures. In addition, a study on active noise cancellation in a transformer using the FXLMS algorithm was conducted to develop a system that is capable of multiple-sound/channel control, which resulted in the active noise reduction effect when applied on the field.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.894-897
• /
• 1998

A conventional parallel hybrid active filter has an inherent problem of large current ratings of devices used in inverter. In general, this problem has been solved by adjusting turn ratio of a matching transformer. However, making the transformer with high turn ratio may be not available for high power system due to its requirement for high voltage insulation. In this paper, a new configuration is proposed for parallel hybrid active filter. In the proposed hybrid active filter, the active filter is connected to the passive filter inductor in parallel through a matching transformer for the aim of reducing the size of inverter. Through computer simulations, we have shown the outstanding performances of the proposed topology.

• Journal of Electrical Engineering and Technology
• /
• 제11권1호
• /
• pp.257-264
• /
• 2016

In this paper, new electric railway feeding system which has active transformer is modeled for evaluating the steady state analysis using PSCAD/EMTDC. Equivalent models including power supply, feeder, train and transformers are proposed for simplifying the model of the feeding system in high speed electric railway. In case study, simulation results applied to proposed model are compared with the conventional and new systems through the catenary voltage, three-phase voltage of PCC (Point of Common Coupling) and the efficiency of regenerative braking energy.

• 전력전자학회논문지
• /
• 제23권4호
• /
• pp.247-255
• /
• 2018

This paper proposes a transformer design of a direct cell-to-cell active cell balancing circuit with a multi-winding transformer for battery management system (BMS) applications. The coupling coefficient of the multi-winding transformer and the output capacitance of MOSFETs significantly affect the balancing current transfer efficiency of the cell balancing operation. During the operation, the multi-winding transformer stores the energy charged in a specific source cell and subsequently transfers this energy to the target cell. However, the leakage inductance of the multi-winding transformer and the output capacitance of the MOSFET induce an abnormal energy transfer to the non-target cells, thereby degrading the transfer efficiency of the balancing current in each cell balancing operation. The impacts of the balancing current transfer efficiency deterioration are analyzed and a transformer design methodology that considers the coupling coefficient is proposed to enhance the transfer efficiency of the balancing current. The efficiency improvements resulting from the selection of an appropriate coupling coefficient are verified by conducting a simulation and experiment with a 1 W prototype cell balancing circuit.

• 전력전자학회논문지
• /
• 제24권4호
• /
• pp.279-285
• /
• 2019

This study proposes an enhanced switching pattern that can improve energy transfer efficiency in an active cell-balancing circuit using a multiwinding transformer. This balancing circuit performs cell balancing by transferring energy stored in a specific cell with high energy to another cell containing low energy through a multiwinding transformer. The circuit operates in flyback and buck-boost modes in accordance with the energy transfer path. In the conventional flyback mode, the leakage inductance of the transformer and the stray inductance component of winding can transfer energy to an undesired path during the balancing operation. This case results in cell imbalance during the cell-balancing process, which reduces the energy transfer efficiency. An enhanced switching pattern that can effectively perform cell balancing by minimizing the amount of energy transferred to the nontarget cells due to the leakage inductance components in the flyback mode is proposed. Energy transfer efficiency and balancing speed can be significantly improved using the proposed switching pattern compared with that using the conventional switching pattern. The performance improvements are verified by experiments using a 1 W prototype cell-balancing circuit.