• Journal of Power Electronics
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• 제16권1호
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• pp.111-120
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• 2016

Generally, a single phase H-bridge converter feeding a single primary track is employed in conventional inductive power transfer systems. However, these systems may not be suitable for some high power applications due to the constraints of the semiconductor switches and the cost. To resolve this problem, a novel dual coupled primary tracks IPT system consisting of two high frequency resonant inverters feeding the tracks is presented in this paper. The primary tracks are wound around an E-shape ferrite core in parallel which enhances the magnetic flux around the tracks. The mutual inductance of the coupled tracks is utilized to achieve adjustable power sharing between the inverters by configuring the additional resonant capacitors. The total transfer power can be continuously regulated by altering the pulse width of the inverters' output voltage with the phase shift control approach. In addition, the system's efficiency and the control strategy are provided to analyze the characteristic of the proposed IPT system. An experimental setup with total power of 1.4kW is employed to verify the proposed system under power ratios of 1:1 and 1:2 with a transfer efficiency up to 88.7%. The results verify the performance of the proposed system.

• 전기학회논문지P
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• 제64권3호
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• pp.175-181
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• 2015

In this paper, the neuromuscular electrical stimulation medical devices for non-implantable incontinence treatment other than vaginal insertion type was developed and commercialized. The structure of medical devices for electrical stimulation based on the anatomy of the pelvic floor muscle designed. Then, the optimum parameters that may be effective in pelvic floor muscle electrical stimulation was set. The circuit system based on the optimum parameters were designed and manufactured. The frequency of the pulse voltage for electrical stimulation is 75[Hz], the pulse width is 300[${\mu}s$], the development of medical devices was to have seven program functions to the various treatments. The circuit system of medical devices was composed of microcontroller, comparator and converter. The performance of the developed circuit system in KTC(Korea Testing Certification) were carried out medical equipment inspection test. Test results, test specifications were satisfied with the medical device, the performance was verified to be commercialized as a medical device. The development of medical devices were validated risk assessment and product performance through a software validation. Commercialization of medical equipment was acquired to enable the certification standards of the international standard IEC 60601-1.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.57-60
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• 2004

This paper presents multibit Sigma-Delta ADC using Leslie-Singh Structure to Improve nonlinearity of feedback loop. 4-bit flash ADC for multibit Quantization in Sigma Delta modulator offers the following advantages such as lower quantization noise, more accurate white-noise level and more stability over single quantization. For the feedback paths consisting of DAC, the DAC element should have a high matching requirement in order to maintain the linearity performance which can be obtained by the modulator with a multibit quantizer. Thus a Sigma-Delta ADC usually adds the dynamic element matching digital circuit within feedback loop. It occurs complexity of Sigma-Delta Circuit and increase of power dissipation. In this paper using the Leslie-Singh Structure for improving nonliearity of ADC. This structure operate at low oversampling ratio but is difficult to achieve high resolution. So in this paper propose improving loop filter for single-bit feedback multi-bit quantization Sigma-Delta ADC. It obtained 94.3dB signal to noise ratio over 615kHz bandwidth, and 62mW power dissipation at a sampling frequency of 19.6MHz. This Sigma Delta ADC is fabricated in 0.25um CMOS technology with 2.5V supply voltage.

• ETRI Journal
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• 제31권6호
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• pp.717-724
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• 2009

This paper describes a 1.2 V 12 b 60 MS/s CMOS analog front-end (AFE) employing low-power and flexible design techniques for image signal processing. An op-amp preset technique and programmable capacitor array scheme are used in a variable gain amplifier to reduce the power consumption with a small area of the AFE. A pipelined analog-to-digital converter with variable resolution and a clock detector provide operation flexibility with regard to resolution and speed. The AFE is fabricated in a 0.13 ${\mu}m$ CMOS process and shows a gain error of 0.68 LSB with 0.0352 dB gain steps and a differential/integral nonlinearity of 0.64/1.58 LSB. The signal-to-noise ratio of the AFE is 59.7 dB at a 60 MHz sampling frequency. The AFE occupies 1.73 $mm^2$ and dissipates 64 mW from a 1.2 V supply. Also, the performance of the proposed AFE is demonstrated by an implementation of an image signal processing platform for digital camcorders.

• Journal of Power Electronics
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• 제11권3호
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• pp.311-318
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• 2011

LCL filters installed at converter outputs offer a higher harmonic attenuation than L filters. However, as a three order resonant circuit, it is difficult to stabilize and has a risk of oscillating with the power grid. Therefore, careful design is required to damp LCL resonance. Compared to a passive damping method, an active damping method is a more attractive solution for this problem, since it avoids extra power losses. In this paper, the damping capabilities of capacitor current, capacitor voltage, and grid-side current feedback methods, are analyzed under the discrete-time state-space model. Theoretical analysis shows that the grid-side current feedback method is more suitable for use in active power filters, because it can damp LCL resonance more effectively than the other two methods when the ratio of the resonance and the control frequency is between 0.225 and 0.325. Furthermore, since there is no need for extra sensors for additional states measurements, this method provides a cost-efficient solution. To support the theoretical analysis, the proposed method is tested on a 7-kVA single-phase shunt active power filter.

