In this paper,a flexible modular“Tetris”microsatellite platform is studied to implement the rapid integration and assembly of microsatellites.The proposed microsatellite platform is fulfilled based on a sandwich ass...In this paper,a flexible modular“Tetris”microsatellite platform is studied to implement the rapid integration and assembly of microsatellites.The proposed microsatellite platform is fulfilled based on a sandwich assembly mode which consists of the isomorphic module structure and the standard mechanical-electric-data-thermal interfaces.The advantages of the sandwich assembly mode include flexible reconfiguration and efficient assembly.The prototype of the sandwich assembly mode is built for verifying the performance and the feasibility of the proposed mechanical-electric-data-thermal interfaces.Finally,an assembly case is accomplished to demonstrate the validity and advantages of the proposed“Tetris”microsatellite platform.展开更多
The reconstruction control of modular self-reconfigurable spacecraft (MSRS) is addressed using an adaptive sliding mode control (ASMC) scheme based on time-delay estimation (TDE) technology. In contrast to the ground,...The reconstruction control of modular self-reconfigurable spacecraft (MSRS) is addressed using an adaptive sliding mode control (ASMC) scheme based on time-delay estimation (TDE) technology. In contrast to the ground, the base of the MSRS is floating when assembled in orbit, resulting in a strong dynamic coupling effect. A TED-based ASMC technique with exponential reaching law is designed to achieve high-precision coordinated control between the spacecraft base and the robotic arm. TDE technology is used by the controller to compensate for coupling terms and uncertainties, while ASMC can augment and improve TDE’s robustness. To suppress TDE errors and eliminate chattering, a new adaptive law is created to modify gain parameters online, ensuring quick dynamic response and high tracking accuracy. The Lyapunov approach shows that the tracking errors are uniformly ultimately bounded (UUB). Finally, the on-orbit assembly process of MSRS is simulated to validate the efficacy of the proposed control scheme. The simulation results show that the proposed control method can accurately complete the target module’s on-orbit assembly, with minimal perturbations to the spacecraft’s attitude. Meanwhile, it has a high level of robustness and can effectively eliminate chattering.展开更多
为了研究模块化多电平换流器(modular multilevel converter,MMC)在嵌入储能系统(battery energy storage system,BESS)后内部动态特性的变化规律,对MMC-BESS的运行特性进行了详细分析,并提出了一种桥臂级平均值模型(arm average model,...为了研究模块化多电平换流器(modular multilevel converter,MMC)在嵌入储能系统(battery energy storage system,BESS)后内部动态特性的变化规律,对MMC-BESS的运行特性进行了详细分析,并提出了一种桥臂级平均值模型(arm average model,AAM)进行验证。首先,在假设桥臂中各储能子模块状态一致的前提下,将离散环节连续化,并根据电路特性方程构建了MMC-BESS的AAM电路模型。然后,根据交流端、直流端以及储能端之间的功率关系对MMC-BESS的运行模式进行划分,建立了桥臂电流与电池功率之间的关系,并对电池功率不均衡状态下的桥臂电流进行了分析。最后,利用Matlab/Simulink分别搭建了MMC-BESS的开关模型和AAM模型,并基于AAM验证了多种工况下的桥臂电流响应。仿真结果表明,AAM在显著提高仿真效率的同时可保证较高的准确性,电池功率的大小与均衡状况对桥臂电流的成分有较大影响。展开更多
