• Journal of Power Electronics
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• 제15권3호
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• pp.644-651
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• 2015

This paper introduces a novel digital one cycle control (DOCC) boost power factor correction (PFC) converter. The proposed PFC converter realizes the FPGA-based DOCC control approach for single-phase PFC rectifiers without input voltage sensing or a complicated two-loop compensation design. It can also achieve a high power factor and the operation of low harmonic input current ingredients over universal loads in continuous conduction mode. The trailing triangle modulation adopted in this approach makes the acquisition of the average input current an easy process. The controller implementation is based on a boost topology power circuit with low speed, low-resolution A/D converters, and economical FPGA development board. Experimental results demonstrate that the proposed PFC rectifier can obtain a PF value of up to 0.999 and a minimum THD of at least 1.9% using a 120W prototype.

• 전기학회논문지
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• 제56권6호
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• pp.1064-1070
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• 2007

This paper presents a grid-interactive current controlled voltage source inverter (CCVSI) with uniterruptible power supply (UPS), which uses an inner current control loop (polarized ramp time (PRT)) and outer feedback control loops to improve grid power quality and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, a single stage CCVSI is used. The operation of this system could be divided into the power quality control (PQC) state mode and the UPS state mode. In PQC mode, the system operated to compensate the reactive power demand by nonlinear load or variation in load. In UPS mode. the system is controlled to provide a sinusoidal voltage at the rated value for the load when the gird fail. To verify the proposed system, a comprehensive evaluation with theoretical analysis, simulation and experimental results for 1KVA load capacity is presented.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.282-285
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• 2004

The main purpose of this study is the vibration suppression of rotating composite blade containing distributed piezoelectric sensors and actuators. The blade is modeled by thin-walled, single cell composite beam including the warping function, centrifugal force, Coriolis acceleration and piezoelectric effect. Further, the numerical study is performed m ing finite element method. The vibration of composite rotor is suppressed by piezocomposite actuators and PVDF sensors that are embedded between composite layers. A velocity feedback control algorithm coupling the direct and converse piezoelectric effect is used to actively control the' dynamic response of an integrated structure through a closed control loop. Responses of the rotating blade are investigated. Newmark time integration method is used to calculate the time response of the model. In the numerical simulation, the effect of parameters such as rotating speed, fiber orientation of the blade and size of actuators are studied in detail.

• 대한전기학회논문지
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• 제39권3호
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• pp.301-311
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• 1990

A multiple controller structure consisting of a typical feedback controller and an additive redundant controller is proposed for enhancing the reliability of the control system. For the case where the main controller is chosen as a pole assignment controller with input/output measurements and the redundant controller as the Model Reference Adaptive Controller (MRAC) whose reference model is the closed-loop combination of the plant and the main controller, it is proven that the tracking error between the command input and plant output converges to zero under failure in one of the controllers or parameter perturbations of the plant, and further that the reliability measured by Mean Time To Failure (MTTF) is greater than that of the system with only a single main controller. A simulation Example is provided to illustrate reliable operation of the proposed control system against the controller failure.

• The Plant Pathology Journal
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• 제32권5호
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• pp.414-422
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• 2016

Eucalyptus dieback disease, caused by Cylindrocladium scoparium, has occurred in last few years in large Eucalyptus planting areas in China and other countries. Rapid, simple, and reliable diagnostic techniques are desired for the early detection of Eucalyptus dieback of C. scoparium prior to formulation of efficient control plan. For this purpose, three PCR-based methods of nested PCR, multiplex PCR, loop-mediated isothermal amplification (LAMP) were developed for detection of C. scoparium based on factor 1-alpha (tef1) and beta-tubulin gene in this study. All of the three methods showed highly specific to C. scoparium. The sensitivities of the nested PCR and LAMP were much higher than the multiplex PCR. The sensitivity of multiplex PCR was also higher than regular PCR. C. scoparium could be detected within 60 min from infected Eucalyptus plants by LAMP, while at least 2 h was needed by the rest two methods. Using different Eucalyptus tissues as samples for C. scoparium detection, all of the three PCR-based methods showed much better detection results than regular PCR. Base on the results from this study, we concluded that any of the three PCR-based methods could be used as diagnostic technology for the development of efficient strategies of Eucalyptus dieback disease control. Particularly, LAMP was the most practical method in field application because of its one-step and rapid reaction, simple operation, single-tube utilization, and simple visualization of amplification products.

