当光伏电池被阴影遮挡时,最大功率对应电压会出现偏移,导致传统算法追踪过程显得繁复,为解决传统最大功率点追踪(maximum power point tracking,MPPT)算法在进行功率判断时所存在的判断速度以及准确性方面的问题,提出在扰动观察法基础...当光伏电池被阴影遮挡时,最大功率对应电压会出现偏移,导致传统算法追踪过程显得繁复,为解决传统最大功率点追踪(maximum power point tracking,MPPT)算法在进行功率判断时所存在的判断速度以及准确性方面的问题,提出在扰动观察法基础上加入全局比较算法(global comparison algorithm,GCA),该算法通过检测光伏电池短时间内由开路至短路过程的功率变化来进行最大功率点追踪。根据光伏电池的伏安特性设计四种不同光照强度及阴影遮挡的环境,采用光伏实验平台以及DC-DC升压电路对算法可靠性进行实验研究。结果表明:全局比较算法的加入可以有效提升扰动观察法在不同程度阴影及不同光照强度条件下追踪最大功率的时效性及可靠性,且在一个遮挡周期内,发电效率可提升5%以上。展开更多
当光伏组件受到局部阴影遮挡时,其最大功率点跟踪(maximum power point tracking,MPPT)过程常出现误跟踪、跟踪速度慢、光伏组件输出功率低等问题.为使局部阴影下光伏组件保持快速、稳定、准确地最大功率输出,基于电导增量法(incrementa...当光伏组件受到局部阴影遮挡时,其最大功率点跟踪(maximum power point tracking,MPPT)过程常出现误跟踪、跟踪速度慢、光伏组件输出功率低等问题.为使局部阴影下光伏组件保持快速、稳定、准确地最大功率输出,基于电导增量法(incremental conductance algorithm,INC),结合全局比较算法(global comparison algorithm,GCA),提出一种基于电导增量/全局比较的复合MPPT算法(INC-GCA),并通过搭建Simulink仿真模型和设计光伏试验平台,验证该算法的可行性.结果表明:基于电导增量/全局比较的复合MPPT算法在光伏组件受到局部阴影遮挡时可准确追踪到最大功率,且跟踪速度快、可靠性高,完全避免了误跟踪问题;相较于电导增量法,该算法可有效提高光伏系统的发电效率,提升光伏电站的经济效益.展开更多
Subject to the homogeneous Neumann boundary condition, a ratio-dependent predator-prey reaction diffusion model is discussed. An improved result for the model is derived, that is, the unique positive constant steady s...Subject to the homogeneous Neumann boundary condition, a ratio-dependent predator-prey reaction diffusion model is discussed. An improved result for the model is derived, that is, the unique positive constant steady state is the global stability. This is done using the comparison principle and establishing iteration schemes involving positive solutions supremum and infimum. The result indicates that the two species will ultimately distribute homogeneously in space. In fact, the comparison argument and iteration technique to be used in this paper can be applied to some other models. This method deals with the not-existence of a non-constant positive steady state for some reaction diffusion systems, which is rather simple but sufficiently effective.展开更多
文摘当光伏电池被阴影遮挡时,最大功率对应电压会出现偏移,导致传统算法追踪过程显得繁复,为解决传统最大功率点追踪(maximum power point tracking,MPPT)算法在进行功率判断时所存在的判断速度以及准确性方面的问题,提出在扰动观察法基础上加入全局比较算法(global comparison algorithm,GCA),该算法通过检测光伏电池短时间内由开路至短路过程的功率变化来进行最大功率点追踪。根据光伏电池的伏安特性设计四种不同光照强度及阴影遮挡的环境,采用光伏实验平台以及DC-DC升压电路对算法可靠性进行实验研究。结果表明:全局比较算法的加入可以有效提升扰动观察法在不同程度阴影及不同光照强度条件下追踪最大功率的时效性及可靠性,且在一个遮挡周期内,发电效率可提升5%以上。
文摘当光伏组件受到局部阴影遮挡时,其最大功率点跟踪(maximum power point tracking,MPPT)过程常出现误跟踪、跟踪速度慢、光伏组件输出功率低等问题.为使局部阴影下光伏组件保持快速、稳定、准确地最大功率输出,基于电导增量法(incremental conductance algorithm,INC),结合全局比较算法(global comparison algorithm,GCA),提出一种基于电导增量/全局比较的复合MPPT算法(INC-GCA),并通过搭建Simulink仿真模型和设计光伏试验平台,验证该算法的可行性.结果表明:基于电导增量/全局比较的复合MPPT算法在光伏组件受到局部阴影遮挡时可准确追踪到最大功率,且跟踪速度快、可靠性高,完全避免了误跟踪问题;相较于电导增量法,该算法可有效提高光伏系统的发电效率,提升光伏电站的经济效益.
文摘Subject to the homogeneous Neumann boundary condition, a ratio-dependent predator-prey reaction diffusion model is discussed. An improved result for the model is derived, that is, the unique positive constant steady state is the global stability. This is done using the comparison principle and establishing iteration schemes involving positive solutions supremum and infimum. The result indicates that the two species will ultimately distribute homogeneously in space. In fact, the comparison argument and iteration technique to be used in this paper can be applied to some other models. This method deals with the not-existence of a non-constant positive steady state for some reaction diffusion systems, which is rather simple but sufficiently effective.