基于模块化多电平换流器的静止同步补偿器(stationary synchronous compensator based on modular multilevel converters,MMC-STATCOM)是高压电力系统中无功补偿的关键设备,其传统线性控制器性能会因运行点的大范围变化而恶化。针对该...基于模块化多电平换流器的静止同步补偿器(stationary synchronous compensator based on modular multilevel converters,MMC-STATCOM)是高压电力系统中无功补偿的关键设备,其传统线性控制器性能会因运行点的大范围变化而恶化。针对该问题,该文提出了一种基于滑模状态反馈精确线性化的非线性智能控制策略,首先通过选择合适的输出函数、坐标变换,将不做任何简化的3阶MMC-STATCOM非线性模型转化为一个可控的Brunovsky标准型线性系统,并通过数学理论证明了该模型满足精确线性化条件。然后采用改进的粒子群算法配置其反馈增益矩阵,利用积分滑模控制计算其平衡点。最后通过状态反馈使各个状态变量快速收敛至平衡点。将该控制策略与传统PI控制、LQR状态反馈控制通过硬件在环实时仿真平台进行对比实验,结果表明该控制策略具有更好的动态特性、暂态稳定性、鲁棒性,尤其适用于运行环境发生大扰动时。此外,该控制策略的设计过程可以拓展应用于其他类型的柔性交流输电装置。展开更多
针对多端柔性直流电网(multi-terminal direct current grid based on modular multilevel converter,MMC-MTDC)故障诊断存在的人工整定阈值过程复杂、高阻故障不易检测的问题,提出一种基于行波特征的诊断方法。首先,通过分析系统的故...针对多端柔性直流电网(multi-terminal direct current grid based on modular multilevel converter,MMC-MTDC)故障诊断存在的人工整定阈值过程复杂、高阻故障不易检测的问题,提出一种基于行波特征的诊断方法。首先,通过分析系统的故障特征,得出边界元件对高频信号的阻滞作用;其次,利用经验模态分解(empirical mode decomposition,EMD)对功率进行分解,得到本征模态函数(intrinsic mode function,IMF)分量,将其能量值作为故障特征量训练由卷积神经网络(convolutional neural network,CNN)和双向门控循环单元(bidirectional gated recurrent unit,BiGRU)组成的CNN-BiGRU网络;然后,采用开普勒优化算法(Kepler optimization algorithm,KOA)和注意力机制(attention mechanism,AM)对CNN-BiGRU网络进行改进,实现MMC-MTDC的故障诊断;最后,在PSCAD/EMTDC中搭建仿真模型。结果表明,该方法不仅可以实现母线故障和线路故障的检测,还可以在满足保护可靠性和速动性的前提下,解决高阻故障保护易拒动的问题。展开更多
该文提出一种基于波动功率解耦的模块化多电平换流器(ripple-power decoupling based modular multilevel converter,RPD-MMC)电机调速系统,通过半桥与变压器结构的高频链将子模块(submodule,SM)隔离后进行横向互联,实现三相波动功率在S...该文提出一种基于波动功率解耦的模块化多电平换流器(ripple-power decoupling based modular multilevel converter,RPD-MMC)电机调速系统,通过半桥与变压器结构的高频链将子模块(submodule,SM)隔离后进行横向互联,实现三相波动功率在SM电容中的解耦,进而消除共模电压(common-mode voltage,CMV)低频波动分量;并提出一种脉冲优化控制CPS-SPWM(pulse optimization control CPS-SPWM,POC-CPS-SPWM)策略,控制任一时刻MMC三相的上、下桥臂导通SM个数保持一致,消除CMV高频波动分量,最终实现对CMV的完全消除。该文从CMV的机理与特性分析出发,分别对低频与高频抑制的方案提出、原理分析与效果实现进行探讨,最后通过仿真与实验,验证CMV机理分析与两种策略消除CMV的可行性与有效性。展开更多
为增强模块化多电平换流器(modular multilevel converter,MMC)在电网不平衡条件下的系统性能,该文提出一种分数阶积分滑模控制(fractional order integral sliding mode control,FO‐I‐SMC)策略。首先,分析MMC的拓扑结构,并推导出正...为增强模块化多电平换流器(modular multilevel converter,MMC)在电网不平衡条件下的系统性能,该文提出一种分数阶积分滑模控制(fractional order integral sliding mode control,FO‐I‐SMC)策略。首先,分析MMC的拓扑结构,并推导出正、负序电压与输出电流的基频外特性方程和正负零序环流的二倍频内特性方程。其次,结合控制目标和MMC的数学模型,设计出应用于电网电压不平衡的分数阶滑模控制器。该控制器旨在降低交流侧输出电流与直流侧环流谐波含量。最后,在MATLAB/Simulink仿真平台建立相应模型,验证该算法的有效性。研究结果证明:采用FO‐I‐SMC控制策略的MMC的系统性能要明显优于采用比例积分(proportional integral,PI)控制策略和积分滑模控制(integral sliding mode control,ISMC)策略的。展开更多
基金supported by the National Natural Science Foundation of China(6210333962073261)+1 种基金Shaanxi Natural Science Basic Research Program(2023-JC-YB-569)the Fundamental Research Funds for the Central Universities。
文摘In this paper,a flexible modular“Tetris”microsatellite platform is studied to implement the rapid integration and assembly of microsatellites.The proposed microsatellite platform is fulfilled based on a sandwich assembly mode which consists of the isomorphic module structure and the standard mechanical-electric-data-thermal interfaces.The advantages of the sandwich assembly mode include flexible reconfiguration and efficient assembly.The prototype of the sandwich assembly mode is built for verifying the performance and the feasibility of the proposed mechanical-electric-data-thermal interfaces.Finally,an assembly case is accomplished to demonstrate the validity and advantages of the proposed“Tetris”microsatellite platform.
