This paper presents a novel hexapod as the adjustment mechanism for a telescope to actively align its secondary mirror. The special hexapod provides six degrees of freedom（6-DOFs） with decoupled translation and rota...This paper presents a novel hexapod as the adjustment mechanism for a telescope to actively align its secondary mirror. The special hexapod provides six degrees of freedom（6-DOFs） with decoupled translation and rotation. The decoupled kinematic motions are analyzed and commented on as the alignment mechanism of a secondary mirror from an optical alignment point of view. In terms of performance of the adjustment generally required by the secondary mirror in a telescope, we developed a prototype that uses a novel hexapod design with linear micro-displacement actuators. Especially, in order to achieve high precision, flexures were used to build joints for the hexapod to minimize frictions and eliminate backlashes. Based on the specific configuration and dimension of the prototype hexapod,an analytical model of the reachable workspace was built with the constraints defined by limited rotation angles of the flexure-based joints. We used a laser tracker to verify that the hexapod can reach a spherical translation workspace of φ6 mm and a rotation workspace of±1°. The translational repeatability was tested to be around half a μm by laser displacement sensors. In addition, we also measured the axial and lateral stiffnesses of the hexapod to be around 5500 N mm-^1 and 1750 N mm^-1, respectively. The kinematic analyses and convincing test results jointly encourage implementing the novel hexapod design with decoupled translation and rotation as a favorable alignment mechanism for secondary mirrors in astronomical telescopes.展开更多
Most reflector surface holographic measurements of a large radio telescope utilize a geostationary satellite as the signal source. The shortcoming is that those measurements could only be done at a limited elevation a...Most reflector surface holographic measurements of a large radio telescope utilize a geostationary satellite as the signal source. The shortcoming is that those measurements could only be done at a limited elevation angle due to the satellite’s relatively stationary state. This paper proposed a new wideband microwave holographic measurement method based on radio sources to achieve full-elevation-angle measurement with small size reference antenna. In theoretical derivation, the time delay and phase change due to path length and device difference between the antenna under test and reference antenna are compensated first. Then the correct method of wideband holography effect, which is because of antenna pattern differing under different wavelengths when receiving a wideband signal, is presented. To verify the proposed methodology, a wideband microwave holographic measurement system is established, the data processing procedure is illustrated, and the reflector surface measurement experiments on a 40 m radio telescope at different elevation angles are conducted. The result shows that the primary reflector surface root-mean-square at around elevation angles of 28°, 44°, 49°, and 75° are respectively 0.213 mm, 0.170 mm, 0.188 mm, and 0.199 mm. It is basically consistent with the real data, indicating that the proposed wideband microwave holography methodology is feasible.展开更多
Neutral hydrogen clouds are known to exist in the Universe, however their spatial distributions and physical properties are poorly understood. Such missing information can be studied by the new generation of Chinese r...Neutral hydrogen clouds are known to exist in the Universe, however their spatial distributions and physical properties are poorly understood. Such missing information can be studied by the new generation of Chinese radio telescopes through a blind search of 21-cm absorption systems. We forecast the capabilities of surveys of 21-cm absorption systems by two representative radio telescopes in China - the Five-hundred-meter Aperture Spherical radio Telescope （FAST） and Tianlai 21-cm cosmology experiment （Tianlai）. Facilitated by either the high sensitivity （FAST） or wide field of view （Tianlai） of these telescopes, more than a thousand 21-cm absorption systems can be discovered in a few years, representing orders of magnitude improvement over the cumulative discoveries in the past half a century.展开更多
This paper is concerned with the characteristics of a tracking differentiator(TD)in arranging transition process for the physical system.In order to overcome disadvantages of linear TD(LTD)in practice,a novel variable...This paper is concerned with the characteristics of a tracking differentiator(TD)in arranging transition process for the physical system.In order to overcome disadvantages of linear TD(LTD)in practice,a novel variable parameter linear tracking differentiator(VLTD)is proposed.By designing the speediness factor as a function of the tracking error,the VLTD can track a large range of set values with reasonable speed and acceleration.Analysis shows that VLTD can converge to its set value under certain conditions.Meanwhile,the speed and acceleration bounds are added to the VLTD,which guarantees that the proposed transition signal really plays a transitional role.The numerical simulation results emphasize necessity for adding speed and acceleration bounds to the VLTD.By comparing VLTD with the nonlinear TD(NLTD)in the simulations and experiments,VLTD can achieve almost the same performance as the NLTD while it is easier to be implemented.展开更多
