• Journal of Power Electronics
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• v.17 no.4
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• pp.849-859
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• 2017

This paper illustrates the analysis and design of a multi-resonant converter applied to an electric vehicle (EV) charger. Thanks to the notch resonant characteristic, the multi-resonant converter achieve soft switching and operate with a narrowed switching frequency range even with a wide output voltage range. These advantages make it suitable for battery charging applications. With two more resonant elements, the design of the chosen converter is more complex than the conventional LLC resonant converter. However, there is not a distinct design outline for the multi-resonant converters in existing articles. According to the analysis in this paper, the normalized notch frequency $f_{r2n}$ and the second series resonant frequency $f_{r3n}$ are more sensitive to the notch capacitor ratio q than the notch inductor ratio k. Then resonant capacitors should be well-designed before the other resonant elements. The peak gain of the converter depends mainly on the magnetizing inductor ratio $L_n$ and the normalized load Q. And it requires a smaller $L_n$ and Q to provide a sufficient voltage gain $M_{max}$ at ($V_{o\_max}$, $P_{o\_max}$). However, the primary current increases with $(L_nQ)^{-1}$, and results in a low efficiency. Then a detailed design procedure for the multi-resonant converter has been provided. A 3.3kW prototype with an output voltage range of 50V to 500V dc and a peak efficiency of 97.3 % is built to verify the design and effectiveness of the converter.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.434-437
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• 2007

Cold forging technology of a gear product is being interested in the dimensional accuracy, high stiffness and reduction of stress concentration. Especially it is needed to avoid the damage due to extremely high local pressure. Therefore it is important to ensure high pressure in die design. In this study, single die insert type and splitted die insert type are considered to recognize the notch effects in the die of sprocket forming. The stress concentration has been released at the notch area by the cushion effect in the splitted die insert.

• Transactions of Materials Processing
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• v.16 no.6
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• pp.452-456
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• 2007

Cold forging technology of a gear product is being interested in the dimensional accuracy, high stiffness and reduction of stress concentration. Especially it is needed to avoid the damage due to extremely high local pressure. Therefore it is important to reduce the high pressure in die design of cold forging. In this study, single die insert type and splitted die insert type are considered to recognize the notch effects in the die of sprocket forming. The stress concentration has been released at the notch area by the cushion effect in the splitted die insert.

• Journal of Magnetics
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• v.18 no.2
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• pp.117-124
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• 2013

Single-phase, brushless DC (BLDC) motors have unequal air-gaps to eliminate the dead-point where the developed torque is zero. Unfortunately, these unequal air-gaps can deteriorate the motor characteristics in the cogging torque. This paper proposes a novel design for a single-phase BLDC motor with an asymmetric notch to solve this problem. In the design method, the asymmetric notches were placed on the stator pole face, which affects the change in permanent magnet shape or the residual flux density of the permanent magnet. Parametric analysis was performed to determine the optimal size and position of the asymmetric notch to reduce the cogging torque. Finite element analysis (FEA) was used to calculate the cogging torque. A more than 28% lower cogging torque compared to the initial model with no notch was achieved.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.201-206
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• 2020

A stress-induced brittle failure in deep tunneling generates spalling and slabbing, eventually causing a v-shaped notch formation. An empirical relationship for the depth of the notch to the maximum tangential stress assuming an equivalent circular cross-section was proposed (Martin et al. 1999). While this empirical approach has been well recognized in the industry and used as a design guideline in many projects, its applicability to a non-circular opening is worth revisiting due to the use of equivalent circular profile. Moreover, even though the extent of the notch also contributes to notch failure, it has not been estimated to date. When the estimate of both the depth and the extent of notch are combined, a practical and economically justifiable support design can be achieved. In this study, a new methodology to assess the depth as well as the extent of notch failure is developed. Field data and numerical simulations using the Cohesion Weakening Frictional Strengthening (CWFS) model were collected and correlated with the three most commonly accepted failure criteria (σ₁/σ₃, D_is=σ_max/σ_c, σ_dev/σ_cm). For the numerical analyses, the D-shaped tunnel was used since most civil tunnels are built to this profile. Inferential statistical analysis is applied to predict the failure range with a 95% confidence level. Considering its accuracy and simplicity, the new correlation can be used as an enhanced version of failure assessment.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.58-71
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• 2009

Today is the Information age which Internet service acts a most important Information Source. So A Power Line Communication has been achieved to offer Internet service for Last-Mile area. And Research is achieved to frequence range from 30MHz to 80MHz for High-speed communication service. But, Power Line is not suitable for communication, so, electric wave is generated from flow of communication information. And the electric wave is interfered with Wireless Communication Service using the same frequence range. In this paper, we calculated a 3 steps and 8 steps dynamic Notch Filter to consider the bandwidth of interference signals based on ETSI standard for reduce of interference between Power Line Communication and Wireless Communication Service. And we applied a Notch Filter and verified the application performance from Spectrum and BER.

• Proceedings of the KWS Conference
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• v.43
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• pp.275-277
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• 2004

Fictitious notch radius approach is based on the Neuter's microstructural support hypothesis which assumes that fatigue crack is governed by highly stressed volume of the material right on the weld toe area rather than the surface stress at a pin point of weld toe area. Variety of successes have been achieved in applying this methodology to the fatigue of welded joint, hence, it became one of recommended design procedure in IIW's recommendation as well as many ship classification societies. 1mm fictitious notch radius approach was applied to the various fatigue problems of welded joints in this study covering the effect of weld size, notch stress calculation for 3D geometry and low cycle fatigue problem. It was found that fictitious notch radius approach fumed out to be very effective and accurate in dealing with fatigue strength of welded joint.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.10
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• pp.477-482
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• 2005

In this paper, detent force is minimized using notch and slot-aputure width adjustment in a slotted PMLSM. This time, the moving model node technique has used to reduce the time and the effort for calculation according to changing design parameters. As the result, the detent force of proposed model is decreased from 9.44[N] to 0.97[N] compare with it of basic model greatly. The thrust Is decreased 1.3[$\%$] from 342.07[N] to 337.48[N] a little. The notch is applied to PMLSM simply, the detent force is reduced greatly.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.3
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• pp.113-121
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• 2014

This paper presents a optimization design of 10[W] single phase BLDC motor applied Notch shape. Cogging Torque causes noise, vibration and torque ripple so notched stator is proposed in this paper. Firstly, a single phase BLDC motor needs applying aymmetric air-gap shape because this type motor cannot help having dead-point which is zero torque position. However, using asymmetric air-gap structure causes cogging torque increase. Therefore, this paper proposes the notch shape structure. Notch shape structure has some advantages; low cost, easy to apply. There are 4 optimal factors selected in optimization process, which are position and size of notches. Through building a prototype, the result of FE analysis and the experimental measurement value are compared each other and then vailidity and utility of simulation will be verified.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.65-68
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• 2003

This paper presents a design and construction of IIR multiple notch filter by modifying the pole-zero placement with least square estimation to find the appropriate gain and pole positions for the filter within a unit circle in z-plane. The appropriated gain and pole position will render the controllable unit gain of filter magnitude. Algorithm design and system simulation are performed on MATLAB while the actual implementation is done on the TMS320C31 digital signal processing board.