• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.665-666
• /
• 2015

In this paper, it is proposed to substitute the tilting operation device of hybrid multi-D.O.F system from three phase SPM to single phase torque actuator. When using tilting operation with three phase SPM which is appropriate for continuous rotary operation, there are disadvantages that electricity availability rate is low and controllability is difficult. On the other hand when using a single phase torque actuator instead of SPM, it is appropriate for sequential tilting, electricity availability rate is high, and it is easy to control. Thus this will have a great influence on the development and practical use of the system. This study designed a single phase torque actuator in consideration of the magnetic saturation. Also, this was verified with comparative analysis with SPM through FEM(finite element method) analysis values of the design model and test values of the manufactured model.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.06a
• /
• pp.1096-1101
• /
• 2005

In this study, the experiment of thermal performance about closed-type hybrid cooling tower was conducted. A closed type cooling tower is a device similar to a general cooling tower, but with cooling tower replaced by a heat exchanger. The test section for this experiment has the process that the cooling water flows from top part of heat exchanger to bottom side in the inner side of tube, and spray water flows gravitational direction in the outer side of it. Air contacts of tube outer side are counterflow. The heat transfer pipe used in this experiment is a bare type tube having an outside diameter of 15.88mm. In this experiment, heat performances of the cooling tower are calculated such as overall heat transfer coefficient of between the process fluid and air, cooing capacity and pressure drop.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.292-297
• /
• 2000

In this research, the dynamic photoelastic experimental hybrid method for bimaterial is introduced. Dynamic biaxial loading device is developed, its strain rate is 31.637 s-1 and its maximum impact load is 20 ton. Manufactured methods for model of the dynamic photoelastic experiment for bimaterial are suggested. They are bonding method(bonding material: AW106, PC-1) and molding method. In the bonding method, residual stress is not occurred in the manufactured bimaterial. Crack is propagated along the interface or sometimes deviated from the interface. While in the molding method, residual stress is occurred in the manufactured bimaterial. Crack is always deviated from the interface and propagated in the epoxy region(softer materila). In order to propagate with constant velocity along the interface of bimaterial with arbitrary stiffer material, edge crack should be located along the interface of the acute angle side of the softer material in the bimaterial.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.233-236
• /
• 2002

The solution for PFC(Power Factor Correction), as a regulation in energy Policy, is becoming a hot Issue in every country because of the shortage of electrical energy. Therefore, a new improved idea for PFC problem has been introduced in this study. A lot of merits, effective cost by simple circuit, reduced PCB size, lighter than reactor in the view of weight, lower level of screen noise by leakage inductance in CTV applications, have been stated by comparing to the earlier method of using a Reactor. All test results in this statement were done by using a power device of STR-G9600 series based on the real load condition of color television. furthermore, the study shows that the test results also meets the IEC-1000-3-2 class D, which regulates the PFC when input power of a set is more than 75watts. More improved PFC in other applications hopes to be implemented by using the proposed method.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2007.06a
• /
• pp.251-256
• /
• 2007

The aim of this paper is development of resistivity seismic dilatometer (RSDMT) system. The resistivity module for obtaining apparent resistivity depth plot and seismic module for obtaining shear wave velocity (Vs) depth plot are attached to the conventional flat dilatometer testing equipment. From shear wave velocity profile, the stiffness at low strains of a site can be evaluated in undisturbed condition. And the resistivity value contains some information about water content and mineral characteristics of clayey soil. Specially manufactured resistivity and seismic modules were connected between commercialized DMT blade and drilling rod. To enhance reliability and repeatability of RSDMT test, automatic testing system including notebook based data acquisition system and automatic surface source system were developed. RSDMT system can be performed rapidly and can obtaine more reliable data at the same point compared with the separated testing system. The verification studies for the developed RSDMT system are going to be performed. From these studies, the effectiveness of integrated hybrid testing system will be checked in light of proper evaluation of geotechnical design parameters of clayey soils.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.11
• /
• pp.646-654
• /
• 1999

