The whole analysis process of pneumatic stressed membrane structure contains nine states and seven analysis processes.The zero-stress state is the corner-stone of analysis and design of pneumatic stressed structure,an...The whole analysis process of pneumatic stressed membrane structure contains nine states and seven analysis processes.The zero-stress state is the corner-stone of analysis and design of pneumatic stressed structure,and has significant impact on the pre-stressed state and load state.According to the logical model of the whole numerical analysis process of pneumatic stressed structure,a numerical analysis method to solve the zero-stress state from the elasticized equilibrium state was firstly proposed,called linear compatibility matrix M-P inverse method.Firstly,the pneumatic membrane stressed structure was transferred into grid structure by using membrane link to simulate membrane surface.Secondly,on the basis of equilibrium matrix theory of pin joint structure and small deformation assumption,compatibility equation of system was established.Thirdly,the unstressed length and elongation of links were calculated from the tension and material parameters of elasticized equilibrium state.Finally,using compatibility matrix M-P inverse,the nodal displacement was calculated by solving compatibility equation,the configuration of zero-stress state could be obtained through reverse superposition,and the stress was released.According to the algorithm,the program was coded with MATLAB.The correctness and efficiency of this method were verified by several numerical examples,and it could be found that one elasticized equilibrium state corresponded to one configuration of the zero-stress state.The work has theoretical significance and practical guidance value for pneumatic membrane structural design.展开更多
为解决双有源桥(dual active bridge,DAB)变换器在采用传统控制策略时存在的动态响应慢、电流应力大及零电压开关(zero voltage switch,ZVS)范围受限等问题,笔者提出一种三重移相调制(triple phase shift,TPS)与模型预测控制(model pred...为解决双有源桥(dual active bridge,DAB)变换器在采用传统控制策略时存在的动态响应慢、电流应力大及零电压开关(zero voltage switch,ZVS)范围受限等问题,笔者提出一种三重移相调制(triple phase shift,TPS)与模型预测控制(model predictive control,MPC)的协同控制策略。该方法构建考虑ZVS约束的多模式电流应力模型,并设计包含电压跟踪、电流应力最小化及ZVS约束的复合代价函数;MPC实时求解最优移相角组合,实现TPS占空比的动态优化与实时校验。仿真结果表明:与传统TPS+PI控制策略相比,所提TPS-MPC协同控制策略在负载阶跃扰动下,动态响应速度提升约70%,电流应力降低约7.16%,且输出电压的恢复时间更短、波动幅值显著减小。该策略能有效优化DAB变换器的动态性能与效率,可为实现高功率密度、高效率电力电子变压器提供可行的控制解决方案。展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 50878128, 50808122)
文摘The whole analysis process of pneumatic stressed membrane structure contains nine states and seven analysis processes.The zero-stress state is the corner-stone of analysis and design of pneumatic stressed structure,and has significant impact on the pre-stressed state and load state.According to the logical model of the whole numerical analysis process of pneumatic stressed structure,a numerical analysis method to solve the zero-stress state from the elasticized equilibrium state was firstly proposed,called linear compatibility matrix M-P inverse method.Firstly,the pneumatic membrane stressed structure was transferred into grid structure by using membrane link to simulate membrane surface.Secondly,on the basis of equilibrium matrix theory of pin joint structure and small deformation assumption,compatibility equation of system was established.Thirdly,the unstressed length and elongation of links were calculated from the tension and material parameters of elasticized equilibrium state.Finally,using compatibility matrix M-P inverse,the nodal displacement was calculated by solving compatibility equation,the configuration of zero-stress state could be obtained through reverse superposition,and the stress was released.According to the algorithm,the program was coded with MATLAB.The correctness and efficiency of this method were verified by several numerical examples,and it could be found that one elasticized equilibrium state corresponded to one configuration of the zero-stress state.The work has theoretical significance and practical guidance value for pneumatic membrane structural design.
文摘为解决双有源桥(dual active bridge,DAB)变换器在采用传统控制策略时存在的动态响应慢、电流应力大及零电压开关(zero voltage switch,ZVS)范围受限等问题,笔者提出一种三重移相调制(triple phase shift,TPS)与模型预测控制(model predictive control,MPC)的协同控制策略。该方法构建考虑ZVS约束的多模式电流应力模型,并设计包含电压跟踪、电流应力最小化及ZVS约束的复合代价函数;MPC实时求解最优移相角组合,实现TPS占空比的动态优化与实时校验。仿真结果表明:与传统TPS+PI控制策略相比,所提TPS-MPC协同控制策略在负载阶跃扰动下,动态响应速度提升约70%,电流应力降低约7.16%,且输出电压的恢复时间更短、波动幅值显著减小。该策略能有效优化DAB变换器的动态性能与效率,可为实现高功率密度、高效率电力电子变压器提供可行的控制解决方案。
