• Journal of Power Electronics
• /
• v.15 no.4
• /
• pp.899-909
• /
• 2015

A dual-input boost-buck converter with coupled inductors (DIBBC-CI) is proposed as a thermoelectric generator (TEG) power conditioner with a wide input voltage range. The DIBBC-CI is built by cascading two boost cells and a buck cell with shared inverse coupled filter inductors. Low current ripple on both sides of the TEG and the battery are achieved. Reduced size and power losses of the filter inductors are benefited from the DC magnetic flux cancellation in the inductor core, leading to high efficiency and high power density. The operational principle, impact of coupled inductors, and design considerations for the proposed converter are analyzed in detail. Distributed maximum power point tracking, battery charging, and output control are implemented using a competitive logic to ensure seamless switching among operational modes. Both the simulation and experimental results verify the feasibility of the proposed topology and control.

• Journal of Power Electronics
• /
• v.10 no.6
• /
• pp.769-776
• /
• 2010

The ultracapacitor module has recently been recast for use in hybrid energy storage systems (HESSs). As a result, accurate state-of-charge (SOC) estimation for an ultracapacitor module is as important as that of primary sources in order to be utilized efficiently in an energy storage system (ESS). However, while SOC estimation via the open-circuit voltage (OCV) method is generally used due to its linear characteristics compared with other ESSs, this method results in many errors in cases of highcurrent charging/discharging within a short time period. Accordingly, this paper introduces a dynamic SOC estimation algorithm that is capable of SOC compensation of an ultracapacitor module even when there is a current input and output. A cycle profile that simulates the operating conditions of a mild-HEV was applied to a vehicle simulator to verify the effectiveness of the proposed algorithm.

• Electrical & Electronic Materials
• /
• v.8 no.5
• /
• pp.640-647
• /
• 1995

In this study, the BaTiO$\sub$3/ capacitor add to MnO$\sub$2/ like depressor and shifter were investigated for temperature or voltage compensation by structural and electrical analysis. The relative density of BCTM, generating poly crystall and formation of lattice defect, has a 90[%] over as the CaTiO$\sub$3/ come out to control grain size. The current density of BCTM2 increased non-ohmic in high-electric field but that BCTM3 and BCTM4 had a few changing. The BCTM3 and BCTM4 unformated grain boundary shown temperature compensation properties, so that the dielectric constant was low value. The curie point was near 140[.deg. C] in BCTM1 and BCTM4, but BCTM3 and BCTM4 not shown the curie point. It is found that the charging energy of BCTM4 was changed 6[%] according to rising temperature from room temperature to 417[K]. The formation of BaMnO$\sub$3/ was low dielectric constant to change frequency and temperature.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.125-127
• /
• 1998

The widely used power supply (Switched Mode Power Supply : SMPS) as a source in order to stabilize direct current for electronics or communication systems has merits, when it is compared to the existing source for stability, such as high efficiency, small size, light weight by means of switching process of the semiconductor device which controls the flow of power. However, due to existence of inductors and capacitors used for charging energy, the source part in electronic or communication systems hasn't reached the speed, that is supposed to get, for achieving smaller size and lighter weight. In order to got smallness in size, it is necessary to increase switching frequency. And that makes devices for measuring energy smaller. Nevertheless, the rise switching frequency brings increases in switching loss, inductor loss, and power loss. Also, the occurrence of surge and noise caused by high frequency switching is setting higher. The resonant converter has been considered as one of methods that give solutions for the problems of SMPS and that method has been paid attention as a source technology in electronics and communication.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.10
• /
• pp.803-806
• /
• 2011

1 mol% $Li_2O$ excess $0.9(Na_{0.52}K_{0.48})NbO_3-0.1LiTaO_3$ lead-free piezoelectric multilayer ceramic actuators were investigated to determine their aging properties. To reduce the thermal aging behavior, we applied a rectified unipolar electric field of 5 kV/mm to the specimen to accelerate the electric aging behavior. By employing a rectified unipolar electric field for the piezoelectric actuators, we could remove undesirable heating from the relaxation current in the motion of the ferroelectric domain. To accelerate the aging test, the applied electric fields had a frequency of 900 Hz. To have enough time for charging and discharging, we employed an accurate time constant to design the equivalent circuit model for the aging tester. To extract exact aging behavior, we measured the pseudo-piezoelectric coefficient before and after the aging process. We also measured the electro-mechanical coupling coefficient, the frequency-dependent dielectric permittivity, and the impedance to compare with fresh and aged specimen.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.66-66
• /
• 2007

