• Journal of Power Electronics
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• v.17 no.3
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• pp.579-589
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• 2017

In this study a new high step-up dc-dc converter is presented. The operation of the proposed converter is based on the capacitor switching and coupled inductor with a single active power switch in its structure. A passive voltage clamp circuit with two capacitors and two diodes is used in the proposed converter for elevating the converter's voltage gain with the recovered energy of the leakage inductor, and for lowering the voltage stress on the power switch. A switch with a low $R_{DS}$ (on) can be adopted to reduce conduction losses. In the generalized mode of the proposed converter, to reach a desired voltage gain, capacitor stages with parallel charge and series discharge techniques are extended from both sides of secondary side of the coupled inductor. The proposed converter has the ability to alleviate the reverse recovery problem of diodes with circuit parameters. The operating principle and steady-states analyses are discussed in detail. A 40W prototype of the proposed converter is implemented in the laboratory to verify its operation.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.207-209
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• 2019

This paper proposes a grid-tied photovoltaic (PV) system, consisting of Voltage-fed dual-active-bridge (DAB) dc-dc converter with single phase inverter. The proposed converter allows a small dc-link capacitor, so that system reliability can be improved by replacing electrolytic capacitors with film capacitors. The double line frequency free maximum power point tracking (MPPT) is also realized in the proposed converter by using Ripple Correlation method. First of all, to eliminate the double line frequency ripple which influence the reduction of DC source capacitance, control is developed. Then, a designing of Current control in DQ frame is analyzed and to fulfill the international harmonics standards such as IEEE 519 and P1547, $3^{rd}$ harmonic in the grid is directly compensated by the feedforward terms generated by the PR controller with the grid current in stationary frame to achieve desire Total Harmonic Distortion (THD). 5-kW PV converter and inverter module with a small dc-link film capacitor was built in the laboratory with the proposed control and MPPT algorithm. Experimental results are given to validate the converter performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.3
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• pp.49-60
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• 2002

A systematic design approach for Power distribution network (PDN) is presented aiming at applications to DRAM module designs. Three main stages are comprised in this design approach: modeling and simulation of a PDN based on a two-dimensional transmission line structure employing a partial element equivalent circuit (PEEC); verification of the simulation results through comparison to measured values; and design space scanning with PDN parameters. Impedance characteristics for do-coupling capacitors are analyzed to devise an effective way to stabilize power and ground plane Performance within a target level of disturbances. Self-impedance and transfer-impedance are studied in terms of distance between circuit features and the size of do-coupling capacitors. A simple equation has been derived to find the do-coupling capacitance values yielding impedance lower than design target, and thereby reducing the overall computation time. The effectiveness of the design methodology has been demonstrated using a DRAM module with discrete do-coupling capacitors and a strip structure.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1315-1324
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• 2018

A novel three-phase four-wire inverter topology is presented in this paper. This topology is equipped with a special capacitor balance grid without magnetic saturation. In response to unbalanced load and unequal split DC-link capacitors problems, a qusi-full-bridge DC/DC topology is applied in the balance grid. By using a high-frequency transformer, the energy transfer within the two split dc-link capacitors is realized. The novel topology makes the voltage across two split dc-link capacitors balanced so that the neutral point voltage ripple is inhibited. Under the condition of a stable neutral point voltage, the three-phase four-wire inverter can be equivalent to three independent single phase inverters. As a result, the three-phase inverter can produce symmetrical voltage waves with an unbalanced load. To avoid forward transformer magnetic saturation, the voltages of the primary and secondary windings are controlled to reverse once during each switching period. Furthermore, an improved mode chosen operating principle for this novel topology is designed and analyzed in detail. The simulated results verified the feasibility of this topology and an experimental inverter has been built to test the power quality produced by this topology. Finally, simulation results verify that the novel topology can effectively improve the inhibition of an inverter with a three-phase unbalanced load while decreasing the value of the split capacitor.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.217-220
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• 2000

In this paper, A low-power MOS monolithic peak detector is presented. Designed for monolithic and low-power characteristics, this MOS peak detector can be integrated easily on the same chip as a module of large communication systems. The simulation results of this peak detector which was composed with four NMOSs and two capacitors show the power dissipation of 0.972㎽ and the good operations for 2㎓ operating pulse frequency. Therefore, it may be used as a functional block for various signal processing systems.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.432-435
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• 1997

