• 전력전자학회논문지
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• 제3권1호
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• pp.23-35
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• 1998

영구자석 동기전동기의 제어에 있어서 토오크 맥동은 전동기 제어성능 결정에 큰 요인으로 작용한다. 본 논문에서는 이러한 토오크 맥동을 효과적으로 저감하기 위한 새로운 토오크 추정 및 제어기법에 대해서 다룬다. 제안된 기법에서는 모델 기준 적응시스템(Model reference adaptive system ; MRAS) 기법을 이용하여 순시 토오크를 추정하고 적본형 가변구 조제어(Integral variable structure control ; IVSC)를 이용하여 추정된 토오크를 제어한다. DSP를이용하여 고 토오크 영구자석 동기전동기 제어시스템을 구성하고 실험을 수행하였으며 그 결과 제안된 제어기법이 우수한 토오크 맥동 저감효과를 가짐을 입증하였다.

• 조명전기설비학회논문지
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• 제30권3호
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• pp.94-105
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• 2016

The objective of the work was to evaluate the impact of lighting energy to cooling and heating consumption in medium scale office building, when currently installed fluorescent lights were replaced with various LED lighting fixtures. This evaluation comes from an integrated approach combining the proper indoor lighting environment and the thermal aspects of cooling & heating consumption in office building. These simulations were performed by coupling an appropriate luminaire analysis for energy consumption and a dynamic thermal simulation software (TRNSYS). To analyze comparative study of effects on the heating, cooling loads, and energy consumption of an LED lamp application, 2 types of LED lamp with low light power watt(LPW) 24W and high LPW 7.5W and a fluorescent lights(FL) with 37W are used respectively. Integrated building energy consumption decreased up to 3.2% when fluorescent lamps were replaced with LEDs. Thus, the high LPW of LED(7.5W) replaced with the same number of FL shows an effective energy saving and cost- effective luminary.

• 한국산학기술학회논문지
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• 제8권5호
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• pp.1034-1041
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• 2007

본 논문은 저압 감시 기능을 포함하는 개선된 배전자동화시스템 개발에 관한 연구 결과를 소개한 것으로서 연구배경, 시스템 구성, 설계, 시제품 제작, 시험 및 실계통 시범운영 등 전반적인 사항을 설명한다. 개발 시스템은 배전현장에서 별도로 수행 중인 변압기 부하감시, 전압감시 및 정전감시 및 품질감시 업무를 배전자동화시스템에 통합하여 운영함으로써 보다 경제적이고 효율적인 배전망의 운영을 위하여 개발되었다. 시스템 통합을 위한 통신망은 간선망과 지선망을 갖도록 계층적으로 구성하고, 변압기 부하 측의 저압 감시를 위한 단말장치를 새로 개발하였다. 또한, 기존 배전자동화시스템에 저압 감시 기능을 추가하기 위하여 주장치 소프트웨어를 개선하였다. 개발 시스템은 실계통 시범운영을 통하여 설계 및 성능이 검증되었다.

• 전력전자학회논문지
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• 제24권3호
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• pp.215-227
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• 2019

Grid-connected inverters should satisfy a certain level of total harmonic distortion (THD) to meet harmonics standards, such as IEEE 519 and P1547. The output quality of an inverter is typically degraded due to grid voltage harmonics, dead time effects, and the device's turn-on/turn-off delay, which all contribute to increasing the THD value of the output. The use of a harmonic controller is essential to meet the required THD value for inverter output under a distorted grid condition. In this study, an improved feedforward harmonic compensation method is proposed to effectively eliminate low-order harmonics in the inverter current to the grid. In the proposed method, harmonic components are directly compensated through feedforward terms generated by the proportional resonant controller with the grid current in a stationary frame. The proposed method is simple to implement but powerful in eliminating harmonics from the output. The effectiveness of the proposed method is verified through simulation using PSIM software and experiments with a 5 kW single-phase grid-connected inverter.

