• Journal of Power Electronics
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• v.16 no.4
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• pp.1288-1297
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• 2016

This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.507-515
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• 2012

DC-DC converter which composed of LLC resonant converter, operated by fixed switching frequency with fixed duty cycle (50%), and flyback converter to provide constant output voltage($400V_{DC}$) with variation of input voltage($30-60V_{DC}$) is proposed in this paper. To obtain constant output voltage($400V_{DC}$), flyback converter is not operated in case of above the maximum input voltage($60V_{DC}$) and operated as the input voltage decreases to below 60VDC. Therefore, flyback converter can be designed to the 50% power rating of the maximum power in the proposed DC-DC converter. Operation modes and voltage gain characteristics were analyzed and a 360W prototype converter was tested to verify the proposed converter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.1-6
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• 2008

In this paper, bias control circuit structure have been employed to improve the power added efficiency of the CMOS class-E power amplifier on low input power level. The gate and drain bias voltage has been controlled with the envelope of the input RF signal. The proposed CMOS class-E power amplifier using bias controlled circuit has been improved the PAE on low output power level. The operating frequency is 2.14GHz and the output power is 22dBm to 25dBm. In addition to, it has been evident that the designed the structure has showed more than a 80% increase in PAE for flatness over all input power level, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.355-364
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• 2013

Respect to the input AC voltage and output DC voltage, conventional three-phase PWM rectifier is classified as the voltage type rectifier with boost capability and the current type rectifier voltage with buck capability. Conventional PWM rectifier can not at the same time the boost and buck capability and its bridge is weak in the shoot- through state. These problems can be solved by Z-source PWM rectifier which has all characteristic of voltage and current type PWM rectifier. By shoot-through duty ratio control, the Z-source PWM rectifier can buck and boost at the same time, also, there is no need to consider the dead time. This paper proposes the input AC voltage sensorless control method of a three-phase Z-source PWM rectifier in order to accomplish the unity input power factor and output DC voltage control. The proposed method is estimated the input AC voltage by using input AC current and output DC voltage, hence, the sensor for the input AC voltage detection is no needed. comparison of the estimated and detected input AC voltage, estimated phase angle of the input voltage, the output DC voltage response for reference value, unity power factor, FFT(Fast Fourier Transform) of the estimated voltage and efficiency are verified by PSIM simulation.

• Journal of electromagnetic engineering and science
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• v.18 no.3
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• pp.145-153
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• 2018

In this paper, the efficiency of single-input multiple-output (SIMO) wireless power transfer systems is examined. Closed-form solutions for the receiver loads that maximize either the total efficiency or the efficiency for a specific receiver are derived. They are validated with the solutions obtained using genetic algorithm (GA) optimization. The optimum load values required to maximize the total efficiency are found to be identical for all the receivers. Alternatively, the loads of receivers can be adjusted to deliver power selectively to a receiver of interest. The total efficiency is not significantly affected by this selective power distribution. A SIMO system is fabricated and tested; the measured efficiency matches closely with the efficiency obtained from the theory.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.745-750
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• 2007

In this paper, we propose a new gate modification method using the input vector maximizes the number of gates in WLS within the optimum range of the minimum leakage power. We prove that MLV is not always the optimal solution, and that the leakage power and area can decrease when modifying the gates using the input vector for which the number of gates in WLS is maximized within the optimum range of the minimum leakage power for the circuits applying the IVC technique and gate modification method. Using the proposed method, the gate-level description circuit can be converted to the modified circuit which reduces the leakage power by chip designer, and the modified circuit can be applied without any modification in design flow.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.1
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• pp.1-5
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• 2007

Many nonlinear controllers for the power system are based on nonlinear models involving the power angle as an element of the state, and therefore the reference value for the power angle is needed. As this reference value is not generally available, it is difficult to apply such nonlinear control methods in practice. To deal with this problem, we present an input-output feedback linearizing control scheme by selecting the output as a combination of the squared voltage and the relative frequency. It is shown that the internal dynamics are locally stable with controllable damping, and that the frequency remains bounded for all time. Simulations illustrate the effectiveness of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.5
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• pp.45-51
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• 1993

An erbium doped fiber amplifier(EDFA) pumped by aingle 1.48$\mu$m LD was fabricated, and its gain and noise characteristics were measured. As a signal source, 1548 nm wavelength DFB LD was used. The small signal net gain of the EDFA module was 21.8 dB with maximum gain coefficient 0.7dB/mW for the erbium fiber length of 17.6 m, the pump power of 58 mW, and an input signal power of -25 dBm, respectively. The saturation power of the EDFA was 1 dBm for the input signal power of -5 dBm and the noise figure, measured by using an optical spectrum analyzer, was 5.8 dB for the input signal power of -40 dBm.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.4
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• pp.252-256
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• 2006

A low-power ECC check bit generator is presented with competent DRAM implementation with minimal speed loss, area overhead and power consumption. The ECC used in the proposed scheme is a variant form of the minimum weight column code. The spatial and temporal correlations of input data are analyzed and the input paths of the check bit generator are ordered for the on-line adaptable power savings up to 24.4% in the benchmarked cases. The chip size overhead is estimated to be under 0.3% for a 80nm 1Gb DRAM implementation.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1008-1009
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• 2015

An emergency diesel generator system is an independent source of power that supports important electrical systems on loss of normal power supply. AVR(Automatic Voltage Regulator) is a regulator which regulates the output voltage at a nominal constant voltage level. Specially, a power supply for the AVR must be operated at the very wide input range. In this paper, a flyback power supply with very wide input voltage range is proposed.