• 제목/요약/키워드: harmonic drive

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Power Factor Correction of Switched Reluctance Motor Drive System using Boost Converter (승압형 컨버터를 이용한 SRM의 구동시스템 역률개선)

  • Yoon Yong-Ho;Kim Jae-Moon;Lee Tae-Won;Kim Hack-Seong;Won Chung-Yuen
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.3
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    • pp.211-218
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    • 2005
  • Switched Reluctance Motor(SRM) offers the advantages of simple and robust motor construction, high speed and high efficiency over a wide operating range of torque and speed, excellent controllability. However SRM has the disadvantages of high current harmonics, and low power factor because the required output of speed and torque is produced by the discontinuous and loss of power system, and brings about the incorrect operation of electronic system. This paper deals with an energy efficient converter fed SRM system with the reduced harmonics and improved power factor. The validity of the proposed scheme is verified via experiments. We are implemented the proposed control system using 80C196KC micro-controller.

Line Current Characteristics of Multilevel H-Bridge Inverters: Part I - Connection of Input Transformer and Phase Shift Characteristics (다단 H-브릿지 인버터의 입력전류특성 (I) - 입력단 변압기 결선과 위상이동특성)

  • Jeong, Seung-Gi
    • The Transactions of the Korean Institute of Power Electronics
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    • v.13 no.3
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    • pp.229-236
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    • 2008
  • Recently, multilevel H-bridge inverters have become popular in medium to high power ac drive applications. One of significant advantages of them is low harmonic contents in their input line currents thanks to the transformer with multiple phase-shifted secondary windings. This paper attempts to provide basic guidelines for the design of the phase shifting transformer windings and theoretical analysis of input line current harmonics of H-bridge inverters. The part I provides the derivation of basic relationships between input and output current of the transformer and the relationship between the phase shifting characteristics and design aspects of the transformer.

An Improved High-Resolution Rotor Position Estimation Using Gain Scheduled Speed Observer in PMSM Drives with Hall-Effect Position Sensors (홀-이펙트 위치센서를 갖는 PMSM 드라이브에서 이득 스케줄 속도관측기에 의한 향상된 고 해상도 회전자 위치추정)

  • Kim, Sam-Young;Byun, Hang-Gil;Ko, Bong-Jin;Park, Seung-Yub
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.10
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    • pp.1809-1815
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    • 2010
  • This paper presents an improved method for high-resolution rotor position estimation in the permanent magnet synchronous motor (PMSM) drives with low-resolution Hall-effect sensors. The proposed method adopts a gain-scheduled full-order speed observer. Since the quantized position signal, which is obtained from Hall-effect sensors, is basically used as the input of the observer, the sixth-order harmonics are essentially included in the estimated position. To eliminate the harmonic components, the quantized position is linearized by a linear extrapolation based on the estimated average speed and futhermore the speed-depentent observer gain scheduling strategy is developed. The observer gain is also scheduled by considering the motor acceleration to improve the dynamic performance according to the changes of the motor speed and load. Several experiments are performed for 800W PMSM drive and the results demonstrate the effectiveness of the proposed method.

Injection Molding for a Ultra Thin-Wall Part using Induction Heating (고주파 유도가열을 사용한 초박육 플라스틱 제품의 사출성형)

  • Park, Keun;Choi, Sun;Lee, Se-Jik;Kim, Young-Seog
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.6
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    • pp.481-487
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    • 2008
  • Rapid mold heating has been recent issue to enable the injection molding of thin-walled parts or micro/nano structures. Induction heating is an efficient way to heat material by means of an electric current that is caused to flow through the material or its container by electromagnetic induction. It has various applications such as heat treatment, brazing, welding, melting, and mold heating. The present study covers an experimental investigation of induction heating in order to rapidly raise the mold temperature. It is observed that the mold surface temperature is raised up to $200^{\circ}C$ in 2 seconds. This induction heating is applied to injection molding of a flexspline for a plastic harmonic drive, which has difficulty in cavity filling because its minimum thickness is only 0.35 mm. The induction heating is then successfully implemented on this ultra-thin wall molding by raising the mold surface temperature around the glass-transition temperature of the molding material.

A Hybrid CBPWM Scheme for Single-Phase Three-Level Converters

  • Wang, Shunliang;Song, Wensheng;Feng, Xiaoyun;Ding, Rongjun
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.480-489
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    • 2016
  • A novel hybrid carrier-based pulse width modulation (CBPWM) scheme that combines unipolar and dipolar modulations is proposed for single-phase three-level rectifiers, which are widely applied in railway traction drive systems. The proposed CBPWM method can satisfy the volt-second balancing principle in the complete modulation index region through overmodulation compensation. The modulation scheme features two modulation modes: unipolar and dipolar. The operation range limits of these modulation modes can be modified by changing the separation coefficient. In comparison with the traditional unipolar CBPWM, the proposed hybrid CBPWM scheme can provide advantageous features, such as lower high-order harmonic distortion of the line current and better utilization of switching frequency. The separation coefficient value is optimized to achieve the maximum utilization of these advantages. The experimental results verify the feasibility and effectiveness of the proposed hybrid CBPWM scheme.