This Paper proposes a novel sinusoidal converter which improves input power factor and input current waveform without any complicated switching modulation such as a pulse width modulation or a complicated feed-back control. It is composed of a full bridge diode, a pair of capacitors, a pair of inductors and a pair of switching devices. The configuration and control strategy are both simple however, the sinusoidal converter effectively reduces reactive power and hamonics included in a input line current. Excellent behavior of the proposed converter is verified by theoretical analysis and experimental results.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.187-190
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• 2000

Chua's circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and synchronizations of a power line are investigated. Since the synchronization of the power line system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. As a result, the chaos synchronization has delay characteristics in the power line transmission system caused by the line parameters L and C.

• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.36-42
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• 2007

In general, the battery and the(electric) condenser are pictured as electrical energy storage devices. Although there were lots of inventions and utilizations of morden conveniences according to enormous growth of the science and technologies after the Industrial Revolution, a speed of technology development on these devices being closely used in civilized human lives and many electric or electronic systems as a core component are relatively slower to the other fields of technologies. Nevertheless, based on a remarkable progress of the material science and technologies for the last ten years, a new type of electrical energy storage device so called as 'electrochemical capacitors' are being developed and used practically. The electrochemical capacitors exhibit their own characteristics of much enhanced capacitance over the conventional condensers and also distinctively exhibit a longer lift time and higher power capability that the nickel hydrogen batteries and secondary batteries such as lithium ion and polymer batteries does not show up so for. Hence, in this paper, it is intended to introduce a fundamental understanding and updated technology trends on the electrochemical capacitors.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.677-687
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• 2018

This paper presents a novel power decoupling control scheme with the bidirectional buck-boost converter for primary-side regulation photovoltaic (PV) micro-inverter. With the proposed power decoupling control scheme, small-capacitance film capacitors are used to overcome the life-span and reliability limitations of the large-capacitance electrolytic capacitors. Then, an improved flyback PV inverter is employed in continuous conduction mode with primary-side regulation for the PV power conditioning. The proposed power-decoupling controller shares the reference for primary side current regulation of the flyback PV inverter. The decoupling controller shapes the input current of the bidirectional buck-boost converter. The shared reference eliminates the phase-delay between the input current to the bidirectional buck-boost converter and the double frequency current at the PV primary current. The elimination of the phase-delay in dynamic response enhances the ripple rejection capability of the power decoupling buck-boost converter even with small film capacitor. With proposed power decoupling control scheme, the additional advantage of the primary-side regulation of flyback PV inverter is that there is no need to have an extra current sensor for obtaining the ripplecurrent reference of the decoupling current-controller of the power-decoupling buck-boost converter. Therefore, the proposed power decoupling control scheme is cost-effective as well as the size benefit. A new transient analysis is carried out which includes the source voltage dynamics instead of considering the source voltage as a pure voltage source. For verification of the proposed control scheme, simulation and experimental results are presented.

• Journal of Power Electronics
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• v.4 no.4
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• pp.237-245
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• 2004

In this paper, a two-switch high frequency flyback transformer linked zero voltage soft switching PWM DC-DC power converter implemented for distributed DC- feeding power conditioning supplies is proposed and discussed. This switch mode power converter circuit is mainly based on two main active power semiconductor switches and a main flyback high frequency transformer linked DC-DC converter in which, two passive lossless quasi-resonant snubbers with pulse current regeneration loops for energy recovery to the DC supply voltages composed of a three winding auxiliary high frequency pulse transformer, auxiliary capacitors and auxiliary diodes for inductive energy recovery discharge blocking due to snubber capacitors are introduced to achieve zero voltage soft switching from light to full load conditions. It is clarified that the passive resonant snubber-assisted soft switching PWM DC-DC power converter has some advantages such as simple circuit configuration, low cost, simple control scheme, high efficiency and lowered noises due to the soft switching commutation. Its operating principle is also described using each mode equivalent circuit. To determine the optimum resonant snubber circuit parameters, some practical design considerations are discussed and evaluated in this paper. Moreover, through experimentation the practical effectiveness of the proposed soft switching PWM DC-DC power converter using IGBTs is evaluated and compared with a hard switching PWM DC-DC power converter.