In order to evaluate the ground-based infrared telescope sensitivity affected by the noise from the atmosphere,instruments and detectors,we construct a sensitivity model that can calculate limiting magnitudes and sign...In order to evaluate the ground-based infrared telescope sensitivity affected by the noise from the atmosphere,instruments and detectors,we construct a sensitivity model that can calculate limiting magnitudes and signal-to-noise ratio(S/N).The model is tested with tentative measurements of M’-band sky brightness and atmospheric extinction obtained at the Ali and Daocheng sites.We find that the noise caused by an excellent scientific detector and instruments at-135℃can be ignored compared to the M’-band sky background noise.Thus,when S/N=3 and total exposure time is 1 second for 10 m telescopes,the magnitude limited by the atmosphere is 13.01^(m)at Ali and 12.96^(m)at Daocheng.Even under lessthan-ideal circumstances,i.e.,the readout noise of a deep cryogenic detector is less than 200 e-and the instruments are cooled to below-87.2℃,the above magnitudes decrease by 0.056^(m)at most.Therefore,according to observational requirements with a large telescope in a given infrared band,astronomers can use this sensitivity model as a tool for guiding site surveys,detector selection and instrumental thermal-control.展开更多
An observation control system is the foundation to support automatic observations by any radio telescope.Traditional observation control systems are usually coded using a compiled language,which is of higher efficienc...An observation control system is the foundation to support automatic observations by any radio telescope.Traditional observation control systems are usually coded using a compiled language,which is of higher efficiency compared with interpreted languages.Indeed,observation control systems are usually programmed using the C or C++languages.However,the high execution efficiency of C/C++is at the cost of a long development cycle,which is not only time consuming but also requires considerable skills for the developers.The development of computer hardware performance,as well as the optimization of the just-in-time compiler for new interpreted languages such as Python,provides a good balance between execution and development efficiency.In this paper,we introduce the observation control system developed for the Kunming 40-meter radio telescope run by Yunnan Observatories,Chinese Academy of Sciences.The system is developed mainly with the Python language,and we have optimized computationally intensive components with C++.We demonstrate that it is possible to achieve the required functionality and control precision with such a Python-C++programming paradigm.The performance of the control system is also assessed in this paper,demonstrating that satisfactory pointing accuracy and user experience can be attained.展开更多
We develop a new procedure to improve the angular resolution of coded-mask telescopes by the Direct Demodulation Method （DDM）. DDM has been applied to both real and simulated data of INTEGRAL/IBIS. The angular resol...We develop a new procedure to improve the angular resolution of coded-mask telescopes by the Direct Demodulation Method （DDM）. DDM has been applied to both real and simulated data of INTEGRAL/IBIS. The angular resolution of IBIS/ISGRI has been improved from about 13＇ to 2＇.展开更多
Antarctic Survey Telescopes（AST3） are designed to be fully robotic telescopes at Dome A,Antarctica,which aim for highly efficient time-domain sky surveys as well as rapid response to special transient events（e.g.,g...Antarctic Survey Telescopes（AST3） are designed to be fully robotic telescopes at Dome A,Antarctica,which aim for highly efficient time-domain sky surveys as well as rapid response to special transient events（e.g.,gamma-ray bursts,near-Earth asteroids,supernovae,etc.）.Unlike traditional observations,a well-designed real-time survey scheduler is needed in order to implement an automatic survey in a very efficient,reliable and flexible way for the unattended telescopes.We present a study of the survey strategy for AST3 and implementation of its survey scheduler,which is also useful for other survey projects.展开更多
We report the design concept and performance of a compact,lightweight and economical imaging polarimeter,the Triple Range Imager and POLarimeter(TRIPOL),capable of simultaneous optical imagery and polarimetry.TRIPOL s...We report the design concept and performance of a compact,lightweight and economical imaging polarimeter,the Triple Range Imager and POLarimeter(TRIPOL),capable of simultaneous optical imagery and polarimetry.TRIPOL splits the beam in wavelengths from 400 to 830 nm into g′-,r′-and i′-bands with two dichroic mirrors,and measures polarization with an achromatic half-waveplate and a wire grid polarizer.The simultaneity makes TRIPOL a useful tool for small telescopes for the photometry and polarimetry of time variable and wavelength dependent phenomena.TRIPOL is designed for a Cassegrain telescope with an aperture of^1 m.This paper presents the engineering considerations of TRIPOL and compares the expected with observed performance.Using the Lulin 1-m telescope and 100 seconds of integration,the limiting magnitudes are g′~19.0 mag,r′~18.5 mag and i′~18.0 mag with a signal-to-noise ratio of 10,in agreement with design expectation.The instrumental polarization is measured to be^0.3%in the three bands.Two applications,one to the star-forming cloud IC 5146 and the other to the young variable GM Cep,are presented as demonstrations.展开更多
