• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.9B
• /
• pp.1399-1406
• /
• 2010

Customers can monitor electricity use in real time in smart grid(ICT is grafted onto current grid), so various beneficial services can be provided to customer. We did a qualitative survey, HV(Home Visit) and FGD(Focus Group Discussion), in order to derive customer's cognition of using electricity in home and values that customers consider significantly and a quantitative survey in order to know willingness to use. Customers consider electricity indispensible for using home appliances, want to use safely far from electromagnetic waves, short circuit and electronic shock. Also, customers want to save energy conveniently with no stress. Customers want 'a function', 'information', 'motivation' for energy saving, and 'electromagnetic waves cutting', 'to prevent electronic shock', 'to prevent short circuit' for safe electricity use. In this study, we derived 4 services - energy monitoring, standby power cutting, remote control, energy consulting - based on customer values and unmet needs, which is connected to home network that customers can monitor total and each appliance's electricity usage in real time and control home appliances. The willingness to use of services is over 60% and especially energy monitoring and standby power cutting service have high willingness to use rate, about 80%.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.49 no.2
• /
• pp.39-46
• /
• 2012

The newly designed sense amplifier in this paper has rail-to-rail input range achieving low power consumption. Reducing static power consumption generated due to DC path to ground is key element for low power consumption in this paper. The proposed sense amplifier performs power-saving operation using negative feedback circuit that controls the current flow with the newly added PMOS input terminal. As a simulation result, the proposed sense amplifier consumed about over 50 % efficiency of the average power consumed by the typical Rail-to-Rail sense amplifier.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.6
• /
• pp.130-137
• /
• 2003

Because of falling-off in power quality by harmonics, obstacles like lowering of capability, noise, vibration of power facilities and so on are occurred. Also generation of harmonics is inevitable and the point at harmonics is seriously gathering strength because energy saving installation using semiconductor circuit as countermeasures to enhance energy efficiency will be broadly spread and the use of energy conversion equipment like motor speed control contrivance, energy keeping installation and so on will increase, in the future. In order to eliminate harmonics obstacle, precision measurement and analysis on voltage, current, power factor, the each ingredient of harmonic order, the percentage of total harmonic distortion, and so forth are needed. In this paper, we developed low-cost measurement system to measure and analyze power quality connected with harmonics and verified it's performance by measuring and analyzing power quality in the three-phase and four-wire system.

• Journal of Digital Convergence
• /
• v.14 no.5
• /
• pp.325-331
• /
• 2016

In driving at evening or night, we are not able to recognize the speed bump and so stop suddenly. It could result in accidents. And also, we have a restriction of street light installation in farm road because it could be harmful to the crops and driver could not recognize the walking people. It needs to develop the speed bump with light and streetlight to be non harmful to the crops. So, we develop both the speed bump and streetlight with LED which could be non harmful to the crops and be increased recognition of walking people in farm road. For LED lighting power, we use the solar cells, and piezoelectric elements. It has automatic on/off according to power saving rates without illumination sensor. Minimization of circuit elements and design of minimum resisters and low power LED was used for power saving in assuring 3-days.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.10 no.1
• /
• pp.23-30
• /
• 2017

Currently, road lightings are installed with less than 400W of existing metal halide lamps. These road lightings are being replaced by energy-saving lightings. Induction lamps are expected to be more actively replaced with targets for tunnel lighting and high ceiling lighting. Therefore, it is necessary to develop high efficiency, high power induction lamps system. In this study, the gas type & pressure, amalgam type were designed for the high power of the induction lamps. And induction lamp system was optimized through electrical, optical characteristics analysis. It is optimized to the gas pressure 300~350 [mmHg] for the discharge tube of high power induction lamp and ferrite core. The driving circuit matching was completed with a induction lamp using indium amalgam. The rated power consumption of the induction lamp was optimized with 250 W (rated ${\pm}10%$)

• Journal of the Korean Magnetics Society
• /
• v.26 no.4
• /
• pp.137-141
• /
• 2016

There is a growing demand for non-contact current measurements for efficient use of electrical power and energy saving. In this study, I propose a non-contact current sensor using LC resonance by a resonance circuit composed of a sensor coil and 2 coupling coils for enabling a wireless measurement. The inductance of the sensor coil, which could be changed by applied current, causes the change of resonance frequency of the resonance circuit. A pair of magnet was attached to the ferrite core to apply a bias magnetic field that enabled the determination of the current direction. We obtained an output voltage change of 18 V with the current of -3~3 A. But, the output was nonlinear. In order to realize the non-contact current measuring method proposed in the present study, there is a need for a strict investigation of linearity and resolution for the future study.

