We present an experimental study on tilt-tip（TT） and phase-locking（PL） control in a coherent beam combination（CBC） system of adaptive fiber laser array.The TT control is performed using the adaptive fiber-optics...We present an experimental study on tilt-tip（TT） and phase-locking（PL） control in a coherent beam combination（CBC） system of adaptive fiber laser array.The TT control is performed using the adaptive fiber-optics collimator（AFOC）,and the PL control is realized by the phase modulator（PM）.Cascaded and simultaneous controls of TT and PL using stochastic parallel gradient descent（SPGD） algorithm are investigated in this paper.Two-fiber-laser-,four-fiber-laser-,and six-fiber-laser-arrays are employed to study the TT and PL control.In the cascaded control system,only one high-speed CMOS camera is used to collect beam data and a computer is used as the controller.In a simultaneous control system one high-speed CMOS camera and one photonic detector（PD） are employed,and a computer and a control circuit based on field programmable gate array（FPGA） are used as the controllers.Experimental results reveal that both cascaded and simultaneous controls of TT using AFOC and PL using PM in fiber laser array are feasible and effective.Cascaded control is more effective in static control situation and simultaneous control can be applied to the dynamic control system directly.The control signals of simultaneous PL and TT disturb each other obviously and TT and PL control may compete with each other,so the control effect is limited.展开更多
在太阳能系统的设计中常涉及倾斜面上日总直射辐射的计算。计算倾斜面上日总直射辐射最常用的方法是Liu and Jordan所提出的数学方法,该方法是在假设地球表面没有大气层的情况下得出的,是一个典型的近似计算方法。研究通过直接数值积分...在太阳能系统的设计中常涉及倾斜面上日总直射辐射的计算。计算倾斜面上日总直射辐射最常用的方法是Liu and Jordan所提出的数学方法,该方法是在假设地球表面没有大气层的情况下得出的,是一个典型的近似计算方法。研究通过直接数值积分和Collares-Pereira and Rabl辐射计算经验关系对Liu and Jordan计算方法的正确性进行分析。结果表明:Liu and Jordan所提出的计算倾斜面上日总直射辐射的方法存在明显的计算误差,误差的大小与倾斜面的倾角和方位角有关,且方位角越大,计算误差越大;对于垂直表面,计算误差随着方位角的增加迅速增加,当方位角偏离正南90度时,由Liu andJordan方法所计算出的年总直射辐射误差高达20%以上。展开更多
为了拓展倾斜波束圆极化天线(Circularly Polarized Antenna with Tilted Beam,CPA-TB)的带宽,在分析了该天线结构及其特征的基础上,提出了一种花纹式螺旋臂(Flower-Spiral,FS)协同互补开口谐振环(complementary split ring resontor,CS...为了拓展倾斜波束圆极化天线(Circularly Polarized Antenna with Tilted Beam,CPA-TB)的带宽,在分析了该天线结构及其特征的基础上,提出了一种花纹式螺旋臂(Flower-Spiral,FS)协同互补开口谐振环(complementary split ring resontor,CSRR)的CSRR-FS结构.该结构通过FS增加了天线表面电流路径,实现了天线驻波比(voltage standing wave ratio,VSWR)的拓展;利用CSRR改变了低频点反射板的电流分布,实现反射板小型化的同时,减小了天线的交叉极化分量,增强了天线的辐射性能,拓展了天线的轴比带宽.仿真和实测结果表明:与普通的平面反射板相比,在保证圆极化、波束倾角30°的条件下,基于CSRR-FS结构的CPA-TB相对带宽为24%(5.5-7GHz),天线工作带宽拓展了1.8倍.CSRR-FS结构的提出为CPA-TB带宽的拓展提供了新的途径.展开更多
文摘We present an experimental study on tilt-tip（TT） and phase-locking（PL） control in a coherent beam combination（CBC） system of adaptive fiber laser array.The TT control is performed using the adaptive fiber-optics collimator（AFOC）,and the PL control is realized by the phase modulator（PM）.Cascaded and simultaneous controls of TT and PL using stochastic parallel gradient descent（SPGD） algorithm are investigated in this paper.Two-fiber-laser-,four-fiber-laser-,and six-fiber-laser-arrays are employed to study the TT and PL control.In the cascaded control system,only one high-speed CMOS camera is used to collect beam data and a computer is used as the controller.In a simultaneous control system one high-speed CMOS camera and one photonic detector（PD） are employed,and a computer and a control circuit based on field programmable gate array（FPGA） are used as the controllers.Experimental results reveal that both cascaded and simultaneous controls of TT using AFOC and PL using PM in fiber laser array are feasible and effective.Cascaded control is more effective in static control situation and simultaneous control can be applied to the dynamic control system directly.The control signals of simultaneous PL and TT disturb each other obviously and TT and PL control may compete with each other,so the control effect is limited.
文摘在太阳能系统的设计中常涉及倾斜面上日总直射辐射的计算。计算倾斜面上日总直射辐射最常用的方法是Liu and Jordan所提出的数学方法,该方法是在假设地球表面没有大气层的情况下得出的,是一个典型的近似计算方法。研究通过直接数值积分和Collares-Pereira and Rabl辐射计算经验关系对Liu and Jordan计算方法的正确性进行分析。结果表明:Liu and Jordan所提出的计算倾斜面上日总直射辐射的方法存在明显的计算误差,误差的大小与倾斜面的倾角和方位角有关,且方位角越大,计算误差越大;对于垂直表面,计算误差随着方位角的增加迅速增加,当方位角偏离正南90度时,由Liu andJordan方法所计算出的年总直射辐射误差高达20%以上。