This paper deals with PWM patterns for harmonic reduction in inverter fed traction motors and the gear changing techniques for the variable speed drive of traction motor. GTOs are used as switching device of inverter because traction motor is a large load. To derive PWM rattern which can minimize the harmonics with the limited switching frequency, the output current and torque characteristic of SPWM and SHE PWM was analyzed. GTO inverter used for traction motor drive includes harmonics in the output current and torque by the limitation of switching frequency. However, the hybrid PWM method that adopt SPWM in the range of low frequency and SHE PWM in upper frequency range can achieve less harmonic characteristics in GTO inverters. If the traction motor is driven in variable speed by the proposed PWM pattern, 7 times of gear changing is needed. At the instant of the mode change, magnetic flux and torque may be altered and the large current flow. To reduce such an undesirable transient behavior, it is also presented the technique for the gear changing of inverter fed traction motor drive operated with the hybrid PWM. The results are verified by simulations and experiments.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.2
• /
• pp.21-34
• /
• 2000

Millimeter wave is expected as the unlimited useful frequency resources for the next generation wireless communication services. In the past, its usage was limited to the military warfare due to lack of millimeter devices. The development of GaAs pHEMT in 1980 and the progress in the processing technologies made the new consumer wireless services possible utilizing millimeter waves. Specially, most of passive components necessary for circuit design can be integrated with GaAs pHEMTs and this removes the difficulty in assembly unavoidable in hybrid design. InP based pHEMTs developed later possess all the properties of GaAs and it shows many advantages in higher frequency applications. In this paper, the status and trends of those devices and MMICs are presented and the future developing trends is also described.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.4
• /
• pp.326-333
• /
• 2011

This paper studies battery charging methods using existing motor inductance and 3-phase inverters without an additional charger to charge the battery of Plug-in Hybrid Electric Vehicles (PHEVs). As inverter switch control and motor coil used as the energy storage device for boosting make the system the boost converter, the additional charger is eliminated and volume, weight, and cost for the charger are reduced. Various charging methods according to topologies of the system and configurations of the controller are analyzed and verified by PSIM simulation.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.63-63
• /
• 2010

Ability to transport extracted carriers from NQDs is essential for the development of most NQD based applications. Strategies to facilitate carrier transport while preserving NQDs' optical characteristics include: 1) Fabricating neat films of NQDs with modified surfaces either by adapting series of ligands with certain limitations or by applying physical processes such as heat annealing 2) Coupling of NQDs to one-dimensional nanostructures such as single walled carbon nanotubes (SWNTs) or various types of nanowires. NQD-nanowire hybrid nanostructures are expected to facilitate selective wavelength absorption, charge transfer to 1-D nanostructures, and efficient carrier transport. Even with the vast interests in using NQD-SWNT hybrid materials in optoelectric applications, still, no reports so far have clearly elucidated the optoelectric behavior when they were assembled on the FET mainly because the complexity involving in both components in their preparation and characterization. We have monitored the optical properties of both components (NQDs, SWNTs) from the synthesis, to the assembly, and to the device. More importantly, by using pyridine molecules as a linker to non-covalently attach NQDs to SWNTs, we were able to assemble NQDs on SWNTs with precise density control without harming their electronic structures. Furthermore, by measuring electrical signals from the fabricated aligned SWNTs-FET using dielectrophoresis (DEP), we were able to elucidate the charge transfer mechanism.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.16 no.6
• /
• pp.753-758
• /
• 2006

We present the development of the digital fuzzy controller for maximum power regulation. A hybrid system that comprises wind and photovoltaic generation subsystems, and battery bank is developed in this paper. We use Takaki-Sugeno (T-S) fuzzy model to deal with the power regulation problem, since each power generator has complex nonlinear terms. The problem for regulation control can be simplified into a stabilization one. Also, in order to utilize the advanced digital device, we perform the intelligent digital redesign method. Finally, the performance of the proposed controller is extensively assessed through computer simulation.