The inlfuences of tillage systems on soil carbon （C） stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determi...The inlfuences of tillage systems on soil carbon （C） stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determine the inlfuences of various tillage systems on soil aggregation and aggregate-associated C under wheat （Triticum aestivum L.） and corn （Zea mays L.） double cropping systems in the North China Plain. The experiment was established in 2001, including four treatments：moldboard plow （MP） with residue （MP＋R） and without residue （MP-R）, rotary tillage with residue （RT）, and no-till with residue （NT）. In 2007 soil samples were collected from the 0-5, 5-10, and 10-20 cm depths, and were separated into four aggregate-size classes （〉2 000, 250-2 000, 53-250, and〈53 μm） by wet-sieving method. Aggregate-associated C was determined, and the relationships between total soil C concentration and aggregation-size fractions were examined. The results showed that NT and RT treatments signiifcantly increased the proportion of macroaggregate fractions （〉2 000 and 250-2 000 μm） compared with the MP-R and MP＋R treatments. Averaged across all depths, mean weight diameters of aggregates （MWD） in NT and RT were 47 and 20% higher than that in MP＋R. The concentration of bulk soil organic C was positively correlated with MWD （r=0.98; P=0.024） and macroaggregate fraction （r=0.96; P=0.036） in the 0-5 cm depth. In the 0-20 cm depth, comparing with MP＋R, total C occluded in the〉2 000 μm fraction was increased by 9 and 6%under NT and RT, respectively. We conclude that adoption of conservation tillage system, especially no-till, can increase soil macro-aggregation and total C accumulation in macroaggregates, which may improve soil C sequestration in the intensive agricultural region of the North China Plain.展开更多
由于可再生能源的间歇性特点,储能单元广泛应用于孤岛直流微电网中。为保护储能单元,防止过度充放,需要对储能单元的荷电状态(state of charge,SOC)实行均衡控制,然而各储能单元线路阻抗及容量存在的差异将对SOC均衡造成影响。针对这一...由于可再生能源的间歇性特点,储能单元广泛应用于孤岛直流微电网中。为保护储能单元,防止过度充放,需要对储能单元的荷电状态(state of charge,SOC)实行均衡控制,然而各储能单元线路阻抗及容量存在的差异将对SOC均衡造成影响。针对这一问题,提出了一种基于一致性算法及自适应下垂控制的储能单元SOC均衡控制策略。首先,通过定义电流比例系数,建立了各储能单元下垂系数与SOC之间的函数关系式,实现了储能单元自适应SOC均衡,并通过劳斯判据证明了系统的稳定性。其次,将所提控制策略与其他文献控制方法进行对比,并且考虑了4种不同工况对SOC均衡的影响。最后,通过Matlab/Simulink进行了仿真分析,验证了所提控制策略的有效性。展开更多
本工作以光储氢孤岛直流微电网为研究对象,针对含电/氢混合储能系统的微电网能量流动关系复杂、安全稳定运行要求高的特点,在深入分析系统工作模式的基础上,提出了考虑蓄电池荷电状态(state of charge,SOC)和储氢罐荷氢状态(state of hy...本工作以光储氢孤岛直流微电网为研究对象,针对含电/氢混合储能系统的微电网能量流动关系复杂、安全稳定运行要求高的特点,在深入分析系统工作模式的基础上,提出了考虑蓄电池荷电状态(state of charge,SOC)和储氢罐荷氢状态(state of hydrogen,SOH)融合的分层协调控制策略。该协调控制策略能够协调光伏发电单元工作在最大功率跟踪和负载功率跟踪双模式;电解制氢单元能够自动切除和投入运行,且投入运行时能够在最小功率工作点、最大效率工作点和最大功率工作点3种模式之间自适应切换;燃料电池单元自动介入运行补充微电网的功率缺额;负载按照优先级自动投切;蓄电池荷电状态和储氢罐荷氢状态处于合理工作范围,实现了微电网优化可靠运行。不同工况下的仿真结果验证了所提协调控制策略的正确性和有效性。展开更多
