A signifcant challenge in the progress and development of Building-Integrated-Photovoltaic(B-I-PV)systems is concerned with the extraction of maximum power from PV modules.The PV system archtecture is an essential fea...A signifcant challenge in the progress and development of Building-Integrated-Photovoltaic(B-I-PV)systems is concerned with the extraction of maximum power from PV modules.The PV system archtecture is an essential feature to extract the maximum power.The conventional PV-centralinverter architecture consists of various connections among the PV modules,which are sensitive to shading effects and pro-duces mismatching power loss under partial shading conditions(PSCs),Hence,photovoltaic-distributed-maximum power point tracking(PV-D-MPPT)architecture has been proposed to extract the maximum power.In.PV-1 D-MPPT architecture,the output terminals of DC-DC converters are connected either in series or parallel configuration.The main limitation of the series configuration in open-loop MPPT control is the crosscoupling effect.Because of cross-coupling effects,the maximum-power-point(M-P-P)operation of shaded PV modules is lost under PSCs.The lost in M-P-P operation of shaded PV module also affects the unshaded modules M-P-P operation.Under crosscoupling ffeets,the DC-DC converters are consuming the power instead of delivering to the load.Despite the research activity,there are hardly any papers presenting a clear,comprehensive and mathematical analysis on the existence of cross-couplings in PV string-integrated-converters(S-1-Cs).This article presents a mathematical analysis and also explains the conditions for the existent of cross-coupling ffeets.The experimental results also validate with the mathematically analysed results.This article also discusses the modeling of the two-diode model of PV module,design of boost type S-1C,and the Perturb and Observe(P&O)MPPT algorithm implementation.展开更多
A massive earthquake measuring 9.0 on the Richter scale that occurred on March 11, 2011, on Honshu Island, Japan, caused radioactivity leakage from the Fukushima Nuclear Power Plant, which led to the leakage of artifi...A massive earthquake measuring 9.0 on the Richter scale that occurred on March 11, 2011, on Honshu Island, Japan, caused radioactivity leakage from the Fukushima Nuclear Power Plant, which led to the leakage of artificial nuclides(131I, 137 Cs, and 134Cs) and their global transportation by atmospheric circulation. This paper reports a systematic comparative observation on radioactive concentrations of natural nuclides(7Be and 210Pb) and artificial nuclides(131I, 137 Cs, and 134Cs) at the surface level, measured in weekly continuous aerosol sampling at Mount Guanfeng, Guiyang, China, from March 17, 2011 to April 28, 2011. During this period, the variations in the nuclide concentrations associated with their transport paths were analyzed with 315 hour back-trajectories of air mass initialized 500 m above the surface level at Guiyang. The results show that the pollutants of nuclear leakage from the Fukushima accident were transported to the Guiyang region of China via two significant pathways. In the first pathway the first wave of nuclear pollutants were transported from west to east in air masses at higher altitudes via global atmospheric circulation. The nuclear pollutants encircled the Earth almost once and after about 10 days to two weeks, between March 24 and March 31, 2011, intruded Guiyang from the northwestern region of China. In the second pathway, the nuclear pollutants from the Fukushima region arrived at Guiyang between April 7 and April 14, 2011, via air masses at lower altitudes that moved southwards because of the squeezing of the northeast Asian weather system and then by the influence, in succession, of the northeastern and southeastern air currents in the low-latitude region. The first transport pathway for atmospheric pollutants is on a global scale and based on air masses at higher altitudes, and the second transport pathway is on an eastern Asia regional scale and based on the air masses at lower altitude.展开更多
文摘A signifcant challenge in the progress and development of Building-Integrated-Photovoltaic(B-I-PV)systems is concerned with the extraction of maximum power from PV modules.The PV system archtecture is an essential feature to extract the maximum power.The conventional PV-centralinverter architecture consists of various connections among the PV modules,which are sensitive to shading effects and pro-duces mismatching power loss under partial shading conditions(PSCs),Hence,photovoltaic-distributed-maximum power point tracking(PV-D-MPPT)architecture has been proposed to extract the maximum power.In.PV-1 D-MPPT architecture,the output terminals of DC-DC converters are connected either in series or parallel configuration.The main limitation of the series configuration in open-loop MPPT control is the crosscoupling effect.Because of cross-coupling effects,the maximum-power-point(M-P-P)operation of shaded PV modules is lost under PSCs.The lost in M-P-P operation of shaded PV module also affects the unshaded modules M-P-P operation.Under crosscoupling ffeets,the DC-DC converters are consuming the power instead of delivering to the load.Despite the research activity,there are hardly any papers presenting a clear,comprehensive and mathematical analysis on the existence of cross-couplings in PV string-integrated-converters(S-1-Cs).This article presents a mathematical analysis and also explains the conditions for the existent of cross-coupling ffeets.The experimental results also validate with the mathematically analysed results.This article also discusses the modeling of the two-diode model of PV module,design of boost type S-1C,and the Perturb and Observe(P&O)MPPT algorithm implementation.
基金financially supported jointly by National Natural Science Foundation of China(Grant No.41175115)the EML of the United States of America
文摘A massive earthquake measuring 9.0 on the Richter scale that occurred on March 11, 2011, on Honshu Island, Japan, caused radioactivity leakage from the Fukushima Nuclear Power Plant, which led to the leakage of artificial nuclides(131I, 137 Cs, and 134Cs) and their global transportation by atmospheric circulation. This paper reports a systematic comparative observation on radioactive concentrations of natural nuclides(7Be and 210Pb) and artificial nuclides(131I, 137 Cs, and 134Cs) at the surface level, measured in weekly continuous aerosol sampling at Mount Guanfeng, Guiyang, China, from March 17, 2011 to April 28, 2011. During this period, the variations in the nuclide concentrations associated with their transport paths were analyzed with 315 hour back-trajectories of air mass initialized 500 m above the surface level at Guiyang. The results show that the pollutants of nuclear leakage from the Fukushima accident were transported to the Guiyang region of China via two significant pathways. In the first pathway the first wave of nuclear pollutants were transported from west to east in air masses at higher altitudes via global atmospheric circulation. The nuclear pollutants encircled the Earth almost once and after about 10 days to two weeks, between March 24 and March 31, 2011, intruded Guiyang from the northwestern region of China. In the second pathway, the nuclear pollutants from the Fukushima region arrived at Guiyang between April 7 and April 14, 2011, via air masses at lower altitudes that moved southwards because of the squeezing of the northeast Asian weather system and then by the influence, in succession, of the northeastern and southeastern air currents in the low-latitude region. The first transport pathway for atmospheric pollutants is on a global scale and based on air masses at higher altitudes, and the second transport pathway is on an eastern Asia regional scale and based on the air masses at lower altitude.
