• 한국광학회:학술대회논문집
• /
• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
• /
• pp.234-235
• /
• 2003

All solid-state UV lasers provide efficient, clean and semipermanent light sources for various applications, such as eye surgery, microchip lithography. $CsLiB_{6}O_{10}$ (CLBO) is one of the most suitable crystals for UV generation because of its small walk-off, large effective nonlinear susceptibility in UV region and high damage threshold. We produced fourth (266 nm) and fifth (213 nm) harmonic generation of an Nd：YAG laser (1064 nm) with $LiB_{3}O_{5}$ as a second harmonic generation medium and CLBO as a fourth harmonic and fifth harmonic mediums. (omitted)

• 대한조선학회 특별논문집
• /
• 대한조선학회 2008년도 특별논문집
• /
• pp.38-45
• /
• 2008

The application of the electric propulsion system to the vessels has recently become common due to the latest technology for controlling the electric motors with variable speed. However it has been found that harmonic distortion exists in the electric propulsion system, which consists of an electric motor, a converter and an inverter, and this harmonic distortion has a harmful effect on the system. In this paper, the definition of the harmonic distortion and problems caused by the harmonic distortion in the electric propulsion of the vessels are introduced and the practical solutions for the problems are investigated.

• 조명전기설비학회논문지
• /
• 제19권2호
• /
• pp.35-41
• /
• 2005

전자식 안정기는 형광등을 점등시키기 위하여 널리 사용되고 있다. 전자식 안정기의 실측을 통해 고조파 발생현황을 측정하고 고조파 해석용 등가회로를 모델링 하여 시뮬레이션을 하였다. 본 논문은 단상 부하의 고조파 해석용 등가회로 모델링과 설계 및 적용 시험을 하여 고조파를 저감시키고, IEC 61000-3-2와 IEEE Std 519-1992를 근거로 평가하였다.

• Journal of Power Electronics
• /
• 제16권6호
• /
• pp.2284-2293
• /
• 2016

With the rapid development of clean energy, photovoltaic (PV) generation has been utilized in the harmonic compensation of power systems. This paper presents a novel multi-function PV micro-inverter with three stages (pseudo-two-stage). It can inject active power and compensate harmonic currents in the power grid at the same time. In order to keep the micro-inverter working under the maximum allowable output power, an optimized capacity limitation strategy is presented. Moreover, the harmonic compensation can be adjusted according to the customized requirements of power quality. Additionally, a phase shedding strategy in the DC/DC stage is introduced to improve the efficiency of parallel Boost converters in a wide range. Compared with existing capacity limitation methods, the proposed strategy shows better performance and energy efficiency. Simulations and experiments verify the feasibility of the micro-inverter and the effectiveness of the strategy.

• Journal of international Conference on Electrical Machines and Systems
• /
• 제3권1호
• /
• pp.20-26
• /
• 2014

To enhance torque density by harmonic current injection, optimal slot/pole combinations for five-phase permanent magnet synchronous motors (PMSM) with fractional-slot concentrated windings (FSCW) are chosen. The synchronous and the third harmonic winding factors are calculated for a series of slot/pole combinations. Two five-phase PMSM, with general FSCW (GFSCW) and modular stator FSCW (MFSCW), are analyzed and compared in detail, including the stator structures, star of slots diagrams, and MMF harmonic analysis based on the winding function theory. The analytical results are verified by finite element method, the torque characteristics and phase back-EMF are also taken into considerations. Results show that the MFSCW PMSM can produce higher average torque, while characterized by more MMF harmonic contents and larger ripple torque.

• 대한전자공학회논문지TC
• /
• 제47권6호
• /
• pp.22-25
• /
• 2010

이 논문은 브랜치라인 커플러에서 고조파 신호를 제거할 수 있는 변형된 설계 방법을 제안한다. 기존의 1/4 파장 길의의 전송선로의 중앙에 개방형 스터브를 추가한 후에, 설계 주파수에서는 커플러의 기능을 제공하고 고조파 주파수에서는 전송을 제한하는 특성을 갖는 커플러의 해를 구하는 것이 가능하다. 이의 검증 예로서 1.0GHz에서 커플러를 제작하였으며 2.0GHz와 3.0GHz에서 -37.5dB 및 -42.7dB의 억압비를 나타내었다.

• Journal of electromagnetic engineering and science
• /
• 제11권4호
• /
• pp.257-261
• /
• 2011

A highly efficient 2.4 GHz rectenna is designed using a harmonic rejection bandpass filter. The rectenna is printed on Rogers Duroid 5880 substrate with ${\varepsilon}_r$=2.2 and a thickness of 1.6 mm. The rectenna consists of a microstrip antenna and high order harmonic rejection bandpass filter, microstrip lowpass filter, and Schottky barrier diode (HSMS2820). The use of a $2^{nd}$ and $3^{rd}$ harmonic rejection microstrip bandpass filter in the rectenna results in high conversion efficiency. The proposed rectenna achieves a RF to DC conversion efficiency of 72.17 % when the received RF power is 63.09 mW.

• Journal of electromagnetic engineering and science
• /
• 제14권4호
• /
• pp.387-392
• /
• 2014

In this paper, a size-reduced Wilkinson balun with wide harmonic-suppressed band is presented. An accurate analysis of the parallel coupled line with an open stub (PCL-OS) is carried out. The PCL-OS structure shows excellent low pass filter and harmonic-suppression characteristics, which is useful for designing a low pass filter unit cell (LUC) with a reduced size. The designed Wilkinson balun at a 2.45 GHz center frequency not only shows an excellent harmonic suppression including the 5th harmonics up to 14 GHz over 15 dB, but it also has an area reduced to 48% of the conventional one.

• Journal of Electrical Engineering and Technology
• /
• 제7권3호
• /
• pp.358-365
• /
• 2012

A new third harmonic injection circuit for light-emitting diode (LED) drivers is proposed to eliminate electrolytic capacitors and thereby extend the lifetime of LED drivers. When a third harmonic current is injected to the input current of the LED driver, the required capacitance of the driver can be reduced. The proposed circuit can control an injection ratio and has simple circuitry. The synchronous third harmonic is generated by a phase locked loop (PLL), a 1/3 counter, and op-amps and applied to a power factor correction circuit. Thus, the storage capacitor can install film capacitors instead of the electrolytic capacitor. The value of storage capacitance can be reduced to 78% compared to an input power factor of 100%. The proposed circuit is applied to the 80W prototype LED driver to experimentally verify the performances.

• Journal of Power Electronics
• /
• 제1권2호
• /
• pp.127-132
• /
• 2001

This paper describes two different systems which can compensate harmonic currents generated in a power system. As non-linear loads increase gradually in industry fields, harmonic current generated in the electric power network system also increases. Harmonic current makes a power network current distorted and generates heat, vibration and noise in the power machinery. Many approaches have been applied to compensate harmonic currents generated in the power system. Among various approaches, in this paper, two kinds are compared and evaluated. They are flywheel compensators bases on secondary excitation of WRIM(wounded rotor induction motor) and SCIM(squirrel cage induction motor). Both systems have a common structure. They use a flywheel as an energy storage device and use PWM inverters. The main differences are the size and rating of the converter used.