Lead zirconate titanate (PZT) is one of the most attractive perovskite-type materials for ferroelectric random access memory (FRAM) due to its higher remanant polarization and the ability to withstand higher coercive fields. We first applied the damascene process using chemical mechanical polishing (CMP) to fabricate the PZT thin film capacitor to solve the problems of plasma etching including low etching profile and ion charging. The $0.8{\times}0.8\;{\mu}m$ square patterns of silicon dioxide on Pt/Ti/$SiO_2$/Si substrate were coated by sol-gel method with the precursor solution of PZT. Damascene process by CMP was performed to pattern the PZT thin film with the vertical sidewall and no plasma damage. The polarization-voltage (P-V) characteristics of PZT capacitors and the current-voltage characteristics (I-V) were examined by change of process parameters. To examine the CMP induced damage to PZT capacitor, the domain structure of the polished PZT thin film was also investigated by piezoresponse force microscopy (PFM).

• Journal of the Korean Vacuum Society
• /
• v.22 no.4
• /
• pp.198-203
• /
• 2013

Energy harvesting refers to converting ambient energy from our surroundings, which would be otherwise wasted, into useful electrical energy. A triboelectric energy harvester is a self-charged device for harnessing mechanical energy based on a coupled process of contact charging and electrostatic induction. In this research, we demonstrate simple fabrication of prototype triboelectric energy harvester using soft lithography and its electrical characterization. Triboelectric generation occurs between the two micro patterned layers of Au and PDMS. A micro pattern is simply replicated directly from the bottom layer to the top layer using soft-lithography without an extra transfer process. This generator can produce an output voltage of 2 V and output current of 20 nA.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.593-597
• /
• 2005

FIB equipment can perform sputtering and chemical vapor deposition simultaneously. It is very advantageously used to fabricate a micro structure part having 3D shape because the minimum beam size of ${\phi}$ 10nm and smaller is available. Currently FIB is not being applied in the fabrication of this micro part because of some problems to redeposition and charging effect of the substrate causing reduction of accuracy with regards to shape and productivity. Furthermore, the prediction of the material removal rate information should be required but it has been insufficient for micro part fabrication. The paper have the targets that are FIB-CVD characteristic analysis and minimum line pattern resolution achievement fur 3D micro fabrication. We make conclusions with the analysis of the results of the experiment according to beam current, pattern size and scanning parameters. CVD of 8 pico ampere shows superior CVD yield but CVD of 1318 pico ampere shows the pattern sputtered. And dwell time is dominant parameter relating to CVD yield.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.3
• /
• pp.442-450
• /
• 2001

Experiments were carried out on agglomeration of bipolarly charged particles in an alternating current electric field. Laboratory-scale setup was built and experiments were conducted at atmospheric condition. DOS(Di-octyl Sebacate) particles with 100% purity were generated by an atomizer. The particles were branched into two, each of which passed through a wire-to-plate type charging section where a positive or a negative DC high voltage was applied and was charged positively or negatively. These bipolarly charged particles together passed through an agglomeration section where an $\pm$20kV AC power was applied between two plates. The resident time in the agglomeration section was adjusted as l sec. Particle sampling was made by a cascade impactor (MOUDI). The effect of agglomeration system on the reduction ratio of particles below l ㎛ was 42∼45%. Effect of AC frequency on the particle size distribution was found insignificant.

• Journal of the Korean Society of Industry Convergence
• /
• v.23 no.2_1
• /
• pp.139-147
• /
• 2020

In order to satisfy the voltage levels of the low voltage battery side and high voltage DC bus, a high voltage gain with bidirectional operation is required. In this system, the cost effectiveness of the design is a critical factor; therefore, the system should be designed using a small number of components. This paper propose a novel bidirectional converter composed with a quasi-sepic and switched-indictor network. The proposed converter consists a small number of components with a high voltage gain ratio. Detailed analysis are made with respect to the operating mode, number of components, voltage and current ripple and efficiency. To verify performance of the proposed converter, simulation was performed is this paper. The simulation results are shown to verify the feasibility and performance of the proposed bidirectional converter.