This paper employs the Direct Finite Element Squared(DFE2)method to develop Sparse Polynomial Chaos Expansions(SPCE)models for analyzing the electromechanical properties of multiscale piezoelectric structures.By incor...This paper employs the Direct Finite Element Squared(DFE2)method to develop Sparse Polynomial Chaos Expansions(SPCE)models for analyzing the electromechanical properties of multiscale piezoelectric structures.By incorporating variations in piezoelectric and elastic constants,the DFE2 method is utilized to simulate the statistical characteristics—such as expected values and standard deviations—of electromechanical properties,including Mises stress,maximum in-plane principal strain,electric potential gradient,and electric potential,under varying parameters.This approach achieves a balance between computational efficiency and accuracy.Different SPCE models are used to investigate the influence of piezoelectric and elastic constants on multiscale piezoelectric materials.Additionally,the multiscale parameterization study investigates how microscale material properties affect the macroscopic response of these structures and materials.展开更多
This paper proposes an improved modularizable high-frequency battery equalizer with multi-winding transformer for energy storage systems. The involvement of parasitic components in circuit resonance, along with the ad...This paper proposes an improved modularizable high-frequency battery equalizer with multi-winding transformer for energy storage systems. The involvement of parasitic components in circuit resonance, along with the addition of a resonant network, enables soft-switching for the power switches to reduce the switch voltage stress due to high frequency switching operation. The proposed circuit is designed to operate at switching frequency of 1 MHz. The detailed analysis of circuit operation is provided. At last, the feasibility and performance of the proposed battery equalizer are demonstrated through the system implementation and experimental tests of a prototype circuit. Experimental results have shown zero voltage switching (ZVS) is achieved on the switches.展开更多
为解决电池在工作时出现的能量不一致的问题,以模糊逻辑控制算法为核心,建立以电池荷电状态(state of charge,SOC)差异和电池温度差为根据,可自适应选择均衡模式和开关导通占空比的均衡控制策略。并设计了一种基于环形电感和三绕组变压...为解决电池在工作时出现的能量不一致的问题,以模糊逻辑控制算法为核心,建立以电池荷电状态(state of charge,SOC)差异和电池温度差为根据,可自适应选择均衡模式和开关导通占空比的均衡控制策略。并设计了一种基于环形电感和三绕组变压器的双层均衡拓扑结构,该拓扑拥有多个均衡模式,满足策略需求。使用MATLAB Simulink软件进行模型搭建并仿真,仿真结果表明该均衡方法能够有效缩短均衡时长,缓解电池间的不一致性问题,对比同类型多均衡模式的均衡方法,静置、充电、放电所需均衡时间分别缩短69.78%、39.81%和44.15%,同时有效降低了均衡时的电池温度。展开更多
基金supported by the Zhumadian 2023 Major Science and Technology Special Project(Grant No.ZMDSZDZX2023002)the Postgraduate Education Reform and Quality Improvement Project of Henan Province(Grant No.YJS2023JD52).
文摘This paper employs the Direct Finite Element Squared(DFE2)method to develop Sparse Polynomial Chaos Expansions(SPCE)models for analyzing the electromechanical properties of multiscale piezoelectric structures.By incorporating variations in piezoelectric and elastic constants,the DFE2 method is utilized to simulate the statistical characteristics—such as expected values and standard deviations—of electromechanical properties,including Mises stress,maximum in-plane principal strain,electric potential gradient,and electric potential,under varying parameters.This approach achieves a balance between computational efficiency and accuracy.Different SPCE models are used to investigate the influence of piezoelectric and elastic constants on multiscale piezoelectric materials.Additionally,the multiscale parameterization study investigates how microscale material properties affect the macroscopic response of these structures and materials.
文摘This paper proposes an improved modularizable high-frequency battery equalizer with multi-winding transformer for energy storage systems. The involvement of parasitic components in circuit resonance, along with the addition of a resonant network, enables soft-switching for the power switches to reduce the switch voltage stress due to high frequency switching operation. The proposed circuit is designed to operate at switching frequency of 1 MHz. The detailed analysis of circuit operation is provided. At last, the feasibility and performance of the proposed battery equalizer are demonstrated through the system implementation and experimental tests of a prototype circuit. Experimental results have shown zero voltage switching (ZVS) is achieved on the switches.
文摘为解决电池在工作时出现的能量不一致的问题,以模糊逻辑控制算法为核心,建立以电池荷电状态(state of charge,SOC)差异和电池温度差为根据,可自适应选择均衡模式和开关导通占空比的均衡控制策略。并设计了一种基于环形电感和三绕组变压器的双层均衡拓扑结构,该拓扑拥有多个均衡模式,满足策略需求。使用MATLAB Simulink软件进行模型搭建并仿真,仿真结果表明该均衡方法能够有效缩短均衡时长,缓解电池间的不一致性问题,对比同类型多均衡模式的均衡方法,静置、充电、放电所需均衡时间分别缩短69.78%、39.81%和44.15%,同时有效降低了均衡时的电池温度。