为了准确估计动力电池的SOC(state of charge)值,研究一种基于改进长短期记忆(LSTM)的新能源汽车动力电池SOC联合估计方法。分析不同因素对新能源汽车动力电池SOC的影响。基于此,构建基于卷积神经网络(CNN)-LSTM估计模型,以实现电池SOC...为了准确估计动力电池的SOC(state of charge)值,研究一种基于改进长短期记忆(LSTM)的新能源汽车动力电池SOC联合估计方法。分析不同因素对新能源汽车动力电池SOC的影响。基于此,构建基于卷积神经网络(CNN)-LSTM估计模型,以实现电池SOC联合估计。结果表明,改进后的LSTM训练均方误差更小,说明改进后LSTM拟合程度更好,具有实用性。展开更多
基金funded by the National Natural Science Foundation of China(31000250)the National 973 Program of China(2009CB118607)
文摘The inlfuences of tillage systems on soil carbon （C） stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determine the inlfuences of various tillage systems on soil aggregation and aggregate-associated C under wheat （Triticum aestivum L.） and corn （Zea mays L.） double cropping systems in the North China Plain. The experiment was established in 2001, including four treatments：moldboard plow （MP） with residue （MP＋R） and without residue （MP-R）, rotary tillage with residue （RT）, and no-till with residue （NT）. In 2007 soil samples were collected from the 0-5, 5-10, and 10-20 cm depths, and were separated into four aggregate-size classes （〉2 000, 250-2 000, 53-250, and〈53 μm） by wet-sieving method. Aggregate-associated C was determined, and the relationships between total soil C concentration and aggregation-size fractions were examined. The results showed that NT and RT treatments signiifcantly increased the proportion of macroaggregate fractions （〉2 000 and 250-2 000 μm） compared with the MP-R and MP＋R treatments. Averaged across all depths, mean weight diameters of aggregates （MWD） in NT and RT were 47 and 20% higher than that in MP＋R. The concentration of bulk soil organic C was positively correlated with MWD （r=0.98; P=0.024） and macroaggregate fraction （r=0.96; P=0.036） in the 0-5 cm depth. In the 0-20 cm depth, comparing with MP＋R, total C occluded in the〉2 000 μm fraction was increased by 9 and 6%under NT and RT, respectively. We conclude that adoption of conservation tillage system, especially no-till, can increase soil macro-aggregation and total C accumulation in macroaggregates, which may improve soil C sequestration in the intensive agricultural region of the North China Plain.
文摘由于可再生能源的间歇性特点,储能单元广泛应用于孤岛直流微电网中。为保护储能单元,防止过度充放,需要对储能单元的荷电状态(state of charge,SOC)实行均衡控制,然而各储能单元线路阻抗及容量存在的差异将对SOC均衡造成影响。针对这一问题,提出了一种基于一致性算法及自适应下垂控制的储能单元SOC均衡控制策略。首先,通过定义电流比例系数,建立了各储能单元下垂系数与SOC之间的函数关系式,实现了储能单元自适应SOC均衡,并通过劳斯判据证明了系统的稳定性。其次,将所提控制策略与其他文献控制方法进行对比,并且考虑了4种不同工况对SOC均衡的影响。最后,通过Matlab/Simulink进行了仿真分析,验证了所提控制策略的有效性。
文摘本工作以光储氢孤岛直流微电网为研究对象,针对含电/氢混合储能系统的微电网能量流动关系复杂、安全稳定运行要求高的特点,在深入分析系统工作模式的基础上,提出了考虑蓄电池荷电状态(state of charge,SOC)和储氢罐荷氢状态(state of hydrogen,SOH)融合的分层协调控制策略。该协调控制策略能够协调光伏发电单元工作在最大功率跟踪和负载功率跟踪双模式;电解制氢单元能够自动切除和投入运行,且投入运行时能够在最小功率工作点、最大效率工作点和最大功率工作点3种模式之间自适应切换;燃料电池单元自动介入运行补充微电网的功率缺额;负载按照优先级自动投切;蓄电池荷电状态和储氢罐荷氢状态处于合理工作范围,实现了微电网优化可靠运行。不同工况下的仿真结果验证了所提协调控制策略的正确性和有效性。
文摘为了准确估计动力电池的SOC(state of charge)值,研究一种基于改进长短期记忆(LSTM)的新能源汽车动力电池SOC联合估计方法。分析不同因素对新能源汽车动力电池SOC的影响。基于此,构建基于卷积神经网络(CNN)-LSTM估计模型,以实现电池SOC联合估计。结果表明,改进后的LSTM训练均方误差更小,说明改进后LSTM拟合程度更好,具有实用性。
