建立了光伏电池数学模型,研究了其在不同光照模式下的非线性。在此基础上建立了多片光伏板组成的电池阵列模型,研究了其输出功率的多峰值特性。针对传统最大功率点跟踪(Maximum Power Point Tracking, MPPT)算法无法有效跟踪控制多峰值...建立了光伏电池数学模型,研究了其在不同光照模式下的非线性。在此基础上建立了多片光伏板组成的电池阵列模型,研究了其输出功率的多峰值特性。针对传统最大功率点跟踪(Maximum Power Point Tracking, MPPT)算法无法有效跟踪控制多峰值的问题,研究了改进粒子群算法的MPPT,通过粒子群在历史最佳位置和所有粒子中找到全局最优位置。实验结果表明,该算法能够有效解决传统算法无法解决的复杂多峰值问题,并且具有更高的追踪效率和适应性。展开更多
一类改进的最优转矩(optimal torque, OT)法通过扩大风力机最大功率点跟踪(maximum power point tracking, MPPT)过程中的不平衡转矩来提升转速跟踪能力,进而捕获更多风能。然而,此类方法在提高风能捕获效率的同时会造成电磁转矩的频繁...一类改进的最优转矩(optimal torque, OT)法通过扩大风力机最大功率点跟踪(maximum power point tracking, MPPT)过程中的不平衡转矩来提升转速跟踪能力,进而捕获更多风能。然而,此类方法在提高风能捕获效率的同时会造成电磁转矩的频繁波动,导致风力机传动链载荷显著提升。针对这一问题,文中研究发现在风速变化下补偿转矩引起的额外电磁转矩波动是产生上述现象的主要原因。为此,文中提出一种考虑载荷影响的风力机加速OT法,在风速变化时通过利用恒转矩过渡阶段抑制额外的电磁转矩波动,提升MPPT过程中的转速跟踪能力,从而实现在提升风力机风能捕获效率的同时尽可能避免载荷增大。最后,仿真结果验证表明,文中所提加速OT法不仅可以提升不同风况下的风能捕获效率,而且能够有效抑制传动链载荷的上升。展开更多
局部阴影条件下,光伏阵列的P-U曲线呈多峰状态,常规的最大功率点追踪MPPT(maximum power point tracking)算法容易陷入局部极值,无法及时精确地跟踪光伏发电系统的最大功率点,针对此问题提出1种基于改进蜣螂IDBO(improved dung beetle o...局部阴影条件下,光伏阵列的P-U曲线呈多峰状态,常规的最大功率点追踪MPPT(maximum power point tracking)算法容易陷入局部极值,无法及时精确地跟踪光伏发电系统的最大功率点,针对此问题提出1种基于改进蜣螂IDBO(improved dung beetle optimizer)算法的MPPT控制策略。首先对蜣螂种群的初始化进行针对性优化,并在位置更新过程中引入Levy飞行策略。通过在MATLAB/Simulink平台进行仿真验证及实物实验验证,证明了IDBO算法相较于传统算法,无论是在静态还是动态条件下,均能更快且更稳定地找到全局最大功率点。展开更多
针对传统扰动观察法在光伏系统最大功率点跟踪(Maximum Power Point Tracking,MPPT)中存在步长选取不能同时兼顾跟踪速度及稳态精度的问题,在可变工作环境下建立起光伏系统最大功率点电压与环境温度和光照强度之间的数学表达式,获得可...针对传统扰动观察法在光伏系统最大功率点跟踪(Maximum Power Point Tracking,MPPT)中存在步长选取不能同时兼顾跟踪速度及稳态精度的问题,在可变工作环境下建立起光伏系统最大功率点电压与环境温度和光照强度之间的数学表达式,获得可变环境下光伏系统最大功率点电压值,再将其赋值给小步长扰动观察法。仿真分析结果表明,相比恒定电压-扰动观察法,所提方法具有更快跟踪速度和更高稳态精度。展开更多
光伏系统在局部遮阴条件下,系统输出功率呈现多峰值现象,使用传统的最大功率追踪(maximum power point tracking,MPPT)方法对其进行追踪时存在追踪精度低的缺点。针对该问题提出一种改进粒子群算法的MPPT方法。该方法使用拉丁超立方抽...光伏系统在局部遮阴条件下,系统输出功率呈现多峰值现象,使用传统的最大功率追踪(maximum power point tracking,MPPT)方法对其进行追踪时存在追踪精度低的缺点。针对该问题提出一种改进粒子群算法的MPPT方法。该方法使用拉丁超立方抽样初始化种群代替粒子群算法中随机初始化种群,保证初始化的种群更加均匀。同时使用自适应权重代替固定权重,更好地平衡粒子群的探索和开发能力,避免算法过早地陷入局部最优解。在Matlab/Simulink中搭建光伏系统MPPT仿真模型,通过均匀光照、静态遮阴光照和动态遮阴光照3种情况下的仿真对比,所提的改进粒子群优化算法比扰动观察法和粒子群优化算法有更好的追踪精度,验证所提算法在光伏MPPT控制中的有效性。展开更多
We study a finite number of independent random walks with subexponentially distributed increments and negative drifts.We extend the one-dimensional results to finite and fully general stopping times.Assuming that the ...We study a finite number of independent random walks with subexponentially distributed increments and negative drifts.We extend the one-dimensional results to finite and fully general stopping times.Assuming that the distribution of the lengths of these intervals is relatively light compared to the distribution of the increments of the random walks,we derive the asymptotic tail distribution of the partial maximum sum over the random time interval.展开更多
Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and ...Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and voltage distortion that degrade energy yield and power quality.We propose a drift-aware,power-quality-constrained MPPT framework that co-optimizes MPPT,PLL,and current-loop gains under stochastic frequency drift,while enforcing IEEE-519 limits(per-order Ih/IL and TDD)during optimization.Unlike energy-only or THD-only methods,the design target integrates PQ constraints into the objective and is validated across calibrated drift scenarios with explicit per-order and TDD reporting.Operating scenarios are calibrated to Cameroon’s Southern Interconnected Grid and city-specific profiles(Douala/Yaoundé),combining measured-style irradiance/temperature traces,partial-shading patterns,and stochastic frequency drift up to±0.8 Hz with synthetic contingencies.Across a 30-scenario campaign,the proposed controller achievesηMPPT=99.3%–99.6%(vs.98.6%Incremental Conductance and 97.8%Perturb-and-Observe),lowers DC-link ripple by 35%–48%,reduces oscillatory PCC power by≈41%,maintains THD≤2.5%(5%limit)and PF≥0.99,and shortens irradiance-step settling from 85–110 ms to 50–65 ms.Sensitivity to PLL bandwidth shows a broad optimum(≈60–90 Hz)with minimum THD/ripple,and ablations confirm that explicit drift weighting is pivotal to ripple and THD suppression without sacrificing yield.The approach is controller-agnostic,firmware-deployable,and generalizes to other converter-interfaced renewables;we outline a short hardware-/HIL-validation path for adoption in Sub-Saharan grids.展开更多
为了契合绿色可再生能源发展理念,自供电环境能量收集系统已逐渐成为替代传统电池的高效解决方案,可克服传统电池在重量、尺寸及循环寿命等方面的局限性。针对压电源的时变特性,设计了一种基于其特性的快速最大功率点跟踪(Maximum Power...为了契合绿色可再生能源发展理念,自供电环境能量收集系统已逐渐成为替代传统电池的高效解决方案,可克服传统电池在重量、尺寸及循环寿命等方面的局限性。针对压电源的时变特性,设计了一种基于其特性的快速最大功率点跟踪(Maximum Power Point Tracking,MPPT)电路架构。对压电源的阻抗特性进行分析,采用了基于快速开关电容采样的开路电压采样MPPT算法,有效实现跟踪精度和动态响应速度的协同优化。最后,基于0.18μm BCD工艺对电路进行设计,仿真结果表明:MPPT的跟踪时间为0.36 ms,最大追踪精度可达99.4%。展开更多
