• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.328-338
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• 2017

In this paper, a zero torque control scheme adopting current sharing function (CSF) used in integrated Switched Reluctance Motor (SRM) drive with DC battery charger is proposed. The proposed control scheme is able to achieve the keeping position (KP), zero torque (ZT) and power factor correction (PFC) at the same time with a simple novel current sharing function algorithm. The proposed CSF makes the proper reference for each phase windings of SRM to satisfy the total charging current of the battery with zero torque output to hold still position with power factor correction, and the copper loss minimization during of battery charging is also achieved during this process. Based on these, CSFs can be used without any recalculation of the optimal current at every sampling time. In this proposed integrated battery charger system, the cost effective, volume and weight reduction and power enlargement is realized by function multiplexing of the motor winding and asymmetric SR converter. By using the phase winding as large inductors for charging process, and taking the asymmetric SR converter as an interleaved converter with boost mode operation, the EV can be charged effectively and successfully with minimum integral system. In this integral system, there is a position sliding mode controller used to overcome any uncertainty such as mutual inductance or DC offset current sensor. Power factor correction and voltage adaption are obtained with three-phase buck type converter (or current source rectifier) that is cascaded with conventional SRM, one for wide input and output voltage range. The practicability is validated by the simulation and experimental results by using a laboratory 3-hp SRM setup based on TI TMS320F28335 platform.

• Journal of IKEEE
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• v.23 no.2
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• pp.364-369
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• 2019

The ratios of compliant branch circuit of leakage current and insulation resistance were 68.4% and 90.8%, respectively at the lamp load, 64.6% and 96.5% at the heat load, 86.7% and 88.9% at the power load. Limit of residual current of the zero phase secondary current value at the zero phase primary current was 100 A when rated primary current 400 A more than. The reason why the ratio of branch circuit of the leakage current was less than the ratio of compliant branch circuit of the insulation resistance might be that the leakage current includes the capacitive leakage current and the zero phase current.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.620-622
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• 2001

자성체 코어의 비선형 특성을 이용하여 DC와 AC 전류를 측정하는 Zero-Flux Current Transformer는 정밀 전류 측정용으로 많이 연구되고 있다. Zero-Flux Current Transformer는 DC 대전류 측정에 합당하며 저 전류 측정에 사용될 경우 소모전류, 안정되고 첨예한 필터 제작, magnetic modulator에 의한 zero point drift, 자화 전류가 비대칭일 때 출력 등과 같은 문제가 해결되어야 한다. 그리고 상용으로 사용하기 위하여 Hand-Held Type으로 제작되어야하며 동작시의 소모전류가 작고 정확도가 우수하여야 한다. 본 연구에서는 자화 전류가 비대칭일 때 출력을 zero로 만들기 위하여 사용하는 필터와 복잡한 회로로 구성된 magnetic modulator 부분을 여러개의 peak detector를 사용하여 AC와 DC를 측정하는 클램프미터를 개발하였으며 그 특성에 대한 내용을 기술하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.926-927
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• 2008

This paper presents the ZVZCS(Zero- Voltage and Zero-Current-Switching) Full-Bridge converter using the secondary coupled inductor and auxiliary capacitor. The converter with phase-shift control is proposed to reduce the circulating loss in primary and the voltage stress in secondary side. Using a coupled winding of the output inductor, two auxiliary capacitors are generated to reset the primary current at circulating interval.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.212-218
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• 1999

A new partial resonant three phase boost converter with high power factor and high efficiency is proposed. The proposed boost converter is constructed by using a resonant network in parallel with the swithch of the conventional boost converter. The devices are switched at zero voltage or zero current eliminating the switching loss. A new auxiliary partial resonant boost converter achieves zero-voltage switching(ZVS) or zero-current switching(ZCS) for all switch devices without increasing their voltage and current stresses.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.5
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• pp.404-411
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• 2020

Inductive power transfer (IPT) systems for electric vehicles generally require zero phase angle (ZPA) frequency tracking control to achieve high efficiency. Current sensors are used for ZPA frequency tracking control. However, the use of current sensors causes several problems, such as switching noise, degrading control performance, and control complexity. To solve these problems, this study proposes ZPA frequency tracking control without current sensors. Such control enables ZPA frequency tracking without real-time control and achieves stable zero voltage switching operation closed to ZPA frequency within all coupling coefficient and load ranges. The validity of the proposed control algorithm is verified on LCCL-S topology with a 3.3 kW rating IPT experimental test bed. Simulation verification is also performed.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.949-951
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• 1998

Because of the zero sequence mutual coupling of parallel lines, the distance calculation performed by a distance relay is incorrect. To achieve correct operation, the relay has to use not only the measured quantities of faulty line, but also the zero sequence current of healthy line. But the zero sequence current of the healthy line cannot be always measured. Therefore, we propose the neural network method to estimate the zero sequence current and the criterion to determine whether faulty line or not.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.161-164
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• 2009

This paper presents the ZVZCS(Zero Voltage and Zero-Current-Switching) Three-Level converter using the secondary coupled inductor and auxiliary capacitor. The converter with phase-shift control is proposed to reduce the circulating loss in primary and the voltage stress in secondary side. Using a coupled winding of the output inductor, two auxiliary capacitors are generated to reset the primary current at circulating interval.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.137-140
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• 1998

A new SPWM inverter using three-phase boost converter by auxiliary partial resonant with high power factor and high efficiency is proposed. The proposed boost converter is constructed by using a resonant network in parallel with the switch of the conventional boost converter. The devices are switched at zero voltage or zero current eliminating the switching loss. A new Partial resonant boost converter achieves zero-voltage switching (ZVS) or zero-current switching (ZCS) for all switch devices without increasing their voltage and current stresses. This paper introduces elimination of low-order harmonics compared with conventional SPWM inverter and SPWM inverter using three-phase boost converter by auxiliary Partial resonant.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.231-232
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• 2016

This paper investigates the design of multi-winding coupled inductor for minimum inductor current ripple. Based on the general circuit model of coupled inductor together with the operating principles of dc-dc converter, the relationship between the ripple size of inductor current and the coupling factor is derived under the different duty ratio. The optimal coupling factor of n-phase multi-winding coupled inductor which corresponds to a minimum inductor ripple current becomes -(1/n-1), i.e. a complete inverse coupling without leakage inductance, as the duty ratio of steady-state operating point approaches 1/n, 2/n, ${\cdots}$ or (n-1)/n. In an opposite manner, the optimal coupling factor value of zero, i.e. zero mutual inductance, is required when the duty ratio of steady-state operating point approaches either zero or one. Therefore, coupled inductors having optimal coupling factor can minimize the ripple current of inductor and inductor size.