共查询到20条相似文献,搜索用时 687 毫秒
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以传统光伏电池等效模型为基础,考虑了光伏电池在部分阴影情况下会出现的反向雪崩效应,在仿真光伏模块中模拟了并联旁路二极管,避免了热斑效应的发生,所建立的仿真模型能够根据不同的阴影条件和不同温度变化情况模拟出光伏阵列的输出特性曲线,为进一步研究多峰值最大功率点跟踪打下基础. 相似文献
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以光伏组件的双二极管模型为基础对串联输出特性进行了系统分析,包括分析比较有、无旁路二极管的串联特性、热斑成因,旁路二极管作用机理和不同连接方式以及等效串联结构的光照平衡的影响。结果表明,局部阴影使光伏阵列的I-U曲线呈阶梯状、P-U曲线呈现多峰;旁路二极管抑制热斑作用明显,其重叠和不重叠连接方式效果不同,重叠区的阴影可增大最大输出电流,且最大输出电流与遮阴程度正相关;多个光伏电池元共用一个旁路二极管可有效减少多峰数;等效串联结构的光照平衡可以消除阴影影响。 相似文献
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为了避免光伏电池在局部遮挡情况下的热斑效应,通常在一定数量电池元的两侧并联旁路二极管,然而由于旁路二极管的反向偏置,容易造成模组的局部加热现象,不可避免地导致光伏组件损坏或过早的失效。因此,提出智能规划旁路二极管的拓扑结构,结合串并联的光伏阵列拓扑建立了电路模型,并将太阳能模组电压的大小作为控制二极管拓扑结构的开关状态的判定规则,降低旁路二极管的导通损耗,最大限度地提高电池板的输出电能与使用年限。进一步探究了基于智能控制系统的MPPT策略,在计算获得GMPP点所在的UOVSR区间后,对该特定的区域采用优化粒子群算法进行最大功率点寻优。仿真结果表明该算法可以快速跟踪到GMPP。该方法利用小区域搜索代替全局搜索,具有速度快和准确性高的特点,可有效降低跟踪过程中的能量损耗。 相似文献
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为了提高基于可调谐半导体激光吸收光谱技术(TDLAS)的气体检测系统的精度,通常选用可电流调谐的分布反馈激光器(DFB LD)作为光源,以保证输出中心波长与被测气体吸收峰的高度匹配。结合朗伯—比尔定律与气体吸收谱线理论确定合适的吸收谱线与吸收范围。以FPGA为主控芯片,搭建有稳定电流设计的硬件驱动电路,产生叠加于直流的正弦调制信号与三角波扫描信号。实验结果表明:此方法可以锁定激光器中心波长,使之稳定地与气体吸收峰相匹配,电流稳定度为2×10-2。改变驱动电流进而改变激光器中心波长,该方法亦可以用于CH4,NO2等气体的检测。 相似文献
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Diode array pumped kilowatt laser 总被引:4,自引:0,他引:4
St. Pierre R.J. Mordaunt D.W. Injeyan H. Berg J.G. Hilyard R.C. Weber M.E. Wickham M.G. Harpole G.M. Senn R. 《IEEE journal of selected topics in quantum electronics》1997,3(1):53-58
The diode array pumped kilowatt laser (DAPKL) has demonstrated more than an order of magnitude increase in brightness and average power for short pulse diode-pumped solid-state lasers since its inception in 1991. Significant advances in component technology have been demonstrated, including: development of a diffusion bonding process for producing large slabs of Nd:YAG laser material. Phase conjugation by stimulated Brillouin scattering (SBS) has been demonstrated with high reflectivity and fidelity in a simple focused geometry with input powers of 100 W. Pulse energies at 1.06 μm of 10 J have been demonstrated with a beam quality of 1.5 times diffraction limited at the 500-W level. An average power of 875 W at 100 Hz has been obtained. Efficient frequency doubling with a record power of 165 W has been demonstrated with 5 J per pulse at 0.53 μm. Work is ongoing to enclose the system in a compact brassboard with improved performance and long term stability 相似文献
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《Education, IEEE Transactions on》1969,12(3):189-196
A simple electromechanical device called a tunnel diode motor was described in the "Amateur Scientist" section of the Scientific American [1]. From the construction details presented there a prototype was built with the idea that this would make a good example for the classroom. It has since been used twice in a graduate level course in digital computer simulation. This device has served well to illustrate typical problems in modeling and the automatic numerical solution of model equations. 相似文献
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硅整流管及晶闸管常在内、外部短路情况下损坏,这是由于其瞬时温升计算方法错误的缘故。本文系根据国内外有关文献编写,文中介绍有限差分法计算硅整流管及晶闸管瞬时温升的方法。实验证明此种计算方法是正确的。 相似文献
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KENJI HIRAMOTO HIDEO NAKAI YUKO KANO EIJI YAMADA RYOJI MIZUTANI 《Electrical Engineering in Japan》2017,198(2):81-88
This paper presents a new type of magnet‐free motor that has concentrated stator windings and rotor coils with a pair of diodes. The most important feature of this motor is that currents in the rotor coils can be generated by utilizing the changes in the spatial second harmonic of the magnetic fields due to the concentrated stator windings, which normally increase motor losses. A prototype of the motor was designed and fabricated, and its basic performance was evaluated. First, using simplified analytic models, we explain the mechanism of inducing currents in the rotor coils by the changes in the spatial second harmonic of the magnetic fields. Second, we compare the torque performance of the proposed motor and that of other types of motors including a magnet motor through finite‐element analyses. The analyzed data show that the proposed motor can possess greater torque/volume ratio than that of the other motors. Finally, using the measured data, we validate the mechanism of inducing currents in the rotor coils, and examine the torque and power characteristics of the motor. 相似文献