An injective k-edge coloring of a graph G is k-edge coloringκof G such thatκ(e1)≠κ(e3)for any three consecutive edges ei,e2 and e3 of a path or a triangle.The injective chromatic index of G,denoted by x'i(G),i...An injective k-edge coloring of a graph G is k-edge coloringκof G such thatκ(e1)≠κ(e3)for any three consecutive edges ei,e2 and e3 of a path or a triangle.The injective chromatic index of G,denoted by x'i(G),is the smallest integer k such that G has an injective k-edge coloring.In this paper,we prove that x'i(G)≤9 if G is a planar graph with maximum degreeΔ≤4,girth g≥6 and without intersecting 6-cycles.展开更多
文摘建立了光伏电池数学模型,研究了其在不同光照模式下的非线性。在此基础上建立了多片光伏板组成的电池阵列模型,研究了其输出功率的多峰值特性。针对传统最大功率点跟踪(Maximum Power Point Tracking, MPPT)算法无法有效跟踪控制多峰值的问题,研究了改进粒子群算法的MPPT,通过粒子群在历史最佳位置和所有粒子中找到全局最优位置。实验结果表明,该算法能够有效解决传统算法无法解决的复杂多峰值问题,并且具有更高的追踪效率和适应性。
文摘一类改进的最优转矩(optimal torque, OT)法通过扩大风力机最大功率点跟踪(maximum power point tracking, MPPT)过程中的不平衡转矩来提升转速跟踪能力,进而捕获更多风能。然而,此类方法在提高风能捕获效率的同时会造成电磁转矩的频繁波动,导致风力机传动链载荷显著提升。针对这一问题,文中研究发现在风速变化下补偿转矩引起的额外电磁转矩波动是产生上述现象的主要原因。为此,文中提出一种考虑载荷影响的风力机加速OT法,在风速变化时通过利用恒转矩过渡阶段抑制额外的电磁转矩波动,提升MPPT过程中的转速跟踪能力,从而实现在提升风力机风能捕获效率的同时尽可能避免载荷增大。最后,仿真结果验证表明,文中所提加速OT法不仅可以提升不同风况下的风能捕获效率,而且能够有效抑制传动链载荷的上升。
文摘局部阴影条件下,光伏阵列的P-U曲线呈多峰状态,常规的最大功率点追踪MPPT(maximum power point tracking)算法容易陷入局部极值,无法及时精确地跟踪光伏发电系统的最大功率点,针对此问题提出1种基于改进蜣螂IDBO(improved dung beetle optimizer)算法的MPPT控制策略。首先对蜣螂种群的初始化进行针对性优化,并在位置更新过程中引入Levy飞行策略。通过在MATLAB/Simulink平台进行仿真验证及实物实验验证,证明了IDBO算法相较于传统算法,无论是在静态还是动态条件下,均能更快且更稳定地找到全局最大功率点。
文摘针对传统扰动观察法在光伏系统最大功率点跟踪(Maximum Power Point Tracking,MPPT)中存在步长选取不能同时兼顾跟踪速度及稳态精度的问题,在可变工作环境下建立起光伏系统最大功率点电压与环境温度和光照强度之间的数学表达式,获得可变环境下光伏系统最大功率点电压值,再将其赋值给小步长扰动观察法。仿真分析结果表明,相比恒定电压-扰动观察法,所提方法具有更快跟踪速度和更高稳态精度。
文摘光伏系统在局部遮阴条件下,系统输出功率呈现多峰值现象,使用传统的最大功率追踪(maximum power point tracking,MPPT)方法对其进行追踪时存在追踪精度低的缺点。针对该问题提出一种改进粒子群算法的MPPT方法。该方法使用拉丁超立方抽样初始化种群代替粒子群算法中随机初始化种群,保证初始化的种群更加均匀。同时使用自适应权重代替固定权重,更好地平衡粒子群的探索和开发能力,避免算法过早地陷入局部最优解。在Matlab/Simulink中搭建光伏系统MPPT仿真模型,通过均匀光照、静态遮阴光照和动态遮阴光照3种情况下的仿真对比,所提的改进粒子群优化算法比扰动观察法和粒子群优化算法有更好的追踪精度,验证所提算法在光伏MPPT控制中的有效性。
基金supported by Xinjiang Normal University Outstanding Young Teacher Research Launch Fund Project(Grant No.XJNU202116)。
文摘We study a finite number of independent random walks with subexponentially distributed increments and negative drifts.We extend the one-dimensional results to finite and fully general stopping times.Assuming that the distribution of the lengths of these intervals is relatively light compared to the distribution of the increments of the random walks,we derive the asymptotic tail distribution of the partial maximum sum over the random time interval.
