• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.6
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• pp.321-329
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• 2002

A protection scheme for series active compensator is presented and analyzed in this paper. The proposed series active compensator operated as a high impedance K($\Omega$) to the fundamentals when short-circuit faults occur in the power distribution system, and two control strategies are proposed in this paper The first is the method by detecting the fundamental source current through the p-q theory, the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame(SRF). When the short-circuit faults occur in the power distribution system, the proposed scheme can protect the series active compensator without additional protection circuits. The validity of the Proposed Protection scheme was investigated through experimental results.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.86-88
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• 2003

The efficiency of electric machine is important due to increase of interest about energy saving. Single Phase Line Start Permanent Magnet Synchronous Motor has high efficiency and power factor. LSPMSM offer a high efficiency as compared induction motor which are used in the home appliance. The analysis and design of LSPMSM is difficult because of unbalanced rotating magnetic field, nonlinear characteristics and rotor saliency. To consider these effects, F.E.M(Finite Element Methods) is coupled equivalent circuit methods. In this paper, a methods of analysis and design using F.E.M and equivalent circuit is represented.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.351-357
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• 2004

In this paper, we present an analytical method that provides fast and efficient evaluation of the conversion efficiency for switching power supplies. In the proposed method, the conduction losses are evaluated by calculating the effective values of the ideal current waveform first and incorporating them into an exact equivalent circuit model of the switching power supply that includes all the parasitic resistances of the circuit components. While the winding losses and core losses are accurately accounted for the magnetic components, the skin and proximity effects are assumed to be negligible in order to simplify the analysis. The validity and accuracy of the proposed method are verified with experiments on a prototype active-clamped forward converter with synchronous rectification. An excellent correlation between the experiments and theories are obtained for the input voltages of 36-75 V with 4-6 MOSFETs employed for the synchronous rectification.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.985-986
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• 2011

This paper deals with d-q axis equivalent circuit analysis of IPMSM(Interior Permanent Magnet Synchronous Motors) considering voltage harmonics. In the field weakening region, as the current vector angle increased, back-emf contains large harmonics, therefore, significant underestimation of voltage or overestimation of speed can be occurred from the conventional d-q axis equivalent circuit analysis. In order to consider the effects of voltage harmonics, a harmonic coefficient is introduced and verified by experiments.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1069-1070
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• 2008

This paper presents a high efficient two-stage interleaved synchronous buck CMOS DC-DC converter. The proposed circuit has a fixed duty cycle as 0.5 by an added buck converter. And it causes the best ripple cancelation of the output current ripple. The proposed circuit was simulated by HSPICE with a standard CMOS $0.35{\mu}m$ process parameter.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.119-122
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• 2002

This paper presents detailed characteristic of a Reluctance Synchronous Motor(RSM) which has a transverse-laminated rotor. First of all, the analysis of a magnetic circuit field between stator and rotor should be achieved in order to predict the performance characteristic of the RSM. For the analysis of a magnetic circuit field, the Finite Element(FE) analysis and a experimental method are used. The analytical result of the inductance flux distribution, vector potential, and the output shows some good characteristic along with the load condition.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1914-1918
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• 1998

In the case of synchronous machines, certain power system disturbances cause the induced rotor current to assume negative values when no static converter is present. A converter, however. prevents negative current from flowing, so that overvoltages occur. The overvoltages can be effectively limited as crowbar circuit using GTO. This newly proposed crowbar circuit with current limiting resistor absorbs energy when overvoltage comes from power system repeatedly and is verified through experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.756-761
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• 2013

This paper propose the new demodulation method that can detect resolver signal's peak at the time of position estimation when the position information is required during current controller period. The proposed method is performed in a synchronous demodulation way with exciting signal and also cover a capability which can compensate the lag element of exciting signal caused by the resolver's inductive component and filter circuit. This paper carried out the experiment to investigate the validity and performance of the suggested method by using the test board made up of DSP and demodulation circuit. The test results show that the proposed method is theoretically clear and work completely as expected from making sure of sampling resolver signal's peak at the time of position estimation. In addition, Software position tracking algorithm is executed with the demodulated signals generated by the suggested method and an exact position can be estimated.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.133-135
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• 1999

A simulation method for the direct thrust control of a permanent magnet linear synchronous motor(PMLSM) using the equivalent circuit is presented. The motor self inductance, the initial flux linkage by the permanent magnet is calculated in advance by the finite element analysis, and then the the direct control simulation is carried out. As a result, thrust, flux and speed responses to the commands are examined and the presented simulation method is proved to be very useful.

• Journal of the Korean Magnetics Society
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• v.27 no.2
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• pp.54-62
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• 2017

This paper presents a design of the Interior Permanent Magnet Synchronous Motor (IPMSM). an initial design process is accomplished by using the parametric design. In the design process, motor characteristics of parameters is computed by the d-q axis equivalent circuit model. Then, an optimal design process is accomplished by combination the experimental design and the response surface method. Finally, the design and analysis results are verified with experimental results.