Theoretical And Experimental Research On Complementary Split Ring Resonator To Measure Ice Thickness Of Wind Turbine Blade

In recent years,with the rapid development of wind power industry,China’s wind energy resources are unevenly distributed,mainly concentrated in North China,northeast and northwest regions.In winter,affected by strong cold air,the fan blades in these regions are easy to be covered with ice,resulting in a series of problems such as unstable unit operation,reduced power generation,and threat to the safety of operators.Therefore,it is of great economic and safety significance to monitor the ice thickness of blades in real time.In this paper,a new method of ice thickness measurement based on complementary split ring resonator(CSRR)is proposed innovatively,and the method is demonstrated,analyzed,simulated and verified by experiments.The specific work is as follows:1.Based on the structure model,equivalent circuit and electromagnetic field distribution of CSRR,the mechanism of its excitation by microstrip is recognized,and the relationship among resonance frequency,equivalent capacitance and equivalent inductance of the two coupling structures is established.On this basis,the equivalent circuit model of microstrip CSRR coupling resonator after covering the object to be measured is obtained,the feasibility of its application in thickness measurement is analyzed,and the basic form of thickness measurement expression is derived.2.The coupling resonator model is established by using HFSS software.The structure size of the coupling resonator is determined by calculation and simulation optimization: half of the square side length of the inner ring of CSRR structure,the width of the opening of the inner and outer rings,the spacing between the outer side of the inner ring and the inner side of the outer ring,and the width of the opening of the inner and outer rings are 15 mm,1mm,2mm,1mm respectively.By running the simulation solver,the resonance frequency of the coupling resonator when measuring different dielectric constant and thickness of the object to be measured is obtained.Through data processing,the general relationship among the resonance frequency of the coupling resonator,dielectric constant and thickness of the object to be measured is determined by fitting.3.The coupling resonator sensor is made.Due to the fixed deviation caused by objective factors between the simulation and the actual measurement,the deviation between the measured frequency offset and the simulated frequency offset is calculated by using the quartz glass sheet with known dielectric constant and thickness is about0.005 GHz,and the measurement relationship is modified.4.The ice thickness measurement experiment was carried out.The thickness and vibration frequency of the ice layer on the surface of the coupled resonator are measured.By comparing the measured ice layer thickness and the calculated ice layer thickness at the same resonance frequency,the relative error is found to be within 15%.