• Title/Summary/Keyword: Notch design

Search Result 237, Processing Time 0.028 seconds

THD Analysis of a Hydraulic Servo Valve Using CFD (CFD를 이용한 유압 서보밸브의 열유체 해석)

  • Jeong, Y.H.;Park, T.J.
    • Journal of Drive and Control
    • /
    • v.11 no.1
    • /
    • pp.8-13
    • /
    • 2014
  • Hydraulic servo valves are widely used in various fluid power systems because of their fast response and precision control. In this paper, we studied the effect of metering notch shapes and amount of their openings on the flow characteristics within the spool valve using a computational fluid dynamic (CFD) code, FLUENT. To obtain the results for more realistic operating conditions, viscous heating due to the jet flow and viscosity variation of the hydraulic fluid with temperature were considered. For two types of notch shape, streamlines, oil temperature and viscosity distributions, and variations of flow and friction forces acting on spool were showed. The flow and friction forces affected by the metering notch shapes and their openings, and oil temperature rise near metering notch was significant enough to results in the jamming phenomenon. A thermohydrodynamic (THD) flow analysis adopted in this paper can be used in optimum design of hydraulic servo valves.

The Notch Filter Design for Mitigation Current Ripple of Fuel cell-PCS (연료전지용 PCS의 출력 전류 리플 개선을 위한 노치 필터 설계)

  • Kim, Seung-Min;Park, Bong-Hee;Choi, Ju-Yeop;Choy, Ick;Lee, Sang-Chul;Lee, Dong-Ha
    • Journal of the Korean Solar Energy Society
    • /
    • v.32 no.6
    • /
    • pp.106-112
    • /
    • 2012
  • As a fuel cell converts the chemical energy of the fuel cell into electrical energy by electrochemical reaction, the fuel cell system is uniquely integrated technique including fuel processor, fuel cell stack, power conditioning system. The residential fuel cell-PCS(Power Conditioning System) needs to convert efficiently the DC current produced by the fuel cell into AC current using single-phase DC-AC inverter. A single-phase DC-AC inverter has naturally low frequency ripple which is twice frequency of the output current. This low frequency(120Hz) ripple reduces the efficiency of the fuel cell. This paper presents notch filter with IP voltage controller to reject specific 120Hz current ripple in single-phase inverter. The notch filter is designed that suppress just only specific frequency component and no phase delay. Finally, the proposed notch filter design method has been verified with computer simulation and experimentation.

Design of Inchworm Linear Motor Using Design of Experiment (실험계획법을 이용한 인치웜 리니어 모터의 설계)

  • 예상돈;민병현
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2002.10a
    • /
    • pp.1041-1044
    • /
    • 2002
  • Inchworm linear motor is one of the ultra precision position apparatuses and has many kinds of forms and structures according to the conditions of working space and range. In this paper, the Inchworm linear motor consists of three PZTs(Piezo-electric transducer), three columns ma two plates. finite element method was used to determine the type or hinges installed in column of inchworm linear motor DOE(Design of experiment) was used to determine the optimal design condition of a column by comparing the von-mises stresses according to the change of thickness of hinge, round of hinge, height of arm, angle of v-notch, round of v-notch and thickness of column. From the result, round of hinge, height of arm and thickness of hinge were determined a effective design parameters.

  • PDF

Development of 3-axis Fine Positioning Stage: Part 1. Analysis and Design (초정밀 3축 이송 스테이지의 개발: 1. 해석 및 설계)

  • 강중옥;서문훈;한창수;홍성욱
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.21 no.3
    • /
    • pp.147-154
    • /
    • 2004
  • This paper presents a procedure for analysis and design of a fine positioning stage, which has many applications in industries for machine tools, semiconductor, LCD and so forth. The stage considered here is based on a single module with 3 axes which is composed of flexures hinges, piezoelectric actuators and their peripherals. Through a series of analysis, the structural analysis model is simplified as a rigid body(the moving part) and springs(the flexures hinges). An experimental design procedure is applied to determine the dimension of flexures hinges. A sensitivity analysis on the notch positions is also performed to obtain a guideline of fabrication accuracy for the stage. An actual fine stage is made and verified through an experiment on the dynamic characteristics.

