在磁耦合谐振式无线电能传输系统中,针对线圈间水平方向偏移时互感骤降而导致的系统运行稳定性问题,本文设计了一种具有高偏移容忍度的对称反向串联线圈(symmetrical reverse series coil,SRSC)磁耦合机构。SRSC结构的接收线圈采用两个...在磁耦合谐振式无线电能传输系统中,针对线圈间水平方向偏移时互感骤降而导致的系统运行稳定性问题,本文设计了一种具有高偏移容忍度的对称反向串联线圈(symmetrical reverse series coil,SRSC)磁耦合机构。SRSC结构的接收线圈采用两个同心圆形线圈反向串联连接,在没有额外增加任何谐振补偿网络和辅助控制装置的情况下,能够大幅度提高系统在任意水平方向上的偏移容忍度。本文首先提出一种空心圆形线圈在偏移工况下的互感计算方法,然后分析SRSC磁耦合机构的结构特性和互感特性,并提出一种基于恒定互感的磁耦合机构优化设计方法。仿真和实验结果验证了理论计算分析的正确性,SRSC结构能够有效解决无线电能传输系统线圈水平方向偏移的互感剧烈波动问题,使系统在发射线圈外径50%偏移范围内仍能保持高效运行,提升了系统的稳定性。展开更多
The authors have invented the unique counter-rotating type tidal stream power unit composed of the tandem pro- peUers and the double rotational armature type peculiar generator without the traditional stator. The fron...The authors have invented the unique counter-rotating type tidal stream power unit composed of the tandem pro- peUers and the double rotational armature type peculiar generator without the traditional stator. The front and the rear propellers counter-drive the inner and the outer armatures of the peculiar generator, respectively. The unit has the fixftful advantages that not only the output is sufficiently higher without supplementary equipment such as a gearbox, but also the rotational moment hardly act on the pillar because the rotational torque of both propel- lers/armatures are counter-balanced in the unit. This paper discusses experimentally the performances of the power unit and the effects of the propeller rotation on the sea surface. The axial force acting on the pillar in- creases naturally with the increase of not only the stream velocity but also the drag of the tandem propellers. Be- sides, the force vertical to the stream also acts on the pillar, which is induced from the Karman vortex street and the dominant frequencies appear owing to the front and the rear propeller rotations. The propeller rotating in close to the sea surface brings the abnormal wave and the amplitude increases as the stream velocity is faster and/or the drag is stronger.展开更多
An experimental study was conducted to investigate the effects of relative rotation direction on the wake interferences among two tandemwind turbines models.While the oncoming flow conditions were kept in constant dur...An experimental study was conducted to investigate the effects of relative rotation direction on the wake interferences among two tandemwind turbines models.While the oncoming flow conditions were kept in constant during the experiments,turbine power outputs,wind loads acting on the turbines,and wake characteristics behind the turbines were compared quantitatively with turbine models in either co-rotating or counter-rotating configuration.The measurement results reveal that the turbines in counter-rotating would harvest more wind energy from the same oncoming wind,compared with the co-rotating case.While the recovery of the streamwise velocity deficits in the wake flows was found to be almost identical with the turbines operated in either co-rotating or counter-rotating,the significant azimuthal velocity generated in the wake flow behind the upstream turbine is believed to be the reason why the counter-rotating turbines would have a better power production performance.Since the azimuthal flow velocity in the wake flow was found to decrease monotonically with the increasing downstream distance,the benefits of the counter-rotating configuration were found to decrease gradually as the spacing between the tandem turbines increases.While the counter-rotating downstream turbine was found to produce up to 20%more power compared with that of co-rotating configuration with the turbine spacing being about 0.7D,the advantage was found to become almost negligible when the turbine spacing becomes greater than 6.5D.It suggests that the counter-rotating configuration design would be more beneficial to turbines in onshore wind farms due to the smaller turbine spacing(i.e.,~3 rotor diameters for onshore wind farms vs.~7 rotor diameters for offshore wind farms in the prevailing wind direction),especially for those turbines sited over complex terrains with the turbine spacing only about 1–2 rotor diameters.展开更多
文摘在磁耦合谐振式无线电能传输系统中,针对线圈间水平方向偏移时互感骤降而导致的系统运行稳定性问题,本文设计了一种具有高偏移容忍度的对称反向串联线圈(symmetrical reverse series coil,SRSC)磁耦合机构。SRSC结构的接收线圈采用两个同心圆形线圈反向串联连接,在没有额外增加任何谐振补偿网络和辅助控制装置的情况下,能够大幅度提高系统在任意水平方向上的偏移容忍度。本文首先提出一种空心圆形线圈在偏移工况下的互感计算方法,然后分析SRSC磁耦合机构的结构特性和互感特性,并提出一种基于恒定互感的磁耦合机构优化设计方法。仿真和实验结果验证了理论计算分析的正确性,SRSC结构能够有效解决无线电能传输系统线圈水平方向偏移的互感剧烈波动问题,使系统在发射线圈外径50%偏移范围内仍能保持高效运行,提升了系统的稳定性。
文摘The authors have invented the unique counter-rotating type tidal stream power unit composed of the tandem pro- peUers and the double rotational armature type peculiar generator without the traditional stator. The front and the rear propellers counter-drive the inner and the outer armatures of the peculiar generator, respectively. The unit has the fixftful advantages that not only the output is sufficiently higher without supplementary equipment such as a gearbox, but also the rotational moment hardly act on the pillar because the rotational torque of both propel- lers/armatures are counter-balanced in the unit. This paper discusses experimentally the performances of the power unit and the effects of the propeller rotation on the sea surface. The axial force acting on the pillar in- creases naturally with the increase of not only the stream velocity but also the drag of the tandem propellers. Be- sides, the force vertical to the stream also acts on the pillar, which is induced from the Karman vortex street and the dominant frequencies appear owing to the front and the rear propeller rotations. The propeller rotating in close to the sea surface brings the abnormal wave and the amplitude increases as the stream velocity is faster and/or the drag is stronger.
基金Supports from the Iowa Alliance for Wind Innovation and Novel Development (IAWIND)the National Science Foundation (NSF) (Grant No. CBET-1133751)
文摘An experimental study was conducted to investigate the effects of relative rotation direction on the wake interferences among two tandemwind turbines models.While the oncoming flow conditions were kept in constant during the experiments,turbine power outputs,wind loads acting on the turbines,and wake characteristics behind the turbines were compared quantitatively with turbine models in either co-rotating or counter-rotating configuration.The measurement results reveal that the turbines in counter-rotating would harvest more wind energy from the same oncoming wind,compared with the co-rotating case.While the recovery of the streamwise velocity deficits in the wake flows was found to be almost identical with the turbines operated in either co-rotating or counter-rotating,the significant azimuthal velocity generated in the wake flow behind the upstream turbine is believed to be the reason why the counter-rotating turbines would have a better power production performance.Since the azimuthal flow velocity in the wake flow was found to decrease monotonically with the increasing downstream distance,the benefits of the counter-rotating configuration were found to decrease gradually as the spacing between the tandem turbines increases.While the counter-rotating downstream turbine was found to produce up to 20%more power compared with that of co-rotating configuration with the turbine spacing being about 0.7D,the advantage was found to become almost negligible when the turbine spacing becomes greater than 6.5D.It suggests that the counter-rotating configuration design would be more beneficial to turbines in onshore wind farms due to the smaller turbine spacing(i.e.,~3 rotor diameters for onshore wind farms vs.~7 rotor diameters for offshore wind farms in the prevailing wind direction),especially for those turbines sited over complex terrains with the turbine spacing only about 1–2 rotor diameters.
