Research On Structure Design And Control Strategy Of Push-pull Dielectric Elastomer Generator

Electroactive polymers are a class of polymers whose size and shape change significantly under the excitation of an electric field.Dielectric elastomer is a typical electroactive polymer,which has great application prospects in the fields of power generation,driving,etc.,especially in the field of renewable energy power generation.The principle of dielectric elastomer generator power generation is based on variable capacitor generator,which can convert mechanical energy into electric energy through power generation cycle.Dielectric elastomer has the advantages of good flexibility,impact resistance,high energy density,easy processing and low noise.In this paper,the push-pull generator is studied.The research contents and main conclusions are as follows:The boosting model of the symmetric circuit and the asymmetric circuit were established.According to the MATLAB simulation,the minimum allowable capacitance swing of the asymmetric circuit is less than that of the symmetric one.The asymmetric circuit has a better boosting effect than the symmetric circuit when the capacitance swing is less than 2.83.The symmetrical circuit has a better boosting effect when the capacitance swing is greater than 2.83.The change of capacitance of the dielectric elastomer generator during stretching was studied experimentally.The uniaxial,biaxial and pure shear stretching devices were designed.The fracture limit and The relationship between the output voltage,the generated electric energy,the tensile force and the deformation of DEG were studied experimentally.It has been found that the maximum capacitance swing decreases decreases as the number of stretching increases.By applying the flexible electrode after pre-stretching,the flexible electrode is led to the fixed rod and then the external wire is connected,which can improve the speed of the reduction of the capacitance swing.The dielectric elastomer has the largest rupture limit in the biaxial stretching mode.When the area conversion rate is more than 4 times,the electric energy is greatly increased,and the dielectric elastomer energy density can be maximized.The cone-shaped stretching method was selected,and the theoretical model was established by the Mooney-Rivlin model and simulated by COMSOL.The relationship between the capacitance of dielectric elastomer and the deformation size under different pre-stretching was compared by experiment.The change of dielectric constant of dielectric elastomer was studied.The push-pull DEG of the top-type tapered stretching mode was fabricated by using a 2 times pre-stretching ratio and a symmetrical circuit structure.The energy generation performance of the push-pull dielectric elastomer generator was tested.The DEG self-parallel resistance was calculated by DEG discharge voltage curve.The effects of the ratio of the inner and outer diameter and capacitance swing to the push-pull DEG were studied experimentally.It was found that the optimal internal-to-outper diameter ratio of the push-pull generator in terms of power generation,required maximum external force,mechanical energy and conversion efficiency was inconsistent.Using a push-pull generator structure with an internal capacitance ratio of 25 mm and a maximum tensile distance of 75 mm,the effect of the frequency on boost was studied.When the frequency is less than 1.5 Hz,the voltage boosting in per cycle increase with the increase of the frequency;when the frequency is greater than 1.5 Hz,the multiple of the voltage changes little.The Zener diode energy storage circuit was optimized.Two new energy storage circuits were proposed.The three energy storage circuits were compared.It is found that the Capacitor-type energy storage circuit has the highest energy storage efficiency,and the energy storage efficiency of the Zener diode energy storage circuit is second.The SCM energy storage circuit has the lowest energy storage efficiency.It was proposed that in practical applications,the Capacitor-type energy storage circuit can use a mechanical travel switch instead of the relay switch to advid additional external power supply.