• Journal of Biosystems Engineering
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• 제14권2호
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• pp.80-84
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• 1989

In order to improve the combustion efficiency of the agricultural engine, an ignition timing control system was developed and tested. The control system was composed of the CDI ignition circuit, the microcomputer and the interfacing devices. In this study, the simplicity of the control system and the flexibility of the control strategy were emphasized for the precision, the applicability and the economical efficiency. The hardware was consisted in almost the same compositions as those of the automobile engine. The softwares of the control algorithms were developed to three types depending on the combination of the quasi-adaptive control and the open loop control which had the different spark advance equations according to the input variables such as engine speed, exhaust gas temperature and brake torque. The test results were summarized as follows: 1. By using the computer control system, the fuel consumption efficiency could be improved and the fuel consumption could be reduced by 0 to 57% compared to that of the fixed spark advance system. 2. The fuel consumption of the control mode with the quasi-adaptive algorithm was reduced by average 0.8% compared to that of the control mode without quasi-adaptive algorithm. 3. It was found that the control mode with the quasi-adaptive algorithm adopting single input of engine speed had most applicability and economical efficiency among three types of the control algorithms.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권5호
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• pp.238-245
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• 2003

In this paper, a single Phase voltage source voltage-controlled active power filter(APF) for power quality improvement was proposed. The proposed APF has the performance of harmonic suppression and unity power factor correction. The performance of harmonic suppression can be obtained by controlling the waveshape of the APF output voltage to be sine wave. And, unity power factor is controlled by the reactive power control loop of the APF output. Simulation and experimental results using diode rectifier showed that the voltage-controlled APF, unlike the current-controlled APF, can reduce the voltage harmonics as well as current harmonics. Also the results showed that the input dover factor and power quality were greatly improved.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.166-170
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• 1997

A Single phase induction motor is the predominant fractional horsepower power rated, extensively used in domestic and industrial application. For example, these motors provide the motive power to washing machines, fans, refrigerators, etc. In this paper, single phase induction motor input current was detected by a small current transformer and determined TRIAC gate signal by using op-amp analog circuit. The soft-start strategy is based on limited auxiliary current angle during starting period in the closed-loop control. The Simulation and experimental result show the motor's starting characteristics of the proposal starting system and are compared with centrifugal switch starting motor.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.139-141
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• 2008

This paper presents a PID controller and PI-PI dual loop controller for a single-phase inverter. The control parameters of conventional controllers are very difficult to make. But parameters of controllers based on pole-assignment are easy to make. Simulation results are presented for the system under R-L load, no load and change reference voltage.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권6호
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• pp.817-824
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• 2016

A simultaneous bidirectional transceiver over a single wire has been developed in a 65 nm CMOS technology for a command and control bus. The echo signals of the simultaneous bidirectional link are cancelled by controlling the decision level of receiver comparators without power-hungry operational amplifier (op-amp) based circuits. With the clock information embedded in the rising edges of the signals sent from the source side to the sink side, the data is recovered by an open-loop digital circuit with 20 times blind oversampling. The data rate of the simultaneous bidirectional transceiver in each direction is 75 Mbps and therefore the overall signaling bandwidth is 150 Mbps. The measured energy efficiency of the transceiver is 56.7 pJ/b and the bit-error-rate (BER) is less than $10^{-12}$ with $2^7-1$ pseudo-random binary sequence (PRBS) pattern for both signaling directions.