• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.7
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• pp.296-303
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• 1986

The active filter of current injection type is the device which eliminates the harmonics in ac line by injecting the harmonic compensating current into the ac side. And its harmonic reduction performance is entirely dependent on the control scheme of the current-fed inverter and the harmonic compensating current becomes the PWM wave by the inverter. This PWM compensating current can be determined by selecting the switching function properly which eliminates the harmonics up to any order with using no independent sources. The new injection current model is derived by the proposed method which is called the optimized injection method. The overall characteristics of the proposed method are investigated through digital computation and the feasibility is proved with experimental results obtained from the Z-80 microcomputer control of the active filter.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.1 no.2
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• pp.70-73
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• 1987

This paper itltroduces a simple stair-case PWM using the pseudo-sinusoidal method. In a configuration of controller, the value of sine as a fundamental factor divided into stair-case level and the three-phase PWM inverter is composed by digital compound for each value of stair-case level. The three-phase output pulse at a fixed carrier frequency and a variable reference frequency is obtained under the effect of reduced harmonics. In this experiment, using the power FET as the switching device, 0.5 H.P. induction motor operation is performed when the switching frequency is 20KHz.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2269.1_2270.1
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• 2009

본 논문에서는 원칩 마이크로컨트롤러와 ZigBee IC가 내장된 소형 모듈을 사용한 파워 LED의 디지털 조도제어 시스템의 설계 및 구현에 대해 중점적으로 기술한다. 파워 LED의 조광제어 및 특정 조도에서의 정전류 구동을 위해 전류피드백을 통한 디지털 PI 전류제어 및 PWM 구동방식을 행하였고, 시각적인 깜박거림 없는 충분한 주파수의 스위칭을 통해 부스트 컨버터를 연속도통모드로 동작시켰다. 2.4GHz의 주파수 대역을 이용하는 PAN (Personal Area Network) 형태의 ZigBee 무선모듈과 마이크로컨트롤러와의 UART 통신을 통해 조도제어를 위한 PWM 제어를 행하였다. 본 논문에서 제시한 파워 LED의 디지털 조도제어 시스템은 최근의 에너지 및 환경규제에 적합한 조명관련 응용분야에서 다양하게 적용될 것으로 판단된다.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1517-1523
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• 2015

The wavelet PWM (WPWM) technique has been applied in two-level inverters successfully, but directly applying the WPWM technique to three-level inverters is impossible. This paper proposes a WPWM technique suitable for a single-phase three-level inverter. The work analyzes the control strategy with the WPWM and obtains the design of its parameters. Compared with the SPWM technique for a single-phase three-level inverter under the same conditions, the WPWM can obtain high magnitudes of the output fundamental frequency component, low total harmonic distortion, and simpler digital implementation. The feasibility experiment is given to verify of the proposed WPWM technique.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.729-732
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• 2001

Digital signal processors(DSP) are widely used in modern power conversion devices, ac motor drives. However, generating pulse-width modulation(PWM) gating signals requires so high sampling rates that most computation resources of the DSP must be devoted to generating them. This paper presents an ASIC realization of 2 channel space-vector PWM(SVPWM). The developed DSP(ECLDSP) board can transmit gating signals to 2 converter/inverter and control them. ECLDSP board is used for control the various kinds of power-quality improvement systems.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.821-824
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• 2005

This paper presents a technique to evaluate torque and speed characteristics of induction motor with the Dynamometer. The simple Dynamometer controlled via microcontroller and displayed by computer. The Microcontroller generates the PWM (Pulse Width Modulation) signal and control the duty cycle of signal for control braking level. The Buck converter is a braking unit which uses IGBT as switch in circuit. The output current of the Buck converter and output voltage of tacho generator are converted to digital signals and analyzed by microcontroller. The signals are then sent to computer for displaying torque and speed responds independent on the braking time. The test results of the Dynamometer in this research can coreectly predict the torque and speed response under reasonable tests. Moreover, this Dynamometer is easy and inexpensive to make.

• Journal of Magnetics
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• v.17 no.2
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• pp.124-128
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• 2012

Many different converter topologies have been developed with a view to use the minimum number of switches in order to reduce construction costs. Among this research, the four-switch converter topology with a novel PWM control technique based on the current controlled PWM method is thought to be a good solution. In this paper, a two dimensional time-stepped voltage source finite-element method (FEM) is used to analyze the characteristics of a Flux-Reversal Machine (FRM) with a 4-switch converter. To validate the proposed computational method, a digital signal processor (DSP) installed controller and prototype FRM are built and experiments performed.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.91-97
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• 2004

This paper describes the design of a 2-phase stepping motor driver using CPLD(Complex Programmable Logic Device). The driver IC such as L297(SGS-Thomson Microelectronics), which is mostly used has some difficulties in PWM control because of the switching noise of power MOSFETs. It causes current ripple and acoustic noise. To improve theses characteristics, we proposed a new current control method that the output PWM frequency is almost constant using a digital filter. Also we proposed constant current method for 1-2 phase(half step) excitation. The proposed method is implemented with CPLD(Xilinx, XC9572-PC44). Experimental results show the effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 2003.07e
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• pp.154-157
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• 2003

This paper presents a current-source-inverter based on a buck-boost configuration and its application for residential photovoltaic system. The proposed circuit has five switches. Among them, only one switch acts as chopping, and the other determine the polarity of output; therefore, it can reduce the switching loss. Because the input inductor current is operated on the discontinuous conduction mode, high power factor can be achieved without additional input current controller, So the overall system shows a simple structure. The operational modes are analysed in depth, and then it was verified through the experimental results using a 150 [W] prototype equipped with digital signal processor TMS320F241.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.313-315
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• 2009

In this thesis, A methodology of system implement for PID controller, PWM logic, HSC logic, Host Communication and external DAC interface are implemented into single FPGA chip is proposed. The implemented system is used to control the speed of DC servo motor. A DATA block transfers set point value(SV) and P, I, D gain parameters to the corresponding Blocks respectively by the Host Communication to Computer. A HSC block generates process value(PV) by a pulse and $90^{\circ}$ shifted pulse from the encoder A PID block makes error(E) signal from the set value and process value and output manufacture value(MV) through the PID controller. In PWM block using the MV from the PID block, drives H-bridge controlling the Motor. Also DAC interface controls the DAC to graph the digital signal such as SV, PV, E, MV in FPGA onto the Oscilloscope.