随着因化石燃料过度消耗产生的温室效应成为了全球关注的焦点,我国正在大力推广利用太阳能等可再生清洁能源的发电技术,从而为电网的低碳运行做出贡献。其中,光伏发电的并网化和大型化必将是将来的主要发展趋势,提高光伏发电效率,增加...随着因化石燃料过度消耗产生的温室效应成为了全球关注的焦点,我国正在大力推广利用太阳能等可再生清洁能源的发电技术,从而为电网的低碳运行做出贡献。其中,光伏发电的并网化和大型化必将是将来的主要发展趋势,提高光伏发电效率,增加并网容量,都有助于发展低碳电网。由于光伏发电的随机性强,所以通过Matlab/Simulnik建造光伏电站的模型,根据真实的环境数据得出一年中的典型日光伏输出特性并进行了分析,最后提出了一种大型光伏电站的低碳调度。另一方面,随着光伏电站的容量不断增加,并网时需要考虑并解决更多的负面影响,而且要达到低碳运行的标准,这都对并网逆变器提出了更多的要求,所以提出了一种具有最大功率点跟踪(maximum power point tracking,MPPT)、无功及谐波电流补偿和有功控制相结合的大型光伏电站逆变器的多模式控制策略,并通过Matlab/Simulnik建模仿真验证了该控制策略的可行性及优点。展开更多
The measurement of spherical rotor orientation is crucial to the close-loop control of spherical motors. This paper presents a novel method for the measuring of three-degree-of-freedom (DOF) rotor orientation of spher...The measurement of spherical rotor orientation is crucial to the close-loop control of spherical motors. This paper presents a novel method for the measuring of three-degree-of-freedom (DOF) rotor orientation of spherical motors using optical sensors. The spatial orientation of spherical rotor is output in the form of ZXZ Euler angles. Firstly, the structure of the measuring system composed of optical sensors and the patterns on the rotor surface are presented, and the operational principle of recognizing intersection points between the optical ring detectors and the latitude/longitude on the rotor surface is illustrated. The analytical model of input-output characteristic is established for the measuring system of three-DOF rotor orientation. Afterwards, the effect of parameters of the optical ring detectors on the linearity, sensitivity, resolving power and measuring range of the measuring system is analyzed using the analytical model. Finally, the feasibility of the measurement is validated through experiments of prototype measuring system. The analysis is expected to be a basis for the design parameter optimization of the orientation measuring system of a PM spherical motor.展开更多
The output characteristics of neodymium-doped gadolinium vanadate(Nd:GdVO4) crystals laser with dual c-axis orthogonal gains end-pumped by two fiber-coupled diode lasers are investigated. With two 1 W semiconductor di...The output characteristics of neodymium-doped gadolinium vanadate(Nd:GdVO4) crystals laser with dual c-axis orthogonal gains end-pumped by two fiber-coupled diode lasers are investigated. With two 1 W semiconductor diode lasers pumping, the output power of TEM00 laser is 920 m W, and the optical conversion efficiency is close to 46%. By changing the relative orientations of both Nd:Gd VO4 crystals, the polarization characteristics of laser are varied. In particular, by keeping the c-axes of two Nd:Gd VO4 crystals orthogonal to each other and adjusting two diode pump lasers to operate at the same power level, the completely unpolarized light is obtained.展开更多
A distributed feedback （DFB） fiber laser with a ratio of the backward to forward output power of 1：100 was composed by a 45-ram-length asymmetrical phase-shifted fiber grating fabricated on the 50-mm erbium-doped p...A distributed feedback （DFB） fiber laser with a ratio of the backward to forward output power of 1：100 was composed by a 45-ram-length asymmetrical phase-shifted fiber grating fabricated on the 50-mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL-980-Hp erbium-doped fiber to absorb the surplus pump power after the active phase-shifted fiber grating and get population inversion. By using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with the narrow line-width and low noise, a narrow-band light filter consisting of a fiber Bragg grating （FBG） with the same Bragg wavelength as the laser and an optical circulator was used to filter the amplified spontaneous emission （ASE） noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, and a DFB fiber laser with the 32.5-mW output power, l l.5-kHz line width, and -87-dB/Hz relative intensity noise （R1N） at 300 mW of 980 nm pump power was brought out.展开更多
Four distributed feedback fiber lasers with dual-wavelength operations were studied experimentally in detail. The laser characteristics of these distributed feedback fiber lasers （DFB-FLs） were investigated. The ope...Four distributed feedback fiber lasers with dual-wavelength operations were studied experimentally in detail. The laser characteristics of these distributed feedback fiber lasers （DFB-FLs） were investigated. The operation conditions for the dual-wavelength output are analyzed and presented. Through this study, the guidance of the design and fabrication of some dual-wavelength distributed feedback fiber lasers are provided.展开更多
The output characteristics of nonlinear optical fiber-loop mirror are analyzed in detail when the pump pulses with the same wavelength are input in the both directions for recovering the clock component of the signal ...The output characteristics of nonlinear optical fiber-loop mirror are analyzed in detail when the pump pulses with the same wavelength are input in the both directions for recovering the clock component of the signal spectrum.It is found that the double output pulses are produced in the transmission port of the nonlinear optical fiber-loop mirror.The output pulse peaks are located in time domain at the rising and falling edges of the pump pulses.It is demonstrated that the rising and falling edges of the pump pulse can be directly extracted by this method.Through numerical simulation,the effects of therelative delay of pump pulses and the dispersion of fiber on the characteristics of output pulses are studied.By spectrum analysis,it is found that the spectrum of output pulse sequence includes the clock components of the pump pulse sequence,and a new idea is provided for all-optical clock extraction.展开更多