• 전기의세계
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• 제22권1호
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• pp.35-41
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• 1973

An automatic point traffic control method is recommended for more idealistic traffic flow over coarse road netowrks. The automatic control apparatus recommended, consists of a transceiver, amplifier, digital-to-analog converter, signal light controller for emergency and steady state, and digital counter as monitor. The transmitter sends a signal to the target vy means of Microwave-FM-CW and a diode detector picks up the echo signal. Thus the operation of the entire system will be carried out through an open loop state. Some factors necessary for an ideal detector system are rapid response, longevity and stability. An analytical method of the Doppler effect substitutes the conventional frequency deviation into the amplitude of detector output. The changing rate of amplitude is proportional to the voltage of the detector output. Some induced formula from Maxwell's radiation field theory ensures this new method, and, new method, and proves the fact with an experimental data presentation. Stability depends upon Klystron as an oscillator and a diode as a detector. the transceiver installation affects on the response and sensitivity of the system. In accordance with the detector output, several targets are easily classified by amplitudes on the scope. The traffic flow, i.e., target movement which is analyzed by the amplitude method, is shown through the scope and indicates it on the digital counter. The best efficiency for the amplitude analysis can be attained through use of an antenna having the highest sensitivity.

• 전기학회논문지
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• 제65권1호
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• pp.40-50
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• 2016

In order to recover the power system during the wide power outage or power failure in the power plant, black start system should be properly operated without any problem. Especially power for black start in the geographically isolated areas of electric island is supplied from small emergency start-up generator, and loads are aux systems of gas turbines such as SFC(Static frequency converter). This paper introduces the international practices to overcome the voltage drop problem with harmonics of the system having the DC output such as SFC during black start in weak feed system and analyzes the relationship between house load inputs and harmonics. By varying the house load and input of power supply, this paper identified boundaries between weak feed and strong feed power. In order to verify the theory of stable condition in weak feed power system with DC output, house load is simulated using ETAP. Additionally MATLAB was used for harmonic analysis between the load inertia moment and non load inertia moment.

• 전력전자학회논문지
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• 제15권3호
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• pp.179-187
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• 2010

본 논문에서는 무효전력변동기법을 사용하여 단독운전을 검출을 하기 위해서 선행되어야 하는 주파수 검출 방법 중에서 개선된 이산푸리에변환(Discrete Fourier Transform; DFT), 즉 Goertzel 알고리즘을 이용한 단독운전 검출기법을 제안한다. 실제 태양광 발전 시스템의 설치를 위해서는 전기사고나 시스템에 악영향을 유발하는 단독운전 검출기법의 연구가 선행되어야 한다. 적용하는 주파수 검출방법은 Goertzel 알고리즘을 이용한 기법으로 기존의 영점검출기법과 가상의 2상 PLL(Phase Locked Loop)에 비하여 외란의 영향에 강인하며 빠른 검출이 가능하다. 시뮬레이션 및 실험을 통하여 기존의 주파수검출기법인 영점검출기법과 가상의 2상 PLL을 이용한 주파수 검출과 제안하는 알고리즘을 비교하고 그의 우수성을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1050-1051
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• 2015

In industry, there are several different controllers which can be implemented for power conditioning systems (PCS) such as proportional-resonant (PR), predictive deadbeat (PD), or proportional-integral (PI) controller. But there are not any comparison studies about these controllers. To investigate the differences between the three types of the controllers, this paper presents a comparative study of PR, PI, and PD controllers in a photovoltaic (PV) PCS. These controllers are designed mathematically and simulated for the comparative analysis. The PI controller is designed in the rotating reference (dq) frame. The PR and PD controllers are implemented in the natural (abc) reference frame. The PCS is composed of a DC-DC boost converter and a full bridge inverter. The filter of the PCS is an LCL filter including a passive damping resistor. The parameters of PCS are 3 kW, 25 kHz switching frequency and 220 V-60 Hz grid voltage. The comparison results between these controllers for the grid-connected PCS are clearly shown. The simulation results demonstrate the detailed characteristics of each controller for the PV PCS in order to choose the controller for individual target properly.

• 조명전기설비학회논문지
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• 제20권7호
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• pp.74-80
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• 2006

본 논문은 새로운 태양광 에너지 변환 기술에 의한 연계형 단상 인버터 제어기술을 나타내었다. 최대전력 점 추적제어는 두 부스터 컨버터의 MOSFET 스위치 제어 발생회로에 기초하고 단상 인버터는 풀 브리지의 4개 IGBT 스위치에 의해 전류 추종제어 된다. PV 모듈의 발생전력 제어회로는 PV 모듈의 출력 전압, 전류 검출에 의해 최대전력 점 제어한다. 결국 PV 모듈 양단은 인버터 입력전압으로 낮은 리플 전압을 유지하고 출력은 증가한다. 제안한 태양광 인버터 시스템의 효과가 시뮬레이션과 실험을 통하여 입증되었다.