• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.3
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• pp.207-214
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• 2016

Magnetic circuit is a physical modeling method that is useful in designing and analyzing power transformers, especially for a priori evaluation of leakage and magnetizing inductance before actual production. In this study, a novel modeling approach that uses PSIM magnetic elements adopting gyrator and permeance-capacitances is investigated. A formula to determine the permeance-capacitors in the core and leakage path are established, and a simulation jig is devised to link the physical model and the electrical terminal characteristics with an automated parameter determination process. The derived formula is verified by measurement results of the prototype transformer samples. Given its accuracy and simplicity, this approach is suitable for analyzing and designing LLC resonant transformers whose leakage and magnetizing inductance are very critical to circuit operation.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.17-22
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• 1998

Stator Transient inductance has much influence on rotor flux orientation. In this paper, a new simple on-line tuning scheme of inductances including stator transient inductance for rotor flux orientation control is proposed. Detuned effects caused by inductance variations are shown and simple on-line tuning scheme of them is proposed. Inductances are estimated and tuned by only stator flux and stator current. The proposed scheme is effective in wide speed region including the field weakening region. The proposed on-line tuning scheme is confirmed by the simulation and experiment results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.754-760
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• 2008

In this paper, we introduce an RFID planar coil whose inductance does not change when it is attached on the metal surface. The coil is designed considering the inductance reduction on metal surface so that the inductance is the inverse times the reduction rate, and copper pour is placed in the bottom layer of the coil. This coil configuration is very simple and effective in constructing RFID systems for managing objects with metal surface because it prevents inductance reduction on metal surface.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.101-110
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• 1997

The circuit effects due to the transformer primary side series equivalent inductance in the Zero Voltage Switching Pulse Width Modulated Half Bridge DC/DC Converter and its impact on the effective duty are analyzed. The steady state equations and the small signal model of the converter are derived incorporating the effects of the complementary control and the utilization of transformer primary side series equivalent inductance. The open plant dynamics are analyzed on the basis of the model derived. The model predictions are confirmed by experimental measurements.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.137-139
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• 2003

Micro-Sources arc emerging as a providing environmentally friendly and reliable and effective solution. Micro-Source converter DC voltage of prime mover to AC voltage using voltage source inverter for interjecting with AC grid system. This paper studies optimal series inductance size for interjecting with AC grid system.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.74-77
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• 2001

The saturated winding inductances of a transformer are determined using the instantaneous magnetic saturation curve. The instantaneous curve is obtained from no load saturation curve in rms form by a direct piecewise linearized approach, then it is represented by a four-term ploynominal approximation. The saturated differential, effective and apparent winding inductances are computed from this curve, and these inductances are compared with the measured magnetizing inductance. The results show that the relation of $L_d<L_e<L_a$ exists and the computed apparent inductance is more close to the measured inductance.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.21-26
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• 2009

In order to determine the effective way of measuring the Mode I stress intensity factor($K_1$) by means of the alternating current potential drop(ACPD) technique for a material containing a two-dimensional surface crack, the change in magnetic flux in the air due to load was studied theoretically and experimentally. The magnetic flux in the air between crack surfaces is uniform and is not changed by increasing the load in the specimen and experimental results are the same as those obtained from theoretical analysis. Therefore, the change in potential drop due to load in the measuring system which was designed to induce a large amount of electro-motive force was caused by the change in internal inductance of material and the change in the mutual inductance concerned with internal inductance of material.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.425-430
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• 2018

The battery system of an electric vehicle suffers from the problem the battery output and the service life decrease at low temperature. A Positive Temperature Coefficient(PTC) heater is used for maintaining room temperature but is heavy due to a complicated insulation structure. The larger the weight is, the lower the fuel economy of the electric vehicle is. On the other hand a induction heater have a simple insulation structure, which is effective in weight reduction and has a rapid temperature rise. The induction heater consists of an LC resonance circuit. The larger the capacitance is, the higher the price and weight is. Therefore, the inductance should be increased to reduce the capacitance. Also, the main heat source of the induction heater is coreloss. So, it is important to optimize inductance and coreloss in terms of electromagnetic field design. In this paper, the inductance and the coreloss according to the change of the induction heater structure were optimized through the Taguchi method and Finite Element Method(FEM) simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.3
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• pp.263-269
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• 2013

The flyback converter has been applied widely in isolated DC/DC power converters because this converters employ a single MOSFET switch. The leakage inductance should be minimized for high efficiency of flyback converter. but in reality, it is very difficult. Namely, The Snubber circuit is essential to recover the leakage inductance stored energy when the switch is turn off. Flyback Converter typically operates in DCM mode and when switch is turn off in hard switching, this hard switching action results in a high power losses and switching stresses. In order to overcome these problems, a novel soft switching flyback converter using resonant snubber circuit is proposed in this paper. The resonant snubber circuit is composed of the transformer leakage inductance and a capacitor. To verify and confirm the proposed resonant snubber circuit, PSIM simulation and hardware prototype are implemented. Simulation and Experimental results indicate that the proposed resonant snubber circuit is effective.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.531-537
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• 2018

This paper propose a bidirectional dc-to-dc converter employing dual inductor for current ripple reduction. Conventional bidirectional dc-to-dc converter uses a single inductor for two different modes; boost and buck; therefore it is difficult to satisfy the optimized inductance value for each mode. To improve this problem, the proposed converter adds two switches, a diode, and one inductor. By proper switching of the additional switch, the proposed converter operates with a inductor in boost mode, but it works with dual inductor in buck mode. Hence in both modes the proposed bidirectional converter can be operated with optimized inductance values. Most of all the optimized inductance in buck mode can reduce the current ripple and its effective value(rms), which are directly related to the temperature increase resulted in short lifetime of battery. To verify the validity of the proposed approach, we first analyzes the operation of the proposed converter theoretically, and implement computer-aided simulations and experiments using a prototype.