This paper systematically summarizes previous measuring methods and observational instruments for the magnitude of dewfall on land surface, analyzes the characteristics of common observational instruments for land sur...This paper systematically summarizes previous measuring methods and observational instruments for the magnitude of dewfall on land surface, analyzes the characteristics of common observational instruments for land surface dewfall, and describes several basic dewfall measurement methods. Moreover, the basic principles of these methods and instruments are interpreted, and their advantages, disadvantages, and applicability are analyzed. Recommendations for the further improvement of these observational instruments and the development of dewfall measuring methods are presented, and new technologies and scientific proposals for exploiting dewfall are elucidated.展开更多
A detailed case study of γ-hadron segregation for a ground based atmo- spheric Cherenkov telescope is presented. We have evaluated and compared various supervised machine learning methods such as the Random Forest me...A detailed case study of γ-hadron segregation for a ground based atmo- spheric Cherenkov telescope is presented. We have evaluated and compared various supervised machine learning methods such as the Random Forest method, Artificial Neural Network, Linear Discriminant method, Naive Bayes Classifiers, Support Vector Machines as well as the conventional dynamic supercut method by simulating triggering events with the Monte Carlo method and applied the results to a Cherenkov telescope. It is demonstrated that the Random Forest method is the most sensitive machine learning method for γ-hadron segregation.展开更多
Near-Earth objects are important not only in studying the early formation of the Solar System,but also because they pose a serious hazard to humanity when they make close approaches to the Earth.Study of their physica...Near-Earth objects are important not only in studying the early formation of the Solar System,but also because they pose a serious hazard to humanity when they make close approaches to the Earth.Study of their physical properties can provide useful information on their origin,evolution,and hazard to human beings.However,it remains challenging to investigate small,newly discovered,near-Earth objects because of our limited observational window.This investigation seeks to determine the visible colors of near-Earth asteroids(NEAs),perform an initial taxonomic classification based on visible colors and analyze possible correlations between the distribution of taxonomic classification and asteroid size or orbital parameters.Observations were performed in the broadband BVRI Johnson−Cousins photometric system,applied to images from the Yaoan High Precision Telescope and the 1.88 m telescope at the Kottamia Astronomical Observatory.We present new photometric observations of 84 near-Earth asteroids,and classify 80 of them taxonomically,based on their photometric colors.We find that nearly half(46.3%)of the objects in our sample can be classified as S-complex,26.3%as C-complex,6%as D-complex,and 15.0%as X-complex;the remaining belong to the A-or V-types.Additionally,we identify three P-type NEAs in our sample,according to the Tholen scheme.The fractional abundances of the C/X-complex members with absolute magnitude H≥17.0 were more than twice as large as those with H<17.0.However,the fractions of C-and S-complex members with diameters≤1 km and>1 km are nearly equal,while X-complex members tend to have sub-kilometer diameters.In our sample,the C/D-complex objects are predominant among those with a Jovian Tisserand parameter of T_(J)<3.1.These bodies could have a cometary origin.C-and S-complex members account for a considerable proportion of the asteroids that are potentially hazardous.展开更多
针对传统扰动观察法在光伏系统最大功率点跟踪(Maximum Power Point Tracking,MPPT)中存在步长选取不能同时兼顾跟踪速度及稳态精度的问题,在可变工作环境下建立起光伏系统最大功率点电压与环境温度和光照强度之间的数学表达式,获得可...针对传统扰动观察法在光伏系统最大功率点跟踪(Maximum Power Point Tracking,MPPT)中存在步长选取不能同时兼顾跟踪速度及稳态精度的问题,在可变工作环境下建立起光伏系统最大功率点电压与环境温度和光照强度之间的数学表达式,获得可变环境下光伏系统最大功率点电压值,再将其赋值给小步长扰动观察法。仿真分析结果表明,相比恒定电压-扰动观察法,所提方法具有更快跟踪速度和更高稳态精度。展开更多
基金funded by the National Natural Science Foundation of China(No.U1531110)
