• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1303-1304
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.93-94
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• 2007

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.979-984
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• 2007

This paper presents a new control mechanism for the proportional pressure control which is accomplished by electro-pneumatic regulator using two PZT actuators. The electro-pneumatic regulator of this study is 2-stage type and consists of two piezoelectric actuators, a controller and a main poppet valve. The piezoelectric actuators are multilayer bender type and are controlled by digital signal. Proportional pressure control technique is very important because that can derive improvement of product quality and driving ability in the pneumatic system. Solenoid actuator method for pressure control is widely used but this actuator has a high power consumption characteristics. So new actuator is required for the energy saving. In this study, PZT actuator for the pressure control was fabricated and experimented instead of the conventional type solenoid actuator. Experiments for the new control mechanism of the elector-pneumatic regulator were operated under the input condition of 0.4[MPa] and it was confirmed that this mechanism has a good control characteristics to the response sensitivity and hysteresis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.5709-5715
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• 2012

Injection molding product is commonly used for reducing the weight of automotive vehicle, and door regulator guide rail with plastic material is also made by injection molding process. In order to improve the injection molding performance of plastic regulator guide rail, optimal molding condition is suggested by numerical simulation and DOE after obtaining the sensitivity of parameters for regulator rail manufacturing on warpage and fill time. Furthermore, multi direct gate method and optimal cooling circuit are introduced to get the uniform temperature distribution and better cooling efficiency in molding product. The effect of the proposed design on the injection molding performance is verified by the test of prototype of plastic regulator guide rail.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1283-1290
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• 2003

Recently, PWM Buck AC-AC Converter is widely employed in various industrial applications such as voltage and power regulator, electronic transformer, phase shifter and so on. This paper presents static and dynamic modeling and complete characteristic analysis of a PWM Buck AC-AC converter. Firstly, the three phase converter system is modelled by using DQ transformation whereby we can obtain basic characteristic equations such as voltage gain and power factor as well as state equation and transfer function for control. Secondly, based on the analysis, the feedforward-feedback control technique is also proposed to obtain instantaneous duty level change whereby very fast dynamic response is achieved. Finally, the experimental results show the validity of the modeling, analysis and control.

• Journal of IKEEE
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• v.22 no.2
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• pp.384-392
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• 2018

A multiple-output LDO regulator is a good choice in terms of the efficiency in embedded systems requiring various supply voltages. A small feedback factor in LDO incurs the long settling time, resulting in large ripples in the time-multiplexing strategy. A new proposed topology enhances the settling time, and hence the ripples by incorporating the constant feedback factor with different reference voltages. The simulation results of a prototype design in a standard $0.35{\mu}m$ CMOS process verify that the proposed strategy enhances the settling time and ripple characteristic by more than doubled than a conventional circuit using the feedback factor of less than 0.4.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.7
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• pp.398-405
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• 2013

Small and medium-size buildings employ a multi-distributed individual air-conditioning system that utilizes package air conditioners instead of centralized cooling systems, which can allow easier building management and maintenance, along with a diversification of facility use. Inverter driven system heat pumps have been developed to achieve not only an easy distribution control, allowing free combination of indoor units with different models and different capacities, but also wide applications to intelligent air conditioning. However, the control algorithms of the system heat pump are limited in the open literature, due to complicated operating conditions. In this paper, an inverter-driven system heat pump having two indoor units with electronic expansion valves (EEV) was simulated in the cooling mode. An integral optimum regulating controller employing the state space control method was also simulated, and applied to the system-heat pump system, to obtain efficient control of the MIMO (multi input multi output) system. The simulation model for the controller yielded satisfactory prediction results. The new control model can be successfully utilized as a basic tool in controller design.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.188-191
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• 2007

This paper shows the Development of In-tank pressure regulator and Solenoid Valve used in FCV(Fuel Cell Vehicle). We have developed new type of Regulator and Solenoid through analysis of the structure and characteristics of component of FCS(Fuel Cell System) from the advanced technology. Now it is possible to localize the component by making use of the development of Regulator and Solenoid made by us. Regulator and Solenoid is a equipment to control hydrogen pressure supplied into a stack. Therefore, outlet pressure, a flow of fluid and temperature are important parameters according to a inlet pressure. And leak test, endurance test and burst test should be done to guarantee the performance and safety of Regulator and Solenoid used in the fuel of high pressure. Also, Hydrogen friendly materials are applied to inner parts of the Regulator, Solenoid and weight reduction is done to cost saving in part not related to performance. As a result, we have proven the good performance and reliability in endurance of Regulator, Solenoid and will make an development in performance as well as durability to ensure industrialization.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.151-156
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• 2011

This study examined the casting analysis of fuel pressure regulator of LPI vehicles. We aims to predict all the phenomenon accompanied by flow and solidification in die casting, and maximize productivity and quality through optimal casting design. As a result of comparing Types A and B of casting design, it was found that the number of overflow affected flow, flowspeed and solidification temperature. And there was a minute difference between solidification temperatures at thick section of the spare parts. Solidification began at temperatures of $624^{\circ}C{\sim}630^{\circ}C$ but after the casting was completed, temperatures at the center of the parts were $600^{\circ}C{\sim}614^{\circ}C$ Temperature of molten metal showed optimal flow at temperature of $680^{\circ}C$. It began to solidity around at $650^{\circ}C$ and to be cooled between $580^{\circ}C{\sim}550^{\circ}C$ in high speed. When the process was analysed through a computer simulation, it was found that hardness of regulators manufactured through Type B of overflow was above $H_R60$.

• Journal of IKEEE
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• v.20 no.3
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• pp.318-321
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• 2016

As IoT industry are growing fast, The importance of power management system is also being magnified. CMOS High power-supply rejection ratio(PSRR) Low-dropout(LDO) regulator is achieved by the proposed ripple Subtractor, Feed-forward capacitor and OTA in this paper. The LDO is implemented in $0.18-{\mu}m$ CMOS technology. With the proposed structures, in the maximum loading of 40mA, Simulation result achieves PSRR of -73.4dB at 500kHz and PSRR better than -40dB when frequency is below 10MHz with $6.8-{\mu}F$ output capacitor.