• Advances in aircraft and spacecraft science
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• 제8권4호
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• pp.303-330
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• 2021

The paper discusses the effect of the winglets on the aerodynamic and aeroacoustic performance of Boeing 737-800 aircraft by numerical approach. For this purpose, computational fluid dynamics and fluent commercial software are used to solve the compressible flow governing equations. The RANS method and the K-ω SST turbulence model are selected to simulate the subsonic flow around the wing with acceptable accuracy and low computational cost. The main variables of steady flow around the simple and blended wing in constant atmospheric conditions are computed by numerical solution of governing equations. The solution of the acoustic field has also been accomplished by the broad-band acoustic source model. The results reveal that adding a blended winglet increases the pressure difference near the wingtip,which increases the lift force. Also, the blended winglet reduces the power and magnitude of vorticities around the wingtip, which reduces the wing's drag force. The effects of winglets on aerodynamic forces lead to a 3.8% increase in flight range and a 3.6% increase in the maximum payload of the aircraft. Also, the acoustic power level variables on the surfaces and fields around the wing have been investigated integrally and locally.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.414-417
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• 2001

SRG (Switched Reluctance Generator) have many advantages such as high efficiency, low cost, high-speed capability and robustness compared with characteristics of other machines. However, the control methods that have been adopted for SRGs are complicated. This paper proposes a simple control method using PID controller that only controls turn-off angles while keeping turn-on angles of SRG constant. The linear characteristics between the generated current and the turn-off angle can be used to control the turn-off angle for load variations. Since the reference current for generation can be produced from an error between the reference and the real voltage, it can be controlled to keep the output voltage constant. The proposed control method enhances the robustness of this system and simplifies the hardware and software by using only the voltage and speed sensors. The proposed method is verified by experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.360-362
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• 1994

This paper presents a design and implementation of DSP-based full-digitalized sliding mode controller(SMC) for an induction motor(IM) fed by voltage source inverter(VSI) with intelligent power module(IPM). By using SMC with load torque observer, we can obtain improved control performances, i.e., robustness, high precision and low chattering. Furthermore, this paper emploies space vector modulation (SVM) method which is implemented to minimize hard ware configuration and to obtain modulation flexibility along with only DSP software operation.

• Journal of information and communication convergence engineering
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• 제15권3호
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• pp.160-164
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• 2017

Public key cryptography (PKC) is the basic building block for the cryptography applications such as encryption, key distribution, and digital signature scheme. Among many PKC, elliptic curve cryptography (ECC) is the most widely used in IT systems. Recently, very efficient Montgomery-Twisted-Edward (MoTE)-ECC was suggested, which supports low complexity for the finite field arithmetic, group operation, and scalar multiplication. However, we cannot directly adopt the MoTE-ECC to new PKC systems since the cryptography is not fully evaluated in terms of performance on the Internet of Things (IoT) platforms, which only supports very limited computation power, energy, and storage. In this paper, we fully evaluate the MoTE-ECC implementations on the representative IoT devices (16-bit MSP processors). The implementation is highly optimized for the target platform and compared in three different factors (ROM, RAM, and execution time). The work provides good reference results for a gradual transition from legacy ECC to MoTE-ECC on emerging IoT platforms.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.701-704
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• 2000

A SRG(Switched Reluctance Generator) has many advantages such as efficiency simple controllability low cost and robustness compared with outer machines. But the theories that have been adopted as SRG control methods up to the present are complicated. This paper proposes a simple control methods using PID which controls only a turn-off angle while making turn-on angle signals of SRG constant. controlling the voltage differences between the reference and the real value and calculating the proper turn-off angle of the load variations can implement to keep the output voltage constant. the control method suggested in this paper enhances the efficiency of this system and simplifies the hardware and software by using only the voltage and speed sensors. The proposed method is verified by experiment

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.615-619
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• 2000

This paper presents an implementation of digital motion control system of Surface Permanent-Magnet Synchronous Motor(SPMSM) vector drives with a direct torque control(DTC) using the 16bit DSP TMS320F240 The DSP controller enable enhanced real time algorithm and cost-effective design of intelligent control for motors which can be yield enhanced operation fewer system components lower system cost increased efficiency and high performance The system presented are stator flux and torque observer of stator flux feedback model that inputs are current and voltage sensing of motor terminal and angle for a low speed operating area two hysteresis band controllers an optimal switching look-up table and IGBT voltage source inverter by using fully integrated control software. The developed control system are shown a good motion control response characteristic results and high performance features using 1.0Kw purposed servo drive SPMSM.