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伴随着电力电子技术的飞速发展以及广泛应用,在提高输电效率的同时,其带来的弊端也日益凸显,最严重的是造成了电网中的谐波污染,对电力系统的运行、电能的生产及输送都造成很大的危害。现如今治理谐波最有效的方法之一就是使用有源电力滤波器对谐波电流进行补偿。该文对有源电力滤波器的工作原理、分类、控制技术现状以及应用前景进行阐述。 相似文献
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二次谐波是器件非线性造成的,为了有效的抑制二次谐波对其它频率的干扰,本文主要通过设计LC滤波器,解决TDD—LTE的二次谐波问题。 相似文献
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有源电力滤波器的研究热点和发展 总被引:1,自引:0,他引:1
有源电力滤波器研究已成为目前国内外供电系统谐波抑制研究的热点。本文首先介绍了两种谐波治理的措施。然后重点对有源电力滤波器研究中的拓扑结构、检测和控制理论、数字化控制技术发展等研究热点进行介绍和分析。最后指出了有源电力滤波器今后发展的一些主要方向。[编者按] 相似文献
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SPWM逆变电源LC滤波器的研究与设计 总被引:1,自引:0,他引:1
为了使基于SPWM的逆变器输出较好的正弦波形,针对SPWM逆变器的谐波特点,采用单级LC低通交流输出滤波网络.为使滤波器传送较多的有功功率,而返回逆变器的无功功率较少,同时将特定次谐波含量控制在设定的范围内,提出了一种单级LC滤波器的设计方法,根据该方法选择滤波器的L、C参数,可以有效控制谐波含量和逆变器的无功功率,得到较好的正弦波形输出. 相似文献
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《Solid-State Circuits, IEEE Journal of》1972,7(3):266-267
A simple modification of the time-multiplexed active filter allows the transfer function to be electronically tuned. The method is to allow the switched memoryless active subnetwork to be multiplexed in such a way that a variable time slot is allocated to each stage of the filter. Electronic variation of this time slot achieves a corresponding tuning of the transfer function. In terms of circuitry, a simple modification to the logic drive circuitry is required to make tuning possible. 相似文献
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A coplanar waveguide (CPW)-slotline bandpass filter is described. The circuit allows planar integration of active and passive semiconductor devices both in series and in shunt. A microstrip-to-slotline transition designed to test the filter is also described. Two of the transitions exhibit an insertion loss of less than 1.0 dB over the 2.0-4.0-GHz range. A three-section CPW-slotline bandpass filter demonstrates an insertion loss of less than 0.2 dB over the passband centered at 2.9 GHz. A three-section CPW-slotline switchable bandpass filter integrated with three p-i-n diodes is discussed. It has a 0.7-dB insertion loss in the passband when the p-i-n diodes are off and a 25.0-dB isolation across the entire band when the p-i-n diodes are on. A three-section CPW-slotline varactor-tunable filter integrated with three varactor diodes is presented, showing a 2.0-dB insertion loss and over 20% electronic tuning range. Simple transmission line circuit models are used to optimize the design 相似文献
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Miniature and tunable filters using MEMS capacitors 总被引:4,自引:0,他引:4
Microelectromechanical system (MEMS) bridge capacitors have been used to design miniature and tunable bandpass filters at 18-22 GHz. Using coplanar waveguide transmission lines on a quartz substrate (/spl epsiv//sub r/ = 3.8, tan/spl delta/ = 0.0002), a miniature three-pole filter was developed with 8.6% bandwidth based on high-Q MEMS bridge capacitors. The miniature filter is approximately 3.5 times smaller than the standard filter with a midband insertion loss of 2.9 dB at 21.1 GHz. The MEMS bridges in this design can also be used as varactors to tune the passband. Such a tunable filter was made on a glass substrate (/spl epsiv//sub r/ = 4.6, tan/spl delta/ = 0.006). Over a tuning range of 14% from 18.6 to 21.4 GHz, the miniature tunable filter has a fractional bandwidth of 7.5 /spl plusmn/ 0.2% and a midband insertion loss of 3.85-4.15 dB. The IIP/sub 3/ of the miniature-tunable filter is measured at 32 dBm for the difference frequency of 50 kHz. The IIP/sub 3/ increases to >50 dBm for difference frequencies greater than 150 kHz. Simple mechanical simulation with a maximum dc and ac (ramp) tuning voltages of 50 V indicates that the filter can tune at a conservative rate of 150-300 MHz//spl mu/s. 相似文献
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文章在衰减全反射原理的基础上提出一种新的滤波器制作方法.衰减全反射结构对其被激发出的高阶导模具有很强的波长选择性,利用这一特性以及有机聚合物的电光特性,制备出了一种具有全新结构的可调谐滤波器.和其他可调谐滤波器相比,该滤波器具有插入损耗低、制备简单、成本低廉以及稳定性高等优点.通过进一步优化参数,可以得到带宽为0.4 nm的可调窄带滤波器. 相似文献
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A tunable double-grating resonant leaky mode microelectromechanical-type element is introduced. A significant level of tunability is demonstrated by adjusting mechanically the structural symmetry of the grating profile. Tuning is also possible by variation of the thickness of the resonant layer. For a particular example silicon-on-insulator structure treated, it is shown that the resonance wavelength can be shifted by /spl sim/300 nm with a horizontal movement of /spl sim/120 nm within the 1.4-1.7-/spl mu/m wavelength band. Additionally, the reflectance can be varied from /spl sim/10/sup -3/ to 1 at central wavelength of 1.55 /spl mu/m with a vertical movement of /spl sim/200 nm. These results demonstrate new possibilities in design of tunable optical devices. 相似文献
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A laser detection technique was developed utilizing frequency modulated tunable acoustooptic filters. CW laser radiation measuring about5(10^{-7}) mW was detected in the presence of an incoherent background irradiance of 0.1 W/cm2. 相似文献
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Electrooptic tunable filters for infrared wavelengths 总被引:1,自引:0,他引:1
This paper describes the performance characteristics of an electronically tunable infrared filter based on the electrooptic effect. Like the acoustooptic tunable filter, this device operates by selectively coupling principal polarizations in a birefringent crystal at a Phase-matched wavelength by means of a spatially periodic refractive index perturbation. Instead of a traveling acoustic wave, however, the electrooptic tunable filter employs a temporally static electric field. The main advantages of this filter are its very low power consumption and its versatility of passband programming by virtue of separately addressable voltages under microprocessor control. Two experimental embodiments of the filter are described, one using longitudinal fields, collinear with the light beam, the other using transverse fields in a "thick waveguide" configuration. Experimental results of filter characteristics in the wavelength range2-10 mu m are presented. We also present examples of passband synthesis that are achieved by apodizing the amplitude of the applied electric field perturbations. These include passband broadening and sidelobe suppression. The experimental transfer characteristics exhibit good agreement with the theoretical computer plots. Typical driver voltages are ∼ 500 V. 相似文献
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ZHANG Jian LI Guo-hua 《光电子快报》2006,2(4):266-268
The Lyot filter is a monocolour birefringent filterwhichis invented by the French physicist Lyot for theresearches of astronomy,especiallyfor observingthe so-lar corona.Becausethe birefringent filter can be designedof the special optical characters such a… 相似文献