具有目标面最优磁屏蔽效果的IPT谐振式无功屏蔽系统研究

IPT Resonant Reactive Shielding Systems With the Characteristics of Optimal Magnetic Shielding Effect on the Target Surface

感应电能传输系统的漏磁会威胁人体安全,干扰电子设备。为最大限度减少漏磁,基于谐振式无功屏蔽的研究,提出一种优化屏蔽线圈等效电感的方法。首先,基于串串拓扑,建立目标面磁感应强度平方和与等效电感的函数关系,以磁感应强度平方和最小为目标推导出最优电感表达式,发现最优电感与输入电压、输出电压、屏蔽线圈匝数有关;然后,利用磁感应强度平方和表达式,优化输入电压与输出电压,利用有限元仿真,优化屏蔽线圈匝数,进而确定最优电感;最后,搭建功率为500W的实验样机,选取3组屏蔽参数与无屏蔽工况进行对比实验,结果表明,磁屏蔽效果会随等效电感的减小先减小后增大,等效电感为最优电感时测量点的磁感应强度平方和约占无屏蔽工况时的16.05%。此外,该方法对原系统几乎无影响,效率仅变化0.177%。

The leakage magnetic field from an inductive power transfer system is harmful to the human body and electronic devices.To reduce the leakage magnetic field to the maximal degree,a method of optimizing equivalent inductance of shielding coil was presented based on the resonant reactive shield.Firstly,the functional relationship between the sum of square of magnetic flux density on the target surface and equivalent inductance was established based on the series-series(SS)topology.The expression of optimal inductance was obtained when the sum of square of magnetic flux density was minimized.It is found that the optimal inductance is related to input voltage,output voltage and the number of turns of shielding coil.Then,by using the expression of the sum of square of magnetic flux density,the input voltage and output voltage were optimized and by using the finite element simulation,the number of turns of shielding coil was optimized,thus,the optimal inductance was determined.At last,500 W experimental prototypes was built,three groups of shielding parameters and without shielding condition were selected for comparison experiment.The experiment results show that the magnetic shielding effect decreases first and then increases with the decrease of the equivalent inductance.And the sum of square of magnetic flux density of the measuring points accounts for 16.05%of that without shielding when the equivalent inductance is the optimal inductance.In addition,the proposed method has little effect on original system,and the efficiency changes only 0.177%.