The Feed-forward Controller and Notch Filter Design of Single-Phase Photovoltaic Power Conditioning System for Current Ripple Mitigation (단상 PVPCS 출력 전류의 리플 개선을 위한 노치 필터 및 피드 포워드 제어기 설계)

  • Kim, Seung-Min;Yang, Seung-Dae;Choi, Ju-Yeop;Choy, Ick;Lee, Young-Gwon
    • 한국태양에너지학회:학술대회논문집
    • /
    • 2012.03a
    • /
    • pp.325-330
    • /
    • 2012
  • A single-phase PVPCS(photovoltaic power conditioning system) that contains a single phase dc-ac inverter tends to draw an ac ripple current at twice the out frequency. Such a ripple current may shorten passive elements life span and worsen output current THD. As a result, it may reduce the efficiency of the whole PVPCS system. In this paper, the ripple current propagation is analyzed, and two methods to reduce the ripple current are proposed. Firslyt, this paper presents notch filter with IP voltage controller to reject specific current ripple in single-phase PVPCS. The notch filter can be designed that suppress just only specific frequency component and no phase delay. The proposed notch filter can suppress output command signal in the ripple bandwidth for reducing output current THD. Secondly, for reducing specific current ripple, the other method is feed-forward compensation to incorporate a current control loop in the dc-dc converter. The proposed notch filter and feed-forward compensation method have been verified with computer simulation and simulation results obtained demonstrate the validity of the proposed control scheme.

  • PDF

Design of UWB Hexagon Patch Antenna with WLAN Notch Band Characteristic (WLAN 노치 대역 특성을 갖는 UWB 육각형 패치 안테나)

  • Kim, Young-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.42 no.1
    • /
    • pp.286-290
    • /
    • 2017
  • In this paper, we have proposed a hexagonal patch UWB antenna with a band notch characteristic where the notch band of 5.15 ~ 5.85 GHz band of WLAN was induced by inserting a circular slit in the patch. The impedance bandwidth of the proposed antenna meet the band width criteria of UWB communication system where is mentioned as frequencies range form 3.1 ~ 11.8 GHz. The characteristic band at 5.2 ~ 5.8 GHz notch band was observed. The radiation pattern of the antenna shows a directinal radiation pattern at $0^{\circ}$ and $180^{\circ}$ in XZ-plane and YZ-plane is an omni-directional pattern, respectively. In addition, it is observed that increase in frequency results in increases of the antenna gain whereas the notch band section is decreased. The proposed antenna was designed TRF-45 substrate with thickness of 1.62 mm, a loss tangent of 0.0035, a relative permittivity of 4.5 and designed were used Ansys Inc. HFSS.

A method for eliminating periodic interference by sampling frequency control of discrete-time notch filter (이산-시간 노치 여파기의 표본화 주파수 제어에 의한 주기성 간섭의 제거방법)

  • 염동홍;안수길
    • 전기의세계
    • /
    • v.31 no.6
    • /
    • pp.450-456
    • /
    • 1982
  • This paper proposes a new method for eliminating periodic interference corrupting a signal. The method proposed herein uses a variable notch filter by sampling frequency control to eliminate the interference. This method is applicable when an auxiliary reference input is available containing the interference alone. The sampling frequency is determined by the fundamental frequency of the periodic interference. Also, this paper proposes a design procedure so that it can be easily applied.

