Research On Power Line Energy Harvesting And Management Technology Based On Electromagnetic Coupling Principle

The development and application of smart grid technology require the installation of a large number of sensor nodes on transmission lines,which can monitor and control various parameters of the lines in real-time,thus improving the efficiency and safety of the grid.However,the power supply problem of sensor nodes has always been a challenge,because they are usually located in high-altitude or inaccessible places,and using batteries as power sources not only has problems such as replacement difficulty,high maintenance cost,environmental pollution but also limits the functionality and lifespan of sensor nodes.Therefore,developing a self-powered technology that can utilize the energy in the environment and convert it into usable electric energy is an ideal solution to the power supply problem of sensor nodes.Based on this idea,this paper studies a method of harvesting energy from the magnetic field on power lines and designs a miniaturized and high-efficiency harvesting device,which realizes autonomous power supply for sensor nodes.This thesis first establishes the electromagnetic model and circuit model of the core.It analyzes the influence of the core saturation phenomenon on the power line energy harvesting and concludes that there is still room for improvement in the energy harvesting scheme of the core working in the linear region,and there is a critical saturation point that maximizes the energy harvesting power.To describe the saturation state of the core,this article fits the B-H curve of the ring core with fractions,and based on this,establishes the electromagnetic model and circuit model,conducts loss analysis and Matlab simulation research,and verifies the accuracy of the fitting and model.The thesis then proposes an active rectification control scheme to improve the energy harvesting efficiency of the core and designs an energy management circuit based on this scheme.This article analyzes and simulates the active rectification control scheme with LTspice,and compares it with the FSC scheme to verify its superiority.Then,this article analyzes the loss problem of the active rectification control scheme under large current conditions and proposes a comprehensive control scheme combining active and passive rectification to balance efficiency and loss.Finally,this article designs an energy management circuit based on the active rectification control idea,which realizes the stable control of the load output through energy storage control and voltage monitoring.Finally,to improve the generality of the system,this thesis optimizes the active control scheme and proposes an adaptive control scheme.This scheme can adjust the saturation time in real-time according to the changes in line parameters so that the core always works at the maximum power point.The performance of the actual energy harvesting circuit is tested in this paper,including the experimental verification of adaptive control,and the consistency verification of simulation and experiment.The experimental results show that when the primary side current RMS is 10 A,the load voltage is 5V,the output power of the energy harvesting device is 127.86 m W,and the equivalent performance index is 2.2,which is three times that of the existing energy harvesting scheme.