In order to identify all the appropriate system schemes for the compound split systems formed primarily with a four-port mechanical power split device, power transmission characteristics of the compound split systems ...In order to identify all the appropriate system schemes for the compound split systems formed primarily with a four-port mechanical power split device, power transmission characteristics of the compound split systems was analyzed. Considering the structural symmetry and according to the different connection arrangement of the four ports, compound split system was classified into four types. Using black-box modeling method, the generalized models of the speed ratio, the torque ratio and the power split ratio were established. Moreover, a semi-invert diagram was used to distin- guish the different schemes in each type. The characteristics of the speed ratio, the torque ratio and the power split ratio in each domain were also analyzed and compared. Through the semi-invert dia- gram, a selection method based on the rated-power speed ranges in different schemes was presented and all suitable compound split systems were identified, which can be used as references for the scheme selection of this kind of continuously variable power split transmission.展开更多
Electric furnace short process steelmaking is one of the most important steelmaking methods in the world today, and the waste heat recovery potential of electric furnace flue gas is huge.?The research on the recovery ...Electric furnace short process steelmaking is one of the most important steelmaking methods in the world today, and the waste heat recovery potential of electric furnace flue gas is huge.?The research on the recovery of electric furnace flue gas waste heat is of great significance. In order to make better use of this part of the heat,?in this paper, a compound cycle of nitrogen Brayton cycle as a first-order cycle and toluene transcritical Rankine cycle as a second-order cycle is proposed to recover waste heat from furnace flue gas in steelmaking process for power generation. A mathematical model was established with the net output power as the objective function and the initial expansion pressure, the final expansion pressure, the initial expansion temperature and the initial pressure of the second cycle as the independent variables. The effect of multivariate on the net output power of the waste heat power generation cycle is studied, and then, the optimal parameters of the compound cycle are determined. The results show that under the general electric furnace steelmaking process, the power generation efficiency of this new cycle can be increased by 21.02% compared with the conventional cycle.展开更多
为改善风火打捆系统的暂态稳定性,提出将具有串补功能的复合型故障限流器(Fault Current Limiter,FCL)接入到风火打捆系统中。将双馈风电机组(Doubly-Fed Induction Generator,DFIG)对系统的影响用等效外特性参数表示,在分析DFIG接入系...为改善风火打捆系统的暂态稳定性,提出将具有串补功能的复合型故障限流器(Fault Current Limiter,FCL)接入到风火打捆系统中。将双馈风电机组(Doubly-Fed Induction Generator,DFIG)对系统的影响用等效外特性参数表示,在分析DFIG接入系统对暂态稳定的影响和复合型FCL工作原理的基础上,分析带复合型FCL的风火打捆系统的功率特性方程,通过分析在不同运行状态下复合型FCL对功率特性方程中输入阻抗、转移阻抗的影响,确定其对传输功率极限的作用,分析其提高暂态稳定性的机理。制定了故障发生前、中、后不同阶段,复合型FCL提高风火打捆系统暂态稳定性的控制策略。正常运行及故障切除后发挥复合型FCL的串补功能;故障状态下通过确定目标功率差与触发角之间的关系,通过控制限流电抗,发挥FCL限制短路电流、提高母线电压的作用,达到提高功率输送能力,改善暂态稳定性的目的。仿真分析表明机理分析和所提控制策略的有效性。展开更多
有源电力滤波器(Active Power Filter,APF)是一种新型的用于补偿谐波和无功功率的电力电子装置,为提高并联型APF的补偿精度。以三相三线制带LLCL型滤波器的APF为研究对象,对APF的控制策略包括电流内环的控制和直流侧电压外环的控制进行...有源电力滤波器(Active Power Filter,APF)是一种新型的用于补偿谐波和无功功率的电力电子装置,为提高并联型APF的补偿精度。以三相三线制带LLCL型滤波器的APF为研究对象,对APF的控制策略包括电流内环的控制和直流侧电压外环的控制进行研究,分析得出电压外环采用PI控制,电流内环采用PI控制和重复控制有机结合的复合控制策略。利用Matlab/Simulink仿真工具搭建了仿真模型,验证了带LLCL型滤波器的并联APF具有良好的补偿性能,可以明显的降低电网电流的波形失真度(Total Harmonic Distortion,THD)。展开更多
基金Supported by the Ministerial Level Advanced Research Foudation (111044)
文摘In order to identify all the appropriate system schemes for the compound split systems formed primarily with a four-port mechanical power split device, power transmission characteristics of the compound split systems was analyzed. Considering the structural symmetry and according to the different connection arrangement of the four ports, compound split system was classified into four types. Using black-box modeling method, the generalized models of the speed ratio, the torque ratio and the power split ratio were established. Moreover, a semi-invert diagram was used to distin- guish the different schemes in each type. The characteristics of the speed ratio, the torque ratio and the power split ratio in each domain were also analyzed and compared. Through the semi-invert dia- gram, a selection method based on the rated-power speed ranges in different schemes was presented and all suitable compound split systems were identified, which can be used as references for the scheme selection of this kind of continuously variable power split transmission.
文摘Electric furnace short process steelmaking is one of the most important steelmaking methods in the world today, and the waste heat recovery potential of electric furnace flue gas is huge.?The research on the recovery of electric furnace flue gas waste heat is of great significance. In order to make better use of this part of the heat,?in this paper, a compound cycle of nitrogen Brayton cycle as a first-order cycle and toluene transcritical Rankine cycle as a second-order cycle is proposed to recover waste heat from furnace flue gas in steelmaking process for power generation. A mathematical model was established with the net output power as the objective function and the initial expansion pressure, the final expansion pressure, the initial expansion temperature and the initial pressure of the second cycle as the independent variables. The effect of multivariate on the net output power of the waste heat power generation cycle is studied, and then, the optimal parameters of the compound cycle are determined. The results show that under the general electric furnace steelmaking process, the power generation efficiency of this new cycle can be increased by 21.02% compared with the conventional cycle.
文摘为改善风火打捆系统的暂态稳定性,提出将具有串补功能的复合型故障限流器(Fault Current Limiter,FCL)接入到风火打捆系统中。将双馈风电机组(Doubly-Fed Induction Generator,DFIG)对系统的影响用等效外特性参数表示,在分析DFIG接入系统对暂态稳定的影响和复合型FCL工作原理的基础上,分析带复合型FCL的风火打捆系统的功率特性方程,通过分析在不同运行状态下复合型FCL对功率特性方程中输入阻抗、转移阻抗的影响,确定其对传输功率极限的作用,分析其提高暂态稳定性的机理。制定了故障发生前、中、后不同阶段,复合型FCL提高风火打捆系统暂态稳定性的控制策略。正常运行及故障切除后发挥复合型FCL的串补功能;故障状态下通过确定目标功率差与触发角之间的关系,通过控制限流电抗,发挥FCL限制短路电流、提高母线电压的作用,达到提高功率输送能力,改善暂态稳定性的目的。仿真分析表明机理分析和所提控制策略的有效性。
文摘有源电力滤波器(Active Power Filter,APF)是一种新型的用于补偿谐波和无功功率的电力电子装置,为提高并联型APF的补偿精度。以三相三线制带LLCL型滤波器的APF为研究对象,对APF的控制策略包括电流内环的控制和直流侧电压外环的控制进行研究,分析得出电压外环采用PI控制,电流内环采用PI控制和重复控制有机结合的复合控制策略。利用Matlab/Simulink仿真工具搭建了仿真模型,验证了带LLCL型滤波器的并联APF具有良好的补偿性能,可以明显的降低电网电流的波形失真度(Total Harmonic Distortion,THD)。