• Journal of Drive and Control
• /
• v.15 no.3
• /
• pp.49-56
• /
• 2018

Construction machinery is used to improve productivity in civil engineering work and construction work, and it is a lengthy operation, and consumes considerable fuel to cope with large loads. As a result, productivity and fuel consumption of the construction machine become the main deciding factors. In the hydraulic system of the excavator, the main control valve is the most critical position for control. The flow distribution for control performance is achieved by the metering orifice, that causes critical energy loss. To improve this, we propose a combination of a three port proportional pressure reducing valve and a poppet type flow control valve as an IMV to replace the existing spool type MCV. To validate the proposal, we analyze static characteristics by modeling mathematically, and analyze dynamic characteristics. Simulation using the AMESim software on the regeneration circuit of the boom cylinder up-down operation, verifies the energy-saving effect compared to the existing MCV when IMV is used.

• Journal of Drive and Control
• /
• v.15 no.2
• /
• pp.46-51
• /
• 2018

Many research studies have been carried out related to saving energy and environmental pollution in the field of construction machinery. The best solution for reducing the related environmental pollution is to reduce fuel consumption by upgrading the energy efficiency of machinery used in this field. An efficiency upgrade in the field of construction machinery would mean minimizing the pressure loss in hydraulic pipe lines or achieving optimal operating conditions while responding to a load. One way to achieve this is to make an equivalent circuit, like an electrohydrostatic actuator, or to improve the spool type valve using the 4/3 way method. This study deals with an electrohydraulic proportional flow control valve. SimulationX software is used as a simulation tool for analyzing the dynamic characteristics. The analysis results, including the performance and characteristics of design parameters, are discussed and the validity of the theoretical analysis is also evaluated.

• Journal of Power Electronics
• /
• v.16 no.3
• /
• pp.1209-1217
• /
• 2016

This paper presents a novel charge pump scheme that combines the advantages of Fibonacci and Dickson charge pumps to obtain 30 V voltage for display driver integrated circuit application. This design only requires four external capacitors, which is suitable for a small-package application, such as smart card displays. High-amplitude (<6.6 V) clocks are produced to enhance the gate drive of a Dickson charge pump and improve the system's current drivability by using a voltage-doubler charge pump with a pulse skip regulator. This regulation engages many middle-voltage devices, and approximately 30% of chip size is saved. Further optimization of flying capacitors tends to decrease the total chip size by 2.1%. A precise and simple model for a one-stage Fibonacci charge pump with current load is also proposed for further efficiency optimization. In a practical design, its voltage error is within 0.12% for 1 mA of current load, and it maintains a 2.83% error even for 10 mA of current load. This charge pump is fabricated through a 0.11 μm 1.5 V/6 V/32 V process, and two regulators, namely, a pulse skip one and a linear one, are operated to maintain the output of the charge pump at 30 V. The performances of the two regulators in terms of ripple, efficiency, line regulation, and load regulation are investigated.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.1
• /
• pp.70-79
• /
• 2003

In this paper, T5 28-watt fluorescent lamp ballast using a piezoelectric transformer is fabricated and its characteristic is investigated. Developed electronic ballast is composed of basic circuits and blocks, such as rectifier part, active power factor corrector part, frequency oscillation part using microcontroller and feedback control, piezoelectric transformer and resonant half bridge inverters. The fabricated ballast uses to variable frequency methode in external so exciting that the frequency of piezoelectric transformer could be generated by voltage control oscillator using microcontroller(AT90S4433). The current of fluorescent lamp is detected by feedback control circuit. The signal of inverter output is received using Piezoelectric transformer, and then its output transmitted to fluorescent lamp. Traditional electromagnetic ballasts operated at 50-60Hz have been suffered from noticeable flicker, high loss, large crest factor and heavy weight. A new electronic ballast is operated at high frequency about 75kHz, and then Input power factor, distortion of total harmonic and lamp current crest factor are measured about 0.9!35, 12H and 1.5, respectively Accordingly, the traditional ballast is by fabricated electronic ballast using piezoelectric transformer and voltage control oscillator because of its lighter weight, high efficiency, economic merit and saving energy.