文摘This paper presents a novel hexapod as the adjustment mechanism for a telescope to actively align its secondary mirror. The special hexapod provides six degrees of freedom（6-DOFs） with decoupled translation and rotation. The decoupled kinematic motions are analyzed and commented on as the alignment mechanism of a secondary mirror from an optical alignment point of view. In terms of performance of the adjustment generally required by the secondary mirror in a telescope, we developed a prototype that uses a novel hexapod design with linear micro-displacement actuators. Especially, in order to achieve high precision, flexures were used to build joints for the hexapod to minimize frictions and eliminate backlashes. Based on the specific configuration and dimension of the prototype hexapod,an analytical model of the reachable workspace was built with the constraints defined by limited rotation angles of the flexure-based joints. We used a laser tracker to verify that the hexapod can reach a spherical translation workspace of φ6 mm and a rotation workspace of±1°. The translational repeatability was tested to be around half a μm by laser displacement sensors. In addition, we also measured the axial and lateral stiffnesses of the hexapod to be around 5500 N mm-^1 and 1750 N mm^-1, respectively. The kinematic analyses and convincing test results jointly encourage implementing the novel hexapod design with decoupled translation and rotation as a favorable alignment mechanism for secondary mirrors in astronomical telescopes.
基金funded by the Astronomical Joint Fund of the National Natural Science Foundation of China and Chinese Academy of Sciences (Grant Nos. U1831114, 11941002, and12073048)。
文摘Most reflector surface holographic measurements of a large radio telescope utilize a geostationary satellite as the signal source. The shortcoming is that those measurements could only be done at a limited elevation angle due to the satellite’s relatively stationary state. This paper proposed a new wideband microwave holographic measurement method based on radio sources to achieve full-elevation-angle measurement with small size reference antenna. In theoretical derivation, the time delay and phase change due to path length and device difference between the antenna under test and reference antenna are compensated first. Then the correct method of wideband holography effect, which is because of antenna pattern differing under different wavelengths when receiving a wideband signal, is presented. To verify the proposed methodology, a wideband microwave holographic measurement system is established, the data processing procedure is illustrated, and the reflector surface measurement experiments on a 40 m radio telescope at different elevation angles are conducted. The result shows that the primary reflector surface root-mean-square at around elevation angles of 28°, 44°, 49°, and 75° are respectively 0.213 mm, 0.170 mm, 0.188 mm, and 0.199 mm. It is basically consistent with the real data, indicating that the proposed wideband microwave holography methodology is feasible.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11573006 and 11528306)General Financial (Grant No. 2015M570884) and Special Financial Grant (No. 2016T90009) from the China Postdoctoral Science Foundation+3 种基金support of the National Science and Engineering Research Council of Canadasupport from the FAST fellowship program administered by the Astronomical Mega-science center of the Chinese Academy of Sciencespartially supported by the International Partnership Program of CAS, Grant No. 114A11KYSB20160008CAS Interdisciplinary Innovation Team program
文摘Neutral hydrogen clouds are known to exist in the Universe, however their spatial distributions and physical properties are poorly understood. Such missing information can be studied by the new generation of Chinese radio telescopes through a blind search of 21-cm absorption systems. We forecast the capabilities of surveys of 21-cm absorption systems by two representative radio telescopes in China - the Five-hundred-meter Aperture Spherical radio Telescope （FAST） and Tianlai 21-cm cosmology experiment （Tianlai）. Facilitated by either the high sensitivity （FAST） or wide field of view （Tianlai） of these telescopes, more than a thousand 21-cm absorption systems can be discovered in a few years, representing orders of magnitude improvement over the cumulative discoveries in the past half a century.
基金supported in part by the National Natural Science Foundation of China under Nos.12122304 and 11973041in part by the Youth Innovation Promotion Association CAS,under No.2019218。
文摘This paper is concerned with the characteristics of a tracking differentiator(TD)in arranging transition process for the physical system.In order to overcome disadvantages of linear TD(LTD)in practice,a novel variable parameter linear tracking differentiator(VLTD)is proposed.By designing the speediness factor as a function of the tracking error,the VLTD can track a large range of set values with reasonable speed and acceleration.Analysis shows that VLTD can converge to its set value under certain conditions.Meanwhile,the speed and acceleration bounds are added to the VLTD,which guarantees that the proposed transition signal really plays a transitional role.The numerical simulation results emphasize necessity for adding speed and acceleration bounds to the VLTD.By comparing VLTD with the nonlinear TD(NLTD)in the simulations and experiments,VLTD can achieve almost the same performance as the NLTD while it is easier to be implemented.