  • PDF

Study on Satellite Vibration Control Using Adaptive Algorithm

  • Oh, Choong-Seok;Oh, Se-Boung;Bang, Hyo-Choong
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.2120-2125
    • /
    • 2005
  • The principal idea of vibration isolation is to filter out the response of the system over the corner frequency. The isolation objectives are to transmit the attitude control torque within the bandwidth of the attitude control system and to filter all the high frequency components coming from vibration equipment above the bandwidth. However, when a reaction wheels or control momentum gyros control spacecraft attitude, vibration inevitably occurs and degrades the performance of sensitive devices. Therefore, vibration should be controlled or isolated for missions such as Earth observing, broadcasting and telecommunication between antenna and ground stations. For space applications, technicians designing controller have to consider a periodic vibration and disturbance to ensure system performance and robustness completing various missions. In general, past research isolating vibration commonly used 6 degree order freedom isolators such as Stewart and Mallock platforms. In this study, the vibration isolation device has 3 degree order freedom, one translational and two rotational motions. The origin of the coordinate is located at the center-of-gravity of the upper plane. In this paper, adaptive notch filter finds the disturbance frequency and the reference signal in filtered-x least mean square is generated by the notch frequency. The design parameters of the notch filter are updated continuously using recursive least square algorithm. Therefore, the adaptive filtered-x least mean square algorithm is applied to the vibration suppressing experiment without reference sensor. This paper shows the experimental results of an active vibration control using an adaptive filtered-x least mean squares algorithm.

  • PDF

Adaptive Suppression of Mechanical Resonance in High-Density Disk Drives (고밀도 디스크 드라이브의 적응형 공진 보상 알고리즘)

  • 강창익;김창환
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.9 no.9
    • /
    • pp.679-691
    • /
    • 2003
  • The band-width of disk drive servo system is rapidly increasing for the robustness to external disturbance as the track density is increasing. The increase of the band-width may cause mechanical resonance of an actuator. In disk drive servo system, a notch filter is usually used to suppress the mechanical resonance of the actuator. However, the resonance frequency differs from drive to drive because of manufacturing tolerance and varies with temperature even within a single drive. The variation of resonance frequency degrades the suppression performance of the notch filter. In this paper, we present an adaptive digital notch filter that identifies the resonance frequency of the disk drive servo actutaor precisely and adjusts automatically its center frequency. For this, we design an adaptive FIR digital filter for the estimation of the resonance frequency. The estimation filter identifies the resonance frequency adaptively using the output signal generated from the servo system, which is excited with an excitation signal including all the expected resonance frequency components. We prove mathematically the convergence of the resonance frequency estimation filter. Furthermore, in order to demonstrate the practical use of our work, we present some experimental results using a commercially available disk drive.

COMPARISON OF MARGINAL LEAKAGE OF CLASS 5 GIC RESTORATIONS ACCORDING TO CAVITY DESIGNS (와동 형태에 따른 5급 글라스 아이오노머 시멘트 수복물의 변연누출 비교)

  • Lee, Seon-Hwa;Hur, Bock;Lee, Hee-Joo
    • Restorative Dentistry and Endodontics
    • /
    • v.23 no.1
    • /
    • pp.296-303
    • /
    • 1998
  • The purpose of this study was to assess the effects of cavity designs on the marginal leakage of class 5 glass ionomer restorations. The five cavity designs were as follows ; notch shape(A group), notch shape with groove(B group), combined lesion(C group), combined lesion with groove and deep chamfer margin(D group) and combined lesion with groove and shoulder(E group), and each design had 10 cavities. After the cavities were restored with GIC, they were immersed in 0.5% basic fuchsin solution for 6 hours. The specimens were washed thoroughly and sectioned longitudinally in a buccolingual direction through the center of the restorations. The degree of marginal leakage was measured as the extent of dye penetration under the stereoscope. The results of this study were as follows 1. The enamel margins of all groups showed lesser leakage than dentin/cementum margins(p<0.05). 2. The combined lesion(C group) showed more leakage than notch shape(A group), but there was no siginificant difference(p>0.05). 3. In the notch shape, there was no influence on the marginal leakage by the groove preparation. 4. In the combined lesion, marginal leakage was decreased by the groove preparation and marginal modification.

  • PDF