Jin-Sik Park

Korea Advanced Institute of Science and Technology , Sŏul, Seoul, South Korea

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Publications (16)28.63 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, a simple and low-cost open-circuit fault detection and identification method for a pulse-width modulated (PWM) voltage-source inverter (VSI) employing a permanent magnet synchronous motor is proposed. An open-circuit fault of a power switch in the PWM VSI changes the corresponding terminal voltage and introduces the voltage distortions to each phase voltage. The proposed open-circuit fault diagnosis method employs the model reference adaptive system techniques and requires no additional sensors or electrical devices to detect the fault condition and identify the faulty switch. The proposed method has the features of fast diagnosis time, simple structure, and being easily inserted to the existing control algorithms as a subroutine without major modifications. The simulations and experiments are carried out and the results show the effectiveness of the proposed method.
    IEEE Transactions on Power Electronics 01/2013; 28(5):2514-2526. · 5.73 Impact Factor
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    ABSTRACT: A transformer magnetizing current offset for a phase-shift full-bridge (PSFB) converter is dealt with in this paper. A model of this current offset is derived and it is presented as a first-order system having a pole at a low frequency when the effects from the parasitic components and the switching transition are considered. A digital offset compensator eliminating this current offset is proposed and designed considering the interference in an output voltage regulation. The performances of the proposed compensator are verified by experiments with a 1.2-kW PSFB converter. The saturation of the transformer is prevented and the efficiency is improved by this compensator.
    IEEE Transactions on Power Electronics 01/2012; 27(1):331-341. · 5.73 Impact Factor
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    ABSTRACT: This paper proposes a simple position observer based on the instantaneous power and a tuning procedure for the proposed observer in driving the surface-mounted permanent magnet synchronous motor. In the instantaneous power of a three-phase system, the imaginary and real powers have the information related to the position and velocity. Using the instantaneous power, the difference between real rotor position and estimated rotor position is calculated. For easy design, gain parameters are described as a bandwidth of position observer. The proper bandwidth is expressed in terms of the desired load transient response, system inertia, and permitted acceleration range. Also, the sensitivity of phase resistance and inductance is analyzed. The described mathematical results show the necessity of accurate parameter information. Simulation and experimental results show the validity of the proposed design method and analysis.
    IEEE Transactions on Power Electronics 01/2012; 27(5):2585-2594. · 5.73 Impact Factor
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    ABSTRACT: A digital lamp balance system that equalizes lamp current of liquid crystal display (LCD) backlight is implemented in this letter. The proposed digital balance circuit consists of a balance switch which is in series with the lamp and a dc-blocking capacitor which also acts as a ballast capacitor for parallel lighting. The parasitic capacitance of the balance switch is used as parallel impedance which makes the lamp current decrease. Microcontroller unit controls each lamp current by changing the pulsewidth modulation duty ratio of a balance switch. The specified circuit, analysis, balance principles, and experimental results of the proposed system will be presented for a 46-in LCD TV.
    IEEE Transactions on Power Electronics 01/2012; 27(2):637-641. · 5.73 Impact Factor
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    ABSTRACT: A transformer magnetizing current offset for a phase-shift full-bridge (PSFB) converter is dealt in this paper. A model of this current offset is derived and it is presented as a first order system having a pole at a low frequency when the effects from the parasitic components and the switching transition are considered. A digital offset compensator eliminating this current offset is proposed and designed considering the interference in an output voltage regulation. The performances of the proposed compensator are verified by experiments with a 1.2kW PSFB converter. The saturation of the transformer is prevented by this compensator.
    Power Electronics and ECCE Asia (ICPE & ECCE), 2011 IEEE 8th International Conference on; 07/2011
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    ABSTRACT: This paper proposes the reduction technique of commutation torque ripple in brushless DC motor drive. The proposed method modulates the current slope of the incoming phase and the outgoing phase in commutation interval respectively. These slopes can be modulated by using specific duty ratio during commutation. Since the proposed method controls the commutation interval, it does not require additional control loop and sensing circuit to acquire the interval. Hence, motor drive system can be achieved at a low cost with the proposed scheme. The motor drive scheme with the proposed technique is implemented by digital controller employed digital signal processor. The experimental results verify that the proposed method is valid and useful in reduction of commutation torque ripple.
