In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the m...In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the mirror image theory.Combined with the distribution of the underwater electric potential measured in laboratory,an electric dipole model for physical scale of ship was established and the distribution characteristics of an actual ship' s corrosion related magnetic field were obtained.Based on established models,theoretical analysis and calculation were made to catch out the distribution characteristics of static magnetic field related with corrosion and anticorrosion,which can not be measured directly in seawater.The results show that the static magnetic field related with corrosion and anticorrosion is a kind of noteworthy obstacle signal for degaussed ships.展开更多
静止变频器(static frequency converter,SFC)是抽水蓄能电站大型同步机组启动过程的重要设备。在抽蓄机组启动的过程中,由于SFC机、网两侧电流频率不一致,使得基于工频相量的常规差动保护配置困难,且现有保护方案在速动性和可靠性上存...静止变频器(static frequency converter,SFC)是抽水蓄能电站大型同步机组启动过程的重要设备。在抽蓄机组启动的过程中,由于SFC机、网两侧电流频率不一致,使得基于工频相量的常规差动保护配置困难,且现有保护方案在速动性和可靠性上存在不足。为解决上述问题,提出了一种基于模型校核的SFC采样值差动保护原理。首先充分研究SFC的工作原理和控制策略,并基于电流采样值在时域内构建符合SFC工作原理的数学模型,然后采用模型校核的方法寻找故障前后差异并提出相应的保护判据。最后,在PSCAD/EMTDC中搭建抽蓄机组SFC启动的电磁暂态仿真模型,验证所提保护原理的有效性。仿真结果表明,所提保护原理不受SFC两侧不同频率的干扰,具有良好的选择性、速动性和可靠性。展开更多
针对一种适用于斜坡极点平衡的自平衡机器人,提出了一种递推最小二乘法参数辨识和模型预测控制(Recursive least squares and model predictive control, RLS-MPC)相结合的方法,以实现自平衡机器人在不同斜坡极点的静态平衡控制。该方...针对一种适用于斜坡极点平衡的自平衡机器人,提出了一种递推最小二乘法参数辨识和模型预测控制(Recursive least squares and model predictive control, RLS-MPC)相结合的方法,以实现自平衡机器人在不同斜坡极点的静态平衡控制。该方法使用递推最小二乘(Recursive least squares,RLS)法辨识系统状态参数,并与模型预测控制(Model predictive control, MPC)方法相结合,解决了自平衡机器人在斜坡极点平衡时状态参数未知的控制问题。同时,对闭环系统进行了基于Lyapunov的稳定性分析。最后通过与线性二次调节器(Linear quadratic regulator, LQR)和MPC方法进行数值仿真对比和性能指标对比,结果表明所提出的RLS-MPC控制方法相较于传统的LQR和MPC方法,不仅趋于稳定时间短,而且精度更高,能有效地改善自平衡机器人的控制性能。展开更多
基金Sponsored by National Defense Pre-research Foundation(51444070105JB11)
文摘In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the mirror image theory.Combined with the distribution of the underwater electric potential measured in laboratory,an electric dipole model for physical scale of ship was established and the distribution characteristics of an actual ship' s corrosion related magnetic field were obtained.Based on established models,theoretical analysis and calculation were made to catch out the distribution characteristics of static magnetic field related with corrosion and anticorrosion,which can not be measured directly in seawater.The results show that the static magnetic field related with corrosion and anticorrosion is a kind of noteworthy obstacle signal for degaussed ships.
文摘静止变频器(static frequency converter,SFC)是抽水蓄能电站大型同步机组启动过程的重要设备。在抽蓄机组启动的过程中,由于SFC机、网两侧电流频率不一致,使得基于工频相量的常规差动保护配置困难,且现有保护方案在速动性和可靠性上存在不足。为解决上述问题,提出了一种基于模型校核的SFC采样值差动保护原理。首先充分研究SFC的工作原理和控制策略,并基于电流采样值在时域内构建符合SFC工作原理的数学模型,然后采用模型校核的方法寻找故障前后差异并提出相应的保护判据。最后,在PSCAD/EMTDC中搭建抽蓄机组SFC启动的电磁暂态仿真模型,验证所提保护原理的有效性。仿真结果表明,所提保护原理不受SFC两侧不同频率的干扰,具有良好的选择性、速动性和可靠性。
文摘针对一种适用于斜坡极点平衡的自平衡机器人,提出了一种递推最小二乘法参数辨识和模型预测控制(Recursive least squares and model predictive control, RLS-MPC)相结合的方法,以实现自平衡机器人在不同斜坡极点的静态平衡控制。该方法使用递推最小二乘(Recursive least squares,RLS)法辨识系统状态参数,并与模型预测控制(Model predictive control, MPC)方法相结合,解决了自平衡机器人在斜坡极点平衡时状态参数未知的控制问题。同时,对闭环系统进行了基于Lyapunov的稳定性分析。最后通过与线性二次调节器(Linear quadratic regulator, LQR)和MPC方法进行数值仿真对比和性能指标对比,结果表明所提出的RLS-MPC控制方法相较于传统的LQR和MPC方法,不仅趋于稳定时间短,而且精度更高,能有效地改善自平衡机器人的控制性能。