Design and optimization of 900kW class PMSG, based on Unison U50 model (Unison U50 직접구동 영구자석 발전기를 기반으로 한 900kW급 동기발전기 설계 및 최적화)

  • Kim, Tae-Hun;Lee, Sang-Woo;Kim, Dong-Eon;Chung, Chin-Wha;Park, H.C.
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.423-426
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    • 2009
  • POSTECH Graduate School of Wind Energy is trying to upgrade the PMSG used for Unison U50 to 900 kW class. Intensive optimization efforts are carried out the reduce the axial size and total weight of the generator while increasing the rated output to 900 kW. The generator features 3.32m stator inner radius, 671mm stator length, 84 pole, 25 rated rpm and 31.6kN/$m^2$ shear force density. To reduce the gross weight, the stronger magnetic material is applied with optimal magnet size resulting lowest cogging torque. Also, instead of stator skewing the stator, the magnet position along the circumference is optimized to further reduce the cogging torque. This scheme eliminates the stator skewing procedure and may enhance the productivity. This method also reduces the total harmonic distortion. In this report, upgrade method, no-load line to line voltage and phase voltage, cogging torque, loss calculations and thermal analysis are presented.

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Implementation of Multilevel Boost DC-Link Cascade based Reversing Voltage Inverter for Low THD Operation

  • Rao, S. Nagaraja;Kumar, D.V. Ashok;Babu, Ch. Sai
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1528-1538
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    • 2018
  • In this paper, configuration of $1-{\phi}$ seven-level boost DC-link cascade based reversing voltage multilevel inverter (BDCLCRV MLI) is proposed for uninterrupted power supply (UPS) applications. It consists of three level boost converter, level generation unit and full bridge circuit for polarity generation. When compared with conventional boost cascaded H-bridge MLI configurations, the proposed system results in reduction of DC sources, reduced power switches and gate drive requirements. Inverter switching is accomplished by providing appropriate switching angles that is generated by any optimization switching angle techniques. Here, round modulation control (RMC) method is taken as the optimization method and switching angles are derived and the same is compared with various switching angles methods i.e., equal-phase (EP) method, and half-equal-phase (HEP) method which results in improved quality of obtained AC power with lowest total harmonic distortion (THD). Reduction in DC sources and switch count makes the system more cost effective. A simulation and prototype model of $1-{\phi}$ seven-level BDCLCRV MLI system is developed and its performance is analyzed for various operating conditions.

Distortion Elimination for Buck PFC Converter with Power Factor Improvement

  • Xu, Jiangtao;Zhu, Meng;Yao, Suying
    • Journal of Power Electronics
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    • v.15 no.1
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    • pp.10-17
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    • 2015
  • A quasi-constant on-time controlled buck front end in combined discontinuous conduction mode and boundary conduction mode is proposed to improve power factor (PF).When instantaneous AC input voltage is lower than the output bus voltage per period, the buck converter turns into buck-boost converter with the addition of a level comparator to compare input voltage and output voltage. The gate drive voltage is provided by an additional oscillator during distortion time to eliminate the cross-over distortion of the input current. This high PF comes from the avoidance of the input current distortion, thereby enabling energy to be delivered constantly. This paper presents a series analysis of controlling techniques and efficiency, PF, and total harmonic distortion. A comparison in terms of efficiency and PF between the proposed converter and a previous work is performed. The specifications of the converter include the following: input AC voltage is from 90V to 264V, output DC voltage is 80V, and output power is 94W.This converter can achieve PF of 98.74% and efficiency of 97.21% in 220V AC input voltage process.

Analysis on Eddy Current Losses for Cylindrical Linear Oscillatory Actuator with Halbach Array according to Drive Voltage Waveform (영구자석 Halbach형 원통형 액추에이터의 구동전압 파형에 따른 와전류 손실)

  • Jang, Seok-Myeong;Kim, Hyun-Kyu;Park, Ji-Hoon;Ko, Kyoung-Jin;Choi, Jang-Young;Kim, Il-Jung
    • Proceedings of the KIEE Conference
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    • 2009.04b
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    • pp.49-51
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    • 2009
  • This paper deals with the analysis on eddy current losses for cylindrical linear oscillatory actuator (LOA) with Halbach array mover according to voltage waveform. This paper presents analytical procedures for calculation of eddy current losses using Poynting theorem. On the basis of the magnetic vector potential and a two-dimensional (2-d) cylindrical coordinate system, this paper derived analytical solutions of eddy current tosses using phase current analysis. The eddy current losses of each harmonic obtained by fast Fourier transform (FFT) analysis of phase current are compared with results obtained from finite-element method (FEM). Particularly, this paper shows that the eddy current losses of cylindrical LOA according to square voltage waveform are more significant than those according to sinusoidal voltage waveform.

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Compound damping cable system for vibration control of high-rise structures

  • Yu, Jianda;Feng, Zhouquan;Zhang, Xiangqi;Sun, Hongxin;Peng, Jian
    • Smart Structures and Systems
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    • v.29 no.4
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    • pp.641-652
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    • 2022
  • High-rise structures prone to large vibrations under the action of strong winds, resulting in fatigue damage of the structural components and the foundation. A novel compound damping cable system (CDCS) is proposed to suppress the excessive vibrations. CDCS uses tailored double cable system with increased tensile stiffness as the connecting device, and makes use of the relative motion between the high-rise structure and the ground to drive the damper to move back-and-forth, dissipating the vibration mechanical energy of the high-rise structure so as to decaying the excessive vibration. Firstly, a third-order differential equation for the free vibration of high-rise structure with CDCS is established, and its closed form solution is obtained by the root formulas of cubic equation (Shengjin's formulas). Secondly, the analytical solution is validated by a laboratory model experiment. Thirdly, parametric analysis is conducted to investigate how the parameters affect the vibration control performance. Finally, the dynamic responses of the high-rise structure with CDCS under harmonic and stochastic excitations are calculated and its vibration mitigation performance is further evaluated. The results show that the CDCS can provide a large equivalent additional damping ratio for the vibrating structures, thus suppressing the excessive vibration effectively. It is anticipated that the CDCS can be used as a good alternative energy dissipation system for vibration control of high-rise structures.