• JOURNAL OF ELECTRICAL WORLD
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• s.266
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• pp.65-69
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• 1999

• Journal of KIISE
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• v.44 no.6
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• pp.601-606
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• 2017

Recently, we have frequently encountered flying drones with the growth of drone industry. However, it is difficult for a driver to stabilize the motor speed of drones, since the voltage of a Lithium polymer battery used in drones may suddenly drop or rise when its power is exhausted. The instability of the motor speed precludes the drone from maintaining a flight altitude, so that the fuselage of a drone performs ascending and descending repeatedly. For solving this problem, existing techniques either add a compensator considering voltage drop of battery or change the control model. Since these techniques use hardware-implemented modules or depend on motor type and experimental results, there is a problem that new suitable modules should be implemented in accordance with the used motor of the fuselage. For solving this problem, in this paper, we implement a motor speed controller in the firmware of drones by considering voltage drop of battery to enhance drone flight stability.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.433-439
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• 2015

Recently, Interest in power the quality was increased because of increasing the use of sensitive load equipment into an electrical disturbance such as computer, Electricity, Electronics, Telecommunications and semiconductor device. In addition, To enhance power quality, the instantaneous voltage drop occurred in precision load equipment is a need for proper compensation. In order to solve the problem, The developed dynamic voltage restorer (DVR) using an electric double layer capacitor (EDLC) has been applied. In this paper, We will do study to apply hybrid capacitors that have high energy density to the same size compared to the EDLC to DVR. Also, As a emergency luminaires of emergency power supply that we can support more than 10 years of life was confirmed the applicability of hybrid capacitor.

• Journal of IKEEE
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• v.16 no.2
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• pp.109-115
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• 2012

We propose a control system consisted of TRIAC PWM module and sequential start control system attenuating voltage-dip and inrush current caused by starting of inductive load network. To minimize the high voltage-dip and inrush current induced from a large capacity inductive load, we developed a TRIAC PWM module. And we also developed a sequential start control system preventing simultaneous starting of the inductive loads within a same power network. According to the experimental results with the proposed control system, the voltage-dip and inrush current could be effectively attenuated such that they can meet the related international standards and resolve the issues associated with simultaneous starting of multiple inductive loads. By employing this system, power cost usually implemented by the estimation of peak power consumption can be reduced and the power quality of a power distribution system connected to the inductive load network can be stabilized efficiently.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.5
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• pp.13-20
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• 2008

Power quality problems such as momentary interruptions and voltage sags do not great influence on loads at past. However, the interests in power quality problems increase as the use of sensitive loads with microprocessor like computers increases recently. Accordingly, power system reliability research focusing to sustained interruption and momentary interruption partially needs more accurate evaluation methods including momentary and instantaneous problems. That is, many sensitive loads being tripped by voltage sags result in interruption costs. In this paper, new reliability worth evaluation method is presented considering voltage sags. We calculated the magnitude of voltage sags using fault studies and the duration of voltage sags using the trip time of protective relays for each fault. Moreover, we includes the customer interruption cost resulted from sensitive load trip by voltage sags. Through case studies, we evaluate the effects of voltage sags for permanent faults.

• Proceedings of the KAIS Fall Conference
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• 2001.11a
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• pp.147-149
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• 2001

본 논문에서는 산업용 전력시스템의 전기품질을 평가하기 위한 고조파 해석기법을 제시하였다. 먼저 수변전계통의 전압강하, 고조파, 고장전류 등을 PTW Tool을 이용해서 시뮬레이션 하였으며, 실제 계통에서의 운전중 고조파 현상을 실측치와 비교 분석함으로써 기존 시뮬레이션 기법의 정확성을 검증하였다.

• Journal of IKEEE
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• v.12 no.4
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• pp.255-262
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• 2008

In this paper, we proposed the novel IGBT with an additional n-type MOS structure to achieve the improved trade-off between turn-off and on-state voltage drop(Vce(sat)). These low on-resistance and the fast switching characteristics of the proposed IGBT are caused by an enhanced electron current injection efficiency which is caused by additional n-type MOS structure. In the simulation result, the proposed IGBT has the lower on state voltage of 2.65V and the shorter turn-off time of 4.5us than those of the conventional IGBT(3.33V, 5us).

• Journal of IKEEE
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• v.14 no.1
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• pp.55-64
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• 2010

In this paper, we proposed the novel TIGBT with an additional p-type MOS structure to achieve the improved trade-off between turn-off and on-state voltage drop(Vce(sat)). These low on-resistance and the fast switching characteristics of the proposed TIGBT are caused by an enhanced electron current injection efficiency which is caused by additional p-type MOS structure. In the simulation result, the proposed TIGBT has the lower on state voltage of 1.67V and the shorter turn-off time of 3.1us than those of the conventional TIGBT(2.25V, 3.4us).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.3
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• pp.119-126
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• 2003

The size of low voltage level conductor cables can be installed with a long length just like a aviation field, shall be determined for considering the ampacity of cable and the drop of voltage for the power system. Therefore, The size of the conductor cables may be larger one for considering the tolerable voltage drop comparatively, although the allowable ampacity of the conductor cables may have a margin in comparison with the rated full load current In this case, the conductor cables' allowable ampacity will be very larger than the rated full load current and the generated heat of the conductor will be relatively downed. The conductor cables' alternating current resistance corrected with the maximum allowable temperature of the conductors, has been applied on the general formula for the calculating the voltage drop in determinating the size of low voltage level conductor cables, and the resistance is larger than the resistance corrected with the actual temperature of the conductor cables. This paper was studied for the purpose of the conductor resistance corrected with the actual temperature rise of the conductor and address the economic design formula so that this studies shall minimize the errors which can be occurred in comparison with the general formula and which can be applied in design work for determining the size of low voltage level conductor cables.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.146-151
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• 2005

This paper describes a new voltage disturbance generator for the performance test of a 1-phase UPS(Uninterruptible Power Supply). The proposed scheme has the ability of voltage sag, swell, and outage generation. The structure of the proposed generator is simple and cost-effective. The voltage disturbance can be generated with easy control system. The circuit operation and characteristics of the proposed converter are described and the usefulness of the converter is verified through computer simulations and experimental results.