The paper presents researches on increasing the energetic ＆ economic efficiency of the photovoltaic （PV） conversion by designing and optimizing a dual-axis tracking mechanism that simultaneously changes the positio...The paper presents researches on increasing the energetic ＆ economic efficiency of the photovoltaic （PV） conversion by designing and optimizing a dual-axis tracking mechanism that simultaneously changes the position of the modules using two motor sources. The driving source for the daily motion is a rotary motor, while the elevation motion is performed with a linear actuator. The main task in optimizing the tracking mechanism is to maximize the energetic gain by increasing the solar input and minimizing the energy consumption for tracking. The design strategy aims to identify the optimum angular field for the daily motion, as well as the optimum actuating time in the step-by-step motion. The study is made by developing the virtual prototype of the tracking mechanism, in the mechatronic concept. The virtual prototyping platform includes the following software solutions： CATIA （Computer Aided Tri-Dimensional Interface Application）--to create the solid model, which contains information about the mass ＆ inertia properties of the parts, ADAMS （Automatic Dynamic Analysis of Mechanical Systems）/View--to model the mechanical structure of the solar tracker, and EASY5 ＆ ADAMS/Controls-for the control system design.展开更多
The front-row shading reduction coefficient is a key parameter used to calculate the system efficiency of a photovoltaic(PV)power station.Based on the Hay anisotropic sky scattering model,the variation rule of solar r...The front-row shading reduction coefficient is a key parameter used to calculate the system efficiency of a photovoltaic(PV)power station.Based on the Hay anisotropic sky scattering model,the variation rule of solar radiation intensity on the surface of the PV array during the shaded period is simulated,combined with the voltage-current characteristics of the PV modules,and the shadow occlusion operating mode of the PV array is modeled.A method for calculating the loss coefficient of front shadow occlusion based on the division of the PV cell string unit and Hay anisotropic sky scattering model is proposed.This algorithm can accurately evaluate the degree of influence of the PV array layout,wiring mode,array spacing,PV module specifications,and solar radiation on PV power station system efficiency.It provides a basis for optimizing the PV array layout,reducing system loss,and improving PV system efficiency.展开更多
Photovoltaic(PV)inverters have been widely used in large-scale PV power generation systems to reduce the system mismatch and increase the output power.With the increasing installed capacity of PV power stations,the nu...Photovoltaic(PV)inverters have been widely used in large-scale PV power generation systems to reduce the system mismatch and increase the output power.With the increasing installed capacity of PV power stations,the number of string PV inverters increases,which brings about risk of inverter resonance and influences the quality and stability of multi-parallel inverters grid-connected system.Thus,the problems of multi-parallel inverters resonance have become a hot research topic.This paper is focused on the case of grid-connected string PV inverter systems,and the grid-connected PV inverter resonance where resonance suppression strategy will be analyzed and discussed.Firstly,the structure of string PV inverter and multi-parallel inverters system are presented.Secondly,discussions are made about the model of multi-parallel inverters system and its resonance characteristics based on the multi-input-multi-output(MIMO)system,Norton equivalent circuit and carrier synchronization.Thirdly,two strategies of^inverter level"and"system level"are provided to summarize the multi-parallel inverters resonance suppression strategy.Finally,the development tendency of resonance suppression strategy and conclusions are prospected.展开更多
文摘The paper presents researches on increasing the energetic ＆ economic efficiency of the photovoltaic （PV） conversion by designing and optimizing a dual-axis tracking mechanism that simultaneously changes the position of the modules using two motor sources. The driving source for the daily motion is a rotary motor, while the elevation motion is performed with a linear actuator. The main task in optimizing the tracking mechanism is to maximize the energetic gain by increasing the solar input and minimizing the energy consumption for tracking. The design strategy aims to identify the optimum angular field for the daily motion, as well as the optimum actuating time in the step-by-step motion. The study is made by developing the virtual prototype of the tracking mechanism, in the mechatronic concept. The virtual prototyping platform includes the following software solutions： CATIA （Computer Aided Tri-Dimensional Interface Application）--to create the solid model, which contains information about the mass ＆ inertia properties of the parts, ADAMS （Automatic Dynamic Analysis of Mechanical Systems）/View--to model the mechanical structure of the solar tracker, and EASY5 ＆ ADAMS/Controls-for the control system design.
基金This work was supported by the Global Energy Interconnection Group Limited Science&Technology Project(Project No.:SGGEIG00JYJS1900046).
文摘The front-row shading reduction coefficient is a key parameter used to calculate the system efficiency of a photovoltaic(PV)power station.Based on the Hay anisotropic sky scattering model,the variation rule of solar radiation intensity on the surface of the PV array during the shaded period is simulated,combined with the voltage-current characteristics of the PV modules,and the shadow occlusion operating mode of the PV array is modeled.A method for calculating the loss coefficient of front shadow occlusion based on the division of the PV cell string unit and Hay anisotropic sky scattering model is proposed.This algorithm can accurately evaluate the degree of influence of the PV array layout,wiring mode,array spacing,PV module specifications,and solar radiation on PV power station system efficiency.It provides a basis for optimizing the PV array layout,reducing system loss,and improving PV system efficiency.
基金the key program of National Natural Science Foundation of China under Grant 51277051。
文摘Photovoltaic(PV)inverters have been widely used in large-scale PV power generation systems to reduce the system mismatch and increase the output power.With the increasing installed capacity of PV power stations,the number of string PV inverters increases,which brings about risk of inverter resonance and influences the quality and stability of multi-parallel inverters grid-connected system.Thus,the problems of multi-parallel inverters resonance have become a hot research topic.This paper is focused on the case of grid-connected string PV inverter systems,and the grid-connected PV inverter resonance where resonance suppression strategy will be analyzed and discussed.Firstly,the structure of string PV inverter and multi-parallel inverters system are presented.Secondly,discussions are made about the model of multi-parallel inverters system and its resonance characteristics based on the multi-input-multi-output(MIMO)system,Norton equivalent circuit and carrier synchronization.Thirdly,two strategies of^inverter level"and"system level"are provided to summarize the multi-parallel inverters resonance suppression strategy.Finally,the development tendency of resonance suppression strategy and conclusions are prospected.
