在服务器电源和通信电源应用领域，谐振变换器是一种十分令人关注的拓扑。它具有提升功效，减少元器件数量和抑制电磁干扰等优点，但是体二极管的使用有时会导致系统故障。为适应谐振变换器，提出了一种被称为UniFETII的新型功率MOSFET...在服务器电源和通信电源应用领域，谐振变换器是一种十分令人关注的拓扑。它具有提升功效，减少元器件数量和抑制电磁干扰等优点，但是体二极管的使用有时会导致系统故障。为适应谐振变换器，提出了一种被称为UniFETII的新型功率MOSFET。它提升了体二极管的耐用性和COSS中的输出存储能量，使负面影响最小化。首先介绍了LLC谐振变换器和MOSFET的故障机理，在此基础上详细描述了UniFETTM II MOSFET技术和应用优势，并通过实验验证其正确性。结果证明MOSFET—UniFETTM在减少了门极电荷和输出电容存储能量的同时，提高了开关频率，降低了驱动损耗和输出电容损耗。展开更多
提出一族基于反向耦合电感的非隔离双向直流变换器(bi-directional DC converter,BDC),通过引入反向耦合电感,利用电感感应电势阻断不工作MOSFET的体二极管,消除了传统双向变换器中开关管寄生体二极管的反向恢复问题;通过反向耦合电感...提出一族基于反向耦合电感的非隔离双向直流变换器(bi-directional DC converter,BDC),通过引入反向耦合电感,利用电感感应电势阻断不工作MOSFET的体二极管,消除了传统双向变换器中开关管寄生体二极管的反向恢复问题;通过反向耦合电感与滤波电感等效电路的分析,将反向耦合电感与滤波电感用一个同向耦合电感代替,提出一族基于PCI的非隔离双向直流变换器。所提出的变换器控制与传统单向变换器相同,不需要专门的软启动电路,兼顾了较高变换效率、控制简单和高可靠性。给出拓扑推演过程,详细分析拓扑工作原理,并通过实验验证理论分析的正确性。展开更多
As the energy supply problem worsens, the development and utilization of marine renewable energy have become a research hotspot. The development of wave energy is moving from the near shore to the distant sea. The pow...As the energy supply problem worsens, the development and utilization of marine renewable energy have become a research hotspot. The development of wave energy is moving from the near shore to the distant sea. The power-generation efficiency of a single two-floating-body wave-energy converter is relatively low. To fully utilize wave energy and improve the wave-energy capture rate of a fixed sea area, arranging a two-floating-body wave-energy converter array is necessary. This paper first introduces the basic theory of multi-floating flow field, time-domain calculation method, and influence factor of the waveenergy converter array. Then, the development of AQWA software in Fortran language considers the effect of power takeoff. A calculation method based on ANSYS–AQWA is proposed to simulate the motion of the oscillating-buoy two-floating-body wave-energy converter. The results are compared with the experimental results from the National Renewable Energy Laboratory. Finally, the ANSYS–AQWA method is used to study the power characteristics of simple and complex arrays of wave-energy converters. The average power generation of simple arrays is largest at 0°, and the average power generation of complex arrays does not change with the wave direction. Optimal layout spacing exists for the simple and complex arrays. These findings can serve as a valuable reference for the large-scale array layout of wave-energy converters in the future.展开更多
文摘在服务器电源和通信电源应用领域，谐振变换器是一种十分令人关注的拓扑。它具有提升功效，减少元器件数量和抑制电磁干扰等优点，但是体二极管的使用有时会导致系统故障。为适应谐振变换器，提出了一种被称为UniFETII的新型功率MOSFET。它提升了体二极管的耐用性和COSS中的输出存储能量，使负面影响最小化。首先介绍了LLC谐振变换器和MOSFET的故障机理，在此基础上详细描述了UniFETTM II MOSFET技术和应用优势，并通过实验验证其正确性。结果证明MOSFET—UniFETTM在减少了门极电荷和输出电容存储能量的同时，提高了开关频率，降低了驱动损耗和输出电容损耗。
文摘提出一族基于反向耦合电感的非隔离双向直流变换器(bi-directional DC converter,BDC),通过引入反向耦合电感,利用电感感应电势阻断不工作MOSFET的体二极管,消除了传统双向变换器中开关管寄生体二极管的反向恢复问题;通过反向耦合电感与滤波电感等效电路的分析,将反向耦合电感与滤波电感用一个同向耦合电感代替,提出一族基于PCI的非隔离双向直流变换器。所提出的变换器控制与传统单向变换器相同,不需要专门的软启动电路,兼顾了较高变换效率、控制简单和高可靠性。给出拓扑推演过程,详细分析拓扑工作原理,并通过实验验证理论分析的正确性。
基金Supported by the National Natural Science Foundation of China under Grant Nos.5171101175,11572094,51809083,and 51579055
文摘As the energy supply problem worsens, the development and utilization of marine renewable energy have become a research hotspot. The development of wave energy is moving from the near shore to the distant sea. The power-generation efficiency of a single two-floating-body wave-energy converter is relatively low. To fully utilize wave energy and improve the wave-energy capture rate of a fixed sea area, arranging a two-floating-body wave-energy converter array is necessary. This paper first introduces the basic theory of multi-floating flow field, time-domain calculation method, and influence factor of the waveenergy converter array. Then, the development of AQWA software in Fortran language considers the effect of power takeoff. A calculation method based on ANSYS–AQWA is proposed to simulate the motion of the oscillating-buoy two-floating-body wave-energy converter. The results are compared with the experimental results from the National Renewable Energy Laboratory. Finally, the ANSYS–AQWA method is used to study the power characteristics of simple and complex arrays of wave-energy converters. The average power generation of simple arrays is largest at 0°, and the average power generation of complex arrays does not change with the wave direction. Optimal layout spacing exists for the simple and complex arrays. These findings can serve as a valuable reference for the large-scale array layout of wave-energy converters in the future.
