• 한국산학기술학회논문지
• /
• 제17권5호
• /
• pp.146-152
• /
• 2016

본 논문에서는 고정밀 각도 센싱을 요구하는 응용분야에 이용되는 권선형 레졸버의 변압부와 레졸버 파트의 유한요소법 (Finite Element Method, FEM)을 이용한 연동해석을 통해 권선형 레졸버 시스템의 성능을 도출하는 과정을 연구하였다. 외부 인가 전원을 증폭시키는 회전형 변압기부와 증폭된 변압기 출력을 이용하는 레졸버의 회전자 입력부의 연동해석을 통하여 전자기적인 정밀도를 향상시킬 수 있는 권선형 레졸버의 연동해석 모델을 제시하고 출력 신호의 특성을 분석하였다. 회전형 변압기에서 승압된 전압이 레졸버 회전자 권선에 인가될 때 회전자 권선의 임피던스를 고려하여 레졸버 입력 전류를 계산하여야 한다. 따라서 레졸버 회전자 권선부 인터페이스 부분은 회로 모델로 구성하여 변압기의 유한요소 모델, 인터페이스 회로 모델, 레졸버 유한요소 모델을 한 번에 연성해석을 수행하였다. 고정밀 각도 도출을 위해 레졸버 고정자 권선은 32x와 1x의 혼합 권선이 설치되어 있으며 서로간의 자기적인 간섭은 없다. 본 논문에서는 슬롯에 적절한 분포적인 권선법이 제시되어 정현적인 SIN, COS 파형과 이들간의 위상각 $90^{\circ}$를 만족시킬 수 있음을 확인하였다.

• Journal of Electrical Engineering and Technology
• /
• 제13권4호
• /
• pp.1586-1595
• /
• 2018

For the problem that the complexity of 3-D modeling and multi parameter optimization, as well as the uncertainty of the winding factor of axial flux permanent magnet generator with coreless windings. The complex 3-D model was simplified into 2-D analytic model, and an analytical formula for the winding factor that adapting different coreless stator winding is proposed in this paper. The analytical solution for air-gap magnetic fields, no-load back EMF, electromagnetic torque, and efficiency are calculated by using this method. The multiple objective and multivariable optimization of the maximum fundamental and the minimum harmonic content of back EMF are performed by using response surface methodology. The proposed optimum design method was applied to make a generator. The generator was tested and the calculated results are compared with the proposed method, which show good agreements.

• 한국전기전자재료학회논문지
• /
• 제19권10호
• /
• pp.976-983
• /
• 2006

Multi-resolution Signal Decomposition (MSD) Technique of Wavelet Transform has interesting properties of capturing the embedded horizontal, vertical and diagonal variations within an image in a separable form. This feature was exploited to identify individual partial discharge sources present in multi-source PD pattern, usually encountered during practical PD measurement. Employing the Daubechies wavelet, feature were extracted from the third level decomposed and reconstructed horizontal and vertical component images. These features were found to contain the necessary discriminating information corresponding to the individual PD sources and multi-PD soruces.

• Journal of Electrical Engineering and Technology
• /
• 제6권1호
• /
• pp.59-66
• /
• 2011

This work treat the modeling and simulation of non-linear dynamic behavior of a web winding process during traction. We designate by a winding process any system applying the cycles of unwinding, transport, treatment, and winding to various flat products. This system knows several constraints, such as the thermal effects caused by the frictions, and the mechanical effects provoked by metal elongation, that generates dysfunctions due to the influence of the process conditions. Several controllers are considered, including Proportional-integral (PI) and Backstepping control. This paper presents the study of Backstepping controls strategy of the winding system. Our winding system is simulated in MATLAB SIMULINK environment, the results obtained illustrate the efficiency of the proposed control with no overshoot, and the rising time is improved with good disturbances rejections comparing with the classical control law.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.514-521
• /
• 2017

This paper proposes a shadowing compensation method for the solar modules of grid-connected photovoltaic generation systems. The shadowing compensator (SC) implemented by the proposed shadowing compensation method is used only for the solar modules that can be shaded by predictable sources of shading. The proposed SC can simplify both the power circuit and the control circuit as well as improve power efficiency and utilizes a voltage equalizer configured by a modified multi-winding fly-back converter. The proposed SC harvests energy from the entire solar cell array to compensate for the shaded sub-modules of the solar cell array, producing near-identical voltages of all shaded and un-shaded sub-modules in the solar cell array. This setup prevents the formation of multiple peaks in the P-V curve under shaded conditions. Hardware prototypes are developed for the SCs implemented by the conventional and modified multi-winding fly-back converters, and their performance is verified through testing. The experimental results show that both SCs can overcome the multiple peaks in the P-V curve. The proposed SC is superior to the SC implemented by the conventional multi-winding fly-back converter.

