Based on the traditional measurement theory of transient plane source (TPS) technique, single-side TPS method is proposed for measuring the thermal conductivity of single specimen. The problem of transient heat conduc...Based on the traditional measurement theory of transient plane source (TPS) technique, single-side TPS method is proposed for measuring the thermal conductivity of single specimen. The problem of transient heat conduction in a semi-infinite boundary condition is studied and the theoretical formula of single-side TPS method is deduced. During the measurement, the influence of the probe heat capacity on the results is analyzed and the corresponding mathematical compensation model is established, and a series of experiments on different materials are conducted by hot disk probe at normal temperature and pressure. The results show that the relative error with the single-side TPS method is less than 5% and the relative standard deviation is no greater than 3%. This method has high accuracy and good reproducibility, which provides a feasible measuring method for single material that does not meet the requirements of the standard TPS theory.展开更多
该文通过分析三重移相(triple phase shift,TPS)控制下双主动全桥(dual active bridge,DAB)变换器的等效电路,推导出传输功率以及电感电流有效值与控制量输入之间的统一模型,并根据控制量之间的关系,划分DAB变换器的6种工作模式。然后,...该文通过分析三重移相(triple phase shift,TPS)控制下双主动全桥(dual active bridge,DAB)变换器的等效电路,推导出传输功率以及电感电流有效值与控制量输入之间的统一模型,并根据控制量之间的关系,划分DAB变换器的6种工作模式。然后,通过揭示控制量的扰动对于传输功率及电感电流有效值的影响,提出针对电流有效值的全局最优化条件,统一不同功率段和不同工作模式的优化问题。全局最优化条件的解即为电感电流有效值最小的控制策略。最后搭建实验平台进行验证,实验结果证明了文中理论分析的正确性和控制策略的有效性。展开更多
The transient plane source(TPS)method is developed recently to measure the thermal conductivity of materials.In the measurement,the heating power is influenced by the heat which is transferred via the probe electrical...The transient plane source(TPS)method is developed recently to measure the thermal conductivity of materials.In the measurement,the heating power is influenced by the heat which is transferred via the probe electrical leads.This fact further influences the measurement accuracy of thermal conductivity.To solve this problem,the influence of heat loss through the electrical leads on the heating power is studied theoretically.The mathematical formula of heat loss is deduced,and the corresponding correction model is presented.A series of measurement experiments on different materials have been conducted by using the hot disk thermal constant analyzer.The results show that the influence of the heat loss on the measurement is sensitive to different test materials and probes with different sizes.When the thermal conductivity of the material is greater than 0.2 W/(m·K),the influence of the heat loss is less than 0.16%,which can be ignored.As to the lower thermal conductivity materials,it is necessary to compensate the heat loss through the electrical leads,and the accuracy of thermal conductivity measurement can be effectively improved.展开更多
文摘Based on the traditional measurement theory of transient plane source (TPS) technique, single-side TPS method is proposed for measuring the thermal conductivity of single specimen. The problem of transient heat conduction in a semi-infinite boundary condition is studied and the theoretical formula of single-side TPS method is deduced. During the measurement, the influence of the probe heat capacity on the results is analyzed and the corresponding mathematical compensation model is established, and a series of experiments on different materials are conducted by hot disk probe at normal temperature and pressure. The results show that the relative error with the single-side TPS method is less than 5% and the relative standard deviation is no greater than 3%. This method has high accuracy and good reproducibility, which provides a feasible measuring method for single material that does not meet the requirements of the standard TPS theory.
文摘该文通过分析三重移相(triple phase shift,TPS)控制下双主动全桥(dual active bridge,DAB)变换器的等效电路,推导出传输功率以及电感电流有效值与控制量输入之间的统一模型,并根据控制量之间的关系,划分DAB变换器的6种工作模式。然后,通过揭示控制量的扰动对于传输功率及电感电流有效值的影响,提出针对电流有效值的全局最优化条件,统一不同功率段和不同工作模式的优化问题。全局最优化条件的解即为电感电流有效值最小的控制策略。最后搭建实验平台进行验证,实验结果证明了文中理论分析的正确性和控制策略的有效性。
文摘The transient plane source(TPS)method is developed recently to measure the thermal conductivity of materials.In the measurement,the heating power is influenced by the heat which is transferred via the probe electrical leads.This fact further influences the measurement accuracy of thermal conductivity.To solve this problem,the influence of heat loss through the electrical leads on the heating power is studied theoretically.The mathematical formula of heat loss is deduced,and the corresponding correction model is presented.A series of measurement experiments on different materials have been conducted by using the hot disk thermal constant analyzer.The results show that the influence of the heat loss on the measurement is sensitive to different test materials and probes with different sizes.When the thermal conductivity of the material is greater than 0.2 W/(m·K),the influence of the heat loss is less than 0.16%,which can be ignored.As to the lower thermal conductivity materials,it is necessary to compensate the heat loss through the electrical leads,and the accuracy of thermal conductivity measurement can be effectively improved.