基金This study was supported by the National Defense Science and Technology Innovation Zone of China(Grant No.00205501).
文摘The reconstruction control of modular self-reconfigurable spacecraft (MSRS) is addressed using an adaptive sliding mode control (ASMC) scheme based on time-delay estimation (TDE) technology. In contrast to the ground, the base of the MSRS is floating when assembled in orbit, resulting in a strong dynamic coupling effect. A TED-based ASMC technique with exponential reaching law is designed to achieve high-precision coordinated control between the spacecraft base and the robotic arm. TDE technology is used by the controller to compensate for coupling terms and uncertainties, while ASMC can augment and improve TDE’s robustness. To suppress TDE errors and eliminate chattering, a new adaptive law is created to modify gain parameters online, ensuring quick dynamic response and high tracking accuracy. The Lyapunov approach shows that the tracking errors are uniformly ultimately bounded (UUB). Finally, the on-orbit assembly process of MSRS is simulated to validate the efficacy of the proposed control scheme. The simulation results show that the proposed control method can accurately complete the target module’s on-orbit assembly, with minimal perturbations to the spacecraft’s attitude. Meanwhile, it has a high level of robustness and can effectively eliminate chattering.
文摘为了研究模块化多电平换流器(modular multilevel converter,MMC)在嵌入储能系统(battery energy storage system,BESS)后内部动态特性的变化规律,对MMC-BESS的运行特性进行了详细分析,并提出了一种桥臂级平均值模型(arm average model,AAM)进行验证。首先,在假设桥臂中各储能子模块状态一致的前提下,将离散环节连续化,并根据电路特性方程构建了MMC-BESS的AAM电路模型。然后,根据交流端、直流端以及储能端之间的功率关系对MMC-BESS的运行模式进行划分,建立了桥臂电流与电池功率之间的关系,并对电池功率不均衡状态下的桥臂电流进行了分析。最后,利用Matlab/Simulink分别搭建了MMC-BESS的开关模型和AAM模型,并基于AAM验证了多种工况下的桥臂电流响应。仿真结果表明,AAM在显著提高仿真效率的同时可保证较高的准确性,电池功率的大小与均衡状况对桥臂电流的成分有较大影响。
文摘基于模块化多电平换流器的静止同步补偿器(stationary synchronous compensator based on modular multilevel converters,MMC-STATCOM)是高压电力系统中无功补偿的关键设备,其传统线性控制器性能会因运行点的大范围变化而恶化。针对该问题,该文提出了一种基于滑模状态反馈精确线性化的非线性智能控制策略,首先通过选择合适的输出函数、坐标变换,将不做任何简化的3阶MMC-STATCOM非线性模型转化为一个可控的Brunovsky标准型线性系统,并通过数学理论证明了该模型满足精确线性化条件。然后采用改进的粒子群算法配置其反馈增益矩阵,利用积分滑模控制计算其平衡点。最后通过状态反馈使各个状态变量快速收敛至平衡点。将该控制策略与传统PI控制、LQR状态反馈控制通过硬件在环实时仿真平台进行对比实验,结果表明该控制策略具有更好的动态特性、暂态稳定性、鲁棒性,尤其适用于运行环境发生大扰动时。此外,该控制策略的设计过程可以拓展应用于其他类型的柔性交流输电装置。
文摘该文提出一种基于波动功率解耦的模块化多电平换流器(ripple-power decoupling based modular multilevel converter,RPD-MMC)电机调速系统,通过半桥与变压器结构的高频链将子模块(submodule,SM)隔离后进行横向互联,实现三相波动功率在SM电容中的解耦,进而消除共模电压(common-mode voltage,CMV)低频波动分量;并提出一种脉冲优化控制CPS-SPWM(pulse optimization control CPS-SPWM,POC-CPS-SPWM)策略,控制任一时刻MMC三相的上、下桥臂导通SM个数保持一致,消除CMV高频波动分量,最终实现对CMV的完全消除。该文从CMV的机理与特性分析出发,分别对低频与高频抑制的方案提出、原理分析与效果实现进行探讨,最后通过仿真与实验,验证CMV机理分析与两种策略消除CMV的可行性与有效性。