基金funded by the National Natural Science Foundation of China(NSFC,Nos.11803089,U1931124)。
文摘In order to evaluate the ground-based infrared telescope sensitivity affected by the noise from the atmosphere,instruments and detectors,we construct a sensitivity model that can calculate limiting magnitudes and signal-to-noise ratio(S/N).The model is tested with tentative measurements of M’-band sky brightness and atmospheric extinction obtained at the Ali and Daocheng sites.We find that the noise caused by an excellent scientific detector and instruments at-135℃can be ignored compared to the M’-band sky background noise.Thus,when S/N=3 and total exposure time is 1 second for 10 m telescopes,the magnitude limited by the atmosphere is 13.01^(m)at Ali and 12.96^(m)at Daocheng.Even under lessthan-ideal circumstances,i.e.,the readout noise of a deep cryogenic detector is less than 200 e-and the instruments are cooled to below-87.2℃,the above magnitudes decrease by 0.056^(m)at most.Therefore,according to observational requirements with a large telescope in a given infrared band,astronomers can use this sensitivity model as a tool for guiding site surveys,detector selection and instrumental thermal-control.
基金funded by the National SKA Program of China(2020SKA0120100)the Special Project of Foreign Science and Technology Cooperation of Yunnan Provincial Science and Technology Department(202003AD150010)the National Natural Science Foundation of China(12073076,12173087,12041303 and 12063003),the Foundation of the Chinese Academy of Sciences(Light of West China Program),the CAS-MPG LEGACY Project and the Max-Planck Partner Group.
文摘An observation control system is the foundation to support automatic observations by any radio telescope.Traditional observation control systems are usually coded using a compiled language,which is of higher efficiency compared with interpreted languages.Indeed,observation control systems are usually programmed using the C or C++languages.However,the high execution efficiency of C/C++is at the cost of a long development cycle,which is not only time consuming but also requires considerable skills for the developers.The development of computer hardware performance,as well as the optimization of the just-in-time compiler for new interpreted languages such as Python,provides a good balance between execution and development efficiency.In this paper,we introduce the observation control system developed for the Kunming 40-meter radio telescope run by Yunnan Observatories,Chinese Academy of Sciences.The system is developed mainly with the Python language,and we have optimized computationally intensive components with C++.We demonstrate that it is possible to achieve the required functionality and control precision with such a Python-C++programming paradigm.The performance of the control system is also assessed in this paper,demonstrating that satisfactory pointing accuracy and user experience can be attained.
基金National Natural Science Foundation of China (10603004).
文摘We develop a new procedure to improve the angular resolution of coded-mask telescopes by the Direct Demodulation Method （DDM）. DDM has been applied to both real and simulated data of INTEGRAL/IBIS. The angular resolution of IBIS/ISGRI has been improved from about 13＇ to 2＇.
基金supported by the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes(Grant No.CHINARE2017-02-04)the National Natural Science Foundation of China(Grant Nos.11003027,11403057,11403048,11203039 and 11273019)the National Basic Research Program of China(973 Program,Grant No.2013CB834900)
文摘Antarctic Survey Telescopes（AST3） are designed to be fully robotic telescopes at Dome A,Antarctica,which aim for highly efficient time-domain sky surveys as well as rapid response to special transient events（e.g.,gamma-ray bursts,near-Earth asteroids,supernovae,etc.）.Unlike traditional observations,a well-designed real-time survey scheduler is needed in order to implement an automatic survey in a very efficient,reliable and flexible way for the unattended telescopes.We present a study of the survey strategy for AST3 and implementation of its survey scheduler,which is also useful for other survey projects.
