It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentra...It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>展开更多
为保证燃料电池系统在负载工况变化条件下仍能无扰动地运行在最大效率点,提出一种基于遗忘因子递推最小二乘(forgetting factor recursive least square,FFRLS)在线辨识和Super-Twisting滑模算法的燃料电池系统实时最大效率跟踪方法。...为保证燃料电池系统在负载工况变化条件下仍能无扰动地运行在最大效率点,提出一种基于遗忘因子递推最小二乘(forgetting factor recursive least square,FFRLS)在线辨识和Super-Twisting滑模算法的燃料电池系统实时最大效率跟踪方法。该方法基于非线性曲线拟合原理,根据系统实时测量数据,在单位控制周期内实现对燃料电池最大效率点功率的实时估计。采用Super-Twisting滑模算法,保证燃料电池系统在负载工况变化情况下仍能运行在最大效率点。在搭建的测试平台上,开展了多指标性能测试与对比分析。实验结果表明,与扰动观测(perturb and observe,P&O)算法相比,所提出的方法优势更加明显。另外,针对燃料电池输出存在大扰动问题,与PID控制效果进行了对比实验。实验结果显示:Super-Twisting滑模控制变换器在输入电压大扰动下具有较强的鲁棒性,有利于燃料电池系统长期稳定运行。展开更多
The overall performance of photovoltaic （PV） inverter imphes many different technical issues.One of the key criterias is based on the measurement of the conversion and the maximum power point tracking （MPPT） effic...The overall performance of photovoltaic （PV） inverter imphes many different technical issues.One of the key criterias is based on the measurement of the conversion and the maximum power point tracking （MPPT） efficiency and its applicable evaluation in practice.Intense work has been done in the last few years to formulate applicable standards for measuring static and dynamic efficiencies worldwide.Besides that,this work is presenting on novel methods of analysis on non-trivial system characteristics impacting the final evaluation on the overall performance of the PV inverter.The elaborated testing procedures for complex system behavior under highly nonlinear conditions （unintentional partial shading, mismatching of DC strings） are explained and characterized.With the help of experimental results, the exclusive impact on the overall efficiency is illustrated and helpful statements are given on the resulting technical characteristics of MPP strategies.展开更多
The efficiency of photovoltaic power generation is affected by the changeable weather conditions. This paper improves the efficiency of a standalone PV system over a wider range of operating conditions by employing no...The efficiency of photovoltaic power generation is affected by the changeable weather conditions. This paper improves the efficiency of a standalone PV system over a wider range of operating conditions by employing novel switch adaptive control to an interleaved boost converter. With various loads, simulation and experimental results show that the interleaved boost converter with novel switch adaptive control offers better performance and higher conversion efficiency under changeable weather conditions.展开更多
DC-DC boost power converters play an important role in solar power systems;they step up the input voltage of a solar array for a given set of conditions. This paper presents an overview of the variance boost converter...DC-DC boost power converters play an important role in solar power systems;they step up the input voltage of a solar array for a given set of conditions. This paper presents an overview of the variance boost converter topologies. Each boost converter is evaluated on its capability to operate efficient, size, and cost of implementation. Conventional boost converter and interleaved boost converter are widely used topologies in photovoltaic systems reported;however, they have negative sides of varied efficiency level under changed weather conditions. Therefore, this paper proposes, interleaved boost converter with novel switch adaptive control, to maximise efficiency of standalone photovoltaic system under change of solar power levels, due to illadation condition.展开更多
文摘It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>
文摘为保证燃料电池系统在负载工况变化条件下仍能无扰动地运行在最大效率点,提出一种基于遗忘因子递推最小二乘(forgetting factor recursive least square,FFRLS)在线辨识和Super-Twisting滑模算法的燃料电池系统实时最大效率跟踪方法。该方法基于非线性曲线拟合原理,根据系统实时测量数据,在单位控制周期内实现对燃料电池最大效率点功率的实时估计。采用Super-Twisting滑模算法,保证燃料电池系统在负载工况变化情况下仍能运行在最大效率点。在搭建的测试平台上,开展了多指标性能测试与对比分析。实验结果表明,与扰动观测(perturb and observe,P&O)算法相比,所提出的方法优势更加明显。另外,针对燃料电池输出存在大扰动问题,与PID控制效果进行了对比实验。实验结果显示:Super-Twisting滑模控制变换器在输入电压大扰动下具有较强的鲁棒性,有利于燃料电池系统长期稳定运行。
文摘The overall performance of photovoltaic （PV） inverter imphes many different technical issues.One of the key criterias is based on the measurement of the conversion and the maximum power point tracking （MPPT） efficiency and its applicable evaluation in practice.Intense work has been done in the last few years to formulate applicable standards for measuring static and dynamic efficiencies worldwide.Besides that,this work is presenting on novel methods of analysis on non-trivial system characteristics impacting the final evaluation on the overall performance of the PV inverter.The elaborated testing procedures for complex system behavior under highly nonlinear conditions （unintentional partial shading, mismatching of DC strings） are explained and characterized.With the help of experimental results, the exclusive impact on the overall efficiency is illustrated and helpful statements are given on the resulting technical characteristics of MPP strategies.
文摘The efficiency of photovoltaic power generation is affected by the changeable weather conditions. This paper improves the efficiency of a standalone PV system over a wider range of operating conditions by employing novel switch adaptive control to an interleaved boost converter. With various loads, simulation and experimental results show that the interleaved boost converter with novel switch adaptive control offers better performance and higher conversion efficiency under changeable weather conditions.
文摘DC-DC boost power converters play an important role in solar power systems;they step up the input voltage of a solar array for a given set of conditions. This paper presents an overview of the variance boost converter topologies. Each boost converter is evaluated on its capability to operate efficient, size, and cost of implementation. Conventional boost converter and interleaved boost converter are widely used topologies in photovoltaic systems reported;however, they have negative sides of varied efficiency level under changed weather conditions. Therefore, this paper proposes, interleaved boost converter with novel switch adaptive control, to maximise efficiency of standalone photovoltaic system under change of solar power levels, due to illadation condition.
