• 제목/요약/키워드: Frequency up-conversion

검색결과 107건 처리시간 0.032초

Microphone Array를 이용한 고압설비의 고장위치인식 알고리즘 (An Accidental Position Detection Algorithm for High-Pressure Equipment using Microphone Array)

  • 김득권;한순신;하현욱;이장명
    • 전기학회논문지
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    • 제57권12호
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    • pp.2300-2307
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    • 2008
  • This study receives the noise transmitted in a constant audio frequency range through a microphone array in which the noise(like grease in a pan) occurs on the power supply line due to the troublesome partial discharge(arc). Then by going through a series of signal processing of removing noise, this study measures the distance and direction up to the noise caused by the troublesome partial discharge(arc) and monitors the result by displaying in the analog and digital method. After these, it determines the state of each size and judges the distance and direction of problematic part. When the signal sound transmitted by the signal source of bad insulator is received on each microphone, the signal comes only in the frequency range of 20 kHz by passing through the circuit of amplification and 6th low pass filter. Then, this signal is entered in a digital value of digital signal processing(TMS320F2812) through the 16-bit A/D conversion. By doing so, the sound distance, direction and coordinate of bad insulator can be detected by realizing the correlation method of detecting the arriving time difference occurring on each microphone and the algorithm of detecting maximum time difference.

조명 제어용 LLC 공진형 하프브리지 컨버터 변압기 설계 특성 (The Transformer Characteristics of LLC Resonant Half-Bridge Converter for Universal Lighting control system)

  • 임성진;김창선;유진호;천승환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2011년도 제42회 하계학술대회
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    • pp.1183-1184
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    • 2011
  • In case of the power conversion converter for driving the Lighting control system, the input voltage widens from $90V_{rms}$ to $264V_{rms}$. Among various methods, LLC half-bridge converter has wide input regulation range and limited switching frequency control range and ZVS is possible for even non-loaded case. Also, the converter can be applied for Universal Lighting control system. In this paper, the transformer design is studied. The efficiency measured is up to 90%.

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보급형 인버터식 X선발생장치의 특성에 관한 연구 (A Study on the Characteristics of Inverter Type X-Ray Genertator)

  • 박수강
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2000년도 전력전자학술대회 논문집
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    • pp.26-29
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    • 2000
  • The conventional types of X-ray generators were bulky in physical size and heavy in weight and the control accuracies of the output voltages were not always satisfacotry. The high frequency switching inverter and converter technology on power conversion and control systems have been greatly closed up introducing power semiconducot devices. To decreasing the volume and the weight of high voltage transformer and to stabilize ripple. In this paper the newly developed x-ray generator in a low cost using duty modulation PWM inverter. This system verify improved performance by stabilize ripple of X-ray tube voltage and compared the reproducibility linearity and dose in single phase three phase and PSU.

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근거리 무선전력 전송용 공진형 class Φ2 인버터 고효율 최적설계 (The High Efficiency Optimal Design of Resonant class Φ2 Inverter for short range wireless power transmission)

  • 양해열;박재현;김창선
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2011년도 전력전자학술대회
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    • pp.64-65
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    • 2011
  • The ac power conversion inverter provides the ac power to ECR device for wireless power transfer. In this paper, the operating efficiency of the class-${\Phi}_2$ resonant inverter has been studied through by experiment for optimal design. Its switching frequency is 1MH and the input voltage is 96V which is the output voltage of LLC resonant converter. And its output voltage is 230Vp-p. The efficiency is measured up to 84%.

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최대 에너지 비를 갖는 SRM용 인버터의 제어에 관한 연구 (Study on The SRM Inverter Control with a maximum Energy ratio)

  • 이상훈;박성준;안진우;김철우
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 하계학술대회 논문집 B
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    • pp.980-982
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    • 2001
  • SRM has different characteristics according to their control methods. Therefore, A new magnetizing method with a low-frequency increasing the energy conversion ratio that is related to the efficiency of motor is proposed. As results, it improved the efficiency about 2(%) and decreased the noise level up to 5[dB]. And a torque ripple is also sufficiently reduced compared with that of the conventional switching angle magnetizing approach.

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구조물 안전 모니터링용 파장 스위핑 레이저를 위한 스위핑 자동 선형화 (Sweeping Automatic Linearization for Wavelength Swept Laser Used in Structure Safety Monitoring)

  • 이덕규;엄진섭
    • 센서학회지
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    • 제29권1호
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    • pp.51-58
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    • 2020
  • In this study, a novel method for sweeping automatic linearization of wavelength swept laser is proposed. Through the test performed on the implemented laser, the linear sweeping is held up well with a 97% decrease in nonlinearity, and 60 nm sweeping range, 1 kHz sweeping frequency, and 8.8 mW average optical power were obtained. The proposed method uses fiber Bragg grating array, optical-electronic conversion circuit, FPGA embedded module, and a LabVIEW program to generate new compensated wave patterns which were applied to the fiber Fabry-Perot tunable filter. Linear sweeping can reduce the cumbersome and time-consuming recalibration process required for nonlinear sweeping. Additionally, the proposed method provides more accurate measurement results for the structure safety monitoring system.

