Nonlinear Electromechanical Coupling Characterization Of Rotary Electromagnetic Energy Harvesting Shock Absorbers

Vehicle is an important pillar industry that promote the development of technology and economy for our country.The trend of intelligent vehicle network leads to the increase of electronic equipment used by vehicles,and the demand for electric energy of vehicles increases significantly.Energy harvesting shock absorber(EHSA)is a form to harvesting the vibration energy,which can convert the road excitation into electric energy,so as to increase the electric energy supply of the vehicle.Base on the standpoint,this paper carried out a study on the structural design and dynamic theory of EHSA,mechanical and electrical coupling characteristics and bench experiments.In structural design and dynamic theory,two types of EHSA are designed and fabricated.There is reciprocating EHSA and unidirectional EHSA.The working principle of are revealed,and the reason of the coupling and disengagement behavior in the transmission of unidirectional EHSA is clarified.The two dynamic models are established,including damping force model,engagement/disengagement velocity model and power flow model.The components of damping forces and their working characteristics are analyzed by the models.The backward Euler numerical calculation method and physical modeling method are used to build the models.The built models can solve the sinusoidal excitation,random excitation and other inputs.In electromechanical coupling characteristics,the engagement/disengagement characteristics of unidirectional EHSA are studied.The influence of disengagement on the composition of damping force and power generation is analyzed,and the influence is quantitatively discussed by time disengagement ratio and area disengagement ratio.The components of damping force are disassembled,and the effects of inertia force,electromagnetic damping force and mechanical damping loss on transmission characteristics are analyzed.From the perspective of external excitation,the damping force,generator velocity and the dissipated energy of damping force are analyzed under different excitation frequency,excitation amplitude and load resistance,and the influence of input excitation change on the engagement/disengagement threshold in time is quantitatively revealed,and the engagement region,disengagement region and controllable region under different excitation are divided.The optimal damping force under sinusoidal excitation and the load resistance under optimal generation performance are revealed by the energy flow model,which provides design criteria and help for the optimization work.In bench experiment,the dynamics model is verified by bench experiment.Based on the fluctuation of damping force and generating voltage,the coupling characteristics of the unidirectional EHSA are revealed.The characteristic is that the dynamic and electrical fluctuations of the regenerative shock absorber are linearly related in the engagement state,but not linearly independent in the disengagement state.The characteristic can be used to judge the motion state of regenerative shock absorber.The dynamic model of EHSA and its related research have laid a foundation for the design and practical application of EHSA.