    01/2011;
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    ABSTRACT: This paper proposes a simple position estimator based on instantaneous power and a tuning procedure for the proposed estimator in driving surface mounted permanent magnet synchronous motor. In the instantaneous power of three phase system, the imaginary and real power has the information related to the position and velocity. Using the instantaneous power, the difference between real rotor position and estimated rotor position is calculated. For easy design, gain parameters are described as bandwidth of position estimator. And, the proper bandwidth is expressed as the desired load transient response, system inertia and permitted acceleration range. Also, the sensitivity of phase resistance and inductance is analyzed. The described mathematical results show the necessity of accurate parameter information. Simulation and experimental results show the validity of the proposed design method and analysis.
    01/2011;
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    ABSTRACT: The digital controller of the phase-shift full bridge converter for a server power supply is designed and implemented in this paper. Analog controllers are replaced by single MCU (micro controller unit) that not only manages the protection or the operational flow of a power supply but also controls the converter. Voltage mode controller is designed based on the z-domain small signal model considering effect of variation on output filter inductance. Moreover, gain scheduling is applied to adjust the controller gain according to load current. The current offset flowing through a magnetizing inductor is eliminated by adding PI compensator instead of inserting a blocking capacitor that may increase loss, cost, and volume. The saturation of a transformer and the conduction loss due to the current offset can be prevented. The performance of designed controller is verified by the experiments on 1.2kW phase-shift full bridge converter.
    Energy Conversion Congress and Exposition (ECCE), 2010 IEEE; 10/2010
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    ABSTRACT: Current balance system using MCU (micro controller unit) which controls the individual lamp current is implemented in this paper. The system consists of a ballast capacitor for parallel lighting, an amplitude modulator switching between the on-state and the off-state for regulating the lamp current, a gate driver to shift a voltage level, and a current sensor to send a feedback signal to the MCU. Each lamp current is compared with a reference and appropriate gate signal is generated to balance the lamp current. The MCU controls lamp currents individually by changing the PWM duty cycle of a switch series connected with a lamp. An amplitude modulator using a junction capacitance as an off-state parallel impedance to control the lamp current is a switch having an anti-parallel body diode. Series connected ballast capacitor and off-state parallel capacitance play a role of a bidirectional current amplitude modulation with a switch regardless of the anti-parallel body diode. By employing only one switch for each lamp, the number of power supplies isolated from the system for driving gate signal can be minimized. The specified circuit configuration, analysis, balance principles, and experimental results of the proposed system will be presented for 46 inch LCD-TV.
    01/2010;
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    ABSTRACT: Recently, permanent magnet synchronous motors are applied to various applications such as electric vehicle, aerospace, medical service, and military applications due to several outstanding characteristics. Because of the importance of high reliable operation in these areas, many researches which are related to the fault detection and diagnosis of inverter systems are conducted. In this paper, a new simple fault detection method of voltage source inverter for permanent magnet synchronous motor is proposed. The feasibility of the proposed method is proved by simulation and experiment. By the simulation and experiments, rapid detection characteristic of the proposed method has been proved without any additional voltage sensor.
    Energy Conversion Congress and Exposition, 2009. ECCE 2009. IEEE; 10/2009
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    ABSTRACT: A new technique based on buck-boost topology is proposed to equalize a series-connected battery stack in this paper. The proposed scheme transfers the energy from fully charged battery cell to the weakest charged battery using buck-boost operation. This operation maintains batteries at the same charge and voltage level. Unlike previous battery equalizing schemes, the new battery equalizer uses only one magnetic component, resulting low cost and small size. Experiment results are provided to verify the operation of the proposed battery equalizer.
    Applied Power Electronics Conference and Exposition, 2009. APEC 2009. Twenty-Fourth Annual IEEE; 03/2009
