Vector-to-raster conversion is a process accompanied with errors.The errors are classified into predicted errors before rasterization and actual errors after that.Accurate prediction of the errors is beneficial to dev...Vector-to-raster conversion is a process accompanied with errors.The errors are classified into predicted errors before rasterization and actual errors after that.Accurate prediction of the errors is beneficial to developing reasonable rasterization technical schemes and to making products of high quality.Analyzing and establishing a quantitative relationship between the error and its affecting factors is the key to error prediction.In this study,land cover data of China at a scale of 1:250 000 were taken as an example for analyzing the relationship between rasterization errors and the density of arc length(DA),the density of polygon(DP) and the size of grid cells(SG).Significant correlations were found between the errors and DA,DP and SG.The correlation coefficient(R2) of a model established based on samples collected in a small region(Beijing) reaches 0.95,and the value of R2 is equal to 0.91 while the model was validated with samples from the whole nation.On the other hand,the R2 of a model established based on nationwide samples reaches 0.96,and R2 is equal to 0.91 while it was validated with the samples in Beijing.These models depict well the relationships between rasterization errors and their affecting factors(DA,DP and SG).The analyzing method established in this study can be applied to effectively predicting rasterization errors in other cases as well.展开更多
The paper makes survey of operating principle of power management of photovoltaic system with supercapacitors and a maximum power tracker （MPT） control to achieve the maximum efficiency. Supercapacitors are well sui...The paper makes survey of operating principle of power management of photovoltaic system with supercapacitors and a maximum power tracker （MPT） control to achieve the maximum efficiency. Supercapacitors are well suited to replace classical batteries and conventional capacitors in photovoltaic applications to improve a dynamic behaviors and life-time. It describes the advantages of a supercapacitors solution and shows the results of comparison with convenient batteries. The paper presents different topologies of basic photovoltaic concepts with dc-dc converters and supercapacitors according to the power dimension. The mathematical equations describing the photovoltaic cells, temperature analyses and mathematical solution of MPT are shown in the paper and supported by measurements. The mathematical models were applied in the design of 50 W and 6 kW photovoltaic sources with MPT and supercapacitors. Both models were verified using experimental measurements on the photovoltaic setup.展开更多
In this paper, a PV （photovoltaic） module in renewable energy conversion system is simulated. The simulation of the system is developed using MATLAB/Simulink environments, which can be representative of PV cell, mod...In this paper, a PV （photovoltaic） module in renewable energy conversion system is simulated. The simulation of the system is developed using MATLAB/Simulink environments, which can be representative of PV cell, module and array for easy use on simulation block. The PV model is developed using basic circuit equations of the photovoltaic solar cells including the effects of irradiation and temperature. The output current and power characteristics of PV model are simulated. The results are provided and presented here.展开更多
We characterized a crystalline silicon based mini-module under varying ambient conditions, developed a PSPICE model for this panel, including temperature and irradiation dependence and applied this model to the simula...We characterized a crystalline silicon based mini-module under varying ambient conditions, developed a PSPICE model for this panel, including temperature and irradiation dependence and applied this model to the simulation of the impact of a blocking diode under different shadowing conditions. Different blocking diodes were examined, like germanium and silicon homojunction diodes and silicon Schottky diodes and compared to ＂intelligent＂ diodes, consisting of operational amplifiers with MOSFET switches. The simulations indicate a strongly reduced power loss in a panel integrating the new ＂intelligent＂ blocking diodes even when compared to silicon Schottky diodes, as the best performing traditional blocking diodes.展开更多
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05050000)Special Program for Informatization of Chinese Academy of Sciences(No.INF0-115-C01-SDB3-02)
文摘Vector-to-raster conversion is a process accompanied with errors.The errors are classified into predicted errors before rasterization and actual errors after that.Accurate prediction of the errors is beneficial to developing reasonable rasterization technical schemes and to making products of high quality.Analyzing and establishing a quantitative relationship between the error and its affecting factors is the key to error prediction.In this study,land cover data of China at a scale of 1:250 000 were taken as an example for analyzing the relationship between rasterization errors and the density of arc length(DA),the density of polygon(DP) and the size of grid cells(SG).Significant correlations were found between the errors and DA,DP and SG.The correlation coefficient(R2) of a model established based on samples collected in a small region(Beijing) reaches 0.95,and the value of R2 is equal to 0.91 while the model was validated with samples from the whole nation.On the other hand,the R2 of a model established based on nationwide samples reaches 0.96,and R2 is equal to 0.91 while it was validated with the samples in Beijing.These models depict well the relationships between rasterization errors and their affecting factors(DA,DP and SG).The analyzing method established in this study can be applied to effectively predicting rasterization errors in other cases as well.
文摘The paper makes survey of operating principle of power management of photovoltaic system with supercapacitors and a maximum power tracker （MPT） control to achieve the maximum efficiency. Supercapacitors are well suited to replace classical batteries and conventional capacitors in photovoltaic applications to improve a dynamic behaviors and life-time. It describes the advantages of a supercapacitors solution and shows the results of comparison with convenient batteries. The paper presents different topologies of basic photovoltaic concepts with dc-dc converters and supercapacitors according to the power dimension. The mathematical equations describing the photovoltaic cells, temperature analyses and mathematical solution of MPT are shown in the paper and supported by measurements. The mathematical models were applied in the design of 50 W and 6 kW photovoltaic sources with MPT and supercapacitors. Both models were verified using experimental measurements on the photovoltaic setup.
文摘In this paper, a PV （photovoltaic） module in renewable energy conversion system is simulated. The simulation of the system is developed using MATLAB/Simulink environments, which can be representative of PV cell, module and array for easy use on simulation block. The PV model is developed using basic circuit equations of the photovoltaic solar cells including the effects of irradiation and temperature. The output current and power characteristics of PV model are simulated. The results are provided and presented here.
文摘We characterized a crystalline silicon based mini-module under varying ambient conditions, developed a PSPICE model for this panel, including temperature and irradiation dependence and applied this model to the simulation of the impact of a blocking diode under different shadowing conditions. Different blocking diodes were examined, like germanium and silicon homojunction diodes and silicon Schottky diodes and compared to ＂intelligent＂ diodes, consisting of operational amplifiers with MOSFET switches. The simulations indicate a strongly reduced power loss in a panel integrating the new ＂intelligent＂ blocking diodes even when compared to silicon Schottky diodes, as the best performing traditional blocking diodes.
