• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.116-120
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• 2014

3-phase Induction machines are being used in industry and dq transformation from 3 phase of a, b, c is commonly used to analyze these machines. The equivalent circuits of d and q axis are however generally cross coupled and not simple to analyze. In this study, an analysis method of 3ph induction motor considering current regulator using dq transformation and matrix vector is proposed and it can explain the 3ph induction motor physically. This model does not need the separating process of d and q components. With this technique, the model becomes simple, is easy to understand in physical, and can get the same results with those from the other dq models. These simulation results of the proposed model are compared with those of other models for the conformation of the proposed method.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.263-271
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• 2013

A low dropout regulator (LDO) with fast transient responses is presented. The proposed LDO eliminates the trade-off between slew rate and unity gain bandwidth, which are the key parameters for fast transient responses. In the proposed buffer, by changing the slew current path, the slew rate and unity gain bandwidth can be controlled independently. Implemented in $0.18-{\mu}m$ high voltage CMOS, the proposed LDO shows up to 200 mA load current with 0.2 V dropout voltage for $1{\mu}F$ output capacitance. The measured maximum transient output voltage variation, minimum quiescent current at no load condition, and maximum unity gain frequency are 24 mV, $7.5{\mu}A$, and higher than 1 MHz, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1839-1844
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• 2010

A power management controller circuit with switched capacitor mode down regulator and battery charger block for semi-active RFID tags was proposed and fabricated. The main purposes of the proposed switched capacitor mode down regulator and battery charger block are to reduce standby current and to provide a self-controlled thin film battery charger by detecting the received RF power, respectively. Fabricated chip area is $360,000{\mu}m^2$ and measured standby current was about $1.3{\mu}A$. To further reduction of standby current, a wake-up circuit has to be included in the power management controller.

• Journal of IKEEE
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• v.17 no.2
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• pp.214-220
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• 2013

Small area LDO (Low drop-out) regulator with pass transistor using body-driven technique is presented in this paper. The body-driven technique can decrease threshold voltage (Vth) and increase the current ID flowing from drain to source in current. The technique is applied to the pass transistor to reduce size of area and maintain the same performance as conventional LDO regulator. A pass transistor using the technique can reduce its size by 5.5 %. The proposed LDO regulator works under the input voltage of 2.7 V ~ 4.5 V and provides up to 150mA load current for an output voltage range of 1.2 V ~ 3.3 V.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.11
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• pp.671-679
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• 2004

This paper presents the on-line current controller tuning method of grid-connected inverter using PSO(particle swarm optimization) technique for minimizing the harmonic current. Synchronous frame PI current regulator is commonly used in most distributed generation. However, due to the source voltage distortion, specially in weak AC power system, current may contain large harmonic components, which increase THD(total harmonic distortion) and deteriorates power quality. Therefore, some tuning method is necessary to improve response of current controller. This paper used the PSO technique to tune the current regulator and through simulation and experiments, usefulness of the tuning method has been verified. Especially in simulating the tuning process, ASM(average switching model) of inverter is used to shorten execution time.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.72-75
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• 2012

A solar array makes a Solar Array Regulator (SAR) for Low-Earth-Orbit satellite have different small signal characteristic. Therefore, an Average-Current-Mode (ACM) controller cannot control the BUCK-BOOST type SAR which operates in a current region of the solar array. In this paper, we present the Pseudo-Continuous Current Mode (PCCM) BUCK-BOOST Type SAR which can be controller by the ACM Controller. We explain the circuit operation of the PCCM BUCK-BOOST Type SAR, derive its small signal transfer function and design ACM Controller. Finally, we verify the ACM control of the PCCM BUCK-BOOST Type SAR by using a simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1606-1610
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• 2012

Hysteresis current regulator has been used widely because of its simple principle and structure. However, when the current band width is too narrow or the applied voltage is relatively too high, the switching frequency may increase abruptly and it generates a large amount of heat. Thus, this study will suggest a better and simple method to reduce the switching frequency. For single phase current control, the proposed hysteresis current control is executed by adding 0 mode state and comparing the slope of the current reference. This simple method decreases the generated switching frequency and significantly reduces the generated heat. This proposed method was proved with simulations and experiments comparing with the classical hysteresis current control method.

• Journal of Power Electronics
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• v.16 no.1
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• pp.66-73
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• 2016

The quantity of alternating current (AC) leakage and the value of distortion factor in capacitor currents are discussed with regard to a new power component called variable capacitance device (VCD). This component has terminals for controlling its capacitance. Nonlinear dielectric characteristics are utilized in this device to vary the capacitance. When VCD operates in an AC circuit, the AC leakage from this device through direct current (DC) control voltage source increases according to the conditions of DC control voltage and so on. To solve this problem, we propose techniques for suppressing AC leakage. Although VCD has strong nonlinear characteristics, the current through the capacitor is not distorted significantly. The relations between AC leakage and the distortion in current waveforms are investigated. An application example for an AC power regulator is also introduced to evaluate the distortion in waveforms.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.254-259
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• 2011

In this paper, a current stimulator circuit with adaptive supply regulator for retinal prosthesis is proposed. In current stimulation systems, the stimulating circuits with wide voltage swing range are needed due to the high impedance of the retina cell and microelectrodes. Thus, previous researches adopt the high voltage architecture to obtain the enough operating range. The high voltage architecture, however, could increase the power consumption and can damage the retina cells. The proposed circuit provides the adaptively regulated supply voltage by measuring the difference between desired stimulation current and the actual stimulation current. The proposed circuit can achieve the extended range of the allowable cell impedance, improved accuracy of the stimulation current, and higher biosafety.

• Journal of IKEEE
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• v.26 no.2
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• pp.313-318
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• 2022

The feedback voltage detection structure is proposed to alleviate overshoot and undershoot caused by the removal of the existing external output capacitor. Conventional LDO regulators suffer from overshoot and undershoot caused by imbalances in the power supply voltage. Therefore, the proposed LDO is designed to have a more improved transient response to form a new control path while maintaining only the feedback path of the conventional LDO regulator. A new control path detects overshoot and undershoot events in the output stage. Accordingly, the operation speed of the pass element is improved by charging and discharging the current of the gate node of the pass element. LDO regulators with feedback voltage sensing architecture operate over an input voltage range of 3.3V to 4.5V and have a load current of up to 200mA at an output voltage of 3V. According to the simulation result, when the load current is 200mA, it is 73mV under the undershoot condition and 61mV under the overshoot condition.