Currently, the production and the number of installations of PV （photovoltaic） modules have been increasing rapidly because of a feed-in tariff in Japan. Accordingly, the number of failures has also increased. Many ...Currently, the production and the number of installations of PV （photovoltaic） modules have been increasing rapidly because of a feed-in tariff in Japan. Accordingly, the number of failures has also increased. Many failures are a result of the Hot-Spot phenomenon in which defective cell becomes hot when shadow occurs on the cell, On the other hand, if shadow occurs on normal cell, there are cases that P＆O method that is MPPT （maximum power point tracking） control method incorporated in conventional PV system cannot track maximum power point and generated power decreases. The correspondence is required rapidly if these trouble occur. However, conventional PV system monitors generated power, correspondence is impossible by monitoring generated power. Previously, the authors developed real time Hot-Spot detection system that incorporates into PCS （power conditioning system）. Thus, the authors developed plug-in type Hot-Spot monitoring system that includes ＂PV peak shift method＂ and confirmed effectiveness of the system in this time. ＂PV peak shift method＂ loads ＂Scan method＂ that is MPPT control method and measures I-V （current-voltage） characteristic by changing voltage of module from open to short by ＂Scan method＂ on a regular basis. The developed Hot-Spot monitoring system uses slope of I-V characteristic of PV module. Inserting developed system into already installed PV system, Hot-Spot can be easily monitored in real time and PV system can be operated at maximum power point.展开更多
Lunar Laser Ranging has extremely high requirements for the pointing accuracy of the telescopes used.To improve its pointing accuracy and solve the problem of insufficiently accurate telescope pointing correction achi...Lunar Laser Ranging has extremely high requirements for the pointing accuracy of the telescopes used.To improve its pointing accuracy and solve the problem of insufficiently accurate telescope pointing correction achieved by tracking stars in the all-sky region,we propose a processing scheme to select larger-sized lunar craters near the Lunar Corner Cube Retroreflector as reference features for telescope pointing bias computation.Accurately determining the position of the craters in the images is crucial for calculating the pointing bias;therefore,we propose a method for accurately calculating the crater position based on lunar surface feature matching.This method uses matched feature points obtained from image feature matching,using a deep learning method to solve the image transformation matrix.The known position of a crater in a reference image is mapped using this matrix to calculate the crater position in the target image.We validate this method using craters near the Lunar Corner Cube Retroreflectors of Apollo 15 and Luna 17 and find that the calculated position of a crater on the target image falls on the center of the crater,even for image features with large distortion near the lunar limb.The maximum image matching error is approximately 1″,and the minimum is only 0.47″,which meets the pointing requirements of Lunar Laser Ranging.This method provides a new technical means for the high-precision pointing bias calculation of the Lunar Laser Ranging system.展开更多
The maximum power point of PV （photovoltaic） generation moves depending on weather conditions and load. Therefore, it is significant to make sure that the panels can work at the maximum power point under MPPT （maxi...The maximum power point of PV （photovoltaic） generation moves depending on weather conditions and load. Therefore, it is significant to make sure that the panels can work at the maximum power point under MPPT （maximum power point tracking） control. However, it has the problems of low efficiency and unstable operation when panels are covered by the partial shadow. The result is that the output power may be substantially decreased. To overcome this issue, the authors propose a new plug-in operation point correction system. This system is put between PV panels and PCS （power conditioning system） in the existing PV generation system. In this paper, the experimental results describe that the output electric energy increases approximately 1.4 times as compared with the conventional system when the proposed correction system is inserted.展开更多
The beam pointing is the most crucial issue for beam combining to achieve high energy laser output. In order to meet the turbulence situation, a beam pointing method that cooperates with the stochastic parallel gradie...The beam pointing is the most crucial issue for beam combining to achieve high energy laser output. In order to meet the turbulence situation, a beam pointing method that cooperates with the stochastic parallel gradient descent(SPGD) algorithm is proposed. The power-in-the-bucket(PIB) is chosen as the merit function, and its radius changes gradually during the correction process. The linear radius and the exponential radius are simulated. The results show that the exponential radius has great promise for beam pointing.展开更多
