Research On Energy Scavenging Technology Based On Spatial Electric-Field Energy

The smart grid is the future of electric power industry, which requires dvanced measurement and information interaction technology in order to monitor and control operation state of the power grid. Wireless sensor network has a promising future in the smart grid because of its advanced sensing and measurement characters, but energy supply has become the bottleneck for its further development. Energy scavenging technology based on the ambient energy provides an effective solution, especially in high-voltage substations, energy scavenging technology based on electric-fild energy has more advantages than any other forms and becomes a hot area of research preference.The capacitive plate converter is a simple topology. The factors are analyzed that impact its energy scavenging performance based on the derived equivalent mode, among them direction of electric field affects obvious. A new hemisphere topology for energy scavenging is proposed to overcome the unsatisfactory adaptability and low efficiency at different electric-field direction. By integrating the expression of capacitance for two parallel thin rings, a corresponding analytical model for hemisphere converter is further established and compared with the experimental measurement results. With the same spatial volume, the energy scavenging effect of two topologies is studied contrastively. No-load tests for two topologies and different parameters are done to verify the validity of the theoretical analysis.An appropriate energy storage unit is selected by comparing different energy storage methods. Charging current of the traditional conditioning unit is deduced to optimize the energy converter and conditioning circuit. A novel conditioning unit with better output voltage stabilization is designed for obvious equivalent load and external electric field. From the view of nolinear theory, the performance of main circuit is analyzed in a varying external electric field in order to get the right input voltage fluctuation range. A large-signal model as well as a dynamic disturbance model is established so as to build a feedback network. Finally, simulation results verified the effectiveness of the proposed topology structure and the parameter selection methodologies.An experimental rig is set up for overall performance test of the energy scavenging devices. Combining the energy converter with the typical conditioning circuit, the effect of energy scavenging system in different operating conditions is observed to verify the theoretical analysis. Combining the hemisphere converter and conditioning circuit with voltage stabilization, the output voltage characteristics and stability of the apparatus are studied in this experiment, which is of sensible significance for engineering application of the energy scavenging devices.