An optimal dimension-down iterative algorithm （DDIA） is proposed for solving a mixed （continuous/ discrete） transportation network design problem （MNDP）, which is generally expressed as a mathematical programmin...An optimal dimension-down iterative algorithm （DDIA） is proposed for solving a mixed （continuous/ discrete） transportation network design problem （MNDP）, which is generally expressed as a mathematical programming with equilibrium constraints （MPEC）. The upper level of the MNDP aims to optimize the network performance via both the expansion of existing links and the addition of new candidate links, whereas the lower level is a traditional Wardrop user equilibrium （UE） model. The idea of the proposed DDIA is to reduce the dimensions of the problem. A group of variables （discrete/continuous） are fixed to altemately optimize another group of variables （continuous/discrete）. Some continuous network design problems （CNDPs） and discrete network design problems （DNDPs） are solved repeatedly until the optimal solution is obtained. A numerical example is given to demonstrate the efficiency of the proposed algorithm.展开更多
针对多源配电网运行面临的供电电压不合格和运行经济性欠优的问题,该文提出了基于改进两阶段鲁棒优化的主动配电网经济调度策略。首先,量化分析了全电驱动的移动式储能(mobile energy storage,MES)的时空转移特性,评估了基于变频空调的...针对多源配电网运行面临的供电电压不合格和运行经济性欠优的问题,该文提出了基于改进两阶段鲁棒优化的主动配电网经济调度策略。首先,量化分析了全电驱动的移动式储能(mobile energy storage,MES)的时空转移特性,评估了基于变频空调的建筑虚拟储能(virtual energy storage,VES)的调节能力,建立统一的多类型储能模型。进而,考虑预测误差,通过离散不确定域,改进现有的鲁棒优化方法,获得更加精确的"最恶劣"场景。在此基础上,针对优化模型中的min-max-min结构,提出了主–子问题交互迭代的求解方法。基于41节点配网的仿真结果表明,采用改进两阶段鲁棒优化模型的主动配电网经济调度切实可行,相应的求解算法具有高效性。该方法为配电网安全、经济运行提供了一个崭新的视角。展开更多
A comparison of arithmetic operations of two dynamic process optimization approaches called quasi-sequential approach and reduced Sequential Quadratic Programming(rSQP)simultaneous approach with respect to equality co...A comparison of arithmetic operations of two dynamic process optimization approaches called quasi-sequential approach and reduced Sequential Quadratic Programming(rSQP)simultaneous approach with respect to equality constrained optimization problems is presented.Through the detail comparison of arithmetic operations,it is concluded that the average iteration number within differential algebraic equations(DAEs)integration of quasi-sequential approach could be regarded as a criterion.One formula is given to calculate the threshold value of average iteration number.If the average iteration number is less than the threshold value,quasi-sequential approach takes advantage of rSQP simultaneous approach which is more suitable contrarily.Two optimal control problems are given to demonstrate the usage of threshold value.For optimal control problems whose objective is to stay near desired operating point,the iteration number is usually small.Therefore,quasi-sequential approach seems more suitable for such problems.展开更多
基金The National Natural Science Foundation of China(No. 50908235 )China Postdoctoral Science Foundation (No.201003520)
文摘An optimal dimension-down iterative algorithm （DDIA） is proposed for solving a mixed （continuous/ discrete） transportation network design problem （MNDP）, which is generally expressed as a mathematical programming with equilibrium constraints （MPEC）. The upper level of the MNDP aims to optimize the network performance via both the expansion of existing links and the addition of new candidate links, whereas the lower level is a traditional Wardrop user equilibrium （UE） model. The idea of the proposed DDIA is to reduce the dimensions of the problem. A group of variables （discrete/continuous） are fixed to altemately optimize another group of variables （continuous/discrete）. Some continuous network design problems （CNDPs） and discrete network design problems （DNDPs） are solved repeatedly until the optimal solution is obtained. A numerical example is given to demonstrate the efficiency of the proposed algorithm.
文摘针对多源配电网运行面临的供电电压不合格和运行经济性欠优的问题,该文提出了基于改进两阶段鲁棒优化的主动配电网经济调度策略。首先,量化分析了全电驱动的移动式储能(mobile energy storage,MES)的时空转移特性,评估了基于变频空调的建筑虚拟储能(virtual energy storage,VES)的调节能力,建立统一的多类型储能模型。进而,考虑预测误差,通过离散不确定域,改进现有的鲁棒优化方法,获得更加精确的"最恶劣"场景。在此基础上,针对优化模型中的min-max-min结构,提出了主–子问题交互迭代的求解方法。基于41节点配网的仿真结果表明,采用改进两阶段鲁棒优化模型的主动配电网经济调度切实可行,相应的求解算法具有高效性。该方法为配电网安全、经济运行提供了一个崭新的视角。
基金Supported by the National Natural Science Foundation of China（20676117） the National Creative Research Groups Science Foundation of China（60421002）
文摘A comparison of arithmetic operations of two dynamic process optimization approaches called quasi-sequential approach and reduced Sequential Quadratic Programming(rSQP)simultaneous approach with respect to equality constrained optimization problems is presented.Through the detail comparison of arithmetic operations,it is concluded that the average iteration number within differential algebraic equations(DAEs)integration of quasi-sequential approach could be regarded as a criterion.One formula is given to calculate the threshold value of average iteration number.If the average iteration number is less than the threshold value,quasi-sequential approach takes advantage of rSQP simultaneous approach which is more suitable contrarily.Two optimal control problems are given to demonstrate the usage of threshold value.For optimal control problems whose objective is to stay near desired operating point,the iteration number is usually small.Therefore,quasi-sequential approach seems more suitable for such problems.