文摘随着因化石燃料过度消耗产生的温室效应成为了全球关注的焦点,我国正在大力推广利用太阳能等可再生清洁能源的发电技术,从而为电网的低碳运行做出贡献。其中,光伏发电的并网化和大型化必将是将来的主要发展趋势,提高光伏发电效率,增加并网容量,都有助于发展低碳电网。由于光伏发电的随机性强,所以通过Matlab/Simulnik建造光伏电站的模型,根据真实的环境数据得出一年中的典型日光伏输出特性并进行了分析,最后提出了一种大型光伏电站的低碳调度。另一方面,随着光伏电站的容量不断增加,并网时需要考虑并解决更多的负面影响,而且要达到低碳运行的标准,这都对并网逆变器提出了更多的要求,所以提出了一种具有最大功率点跟踪(maximum power point tracking,MPPT)、无功及谐波电流补偿和有功控制相结合的大型光伏电站逆变器的多模式控制策略,并通过Matlab/Simulnik建模仿真验证了该控制策略的可行性及优点。
基金supported in part by the National Key Basic Research Program of China ("973" Project) (Grant No. 2013CB035602)the Key Program of National Natural Science Foundation of China (Grant No.51037004)the National Natural Science Foundation of China (Grant No. 51007061)
文摘The measurement of spherical rotor orientation is crucial to the close-loop control of spherical motors. This paper presents a novel method for the measuring of three-degree-of-freedom (DOF) rotor orientation of spherical motors using optical sensors. The spatial orientation of spherical rotor is output in the form of ZXZ Euler angles. Firstly, the structure of the measuring system composed of optical sensors and the patterns on the rotor surface are presented, and the operational principle of recognizing intersection points between the optical ring detectors and the latitude/longitude on the rotor surface is illustrated. The analytical model of input-output characteristic is established for the measuring system of three-DOF rotor orientation. Afterwards, the effect of parameters of the optical ring detectors on the linearity, sensitivity, resolving power and measuring range of the measuring system is analyzed using the analytical model. Finally, the feasibility of the measurement is validated through experiments of prototype measuring system. The analysis is expected to be a basis for the design parameter optimization of the orientation measuring system of a PM spherical motor.
基金supported by the National Natural Science Foundation of China(No.11104234)
文摘The output characteristics of neodymium-doped gadolinium vanadate(Nd:GdVO4) crystals laser with dual c-axis orthogonal gains end-pumped by two fiber-coupled diode lasers are investigated. With two 1 W semiconductor diode lasers pumping, the output power of TEM00 laser is 920 m W, and the optical conversion efficiency is close to 46%. By changing the relative orientations of both Nd:Gd VO4 crystals, the polarization characteristics of laser are varied. In particular, by keeping the c-axes of two Nd:Gd VO4 crystals orthogonal to each other and adjusting two diode pump lasers to operate at the same power level, the completely unpolarized light is obtained.
文摘A distributed feedback （DFB） fiber laser with a ratio of the backward to forward output power of 1：100 was composed by a 45-ram-length asymmetrical phase-shifted fiber grating fabricated on the 50-mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL-980-Hp erbium-doped fiber to absorb the surplus pump power after the active phase-shifted fiber grating and get population inversion. By using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with the narrow line-width and low noise, a narrow-band light filter consisting of a fiber Bragg grating （FBG） with the same Bragg wavelength as the laser and an optical circulator was used to filter the amplified spontaneous emission （ASE） noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, and a DFB fiber laser with the 32.5-mW output power, l l.5-kHz line width, and -87-dB/Hz relative intensity noise （R1N） at 300 mW of 980 nm pump power was brought out.
基金This work is financially supported by the International Science and Technology Cooperation Program of China （2012DFA10730） and Natural Science Foundation of China （60977058）. Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author（s） and source are credited.
文摘Four distributed feedback fiber lasers with dual-wavelength operations were studied experimentally in detail. The laser characteristics of these distributed feedback fiber lasers （DFB-FLs） were investigated. The operation conditions for the dual-wavelength output are analyzed and presented. Through this study, the guidance of the design and fabrication of some dual-wavelength distributed feedback fiber lasers are provided.
基金supported by the National High Technology Research and Development Program of China(No.2009AA01Z216)the Major State Basic Research and Development Program of China(No.2011CB301703)
文摘The output characteristics of nonlinear optical fiber-loop mirror are analyzed in detail when the pump pulses with the same wavelength are input in the both directions for recovering the clock component of the signal spectrum.It is found that the double output pulses are produced in the transmission port of the nonlinear optical fiber-loop mirror.The output pulse peaks are located in time domain at the rising and falling edges of the pump pulses.It is demonstrated that the rising and falling edges of the pump pulse can be directly extracted by this method.Through numerical simulation,the effects of therelative delay of pump pulses and the dispersion of fiber on the characteristics of output pulses are studied.By spectrum analysis,it is found that the spectrum of output pulse sequence includes the clock components of the pump pulse sequence,and a new idea is provided for all-optical clock extraction.