基金Deanship of Research and Graduate Studies at King Khalid University for funding this work through the Large Research Project(Grant No.RGP2/587/46).
文摘Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and voltage distortion that degrade energy yield and power quality.We propose a drift-aware,power-quality-constrained MPPT framework that co-optimizes MPPT,PLL,and current-loop gains under stochastic frequency drift,while enforcing IEEE-519 limits(per-order Ih/IL and TDD)during optimization.Unlike energy-only or THD-only methods,the design target integrates PQ constraints into the objective and is validated across calibrated drift scenarios with explicit per-order and TDD reporting.Operating scenarios are calibrated to Cameroon’s Southern Interconnected Grid and city-specific profiles(Douala/Yaoundé),combining measured-style irradiance/temperature traces,partial-shading patterns,and stochastic frequency drift up to±0.8 Hz with synthetic contingencies.Across a 30-scenario campaign,the proposed controller achievesηMPPT=99.3%–99.6%(vs.98.6%Incremental Conductance and 97.8%Perturb-and-Observe),lowers DC-link ripple by 35%–48%,reduces oscillatory PCC power by≈41%,maintains THD≤2.5%(5%limit)and PF≥0.99,and shortens irradiance-step settling from 85–110 ms to 50–65 ms.Sensitivity to PLL bandwidth shows a broad optimum(≈60–90 Hz)with minimum THD/ripple,and ablations confirm that explicit drift weighting is pivotal to ripple and THD suppression without sacrificing yield.The approach is controller-agnostic,firmware-deployable,and generalizes to other converter-interfaced renewables;we outline a short hardware-/HIL-validation path for adoption in Sub-Saharan grids.
文摘为了契合绿色可再生能源发展理念,自供电环境能量收集系统已逐渐成为替代传统电池的高效解决方案,可克服传统电池在重量、尺寸及循环寿命等方面的局限性。针对压电源的时变特性,设计了一种基于其特性的快速最大功率点跟踪(Maximum Power Point Tracking,MPPT)电路架构。对压电源的阻抗特性进行分析,采用了基于快速开关电容采样的开路电压采样MPPT算法,有效实现跟踪精度和动态响应速度的协同优化。最后,基于0.18μm BCD工艺对电路进行设计,仿真结果表明:MPPT的跟踪时间为0.36 ms,最大追踪精度可达99.4%。
基金Supported by the National Natural Science Foundation of China(Grant Nos.12071265,12001481)the Natural Science Foundation of Shandong Province(Grant No.ZR2021MA103)the Youth Innovation Team Project of Shandong Province Universities(Grant No.2024KJG078).
文摘An injective k-edge coloring of a graph G is k-edge coloringκof G such thatκ(e1)≠κ(e3)for any three consecutive edges ei,e2 and e3 of a path or a triangle.The injective chromatic index of G,denoted by x'i(G),is the smallest integer k such that G has an injective k-edge coloring.In this paper,we prove that x'i(G)≤9 if G is a planar graph with maximum degreeΔ≤4,girth g≥6 and without intersecting 6-cycles.
