• Transactions on Electrical and Electronic Materials
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• v.7 no.3
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• pp.103-107
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• 2006

In this paper, a CMOS complementary bridge rectifier for driving RFID transponder chips is presented. The proposed RFID CMOS complementary bridge rectifier is designed with two NMOSs at the input, which are configured by cross-connected gate structures, and two PMOSs and two NMOSs at the output, which are configured by diode-connected MOS structures. Output characteristics of the proposed rectifier are analyzed with the high frequency small-signal equivalent circuit and verified with SPICE for RFID operating frequencies of 13.56 MHz HF for ISO 18000-3, 915MHz UHF for ISO 18000-6, and 2.45 GHz microwave for ISO 18000-4. Simulation results show well-rectified and high enough DC output voltages for driving the low power microchip in the RFID transponder for the frequency range from HF to microwave. DC output voltages are dropped by only around 0.7 V from the input peak-to-peak voltages.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.303-304
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• 2014

This paper describes Four Switch Three-Phase Z-Source rectifier with reduced value capacitors. This configuration has some advantages in term of small size of the circuit. The rectifier has buck-boost function by shoot-through state. Also, the rectifier has the advantage of decreasing inrush current in start-up and transient states. In order to reduce harmonics PWM modulation technique with a variable index has been suggested. Four Switch Three-Phase Z-Source rectifier with reduced value capacitors can output stable DC. Principles and dynamics of the system are discussed in detail.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.5
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• pp.440-449
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• 2014

This study proposes an LLC series resonant converter with a current doubler using a coupled inductor as a rectification circuit for the secondary side. The current doubler circuit is generally used for a high-voltage input and low-voltage output circuit to obtain high efficiency with small transformer turn ratio. However, an inductive circuit is not generally used in the secondary side of an LLC series resonant converter. If inductive components exist on the secondary side, the resonant characteristics are changed through the secondary inductive circuit. Mathematical analysis shows that the secondary-side current doubler with coupled inductor is not affected by the resonant characteristic of the primary LLC if leakage inductance occurs in the coupled inductor. Results of the analysis are proven by simulation; an experiment is also conducted for the proposed circuit.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.57-61
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• 2006

In the single-phase switched reluctance motor (SRM) drive, the required DC source is generally supplied by the circuit consisting of bridge rectifier and large filter capacitor connected with DC line terminal. Due to the large capacity of the capacitor, the charged time of capacitor is very short from the AC source. Lead to the bridge rectifiers draws pulsating current from the AC source side, which results in reduction of power factor and low system efficiency. Therefore a novel single-phase SRM drive system is presented in this paper, which includes drive circuit realizing reduction of torque ripple and improvement of power factor with a novel switching topology. The proposed drive circuit consists of one switching part and diode, which can separate the output of AC/DC rectifier from the large capacitor and supply power to SRM alternately, in order to realize the torque ripple reduction and power factor improvement through the switching scheme. In addition, the validity of the proposed method is tested by some simulations and experiments.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.611-616
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• 2001

This paper analyzed PFC of active clamp ZVS flyback converter by adding two methods PFC (power Factor Correction) circuit - two-stage and single-stage. The addition of active clamp circuit also provides a mechanism for achieving ZVS of both the primary and auxiliary switches. ZVS also limits the turn off di/dt of the output rectifier, reducing rectifier-switching loss and switching noise, due to diode reverse recovery. As a result, the proposed converters have characteristics of the reduced switching noise and high efficiency in comparison to conventional flyback converter. The simulation and experimental results show that the proposed converter improve the input PF of 300W ZVS flyback converter by adding single-stage, two-stage PFC circuit.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.77-80
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• 2003

Switching Mode Power Supply(SMPS) is widely used in many industrial fields. Power factor improvement and harmonic reduction technique are very important in SMPS. In this paper, we propose the circuit applied Flying Capacitor Snubber for improving power factor of boost converter on fast switching state. Snubber circuit consists of a inductor, two diodes and a capacitor. The losses of switching are reduced by inserting a snubber inductor in the series path of the boost switch and the rectifier diode to control the di/dt rate of the rectifier during it's turn-off. Prior to actual experiment, the circuit analysis Is implemented by PSPICE simulation.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.237-239
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• 2005

In this paper PLC Power Circuit with Hot-Swap Function is proposed for stable power supplies. The power modules of the proposed devices are implemented by CRM flyback converter using new synchronous rectifier circuit for high efficiency. By a variable switching frequency controller, this converter is operated with a reduced turn-on switching loss. Also, the load current in these power modules are shared by auto master / slave method using Outer loop. The proposed devices are analyzed in detail and optimized for high performance. Experimental results for a 100W power module at the variable switching frequency of 30$^{\sim}$70kHz were obtained to show the performance of the proposed device.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1819-1829
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• 2018

A three-phase, three-switch, and three-level boost-type PWM rectifier (Vienna rectifier) is proposed as an active front-end power factor correction (PFC) rectifier for telecom loads. The proposed active front-end PFC rectifier system is modeled by the switching cycle average model. The relation between duty ratios and DC link capacitor voltages is derived in terms of the system input currents. Furthermore, the feasible switching states are identified and applied to the proposed system to reduce the switching stress and DC ripples. A detailed equivalent circuit analysis of the proposed front-end PFC rectifier is conducted, and its performance is verified through simulations in MATLAB. Simulation results are verified using an experimental setup of an active front-end PFC rectifier that was developed in the laboratory. Simulation and experimental results demonstrate the improved power quality parameters that are in accordance with the IEEE and IEC standards.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.457-465
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• 2011

The fault analysis and detecting algorithm for a 3 phase diode rectifier is proposed. The 3 phase dioderectifier is used for the AC power rectifier of the PWM inverter. The input power or diode faults cause theripples of the DC voltage, degradation of the control performance and life shortening of the DC link capacitor.In this paper, the ripple of the DC voltage is mathematically analyzed for the earth fault of input power andopen circuit fault of the diode, respectively. The fault detection and type of fault can be obtained by comparingthe average DC voltage and the instant DC voltage which is sampled with 6 times of grid frequency. Theproposed method can be easily applicable and doesn't require additional circuit. The experimental and simulationresults are presented to verify the validity of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.6
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• pp.7-12
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• 2010

A semi-empirical organic schottky diode model is proposed for circuit simulation. We have set up a full custom design environment for organic schottky diode circuit using Spectre AHDL, which is widely used commercial EDA tool. We measured frequency response from fabricated rectifier, and it was compared to circuit simulation results using the AHDL model. The frequency response of the fabricated rectifier circuit is not sufficient for 13.56MHz RFID, however, it is enough for 135kHz-band RFID.