Characteristic Research Of Permanent Magnet Rotor Type Diamagnetically Levitated Airflow Energy Harvester

With the development of the Internet of Things and low-power electronics,powering electronic devices is gaining more and more attention.This paper proposes a permanent magnet rotor type diamagnetically levitated airflow energy harvester using airflow to drive the rotation of a magnet rotor in diamagnetically stable levitation,based on the principle of electromagnetic induction,which generates an induced electric potential in the coil.The main work of the paper is as follows.Firstly,the airflow energy harvester is studied based on relevant fundamental theories,and a detailed theoretical analysis of this energy harvester is discussed in terms of electromagnetic induction analysis,magnetic force analysis,diamagnetic force analysis,fluid-solid coupling analysis,flow field analysis and amplification circuit analysis.Next,the analytical calculations are performed using simulation software,and COMSOL and Matlab are jointly simulated for in-depth analysis of magnetic force,antimagnetic force,magnetic field distribution characteristics,and voltage.ANSYS Electronics Desktop 2019 R3 was used to simulate and analyze the output characteristics of the airflow energy harvester to study the effects of magnet rotor thickness,rotor eccentricity,coil layout,rotor inner through-hole radius,and magnet rotor opening radius on the output voltage,magnetic chain,and electromagnetic damping torque.The amplifier circuit is simulated and compared in Multisim 14 and Matlab,respectively,to analyze the output characteristics of the voltage doubling circuit by varying the power supply frequency,capacitor value and circuit structure.Then,the static characteristics,dynamic characteristics and flow field characteristics of this airflow energy harvester were studied using the control variable method,and the simulation results of the static characteristics were obtained by changing the parameters,and the flux density value obtained from COMSOL simulation was 0.01 T smaller than the analytical method.The dynamic characteristics of the rotor were analyzed using the kinetic theory and Simulink.The Boussinesq assumption,RANS equation and Bernoulli’s principle were used to study the flow field characteristics.Finally,an experimental platform was built for the experimental study of the airflow energy harvester.The rotor was designed and manufactured according to the influencing factors such as plating,number of openings,radius of openings,radius of inner through holes,magnet delamination and hole shape,and the rotor types are A,B,C,D,E,F,G,H,type I and type J.The control variables method was used for the comparison experiments,and the device consisting of type A rotor was used as the base structure,while the other structures were used for the comparison analysis,and the output characteristics were further analyzed by changing the device structure and position.Numerical analysis,analysis of variance and column table test were used for data processing.The experimental results show that the maximum voltage of 1198 m V,maximum speed of 19025 rpm,RMS voltage of 0.85 V,RMS power of 45 m W,peak power of 90 m W,and output voltage of the six-fold amplifier circuit can reach 1.8V.Galvanizing can improve the corrosion resistance of the rotor,but the speed and peak voltage are reduced by 2.394% and 2.923% respectively after galvanizing.The maximum peak voltage obtained by the experiment with the rotor with a gap radius of4 mm is 869.44 m V and the maximum speed is 7933.05 rpm.Increase the number of gaps can increase the output voltage and speed.The maximum speed of the conical hole rotor is 19729 rpm,and the maximum voltage is 1255.6m V.When the rotor has no holes,the stability is reduced,the maximum voltage is reduced by 11.8%,and the maximum speed is reduced by 16.6%.When the rotor is stratified,the magnetic flux density at the same position is reduced by 2.34%,and the voltage and rotational speed are both reduced.The basic rotor is used to collect airflow energy,and its output can light up at least 25 small LED lights after being rectified by the amplifier circuit.