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    ABSTRACT: The PMSM is inherently electronically controlled and requires rotor position information for proper drives. However, the problems of the space, cost, and reliability of rotor position sensors have motivated research in the area of position sensorless PMSM drives. Numbers of rotor position sensorless control techniques have been proposed for PMSM drives, but most rely on the estimation of the rotor flux linkage vector. The performance of this method, however, is poor at low speed region due to the voltage distortions caused by the nonlinear behavior of a pulse width-modulation (PWM) voltage source inverter (VSI). In this paper, a new online voltage distortion compensation method is employed to overcome this problem. To prove effectiveness of the voltage distortion compensation method to the improvement of the rotor position estimation, the proposed method is applied to PMSM drive system and implemented in a digital manner using a digital signal processor.
    Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
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    ABSTRACT: This paper presents a study on a current control of a PM synchronous motor which is fed by two-level voltage source inverter in the large modulation index area. In order to increase dynamic response and extend speed limit caused by voltage limit, overmodulation method is generally used. But, the voltage ripple generate current ripple in overmodulation region. This current ripple reduce current controller bandwidth. In this paper, an improved current controller has been proposed for overmodulation region. The methods are described and analyzed and the experimental results are presented.
    Power Electronics, 2007. ICPE '07. 7th Internatonal Conference on; 11/2007
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    ABSTRACT: A new technique based on buck-boost topology is proposed to equalize a series-connected battery stack in this paper. The proposed scheme transfers the energy from fully charged battery cell to the weakest charged battery using buck-boost operation. This operation maintains batteries at the same charge and voltage level. Unlike previous battery equalizing schemes, the new battery equalizer uses only one magnetic component, resulting low cost and small size. Experiment results are provided to verify the operation of the proposed battery equalizer.
    01/2007;
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    ABSTRACT: This paper presents a zero-voltage switching (ZVS) two-transformer full-bridge (TTFB) pulsewidth modulation (PWM) converter with lossless diode-clamp rectifier for a plasma display panel sustaining power module (PSPM). The TTFB converter has series-connected two transformers which act as an output inductor as well as a main transformer. Although the naturally doubled leakage inductor due to the series-connected two transformers contributes to achieve the ZVS of the lagging leg, it creates a serious voltage ringing across the output rectifier diodes. This results in the heavy voltage stresses across the rectifier diodes. Thus the dissipative snubber circuits are required in spite of the severe power dissipation. To overcome these problems, a new lossless diode-clamp rectifier (LDCR) is employed as the output rectifier, which helps the voltage across rectifier diodes to be clamped at one half the output voltage (V<sub>o</sub>/2) or a full output voltage (V<sub>o</sub>). Therefore, no dissipative snubber circuits for the rectifier diodes are needed and a high efficiency as well as a low noise output voltage can be realized. In addition, the clamping capacitors of the LDCR can help considerably to reduce the primary circulating current. The operations, analysis, and design consideration of proposed converter are presented. Also, a 425-W, 385-Vdc input, 170-Vdc output prototype is constructed and experimental results show the validity of the proposed converter
    IEEE Transactions on Power Electronics 10/2006; · 5.73 Impact Factor
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    ABSTRACT: This paper presents a zero-voltage switching (ZVS) two-transformer full-bridge (TTFB) PWM converter with lossless diode-clamp rectifier for a plasma display panel (POP) sustaining power module (PSPM). The TTFB has series-connected two transformers which act as an output inductor as well as a main transformer, i.e. as the forward and the flyback transformer. Although the doubled leakage inductor of the two-transformer make it easier to achieve the ZVS of the lagging leg switch along the wide load range, it instigates a serious voltage ringing across the output rectifier diodes, which would require the dissipative snubber circuit, cause the serious power dissipation, and increase the voltage stress across those diodes. To overcome these problems, a new lossless diode-clamp rectifier (LDCR) is employed as the output rectifier, which helps the voltage across rectifier diodes to be clamped at a half the output voltage (V<sub>0</sub>/2) or the output voltage (V<sub>0</sub>). Therefore, no dissipative snubber for the rectifier diodes is needed and a high efficiency as well as a low noise output voltage can be realized. In addition, the clamping capacitor of the LDCR can help to considerably reduce the primary circulating current. The operations, analysis and design consideration of proposed converter are presented. Also, a 425 W, 385-170 V dc prototype is constructed and experimental results verified the validity of the proposed converter.
    Industrial Electronics Society, 2004. IECON 2004. 30th Annual Conference of IEEE; 12/2004

Publication Stats

26 Citations
28.63 Total Impact Points

Institutions

  • 2006–2012
    • Korea Advanced Institute of Science and Technology
      • Department of Electrical Engineering
      Sŏul, Seoul, South Korea
  • 2004
    • Korean Institute of Ocean Science and Technology
      Anzan, Gyeonggi Province, South Korea