The local time dependence of the geomagnetic disturbances during magnetic storms indicates the necessity of forecasting the localized magnetic storm indices.For the first time,we construct prediction models for the Su...The local time dependence of the geomagnetic disturbances during magnetic storms indicates the necessity of forecasting the localized magnetic storm indices.For the first time,we construct prediction models for the SuperMAG partial ring current indices(SMR-LT),with the advance time increasing from 1 h to 12 h by Long Short-Term Memory(LSTM)neural network.Generally,the prediction performance decreases with the advance time and is better for the SMR-06 index than for the SMR-00,SMR-12,and SMR-18 index.For the predictions with 12 h ahead,the correlation coefficient is 0.738,0.608,0.665,and 0.613,respectively.To avoid the over-represented effect of massive data during geomagnetic quiet periods,only the data during magnetic storms are used to train and test our models,and the improvement in prediction metrics increases with the advance time.For example,for predicting the storm-time SMR-06 index with 12 h ahead,the correlation coefficient and the prediction efficiency increases from 0.674 to 0.691,and from 0.349 to 0.455,respectively.The evaluation of the model performance for forecasting the storm intensity shows that the relative error for intense storms is usually less than the relative error for moderate storms.展开更多
本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证...本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证明,磁暴环电流增强期间环电流的变化速度,不仅取决于行星际磁场南向分量和太阳风的速度,还取决于太阳风的动压,而且太阳风的动压起着非常重要的作用.研究还发现,采用Burton et al.(1975)方程和O′Brien,McPherron (2000a)方程估算得到的2000年10月5日的两次地磁活动的强度远低于实际的观测值.展开更多
针对传统谐振控制器与PI控制器并联(PIR)无法克服积分环节饱和等因素引起的系统动态过程中超调震荡问题,提出了一种改进双环自抗扰谐振控制器(dual-loop active disturbance rejection control,DLADRC)。DLADRC速度环与电流环均采用自...针对传统谐振控制器与PI控制器并联(PIR)无法克服积分环节饱和等因素引起的系统动态过程中超调震荡问题,提出了一种改进双环自抗扰谐振控制器(dual-loop active disturbance rejection control,DLADRC)。DLADRC速度环与电流环均采用自抗扰控制,速度环采用传统的自抗扰控制。电流环采用一种改进的谐振扩张状态观测器,将观测电流作为谐振控制器的输入,令谐振控制器的输出直接作用到电流环输出,从而降低了谐振电流环设计的复杂性。双环自抗扰谐振控制器保留了谐振控制器抑制特定频率谐波电流的特性,同时优化了系统的超调量与调节时间,有效提升了谐振控制系统的动态性能。仿真结果验证DLADRC系统的有效性。展开更多
基金Supported by National Natural Science Foundation of China grants(42022032,41874203,42188101)project of Civil Aerospace"13 th Five Year Plan"Preliminary Research in Space Science(D020301,D030202),Strategic Priority Research Program of CAS(XDA17010301)+1 种基金Key Research Program of Frontier Sciences CAS(QYZDJ-SSW-JSC028)International Partner-National Program of CAS(183311KYSB20200017)。
文摘The local time dependence of the geomagnetic disturbances during magnetic storms indicates the necessity of forecasting the localized magnetic storm indices.For the first time,we construct prediction models for the SuperMAG partial ring current indices(SMR-LT),with the advance time increasing from 1 h to 12 h by Long Short-Term Memory(LSTM)neural network.Generally,the prediction performance decreases with the advance time and is better for the SMR-06 index than for the SMR-00,SMR-12,and SMR-18 index.For the predictions with 12 h ahead,the correlation coefficient is 0.738,0.608,0.665,and 0.613,respectively.To avoid the over-represented effect of massive data during geomagnetic quiet periods,only the data during magnetic storms are used to train and test our models,and the improvement in prediction metrics increases with the advance time.For example,for predicting the storm-time SMR-06 index with 12 h ahead,the correlation coefficient and the prediction efficiency increases from 0.674 to 0.691,and from 0.349 to 0.455,respectively.The evaluation of the model performance for forecasting the storm intensity shows that the relative error for intense storms is usually less than the relative error for moderate storms.
文摘本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证明,磁暴环电流增强期间环电流的变化速度,不仅取决于行星际磁场南向分量和太阳风的速度,还取决于太阳风的动压,而且太阳风的动压起着非常重要的作用.研究还发现,采用Burton et al.(1975)方程和O′Brien,McPherron (2000a)方程估算得到的2000年10月5日的两次地磁活动的强度远低于实际的观测值.
文摘针对传统谐振控制器与PI控制器并联(PIR)无法克服积分环节饱和等因素引起的系统动态过程中超调震荡问题,提出了一种改进双环自抗扰谐振控制器(dual-loop active disturbance rejection control,DLADRC)。DLADRC速度环与电流环均采用自抗扰控制,速度环采用传统的自抗扰控制。电流环采用一种改进的谐振扩张状态观测器,将观测电流作为谐振控制器的输入,令谐振控制器的输出直接作用到电流环输出,从而降低了谐振电流环设计的复杂性。双环自抗扰谐振控制器保留了谐振控制器抑制特定频率谐波电流的特性,同时优化了系统的超调量与调节时间,有效提升了谐振控制系统的动态性能。仿真结果验证DLADRC系统的有效性。