基金supported by Grant-in-Aid for Science Research from the Ministry of Education,Culture,Sports and Technology of Japan
文摘We report the design concept and performance of a compact,lightweight and economical imaging polarimeter,the Triple Range Imager and POLarimeter(TRIPOL),capable of simultaneous optical imagery and polarimetry.TRIPOL splits the beam in wavelengths from 400 to 830 nm into g′-,r′-and i′-bands with two dichroic mirrors,and measures polarization with an achromatic half-waveplate and a wire grid polarizer.The simultaneity makes TRIPOL a useful tool for small telescopes for the photometry and polarimetry of time variable and wavelength dependent phenomena.TRIPOL is designed for a Cassegrain telescope with an aperture of^1 m.This paper presents the engineering considerations of TRIPOL and compares the expected with observed performance.Using the Lulin 1-m telescope and 100 seconds of integration,the limiting magnitudes are g′~19.0 mag,r′~18.5 mag and i′~18.0 mag with a signal-to-noise ratio of 10,in agreement with design expectation.The instrumental polarization is measured to be^0.3%in the three bands.Two applications,one to the star-forming cloud IC 5146 and the other to the young variable GM Cep,are presented as demonstrations.
基金supported by the National Science Foundation of China (Grant Nos. 40830957 and 40575006)
文摘This paper systematically summarizes previous measuring methods and observational instruments for the magnitude of dewfall on land surface, analyzes the characteristics of common observational instruments for land surface dewfall, and describes several basic dewfall measurement methods. Moreover, the basic principles of these methods and instruments are interpreted, and their advantages, disadvantages, and applicability are analyzed. Recommendations for the further improvement of these observational instruments and the development of dewfall measuring methods are presented, and new technologies and scientific proposals for exploiting dewfall are elucidated.
文摘A detailed case study of γ-hadron segregation for a ground based atmo- spheric Cherenkov telescope is presented. We have evaluated and compared various supervised machine learning methods such as the Random Forest method, Artificial Neural Network, Linear Discriminant method, Naive Bayes Classifiers, Support Vector Machines as well as the conventional dynamic supercut method by simulating triggering events with the Monte Carlo method and applied the results to a Cherenkov telescope. It is demonstrated that the Random Forest method is the most sensitive machine learning method for γ-hadron segregation.
基金funded by the China National Space Administration(KJSP2023020105)supported by the National Key R&D Program of China(Grant No.2023YFA1608100)+2 种基金the NSFC(Grant No.62227901)the Minor Planet Foundationsupported by the Egyptian Science,Technology&Innovation Funding Authority(STDF)under Grant No.48102.
文摘Near-Earth objects are important not only in studying the early formation of the Solar System,but also because they pose a serious hazard to humanity when they make close approaches to the Earth.Study of their physical properties can provide useful information on their origin,evolution,and hazard to human beings.However,it remains challenging to investigate small,newly discovered,near-Earth objects because of our limited observational window.This investigation seeks to determine the visible colors of near-Earth asteroids(NEAs),perform an initial taxonomic classification based on visible colors and analyze possible correlations between the distribution of taxonomic classification and asteroid size or orbital parameters.Observations were performed in the broadband BVRI Johnson−Cousins photometric system,applied to images from the Yaoan High Precision Telescope and the 1.88 m telescope at the Kottamia Astronomical Observatory.We present new photometric observations of 84 near-Earth asteroids,and classify 80 of them taxonomically,based on their photometric colors.We find that nearly half(46.3%)of the objects in our sample can be classified as S-complex,26.3%as C-complex,6%as D-complex,and 15.0%as X-complex;the remaining belong to the A-or V-types.Additionally,we identify three P-type NEAs in our sample,according to the Tholen scheme.The fractional abundances of the C/X-complex members with absolute magnitude H≥17.0 were more than twice as large as those with H<17.0.However,the fractions of C-and S-complex members with diameters≤1 km and>1 km are nearly equal,while X-complex members tend to have sub-kilometer diameters.In our sample,the C/D-complex objects are predominant among those with a Jovian Tisserand parameter of T_(J)<3.1.These bodies could have a cometary origin.C-and S-complex members account for a considerable proportion of the asteroids that are potentially hazardous.
文摘针对传统扰动观察法在光伏系统最大功率点跟踪(Maximum Power Point Tracking,MPPT)中存在步长选取不能同时兼顾跟踪速度及稳态精度的问题,在可变工作环境下建立起光伏系统最大功率点电压与环境温度和光照强度之间的数学表达式,获得可变环境下光伏系统最大功率点电压值,再将其赋值给小步长扰动观察法。仿真分析结果表明,相比恒定电压-扰动观察法,所提方法具有更快跟踪速度和更高稳态精度。
