• Title/Summary/Keyword: PWM control

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Development of a Hydraulic Level Control System for High-speed Rice Transplanting Machines (고속 이앙기의 유압 수평 제어 장치 개발에 관한 연구)

  • 정연근;정병학;김경욱
    • Journal of Biosystems Engineering
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    • v.27 no.2
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    • pp.79-88
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    • 2002
  • This study was conducted to develop system for high speed rice transplanting machines. The control system includes a sensor detecting the tilt angle of the seedling bed, a micro-controller and a hydraulic system consisting of a double acting cylinder, a four-way three-position solenoid valve, a relief valve and a hydraulic pump. The levelling system shared the pump with the existing steering control, resulting in a tandem center circuit for the steering and levelling control systems. Using the input signal from the sensor, the micro-controller determined and generated the output signal to control the cylinder through the solenoid valve to keep the seedling bed always parallel to the water surface regardless of soil unevenness during the transplanting operations. Both an ON/OFF and a PWM control schemes were tested. When the flow rate was more than 1 ι/min in the ON/OFF control, the system showed unstable rolling. However, in the PWM control, the system worked stably although the flow rate was more than 1 ι/min. The PWM control showed a better performance when a large difference between the angle and the dead band of the control system occurred. The characteristics of tile system response to given tilt angles were predicted by a computer simulation. Both the ON/OFF and the PWM control systems worked well providing that the operating and waiting times were properly adjusted.

Fuzzy Puse-Width-Modulated Feedback Control (퍼지 펄스폭 변조 궤환 제어)

  • Young Hoon, Joo;Kwon Kyu, Jang;Jin Bae, Park
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2004.10a
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    • pp.443-446
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    • 2004
  • This paper discusses an intelligent digital redesign technique for designing a fuzzy pulse-width-modulated (PWM) control. First when we are given a well-designed fuzzy analog control, the equivalent digital control is intelligently redesigned. Using the similar technique we intelligently redesign the fuzzy PWM control from the intelligently redesigned fuzzy digital control. A stabilizability of the intelligently redesigned PWM control is rigorously analyzed.

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Design of a Multi-Color Lamp Using High Brightness RGB LEDs (고휘도 RGB 발광다이오드를 이용한 광색가변형 전구의 설계)

  • 송상빈;강석훈;여인선
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.2
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    • pp.98-104
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    • 2003
  • This paper proposes the design of a multi-color lamp using high brightness RGB LEDs for color variation. Appropriate number of RGB LEDs is so chosen according to the color mixing theory that the overall LEDs represent a color temperature of 6500K. Also, the chosen RGB LEDs are suitably arranged by using an optical design program. The lamp has an internal controller circuit, so it can be directly connected to the existing incandescent lamp socket. It's main body is comprised of two PCB layers. The upper layer contains 44 LEDs and the lower one has a simple microcontroller-based PWM control circuit. The lamp has functions of both ON/OFF control and PWM control, and enables color variation of over 100,000 colors and of more than 10 patterns.

Implementation of a PWM Controlled Active AC Power Filter Using a Fast PWM Control Method (PWM 제어 능동 교류 전력 필터의 개발 및 속도 개선)

  • Kim, Jae-Hyun;Park, In-Gyu;Park, Jong-Keun
    • Proceedings of the KIEE Conference
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    • 1987.11a
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    • pp.457-462
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    • 1987
  • This paper deals with the PWM controlled active AC power filter. A new PWM control method from the viewpoint of speed and simplicity is proposed. And a microprocessor-based controller is used to realize the active AC power filter. The existing PWM control methods are primarily based on Fourier series expansion and these methods need FFT calculation and solving nonlinear harmonic equations, which are heavy burden to real-time control. The proposed method is based upon generalized pulse series expansion and needs only definite integrals of harmonic signal. So, computational effort can be reduced by a large margin. The digital circuit using 16-bit microprocessor is designed to implement the actual active power filler.

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A Study on the New PWM Control Method of the Cycloconverter with a Resonant Circuit for Induction Heating (공진회로를 이용한 유도가열용 사이크로콘버터의 새로운 PWM 제어법에 관한 연구)

  • Kim, Hyun-Jung;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.797-799
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    • 1993
  • In this paper, we propose a new PWM control method of cycloconverter with a resonant circuit for induction heating. The proposed new PWM control method determines the switching duty ratio compared the integrated value of load current with the reference value of input current on sampling interval. By the Proposed method, the displacement factor becomes 1.0 and the input current waveforms become sinusoid which is nearly 1.0 in terms of the input power factor. To confirm the validity of the proposed method, the simulations and experiments are carried out.

