Growth and passivation of tunnels within Al foil by on-off controlling DC etching in 6 wt.% HCI solution has been investigated. It was found that, in a given etchant solution at a special temperature, the longest tunn...Growth and passivation of tunnels within Al foil by on-off controlling DC etching in 6 wt.% HCI solution has been investigated. It was found that, in a given etchant solution at a special temperature, the longest tunnel length was only a function of the turn-on interval of DC. The potential of Al foil broke at on-off controlling DC by the result from anode polarization curves and potential-time （E-t） responding curves. When DC was switched on, the potential increased abruptly over pitting potential, leading to nucleation of pits at the surface and the growth of tunnels at special length. When DC was switched off, the potential decreased rapidly to a passive value, leading to stoppage of nucleation and death of tunnels. By this way, the longest tunnel length can be controlled and a non-piercing layer can be obtained. Hence, etching of Al foil at this current is beneficial for maintaining a good mechanical strength.展开更多
无线电能传输WPT(wireless power transfer)技术可在无人工辅助的条件下为无人机提供灵活便捷的电能补给,是未来无人机智能化发展的重要探索方向。为适应无人机WPT系统轻量化、恒流恒压充电、高能量传输效率等实际需求,提出了1种基于压...无线电能传输WPT(wireless power transfer)技术可在无人工辅助的条件下为无人机提供灵活便捷的电能补给,是未来无人机智能化发展的重要探索方向。为适应无人机WPT系统轻量化、恒流恒压充电、高能量传输效率等实际需求,提出了1种基于压控电容的无人机WPT系统高效率恒流/恒压输出调节方法。在系统发射线圈回路中采用压控电容作为补偿电容,通过动态调节该压控电容的等效阻抗,可在实现系统输出电流/电压有效控制的同时,保障宽负载范围条件下逆变器的软开关状态,且无需额外辅助电源及电感器件。详细分析了所提无人机WPT系统的工作原理及损耗模型,设计了1套完整的压控电容直流偏置电压调节模块、闭环控制策略及其参数设计方法。实验证明,在25.2 V-6 A的额定输出条件下,系统整体效率达88.8%。展开更多
基金This study was financially supported by Beijing Education Commission,China.
文摘Growth and passivation of tunnels within Al foil by on-off controlling DC etching in 6 wt.% HCI solution has been investigated. It was found that, in a given etchant solution at a special temperature, the longest tunnel length was only a function of the turn-on interval of DC. The potential of Al foil broke at on-off controlling DC by the result from anode polarization curves and potential-time （E-t） responding curves. When DC was switched on, the potential increased abruptly over pitting potential, leading to nucleation of pits at the surface and the growth of tunnels at special length. When DC was switched off, the potential decreased rapidly to a passive value, leading to stoppage of nucleation and death of tunnels. By this way, the longest tunnel length can be controlled and a non-piercing layer can be obtained. Hence, etching of Al foil at this current is beneficial for maintaining a good mechanical strength.
文摘无线电能传输WPT(wireless power transfer)技术可在无人工辅助的条件下为无人机提供灵活便捷的电能补给,是未来无人机智能化发展的重要探索方向。为适应无人机WPT系统轻量化、恒流恒压充电、高能量传输效率等实际需求,提出了1种基于压控电容的无人机WPT系统高效率恒流/恒压输出调节方法。在系统发射线圈回路中采用压控电容作为补偿电容,通过动态调节该压控电容的等效阻抗,可在实现系统输出电流/电压有效控制的同时,保障宽负载范围条件下逆变器的软开关状态,且无需额外辅助电源及电感器件。详细分析了所提无人机WPT系统的工作原理及损耗模型,设计了1套完整的压控电容直流偏置电压调节模块、闭环控制策略及其参数设计方法。实验证明,在25.2 V-6 A的额定输出条件下,系统整体效率达88.8%。
