• Journal of Information Processing Systems
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• 제19권3호
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• pp.302-309
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• 2023

Artificial intelligence (AI) plays a crucial role in the intelligent development of China's power system. It is also an important part of the digital development of the power grid. The development of AI determines whether the digital transformation of China's power system can be successfully implemented. Therefore, this paper discusses the digital transformation of the power grid based on AI technologies. The author has established a digital evaluation index system to reflect the development of the power grid in one province. Both qualitative and quantitative methods have been adopted in the analysis, which delves into the economic effectiveness, quality, and coordination of power grid development in the province in a comprehensive way. Results show that, to meet the needs of the power grid's digital transformation, the correlation coefficient between the power grid's development and the province's overall coordination has been increasing in recent years.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.1011-1015
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• 2005

Fully digital controlled 20-bit magnet power supplies have been developed and successfully tested for closed orbit correction of PLS(Pohang Light Source). The new digital power supply has used fiber optics for 25kHz switching of IGBT drivers, and implemented DSP, ADC, Interlock, DCCT cards in a compact 3U-sized 19" chassis. Input/Output low-pass filters suppress harmonics of 60Hz line frequency and switching frequency noise effectively. Overall performance of the power supplies have been demonstrated as +/- 2ppm short-term stability(<1 min), and +/- 10ppm long-term stability(<36 hours). All the existing 12-bit 70 power supplies for vertical correction magnets will be replaced with new digital power supplies during 2005 summer shutdown period. In this paper, we will describe the hardware structure and control method of the digital power supply and the experimental results will be shown.

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.517-524
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• 1998

This paper discusses the development of a reactive power controller using digital signal processing. Digital Signal Processing is the technique of using digital devices to Process continuous signals or data, often in real-time. And DSP algorithms are associated with a discrete time interval between input samples. When one designs a digital filter, one can use a Laplace transform to determine the continuous time frequency response. The corresponding discrete time transform is called Z transform and depends upon discrete samples of the input spaced equally in time. The objectives of this paper are to minimize real power losses and improve the power factor of a given system. Also, the implementation of a direct-form non recursive filter on the TMS320C31 has been described. The application of this microprocessor-based controller using DSP on test system reveals its numerous advantages. Performance and features of the controller for the reactive power control are analyzed.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.183-187
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• 2008

This paper describes a power control scheme to improve the performance of a fuel cell battery hybrid power source for residential application. The proposed power control scheme includes a power control strategy to control the power flow of the fuel cell hybrid power system and a digital control technique for a front-end dc-dc converter of the fuel cell. The power control strategy enables the fuel cell to operate within the high efficiency region defined by the polarization curve and efficiency curve of the fuel cell. A dual boost converter with digital control is applied as a front-end dc-dc converter to control the fuel cell output power. The digital control technique of the converter employs a moving-average digital filter into its voltage feedback loop to cancel the low frequency harmonic current drawn from the fuel cell and then limits the fuel cell output current to a current limit using a predictive current limiter to keep the fuel cell operation within the high efficiency region as well as to minimize the fuel cell oxygen starvation.

• 반도체디스플레이기술학회지
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• 제12권4호
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• pp.27-32
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• 2013

In this paper, the boost converter was implemented by digital control in many applications of the step-up. The PWM(pulse width modulation) control module of boost converter was digitized at power converter using the FPGA device and VHDL. The boost converter was designed to output a fixed voltage through the PI control algorithm of the PWM control module even if input voltage and output load are variable. The boost converter was digitized can be simplified by reducing the size of the module and the external control components. Thus, the digital power IC has advantageous for weight reduction and miniaturization of electronic products because it can be controlled remotely by setting the desired output voltage and PWM control module. The boost converter using the digital power IC was confirmed through experiments and the good performances were showed from experiment results.

• Journal of Power Electronics
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• 제12권1호
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• pp.98-103
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• 2012

This paper presents a digital pulse width modulator (DPWM) with a reduced digital modulation delay (a transport delay of the modulator) during the transient response of power converters. During the transient response operation of a power converter, as a result of dynamic variations such as load step-up or step-down, the closed loop controller will continuously adjust the duty cycle in order to regulate the output voltage. The larger the modulation delays, the larger the undesired output voltage deviation from the reference point. The three conventional DPWM techniques exhibit significant leading-edge and/or trailing-edge modulation delays. The DPWM technique proposed in this paper, which results in modulation delay reductions, is discussed, experimentally tested and compared with conventional modulation techniques.

• Journal of Advanced Marine Engineering and Technology
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• 제38권8호
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• pp.1000-1003
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• 2014

There are 70 vertical and 70 horizontal correctors for Pohang Light Source. Until mid of 2000, power supplies for these correctors were based on 1990's technology, so the global orbit feedback system was not possible with poor 12 bit resolution. A new task force team was assembled to develop new power supplies with BESSY type DAC cards. After the project, two vertical correctors in each lattice were connected with new power supplies, and the global orbit feedback was available within the accuracy of 5 microns. However, this replacement was not enough to satisfy the beam stability requirement of 2 microns for PLS. We have launched another power supply design based on all digital technology. This attempt was completed within a year, and 80 units were assembled in house. Currently, the global orbit feedback system is running successfully with new digital power supplies and the compensation of chamber motion due to the thermal load by using digital displacement transducers attached on each BPMs.

• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.868-875
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• 1999

In this paper, digital motor control center using protection relay is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which have various load environments and capacities in power systems. Digital motor control center is employed by power supervisory control systems without separate remote terminal unit and transducers adding communicational ability. Also we develope a maximum demand controller to control the load effectively at peak status and a power factor controller to minimize real power losses and improve the power factor. Therefore, when using the developed controller, real time computation is possible by loading DSP in hardware and applying real-time kernel which can convert each algorithm to task module.

• Journal of Welding and Joining
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• 제27권2호
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• pp.51-56
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• 2009

Film based radiography imaging technique has been applied to the non-destructive test in medical, aircraft, and power industries contributing to the development of the industries. However, the complex process for imaging and analysis has increasingly demanded the reformation of the radiography test. A digital radiography imaging technologies has been com out from the demand. This study was mainly focused on the assessment on the accuracy for the each image from digital radiography test and film radiography test was proven to crate a better image in sensitivity than film radiography test. In the IQI(Image quality indicator) transmission test, one or two more line can be seen in digital image than in film image. When applying to the boiler tube weld, film image is detectable to the 1.0mm depth flaw; and digital image to the 0.5mm depth flaw. As a result of this study, digital radiography technology is determined to enhance the image quality, compared to film radiography technologies

• IEIE Transactions on Smart Processing and Computing
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• 제2권4호
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• pp.248-254
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• 2013

The size and power consumption of digital circuits including the dimming circuit part will increase for high-performance solid state lighting (SSL) systems in the future. This study examined the low-power consumption of adiabatic dynamic CMOS logic (ADCL) due to the principles of adiabatic charging. Furthermore, the designed low-power ADCL digital pulse width modulation (PWM) was optimized for SSL dimming systems. For this purpose, an ADCL digital 3-bit PWM was optimized in two steps. In the first step, the architecture of the ADCL digital 3-bit PWM was miniaturized. In the second step, the clock cut-off circuit was designed and added to the ADCL PWM. As a result, compared to the original configuration, 60 transistors and 15 capacitors of ADCL digital 3-bit PWM were reduced for miniaturization. Moreover, the clock cut-off circuit, which controls wake-up and sleep mode of ADCL D-FFs, was designed. The power consumption of an optimized ADCL digital PWM for all bit patterns decreased by 54 %.