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A Study on the PWM Control of Hydraulic Equipment Using High Speed On-Off Valve (고속전자밸브를 사용한 유압장치의 PWM 제어에 관한 연구)

  • ;Wennmacher,G.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.3
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    • pp.868-876
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    • 1995
  • This study deals with a position control of an electro-hydraulic servo system which consist of cylinder and high speed on-off valves operated by microcomputer. The merits of PWM control of hydraulic equipment are the robustness of the high spee on-off valve, its low price and the direct control without D/A converter. In the PWM control of high speed on-off valve, the time lag and switching time existing between the input and output signals of valve are considered as demerit points. To get analytical results, the effects of these demerits have to be clarified in detail. The object of this study is to propose a mathematical model for the behavior of high speed on-off valve and to get analytical results of this system. The dynamic characteristics of this system is examined by digital computer simulation analytically and compared with experimental results to varify the proposed mathematical model.

Braking Pressure Characteristics of Solenoid-Flow Control Type ABS by PWM Control (PWM 제어에 의한 솔레노이드-유량제어방식 ABS의 제동압력 특성)

  • C.S. Song;H.J. Yang
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.8
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    • pp.146-154
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    • 1997
  • Solenoid-folw control type ABS is used with a 'dump and reapply' pressure control arrangement instead of using 2/2 (normal open/close) solenoid valves in convensional systems(sol. -sol. control type), a flow control valve is used which replaces the (no) inlet valve. The flow control valve controls fluid flow providing a nearly constant reapply rate( .theta. ) after the dump plase of ABS operation. In this study, to investigate a characteristics of brake pressure by PWM control, test rig was consisted of ABS hydraulic modulator, digital controller, pneumatic power supply and brake master cylinder. For comparison with experi- mental results, system modelling and computer simulation were performed. As a result, experiment results showed fairly agreement with the simulation. Also, it is shown that the pressure gradient (tan .theta. ) is affected by pressure, frequency, duty ratio and expressed with an exponential funtion.

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A Study on Estimating Characteristics of ABS Using High Frequency PWM Control (고주파수 PWM 제어를 이용한 ABS의 특성 평가에 관한 연구)

  • Kim, Byeong-Woo;Lee, Yong-Joo;Park, Ho
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.2
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    • pp.69-74
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    • 2004
  • In general the surge pressure generated in hydraulic systems causes noise, vibration and odd effect to the system. To reduce the surge pressure, high frequency PWM control of 20KHz was attempted. To estimate the braking noise caused by surge, a vehicle equipped with on-board ABS hydraulic modulator has been experimented with respect to the various breaking condition. Thorough this experiments, it was found that breaking noise has been reduced using high frequency PWM control method compare with low frequency method. To evaluate high frequency control m practice, including verification of general functionality, EMI tests was experimented. Its was found that it is necessary to have the solution to electromagnetic interference(EMI) generated by switching elements.

Characteristic of Hydrogen-oxygen Mixed Gas Power Conversion System (혼합수소발생기용 전력변환장치의 특성)

  • Mun, Sang-Pil;Lee, Hae-Su;Nakaoka, Mutsuo;Jeong, Jang-Geun;Kim, Chang-Il;Jo, Gil-Je;Kim, Sang-Don
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2007.11a
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    • pp.323-326
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    • 2007
  • In this paper, the basic experiment, electrolytic cell design and basic manufacturing have been made to interpret the characteristics of Hydrogen-Oxygen-Gas-Generator. As for the detailed matters, the data research on basic technology on Hydrogen-Oxygen-Gas and analysis on characteristics of Hydrogen-Oxygen-Gas from basic experiment. Also the experiment of characteristics and comparative evaluation between constant current source using SCR converter from existing method and constant current source using new phase shift PWM control method converter. As results when it has injected constant DC current, we has compared Gas quantities by variable ripple frequencies using phase shift PWM control method converter. Therefore, in linear region, it has not different Gas quantities by constant DC current and by phase shift PWM control method converter. Also, it has increased Gas quantities wilder linear region when put ripple frequency at saturation region. Through, Gas quantities and input rower, it has acquired higher input power per Gas quantities at put pulse current. Therefore, when designing converter or inverter for electrolysis, which has ripple current.

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