• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.758-763
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• 2014

These days, the advantages of DC power system are consistently stand out in korea that was a small power loss and high stability. Needs of DC power transmission technology is focused In the midst of a smart grid and environment friendly generation technology boom that is needed for next generation technology. Researches and businesses for HVDC(High Voltage Direct Current) system has been began. But, Needs of HVDC equipment and system commissioning technology are not on the rise until now. In particular, South Korea's HVDC technology is after the foot runner of advanced country and company. In addition, There is no experience for equipment verification and commissioning technology. And Experts of HVDC are rare. Who has been fully understood hardware and system as a whole, and identified all the equipment's characteristic. Recently, Academia and industry are recognized a needs of HVDC technology. But it does not received a recognition of technical value. In this paper, introduce issues when we apply the IEEE's verification method for HVDC system, especially DC current measurement system, DC CT(Direct Current Transformer), among the HVDC equipments. And Proposes remedial methods on the issue in order to recognize the necessity that was HVDC equipments's verification and commissioning technology research should be focused on.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2045-2047
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• 1998

To store and maintain electron beams in synchrotron machines, it is very important to read and keep precise magnet current ($<{\pm}50$ ppm). However, accurate DC current measurement tools are not readily available. In this paper, we introduce high precision, wide band zero-flux current transformer that is manufactured and tested at Pohang Accelerator Laboratory. This sensor can measure DC as well as AC current. Accuracy of the current transformer is less than ${\pm}$20 ppm. Performance of the manufactured current sensor is compared with a high precision DCCT which is commercially available sensor.

• The Monthly Diabetes
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• s.217
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• pp.21-23
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• 2007

당뇨병환자에서 혈당조절의 중요성은 '앙꼬 없는 찐빵' 또는 '김 없는 김밥'과의 관계와 같다. 당뇨병이 우리가 먹은 음식이 우리 몸에서 잘 활용되지 못하고, 소변으로 당이 넘쳐흘러서 나오는 현상을 보고 붙여진 이름인 것을 생각하면 둘 간의 관계는 땔래야 땔 수 없는 관계라 할 수 있습니다. 우리가 무서워하는 당뇨병의 합병증은 혈당조절을 잘 하게 되면 많은 부분 예방이 가능하다는 것을 알 수 있습니다. 제 1형 당뇨병의 대표적 연구인 DCCT 연구 결과를 보면 당화혈색소를 8.0%에서 7.2%로 낮추면 망막증의 진행을 40$\sim$50%를 줄일 수 있었습니다. 제 2형 당뇨병의 대표적 연구인 UKPDS연구는 당화혈색소 1%를 줄이면 미세혈관합병증은 37%, 심근경색은 14% 감소된다는 것을 확인해 주었습니다. 그 이외에도 많은 연구들에서 결과의 차이는 있지만 적극적이고 엄격한 혈당조절은 합병증의 발생을 예방하며, 발생된 합병증의 진행 속도를 늦출 수 있는 가장 효과적인 방법으로 증명하고 있습니다. 그런데 여러분들께서는 위에 언급한 '당화혈색소'를 알고 계십니까? 공복 혈당조절 목표를 알고 계십니까? 식후 혈당조절 목표를 알고 계십니까? 혹시 모르고 계시다면 100미터 출발 선상에서 출발 신호가 났지만 어디로 달려갈지 모르고 있는 것과 같습니다. 아무리 잘 달리고 훌륭한 선수라도 뛰어갈 방향을 모르고 있다면 좋은 성적을 낼 수 없는 것과 같습니다. 혈당조절의 중요성을 알고 관리 목표를 알고 현재 나의 수치를 그 목표를 행해 열심히 실행한다면 건강한 삶을 영위할 수 있습니다.