Research On Methods Of Coal Mine Micro Energy Harvesting And Device Design

In recent years,the state has put forward new requirements for the level of intelligence in coal mines.It is necessary to deeply integrate new technologies such as artificial intelligence and industrial internet of things with modern coal development and utilization to form comprehensive perception,real-time interconnection,analysis and decision-making,independent learning,dynamic prediction,the intelligent system of collaborative control essentially improves the safety production level of coal mines.The mobility and complexity of the mining environment in underground mines make the perception of comprehensive data rely on a large number of wireless sensor devices,thus making up for the existing wired monitoring system's fixed location and few monitoring points.However,the limited energy of wireless sensor devices restricts their large-scale use in underground mines.Based on it,this thesis proposes a method of using underground environmental energy to power wireless sensor devices.The tiny energy obtained from the environment is converted into electrical energy for storage,which improves the service life of sensor nodes.First,the downhole environmental energy was tested,the types and levels of energy available downhole were analyzed,and the energy that could be used for conversion was determined as low light energy,thermal energy and electromagnetic energy downhole.Secondly,based on the downhole test data,a simulation environment was set up in the laboratory to analyze the performance of the above-mentioned three energy conversion materials,and determine the parameter size of the conversion materials according to the actual conversion output requirements of milliwatts.Thirdly,the energy collection device is designed for DC input and RF input respectively.Aiming at the characteristics of low-voltage input of low light energy and thermal energy,a wide-voltage input DC-DC energy management circuit is designed,and an electric energy buffer mode is proposed to alleviate the impact caused by small and discontinuous environmental energy,that is,using the capacity battery buffers the electric energy.When the voltage reaches the design value,it is powered by it.When the voltage is insufficient,the backup battery is switched to ensure the normal operation of the sensor;for the radio frequency energy,a receiving antenna and a rectifier matching circuit with a receiving frequency band of 2.40-2.48 GHz are designed(RFDC),and designed an energy management circuit;finally,the three kinds of energy harvesting devices were respectively tested for charging and discharging.The experimental results show that the electric energy converted by environmental energy can meet the low transmission cycle of underground in different environments.Power demand for wireless sensors.The full thesis has 57 pictures,20 tables,and 61 references.