电力电缆无线监测网络基于磁场取能的供能电源设计

Power Supply of Wireless Monitoring Network for Power Cable Based on Magnetic Field Energy Harvested

为解决地下电力电缆在线监测系统的电源供应问题,研发一种利用电缆周边磁场变化取能的线圈结构。取能线圈的磁芯设计为可以适用于不同电压等级电力电缆的圆柱开环式结构,材料采用初始磁导率为10 000的高磁导率类锰锌铁氧体,通过理论研究与软件仿真计算进行设计,并经过实验验证结果准确性,从而确定取能线圈的结构参数、磁芯材料、线圈匝数,针对感应线圈输出电压设置电能管理电路,进而获得稳定的电压输出,实现无线传感网络定周期工作的特殊要求。利用该种能量获取方法,在35 kV地下电力电缆在电流20~700 A变化范围内,取能系统正常工作,并输出+5 V、+3.3 V输出电压,供每分钟消耗功率500 mW以内的负载电路稳定运行。

In order to solve the power supply problem of on-line monitoring system for underground power cable, an energy-harvesting coil using the magnetic field around the cable was developed. The energy pick-up coil was designed to be cylindrical structure and could be applicable to the power cables with different voltage levels. The Mn-Zn ferrite material with high initial permeability was used as the coil core, and the theoretical calculation and software simulation were performed.Meanwhile, the experimental results were verified. Thereby, the structure of the pick-up coil, the core material, the number of coil turns, and the output circuit management were confirmed. The results show that the energy-harvesting system can normally operate under a 35 kV underground power cableand in the range of 20~700 A of current.Moreover, the energy-harvesting system can output +5 V and +3.3 V voltage, supplying a stable operation of circuit within a burden of 500 mW/min.