阻尼振荡的GNF统一潮流控制器设计

在现代电力系统中,统一潮流控制器(UPFC)是调节电压和潮流的有效手段。该文提出一种用遗传算法优化参数的基于径向函数单一神经元的神经网络(RBFNN)和TS模糊控制策略综合而成的统一潮流控制器设计方案,TS模糊控制策略应用非线性规则设计了更为有效的控制器,使用RBFNN避免了产生控制器的训练样本,同时利用GA全局优化TS模糊控制的参数,从而提高系统的暂态稳定性。经验证,该方案比传统的PI控制策略具有更好的系统振荡阻尼性能。     

统一潮流控制器的GNF控制策略设计

统一潮流控制器UPFC(Unified Power Flow Controller)是现代电力系统中调节电压和潮流的有效手段。提出了一种由径向基函数神经网络RBFNN(Radial Basic Function Neuro-Network)和TS(Takagi-Sugeno)模糊控制策略综合而成的统一潮流控制器控制策略设计方案,即遗传神经模糊综合控制GNF(Genetic Neural Fuzzy)。利用TS模糊控制策略实时更新RBFNN参数,同时采用多机系统中的转速信号ITAE指数作为适应度函数。利用遗传算法GA(Genetic Algorithm)优化TS模糊控制策略系数以及辅助阻尼信号参数．提高了系统的暂态稳定性。经验证,该方案比传统的PI控制策略具有更好的系统振荡阻尼性能,改善了系统的动态品质。     

Microstructure and properties of high-fraction graphite nanoflakes/6061Al matrix composites fabricated via spark plasma sintering

30–50 wt.% graphite nanoflakes (GNFs)/6061Al matrix composites were fabricated via spark plasma sintering (SPS) at 610 °C. The effects of the sintering pressure and GNF content on the microstructure and properties of the composites were investigated. The results indicated that interfacial reactions were inhibited during SPS because no Al₄C₃ was detected. Moreover, the agglomeration of the GNFs increased, and the distribution orientation of the GNFs decreased with increasing the GNF content. The relative density, bending strength, and coefficient of thermal expansion (CTE) of the composites decreased, while the thermal conductivity (TC) in the X?Y direction increased. As the sintering pressure increased, the GNFs deagglomerated and were distributed preferentially in the X?Y direction, which increased the relative density, bending strength and TC, and decreased the CTE of the composites. The 50wt.%GNFs/6061Al matrix composite sintered at 610 °C under 55 MPa demonstrated the best performance, i.e., bending strength of 72 MPa, TC and CTE (RT?100 °C) of 254 W/(m·K) and 8.5×10^?6 K^?1 in the X?Y direction, and 55 W/(m·K) and 9.7×10^?6 K^?1 in the Z direction, respectively.