• Title/Summary/Keyword: harmonics profile

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Dependence of Harmonics Profiles on Domain Dynamics in Current-Carrying Iron Whisker

  • KIm, C.G.;Kim, D.Y.;Ryu, K.S.;Yang, Y.S.;Lee, J.G.
    • Journal of Magnetics
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    • v.1 no.2
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    • pp.60-63
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    • 1996
  • The first and second harmonics have been measured in the iron whisker with the axial current that produces a circular field. The observed harmonics profiles have been discussed in terms of theoretical analysis based on the nonlinear, asymmetric magnetization that are related to the nucleation, transformation and annihilation of domains. The change of second harmonics profile is more sensitive to the domain variation than that of first harmonics.

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Measurement of Saturation Magnetostriction by the Second-order Higher Harmonics of ac Perturbing Magnetic Field (교류 섭동 자기장의 제 2차 고조파를 이용한 포화자기변헝 측정)

  • Cha, S.Y.;Kim, J.K.;Ryu, K.S.;Cho, Y.R.
    • Journal of the Korean Magnetics Society
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    • v.15 no.2
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    • pp.72-75
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    • 2005
  • The profiles of the second-order higher harmonics during B-H hysteresis loop have been measured as functions of the tensile stress in grain-oriented $3.2{\%}$ Si steels. The observed harmonics profiles have been analyzed in terms of the nonlinear, asymmetric magnetization which reflects the domain reorientation under the field. The field interval of the second-order higher harmonics is related to the nucleation and annihilation fields and a measurement method for the magnetostriction is proposed using the harmonics profiles under tensile stress.

Tooth Modification for Spur Gear for Articulated Hauler's Final Drive (트럭 최종감속기 평기어의 치형최적화에 관한 연구)

  • Oh, Sew-Oong;Zhang, Qi;Lee, In-Bum;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.5
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    • pp.42-47
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    • 2012
  • Construction equipment is heavily loaded during normal operation. In recent years, there is a trend that lower gear noise levels are demanded for drivers to avoid annoyance and fatigue during operation. For articulated hauler's final drive, meshing transmission error(T.E.) is the excitation that leads the tonal noise known as gear whine, and radiated gear whine is also the dominant source of noise in the whole gearbox. This paper presents a method for the analysis of the tooth profile modification, and the prediction of transmission error under the loaded torques for the spur gear pair of the articulated hauler's final drive. And the transmission error, transmission error harmonics and contact stress are also calculated and compared before and after tooth modification under one torque. The simulation result shows that the transmission error and contact stress under the loads can be minimized by the appropriate tooth profile modification.

The calculation of inductance profile for linear switched reluctance motor by analytical method (해석적 방법에 의한 리니어 스위치드 릴럭턴스 전동기의 인덕턴스 프로파일 산정)

  • Jang, Seok-Myeong;Park, Ji-Hoon;Choi, Jang-Young;Sung, Ho-Kyung
    • Proceedings of the KIEE Conference
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    • 2005.10c
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    • pp.138-140
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    • 2005
  • This paper deals with inductance profile of linear switched reluctance motor. Inductance profile of LSRM calculate at align and unalign position using analytical method. Analytical method of this paper used space harmonics method, Also, analysis result compares with data that is derived through an experiment, and proved validity.

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Development of Lorentz Force Type Integrated Motor-Bearing System in Dual Rotor Disk Configuration (두 장의 원판형 회전자를 갖는 로렌츠형 자기 베어링 내장 전동기의 개발)

  • Park, Sung-Ho;Lee, Chong-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.935-940
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    • 2005
  • In this paper, dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor bearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation method effectively attenuates the rotor vibration all over the operating range of rotational speed.

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Development of Lorentz Force Type Integrated Motor-bearing System in Dual Rotor Disk Configuration (두 장의 원판형 회전자를 갖는 로렌츠형 자기 베어링 내장 전동기의 개발)

  • Lee, Chong-Won;Park, Sung-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.9 s.102
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    • pp.1045-1052
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    • 2005
  • Tn this paper. dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor hearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation scheme effectively attenuates the rotor vibration all over the operating range of rotational speed.

