• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.182-186
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• 1999

Evaluation of the AC losses in the HTS tapes which are used in electric power machines in one of the important topics in this field. This paper deals with the calculation and measurement of the magnetization loss in HTS tapes. Bean model is adopted for the theoretical calculation of the magnetization loss. Magnetization method is used for the measurement of the loss. Two types of the HTS tape model, multi-filamentary model and mono-filamentary model, are used to evaluate the magnetization loss in this paper. According to the results of the analysis, large discrepancy between the calculated and measured value is observed in multi-filamentary model is more useful than multi-filamentary model for the evaluation of the magnetization loss.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.190-191
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• 2013

본 논문에서는 고역률 및 고효율 동작이 가능한 단일 전력단 forward-flyback 컨버터를 제안한다. 기존 단일전력단 forward 컨버터의 경우, 입력 전압이 출력 전압보다 낮은 경우 Dead zone 구간이 발생하여 고역률 획득이 어려우며, 자화 인덕터 offset 전류가 크기 때문에 자기소자의 손실로 인한 고효율 동작이 어렵다. 본 논문에서 제안하는 forward-flyback 컨버터는 2차 측에 삽입된 DC 블러킹 캐패시터에 의해 자화 인덕터의 offset 전류를 감소 할 수 있고, 입력 전압에 관계 없이 항상 출력 측으로 에너지를 전달 할 수 있으므로 고효율 및 고역률 획득에 유리하다. 또한 coupled inductor를 사용한 출력 인덕터에 의해 출력 다이오드에는 각 각 동일한 전류가 흐르며, 전압 스트레스를 감소시킬 수 있는 장점이 있다. 제안된 단일 전력단 forward-flyback 컨버터의 타당성을 검증을 위하여 45W급 LED 전원 공급장치의 시작품 제작을 통한 실험 결과를 제시한다.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.34-38
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• 2005

Multi-stacked HTS tapes are needed to conduct large current in the power application. In this paper, magnetization losses of the multi-stacked YBCO coated conductor and the BSCCO tape have been measured and compared. Magnetization losses of single tape, 2-stacked, 3-stacked and 4-stacked HTS tapes have been presented in this paper. Multi-stacked tapes have been fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various angle of external magnetic field to consider the anisotropic characteristics of HTS tapes. Test results show that loss density per unit volume decreased for both YBCO coated conductors and BSCCO tapes when the stacking number of tapes is increased. The magnetization losses of YBCO CC are larger than those of BSCCO tapes when the external magnetic field is increased.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.13-16
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• 2005

Multi-stacked HTS tapes are needed to conduct large current in the power application. In this paper magnetization losses of the multi-stacked YBCO coated conductor and the BSCCO tape have been measured and compared. Magnetization losses of single tape, 2-stacked, 3-stacked and 4-stacked HTS tapes have been presented in this paper. Multi-stacked tapes have been fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various stacked of external magnetic field to consider the anisotropic characteristics of HTS tapes. Test results show that loss density per unit volume decreased for both YBCO coated conductors and BSCCO tapes when the stacking number of tapes is increased. As the external magnetic field decreased, the ratio of decrement has risen because the full penetration magnetic field(Bp) of the multi-stacked tape is larger than that of the single tape.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.95-97
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• 2005

Loss in the multi-stacked HTS wires are affected by a number of factor, such as, number of wires used in the stack, direction of external magnetic field and insulation thickness between the wire. This paper examines the effects of the insulation thickness on the magnetization loss of the multi-stacked YBCO coated conductor. Measurements of magnetization loss were performed using 4 different typo of multi-stacked wires and under various angle of external magnetic field. Test results show that loss density per unit volume increased for YBCO coated conductors when thickness of insulation increased. Loss density per unit volume decreased for YBCO coaled conductors when stacking number of tapes increased.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.961-963
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• 2003

Magnetization losses of HTS depend strongly on the orientation of external magnetic field because of anisotropy characteristics. For parallel and perpendicular magnetic field, analytical models to calculate the loss are well known but there is no analytical model for magetic fields which are applied to surface of HTS with arbitrary angle. In this paper, magnetization losses are measured for various incidence angles($15^{\circ}$, $35^{\circ}$, $45^{\circ}$, $60^{\circ}$) and compared with parallel and perpendicular loss. As a result, magnetization losses in HTS are strongly affected by perpenducular magnetic field component of external magnetic field.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.193-194
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• 2014

본 논문에서는 LLC 공진형 컨버터에 공진 회로를 추가함으로써 높은 자화 인덕턴스를 가지고 전원장치의 hold-up 동작 시 전압 이득 보상을 해주는 회로를 제안한다. 제안된 컨버터는 높은 자화 인덕턴스로 인해 1차측 도통 손실을 감소시킬 수 있으며, 공진회로를 통해 특정 주파수에서 높은 전압 이득을 얻을 수 있어 hold-up 조건을 만족 시킬 수 있다. 본 논문에서는 제안하는 회로의 동작을 이론적으로 해석하고 적절한 설계방법을 제시하여 실험결과를 통해 회로의 동작을 검증한다.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.27-31
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• 2007

For large power applications, multi-stacked tape should be used because single tape is limited in flowing demanded current capacity. Besides insulation between layers is needed for safe operation because high voltages are generated in those applications. In this study, considering those situations which mentioned above, we measure the magnetization loss in several multi-stacked tape samples having the different insulation thicknesses and various packing numbers of tape by external magnetic field having various incidence angles.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.57-60
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• 2007

Superconducting electric power devices need to stack HTS wires to increase the current carrying capacity. Uniform multi-stacked wires(UMS) which were made of the same HTS wires have been used. This paper shows the magnetization loss of hybrid multi-stacked(HMS) wire made of BSCCO wires and YBCO wires. Five HMS wires, YB(YBCO-BSCCO), YYBB. YBYB, YBBY and BYYB, were made and tested. Magnetization losses of each UMS wire were compared with corresponding HMS wire. Test results show that magnetization losses per unit length of HMS wire are between the corresponding UMS BSCCO wire and HMS YBCO wire below critical magnetic field. Above the critical magnetic field, magnetization losses of HMS wires are larger than that of corresponding both VMS wires.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.72-75
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• 2007

Magnetization loss of HTS wire is strongly dependent on the critical current density and the aspect ration of the HTS wire. This paper presents the magnetization loss of stacked BSCCO wire and stacked YBCO wires which had different critical current densities. Width of the BSCCO wire was 4mm and widths of two YBCO wires were 4mm and 8mm. Single wire, two stacked three stacked and four stacked wires were fabricated and tested. Ratio of magnetization loss of BSCCO wire to YBCO wire was presented at single wire. For stacked wire, ratio of magnetization loss of single wire to stacked wire was presented. Test results shows that magnetization losses of stacked wires were greater than that of single wire at large high magnetic field above critical magnetic field.