Coherent combination of laser beam is an important and challenging area of high power laser science. And how to evaluate the high power laser by coherent beam combination is a new research spot. Formulas for the radia...Coherent combination of laser beam is an important and challenging area of high power laser science. And how to evaluate the high power laser by coherent beam combination is a new research spot. Formulas for the radiated intensity distributions of coherent combined Gaussian beam array are derived via Fraunhofer scalar diffraction model by utilizing representations of the cross-spectral density of the far field. Effects of beam array numbers and separate distances etc. on far field radiated profiles are shown and analyzed. A new conception named power in the bucket of the main lobe (PIMm) is advanced to measure the beam quality of combined beams. This evaluation method is useful for efficiently determining the peak irradiance and power in the bucket for single emitting apertures of general shape.展开更多
本文提出了一种MIMO(Multi-Input and Multi-Output)系统中的新型自适应调制和功率分配算法,在奇异值分解的基础上通过注水算法进行功率分配,此后根据所分配的功率与信道状态信息来确定自适应调制的门限及相应的调制阶数,并在自适应调...本文提出了一种MIMO(Multi-Input and Multi-Output)系统中的新型自适应调制和功率分配算法,在奇异值分解的基础上通过注水算法进行功率分配,此后根据所分配的功率与信道状态信息来确定自适应调制的门限及相应的调制阶数,并在自适应调制后通过功率修正因子来弥补常见算法中功率不能得到有效利用的问题,仿真结果表明该算法可以得到较高的频谱效率。展开更多
针对小功率LED驱动电路领域中,由于受体积和成本限制而无法使用有源功率因数校正(PFC)电路从而导致电源功率因数较差的问题,首先分析了需要进行功率因数校正的原因,然后对应用于20 W LED驱动电路中的无源功率因数电源进行设计,以及电容...针对小功率LED驱动电路领域中,由于受体积和成本限制而无法使用有源功率因数校正(PFC)电路从而导致电源功率因数较差的问题,首先分析了需要进行功率因数校正的原因,然后对应用于20 W LED驱动电路中的无源功率因数电源进行设计,以及电容选型等方面进行研究。对4种不同的无源功率因数校正电路进行了比较,实验结果表明在LED驱动电路中一种填谷式无源功率因数校正电路是低成本、高功率因素的功率因数校正电路,符合能源之星的标准,不存在波峰因数等问题。展开更多
In this work, we conduct a study of modeling and simulation of a system in the context of renewable energy in general, and solar system “photovoltaic” in particular;also, the optimizing system adapted by DC-DC conve...In this work, we conduct a study of modeling and simulation of a system in the context of renewable energy in general, and solar system “photovoltaic” in particular;also, the optimizing system adapted by DC-DC converters static. Then the influence of temperature and irradiance on the optimal parameters (Power of MPP, VMPP, ...) of a solar system is analyzed in a way to operate a PV generator at its maximum power. This system includes a photovoltaic generator, “Boost & Buck”, converter and a load. Modeling and simulation system (solar panel, DC-DC converter command and load) is obtained through Matlab-Simulink software.展开更多
文摘Coherent combination of laser beam is an important and challenging area of high power laser science. And how to evaluate the high power laser by coherent beam combination is a new research spot. Formulas for the radiated intensity distributions of coherent combined Gaussian beam array are derived via Fraunhofer scalar diffraction model by utilizing representations of the cross-spectral density of the far field. Effects of beam array numbers and separate distances etc. on far field radiated profiles are shown and analyzed. A new conception named power in the bucket of the main lobe (PIMm) is advanced to measure the beam quality of combined beams. This evaluation method is useful for efficiently determining the peak irradiance and power in the bucket for single emitting apertures of general shape.
文摘本文提出了一种MIMO(Multi-Input and Multi-Output)系统中的新型自适应调制和功率分配算法,在奇异值分解的基础上通过注水算法进行功率分配,此后根据所分配的功率与信道状态信息来确定自适应调制的门限及相应的调制阶数,并在自适应调制后通过功率修正因子来弥补常见算法中功率不能得到有效利用的问题,仿真结果表明该算法可以得到较高的频谱效率。
文摘针对小功率LED驱动电路领域中,由于受体积和成本限制而无法使用有源功率因数校正(PFC)电路从而导致电源功率因数较差的问题,首先分析了需要进行功率因数校正的原因,然后对应用于20 W LED驱动电路中的无源功率因数电源进行设计,以及电容选型等方面进行研究。对4种不同的无源功率因数校正电路进行了比较,实验结果表明在LED驱动电路中一种填谷式无源功率因数校正电路是低成本、高功率因素的功率因数校正电路,符合能源之星的标准,不存在波峰因数等问题。
文摘In this work, we conduct a study of modeling and simulation of a system in the context of renewable energy in general, and solar system “photovoltaic” in particular;also, the optimizing system adapted by DC-DC converters static. Then the influence of temperature and irradiance on the optimal parameters (Power of MPP, VMPP, ...) of a solar system is analyzed in a way to operate a PV generator at its maximum power. This system includes a photovoltaic generator, “Boost & Buck”, converter and a load. Modeling and simulation system (solar panel, DC-DC converter command and load) is obtained through Matlab-Simulink software.
