Research And Design Of Capacitive Divider Energy Harvesting Power Supply

With the development of power and communication technologies,smart grids are the inevitable trend of the global power system.In order to realize intelligent and reasonable allocation of power resources,it is very important to obtain and analyze a large number of real-time data about transmission lines by real-time monitoring of the operating state of transmission lines.The ultimate goal is to achieve efficient use of power resources and early prediction and timely pro.cessing of faults.This requires a large number of monitoring devices.Usually these monitoring devices work on the high voltage side,but the power at the high voltage side cannot be directly used as the working power source,which greatly limits the scope of its use.If the electric energy can be directly obtained from the high-voltage end as the working power source of these monitoring devices,the application range of these devices can be expanded,which is of great significance for improving the intelligent level of the power grid.Since the monitoring equipment on the transmission line is mostly installed in the field,the influence of the current fluctuation of the transmission line and the environmental change on the output power of the energy harvesting power supply is a key problem that needs to be solved for the power supply of the high-voltage terminal.In response to these problems,a capacitive divider energy harvesting power supply composed of high voltage capacitor and power frequency transformer in series is generally adopted,but it still has the problem of low output power.In order to solve this problem,a circuit structure is proposed,which realizes LC parallel resonance by shunt resonant capacitor on primary side of transformer,and combines with high power factor AC/DC circuit to further improve the output of active power.The parameters of voltage dividing capacitor and transformer are reasonably designed according to the power demand of load and the volume requirement of equipment under the condition of meeting the requirement of State Grid for inter-phase harvesting current for different power levels of small power monitoring equipment.The calculation methods of transformer and piezoelectric capacitor parameters under 5W and 10W power requirements are given.Each part of the circuit and device parameters are designed in detail.The hardware design and fabrication were completed.The hardware test was carried out under the high-voltage experimental environment,and the output power was met the design requirements.By comparing and analyzing the experimental results,the importance of resonant capacitor has been proved and the design goal has been achieved.