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光伏并网发电是新能源发展的趋势。目前单相光伏并网过程中存在能量利用率低、电流谐波量大等缺点,且逆变器体积较大、价格昂贵。本文介绍的单相光伏并网逆变器系统在DC/DC变换部分利用LLC谐振半桥电路代替传统的BOOST电路,有效的降低了开关管功耗和噪声,并采用最优梯度法实现了最大功率点跟踪。 相似文献
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为了解决常用的逆变器所带来的问题,我们提出一种新型的带升降压功能的三相DC/AC变换器拓扑,并介绍了其工作原理。借助于PSIM仿真软件,对单相和三相电路进行了仿真研究,提出了由单相组成三相电压输出的构成方法。在列出仿真参数的前提下,给出了负载电压,负载电流以及调制给定电压和逆变器输出电压的仿真结果。仿真结果表明三相DC/AC逆变器可以实现50 kHz高频功率变换下宽输入电压范围工频逆变输出,证明了理论分析的正确性。 相似文献
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随着汽车的普及以及储能技术的发展,车载电源的优化也越来越受关注。此设计通过采用DC/DC变换器和DC/AC逆变器两级结构,移相控制方式逆变器,以及对 DSP2812芯片采用软件编程,使产生SPWM移相控制信号作为电路驱动,结合适当的保护电路,将较市场常见车载逆变电路效率提升25%左右。通过MULTISIM,MATLAB仿真和实物测试,实现了提供车载220 V电压的功能。 相似文献
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一般的DC/DC变换器集成电路由控制器、MOSFET开关管及一些功能电路组成.近年来,DC/DC变换器采用了同步整流技术,又集成了同步整流的MOSFET.凌特公司最近开发出一种微型降压式DC/DC模块,它不仅集成了控制器、开关及同步整流MOSFET及各种功能电路,并且还把可输出10A电流的电感器、软启动电容器做在一个贴片式IC中,外部只要接上输入、输出电容器及一个设定输出电压的电阻就成为完整的DC/DC模块电源.本文介绍这种微型DC/DC模块LTM4600及其应用电路. 相似文献
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传统的两级式微型逆变器高频DC/DC变换器通常采用单反激式变换器,它具有电路结构简单的优点,但其功率却受到变压器铁心磁状态限制,难以应用在高于100瓦的场合。因此提出使用将交错并联反激电路应用在两级式微型逆变器中,其与单反激式电路相比较具有输出功率翻倍,输出电流脉动小,直流母线输出电压纹波小的优点,并且同样具有电路结构简单,容易做最大功率点跟踪的优点。最后通过matlab/simulink进行仿真实验,使用不对称模糊控制进行最大功率点跟踪进行验证,该电路能够应用在200W的微型逆变器中,并且在光照变化的条件下,能够在0.0005s内跟踪到最大功率点。 相似文献
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Raymond Steele 《电信纪事》2001,56(5-6):344-352
Commencing with the advancements that may be expected in 3G during the first decade of this century, we move on to anticipate subsequent developments based on what society might need and the technologies that may be required. The near demise of mobile satellite networks and removal of radio broadcasting from potential mobile radio bands will provide the necessary bandwidth for high capacity, high quality multimedia mobile services utilising a dense concentration of fibre networks coupled to radio cells of all sizes. The integration of many factors from high aerial platforms (haps) (that are located in the stratosphere and from terrestrial cells that can be adjusted in size and moved instantly to suit teletraffic changes) to picocells, body-LANs to the fixed network, software agents to soft telecommunications, will be discussed. Finally the possibility of our networks metamorphosing into a global brain, and how man-kind might adapt to this supra-intelligence will be addressed. 相似文献
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The residual damage is analysed by transmission electron microscopy (TEM) for BF2+, F+ + B+ and Ar+ + B+ implanted silicon after rapid thermal annealing(RTA). And the reverse leakage current of the implanted diodes is measured using a FJ-356 electrometer. The results show that 1 ) The residual damage due to BF2+ implantation is less than that of F+ + B + and Ar++ B+ implantation. 2) The reverse leakage current of BF2+ implanted diodes is less than that of F+ + B+ and Ar++ B + implanted diodes. 3) The reverse leakage current of F++B+ and Ar++ B+ implanted diodes increases with the increase of F+ and Ar+ energies, respectively. Therefore the physical behaviour of the interaction between molecular ion and silicon is different from that of the interaction between individual atom ion and silicon. 相似文献
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p+-n-p+ BARITT diodes have been designed to give maximum output power at X band frequencies. Computed output power against frequency shows good agreement with measured powers. The dominant effect of the maximum n region electric field on output power is demonstrated. 相似文献
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The frequency and current dependence of the noise factor of tuned microwave amplifiers, utilising punchthrough injection transit-time diodes, has been determined. Noise factors as low as 10 and 11 dB were obtained from companion p+-n-p+ and p+-n-v-p+ structures, respectively, when tuned to frequencies in the vicinity of 7.5 GHz. 相似文献
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半绝缘GaAs中Mg~++P~+双注入研究 总被引:1,自引:0,他引:1
本文对Mg~+和P~+双离子注入半绝缘GaAs的行为进行了研究.发现不论是常规热退火还是快速热退火,共P~+注入都能有效地提高注入Mg杂质的电激活率,其效果优于共As~+注入,共P~+注入的最佳条件是其剂量与Mg~+离子剂量相同,电化学C—V测量表明,双注入样品中空穴分布与理论计算值接近,而单注入样品中则发生严重偏离,快速热退火较常规热退火更有利于消除注入损伤. 相似文献
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在有限环F2+uF2+…+u^k F2与F2之间定义一个新的Gray映射,证明了该映射是距离保持映射。考察了F2+uF2+…+u^k F2环上循环码,得到了F2+uF2+…+u^k F2环上循环码的生成多项式。最后,证明了F2+uF2+…+u^k F2环上循环码在新定义的Gray映射下的像是F2上的准循环码。 相似文献
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Punchthrough transit-time diodes have been constructed with both Schottky-barrier and diffused-junction emitters. The microwave and d.c. characteristics of these devices are strikingly similar. Either construction technique appears to be suitable for the future development of low-noise microwave sources. 相似文献