Analysis and Improvement of Low-Frequency Control of Speed-Sensorless AC Drive Fed by Three-Level Inverter

  • Chang Jie (Jay)
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제5B권4호
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    • pp.358-365
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    • 2005
  • In induction machine drive without a speed sensor, the estimation of the motor flux and speed often becomes deteriorated at low speeds with low back EMF. Our analysis shows that, in addition to the state resistance variation, the estimated value of field orientation angle is often corrupted by accumulative errors from the integration of voltage variables at motor terminals that have low signal/noise ratio at low frequencies. A repetitive loop path of integration in the feedback can amplify this type of error, thus speeding up the degradation process. The control system runs into information starvation due to the loss of correct field orientation. The machine's spiral vectors are controlled only in a reduced dimension in this situation. A novel control scheme is developed to improve the control performance of motor's current, torque and speed at low frequencies. The scheme gains a full-dimensional vector control and is less sensitive to the combined effect of the error sources at the low frequencies. Experimental tests demonstrate promising performances are achievable even below 0.5 Hz.

PID 제어를 이용한 파장 스위핑 레이저의 스위핑 선형화 (Sweeping Linearization of Wavelength Swept Laser using PID Control)

  • 엄진섭
    • 센서학회지
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    • 제29권6호
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    • pp.412-419
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    • 2020
  • In this study, a PID control method for sweeping automatic linearization of a wavelength swept laser is proposed. First, the closedloop transfer function embodying the PID control is derived. Through the simulation of the function, Kp = 0.022, Ki = 0.008, Kd = 0.002 were obtained as the best PID coefficients for fast linear sweeping. The performance test using the PID coefficients showed that linear sweeping was held up well with a 98.7% decrement in nonlinearity after the 10th feedback, and 45 nm sweeping range, 1 kHz sweeping frequency, and 8.8 mW average optical power were obtained. The equipment consists of a fiber Bragg grating array, an optical-electronic conversion circuit, and a LabVIEW FPGA program. Every 5s, automatic feedback and PID control generate a new compensated waveform and produce a better linear sweeping than before. Compared with nonlinear sweeping, linear sweeping can reduce the cumbersome and time-consuming recalibration processes and produce more accurate measurement results.

전기자동차용 고효율 무선 온보드 충전기의 설계 (Design of the High Efficiency Wireless On-Board Charger for Electric Vehicles)

  • 트란덕홍;부반빈;최우진
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2015년도 추계학술대회 논문집
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    • pp.27-28
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    • 2015
  • In this paper a high efficiency wireless on-board charger for Electric Vehicle (EV) is proposed and the theoretical analysis based on the two-port network model to come up with suitable design for the battery charge application is presented. The proposed Wireless Power Transfer (WPT) method has adopted four-coil system with air core and its superior performance is proved by comparing it to the conventional two-coil system by the mathematical analysis. In addition, since the proposed WPT converter is able to operate at an almost constant frequency regardless of the load, CC/CV charge of the battery can be simply implemented. A 6.6kW prototype is implemented with 20cm air gap to prove the validity of the proposed method. The experimental results show that the dc to dc conversion efficiency of the proposed system achieves 97.08% at 3.7 kW.

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An Injection-Locked Based Voltage Boost-up Rectifier for Wireless RF Power Harvesting Applications

  • Lee, Ji-Hoon;Jung, Won-Jae;Park, Jun-Seok
    • Journal of Electrical Engineering and Technology
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    • 제13권6호
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    • pp.2441-2446
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    • 2018
  • This paper presents a radio frequency-to-direct current (RF-to-DC) converter for special RF power harvesting application at 915 MHz. The major featured components of the proposed RF-to-DC converter is the combination of a cross-coupled rectifier and an active diode: first, the cross-coupled rectifier boosts the input voltage to desired level, and an active diode blocks the reverse current, respectively. A prototype was implemented using $0.18{\mu}m$ CMOS technology, and the performance was proven from the fact that the targeted RF harvesting system's full-operation with higher power efficiency; even if the system's input power gets lower (e.g., from nominal 0 to min. -12 dBm), the proposed RF-to-DC converter constantly provides 1.47 V, which is exactly the voltage level to drive follow up system components like DC-to-DC converter and so on. And, maximum power conversion efficiency is 82 % calculated from the 0 dBm input power, 2.3 mA load current.