Whine Vibration in Gear Drive (기어구동에 의한 화인진동해석)

  • 최연선;신용호;김기범
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.12
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    • pp.3246-3252
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    • 1994
  • The vibration of meshing gear system is originated form teeth deformation, teeth contact ratio, profile error, etc. The gear vibration is classified as whine vibration during meshing and as rattle vibration during idling. In this study, the whine vibration is investigated under the assumption of piecewise linearity of elastic stiffness due to the variation of meshing. Numerical, theoretical and experimental investigations show the existence of the superharmonic components of the second and the third order. consistently It can be concluded that the superharmonic components in whine vibration of meshing gear is originated from the stiffness variation. It also shows that the higher order harmonics are reduced on the increase of motor speed.

Natural Balancing of the Neutral Point Potential of a Three-Level Inverter with Improved Firefly Algorithm

  • Gnanasundari, M.;Rajaram, M.;Balaraman, Sujatha
    • Journal of Power Electronics
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    • v.16 no.4
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    • pp.1306-1315
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    • 2016
  • Modern power systems driven by high-power converters have become inevitable in view of the ever increasing demand for electric power. The total power loss can be reduced by limiting the switching losses in such power converters; increased power efficiency can thus be achieved. A reduced switching frequency that is less than a few hundreds of hertz is applied to power converters that produce output waveforms with high distortion. Selective harmonic elimination pulse width modulation (SHEPWM) is an optimized low switching frequency pulse width modulation method that is based on offline estimation. This method can pre-program the harmonic profile of the output waveform over a range of modulation indices to eliminate low-order harmonics. In this paper, a SHEPWM scheme for three-phase three-leg neutral point clamped inverter is proposed. Aside from eliminating the selected harmonics, the DC capacitor voltages at the DC bus are also balanced because of the symmetrical pulse pattern over a quarter cycle of the period. The technique utilized in the estimation of switching angles involves the firefly algorithm (FA). Compared with other techniques, FA is more robust and entails less computation time. Simulation in the MATLAB/SIMULINK environment and experimental verification in the very large scale integration platform with Spartan 6A DSP are performed to prove the validity of the proposed technique.

A Study on Application of Electric Propulsion System using AFE Rectifier for Small Coastal Vessels

  • Jeon, Hyeonmin;Kim, Seongwan;Kim, Jongsu
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.3
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    • pp.373-380
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    • 2018
  • The small coastal vessel registered in Korea, small coastal vessels with a gross tonnage of 10 tons or less account for 94.6 % and among them, aged vessels over 16 years age indicate 40.6 %. In order to reduce GHG emissions from small coast vessels, discussions are underway to replace aging ships' propulsion units with eco - friendly propulsion facilities, and the electric propulsion ship is emerging as one of the measures. The electric propulsion system using the DFE rectifier, which was applied in the conventional large commercial vessel, was effective in reducing the harmonics and improving the DC output voltage of the DC link stage, but it occupied a large volume and caused an increase in the overall system price. Therefore, in this paper, we propose an electric propulsion system using AFE rectifier with a small volume of system that can be applied to a small coastal vessel. In order to analyze the effectiveness of the overall system, the load profile was applied to obtain accurate and rapid speed tracking performance of the propulsion motor affected by the speed load. In addition, the power factor and total harmonic distortion factor of the voltage and current on the improved power output side are derived through simulation.

Dynamic Analysis of Linear Switched Reluctance Motor considering Electromagnetic Characteristics (직선형 스위치드 릴럭턴스 전동기의 전자기 특성을 고려한 동특성 해석)

  • Jang, Seok-Myeong;Park, Ji-Hoon;Ko, Kyoung-Jin;Kim, Il-Jung
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.611_612
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    • 2009
  • This paper deals with dynamic analysis of linear switched reluctance motor considering electromagnetic characteristics. First, inductance profile of linear switched reluctance motor calculate at align and unalign position and phase resistance using analytical method. Analytical method of this paper used space harmonics method, also, analysis result compares with data that is derived through an finite element method, and proved validity. In dynamic simulation of linear switched reluctance, we analyzed dynamic characteristic of linear switched reluctance motor according to single pulse waveform and hard chopping voltage PWM.

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