Here is reported an iteration method, which corrects the coordinates of an underwater moving target obtained by a hyperbolic locating system with a short-baseline plane array when the sound velocity varies with depth....Here is reported an iteration method, which corrects the coordinates of an underwater moving target obtained by a hyperbolic locating system with a short-baseline plane array when the sound velocity varies with depth. A series of differential difference equations are used for determining the iterative values. The calculated results show that under the same conditions, the location error is about several meters or tens of meters without correction and less than 0.5 m with correction. The method can be applied to various types of arrays.展开更多
文摘Currently, the production and the number of installations of PV （photovoltaic） modules have been increasing rapidly because of a feed-in tariff in Japan. Accordingly, the number of failures has also increased. Many failures are a result of the Hot-Spot phenomenon in which defective cell becomes hot when shadow occurs on the cell, On the other hand, if shadow occurs on normal cell, there are cases that P＆O method that is MPPT （maximum power point tracking） control method incorporated in conventional PV system cannot track maximum power point and generated power decreases. The correspondence is required rapidly if these trouble occur. However, conventional PV system monitors generated power, correspondence is impossible by monitoring generated power. Previously, the authors developed real time Hot-Spot detection system that incorporates into PCS （power conditioning system）. Thus, the authors developed plug-in type Hot-Spot monitoring system that includes ＂PV peak shift method＂ and confirmed effectiveness of the system in this time. ＂PV peak shift method＂ loads ＂Scan method＂ that is MPPT control method and measures I-V （current-voltage） characteristic by changing voltage of module from open to short by ＂Scan method＂ on a regular basis. The developed Hot-Spot monitoring system uses slope of I-V characteristic of PV module. Inserting developed system into already installed PV system, Hot-Spot can be easily monitored in real time and PV system can be operated at maximum power point.
基金funded by Natural Science Foundation of Jilin Province(20220101125JC)the National Natural Science Foundation of China(12273079).
文摘Lunar Laser Ranging has extremely high requirements for the pointing accuracy of the telescopes used.To improve its pointing accuracy and solve the problem of insufficiently accurate telescope pointing correction achieved by tracking stars in the all-sky region,we propose a processing scheme to select larger-sized lunar craters near the Lunar Corner Cube Retroreflector as reference features for telescope pointing bias computation.Accurately determining the position of the craters in the images is crucial for calculating the pointing bias;therefore,we propose a method for accurately calculating the crater position based on lunar surface feature matching.This method uses matched feature points obtained from image feature matching,using a deep learning method to solve the image transformation matrix.The known position of a crater in a reference image is mapped using this matrix to calculate the crater position in the target image.We validate this method using craters near the Lunar Corner Cube Retroreflectors of Apollo 15 and Luna 17 and find that the calculated position of a crater on the target image falls on the center of the crater,even for image features with large distortion near the lunar limb.The maximum image matching error is approximately 1″,and the minimum is only 0.47″,which meets the pointing requirements of Lunar Laser Ranging.This method provides a new technical means for the high-precision pointing bias calculation of the Lunar Laser Ranging system.
文摘The maximum power point of PV （photovoltaic） generation moves depending on weather conditions and load. Therefore, it is significant to make sure that the panels can work at the maximum power point under MPPT （maximum power point tracking） control. However, it has the problems of low efficiency and unstable operation when panels are covered by the partial shadow. The result is that the output power may be substantially decreased. To overcome this issue, the authors propose a new plug-in operation point correction system. This system is put between PV panels and PCS （power conditioning system） in the existing PV generation system. In this paper, the experimental results describe that the output electric energy increases approximately 1.4 times as compared with the conventional system when the proposed correction system is inserted.
基金supported by the Changchun Technology Project(No.2013270)
文摘The beam pointing is the most crucial issue for beam combining to achieve high energy laser output. In order to meet the turbulence situation, a beam pointing method that cooperates with the stochastic parallel gradient descent(SPGD) algorithm is proposed. The power-in-the-bucket(PIB) is chosen as the merit function, and its radius changes gradually during the correction process. The linear radius and the exponential radius are simulated. The results show that the exponential radius has great promise for beam pointing.
文摘Here is reported an iteration method, which corrects the coordinates of an underwater moving target obtained by a hyperbolic locating system with a short-baseline plane array when the sound velocity varies with depth. A series of differential difference equations are used for determining the iterative values. The calculated results show that under the same conditions, the location error is about several meters or tens of meters without correction and less than 0.5 m with correction. The method can be applied to various types of arrays.