• 한국전기전자재료학회논문지
• /
• 제19권10호
• /
• pp.942-946
• /
• 2006

We simulated insulation defects of stator winding wire on high voltage generator by 5 types. 4 types have one discharge source and other one has multi discharge source by simulation. For accurate decision, measurements used to PRPD pattern to occurred partial discharge source of various types. In this research, when PRPD pattern carried out or analyzed pattern recognition of discharge source, it used to powerful tools. In this result, PRPD Pattern defined to have single discharge source of 4 types by insulation defect. When insulation defect simulated, all the defected winding have not the same result. Errors for a little different can make mistakes from a subtle distinction. The difference between internal and void discharge have magnitude of pulse amplitude of inner discharge bigger than void discharge and have a shape of bisymmetry. But void discharge has a shape of bisymmetry against maximum value on polarity respectively. In cases of slot and surface discharge, we confirmed to show similar results those other researchers. In case of multi-discharge, as a result of we could classify not perfect match with occurred patterns in single discharge eachother. In the future, we will have to recognize and classify with results of multi-discharge.

• 전력전자학회논문지
• /
• 제17권5호
• /
• pp.393-400
• /
• 2012

The modularized equalizers normally use additional components among the modules in the long series-connected lithium-ion battery string. In these approaches, the overall systems are heavy, bulky, and high-priced. Furthermore, the losses related to additional components decrease the system efficiency. To avoid these problems, a modularized equalizer, which has no additional components among the modules, is required. This paper proposes a novel control scheme using the magnetizing energy of the multi-winding transformer for the module equalization. In this scheme, the high duty cycle is applied to the module where the voltage is higher than the reference voltage and the low duty cycle is applied to the module where the voltage is lower than the reference voltage. Due to the different duty cycle, more electric charges are transferred from high voltage module to the low voltage module during the turn-off switching interval. Using the proposed control scheme, the equalizer system does not suffer from the size, cost, and loss related to the modularization. The experimental results are provided to verify the effectiveness of the proposed modularized equalizer.

• Journal of Power Electronics
• /
• 제18권1호
• /
• pp.266-276
• /
• 2018

This paper presents a new step-up and step-down multi-pulse auto-transformer rectifier unit (ATRU) topology. This structure can achieve a wide range of output voltages, which solves the problem of auto-transformer output voltage being difficult to regulate. Adding middle taps to the primary winding and reasonably setting the number of auto-transformer windings, constituted two groups of three-phase output voltages with a $30^{\circ}$ phase difference. Multi-pulse output DC voltage is obtained after a three-phase output voltage across two rectifier bridges and inter-phase reactor. Thus, the output DC voltage is related to the number and configuration of the auto-transformer winding. In this paper, the relationship between the voltage ratio of the auto-transformer and the ratio of winding, input current and auto-transformer kilovoltampere rating are deduced and validated by simulations. On this basis, the output voltage range is optimized. An experiment on two different voltage ratio principle prototypes was carried out to verify the correctness of the analysis design.

• 전력전자학회논문지
• /
• 제19권1호
• /
• pp.31-40
• /
• 2014

This paper describes an optimal configuration for multi-central inverters in a medium-voltage (MV) grid, which is suitable for large-scale photovoltaic (PV) power plants. We theoretically analyze a proposed common-mode equivalent model for problems associated with multi-central transformerless-type three-phase full bridge(3-FB) PV inverters employing two-winding MV transformers. We propose a synchronized PWM control strategy to effectively reduce the common-mode voltages that may simultaneously occur. In addition, we propose that the existing 3-FB topology may also have the configuration of a multi-central inverter with a two-winding MV transformer by making a simple circuit modification. Simulation and experimental results of three 350kW PV inverters in a multi-central configuration verify the effectiveness of the proposed synchronization control strategy. The modified transformerless-type 3-FB topology for a multi-central PV inverter configuration is verified using an experimental prototype of a 100kW PV inverter.

• 한국초전도저온공학회:학술대회논문집
• /
• 한국초전도저온공학회 2003년도 학술대회 논문집
• /
• pp.58-61
• /
• 2003

A typical HTS power transmission cable has multi-layer conductor structure to increase the current capacity. The current distribution among the conductor tapes is controlled mainly by pitches and winding directions of the layers, because the inductance of the layer is determined by the pitch and the winding direction. However, usually the current is not evenly distributed among the layers. This paper describes a method to make the current distribution more uniform and hence reduce the AC loss. If we choose a good combination we can find the optimal pitches and make an even current distribution. We studied the effect of the winding direction on a 2-layer cable by a statistical way. Calculation results and discussions will be presented.