Development And Performance Analysis Of Electrodynamic Active Vibration Absorber

With the increasingly stringent tendency of environmental regulations,more and more small-displacement exhaust gas turbocharged engines have been utilized in automobiles.Compared with previous large-displacement engines,they had many disadvantages in noise,vibration and harshness performance.Now,automobiles mainly rely on mounting systems to reduce the vibration of the powertrain transmitted to the body.Installing a dynamic vibration absorber on the sub-frame provided a new solution for this kind of problem,which had great significance.In this paper,an electrodynamic active vibration absorber was designed for the problem that vibration of a passenger automobile powertrain was too large in a wide frequency band,and its performance parameters were researched deeply.Based on the working principle and magnetic circuit analysis method,the finite element mathematical model was built.The relationship between driving force and electromagnetic force was analyzed.All of these laid the foundation for the subsequent simulation analysis and test.The structure of the electrodynamic active vibration absorber was designed.The design methods of magnetic circuit and sheet spring were elaborated in detail.An orthogonal test was arranged,with structural parameters of magnetizer height,boss radius etc.as test factors.Evaluation indexes included average strength of magnetic induction in the center of air gap and maximum strength of magnetic induction in the main magnetic circuit.It aimed at analyzing the influence rules of these factors.And the magnetic circuit structure of the actuator was determined by test result.The stiffness of the sheet spring was calculated and tested,which met the initial design goal.And the error was within a reasonable range.The theoretical analysis and experimental study of the electrodynamic-current characteristics and the driving force-current characteristics of an electrodynamic active vibration absorber were carried out.Firstly,the finite element software Maxwell wasused to simulate the electrodynamic force of the actuator.The influence of current magnitude and frequency on the electrodynamic force was analyzed,which showed great agreement with formula.Coupling analysis of the heating of the coil under extreme conditions showed that it would not affect the normal operation of the permanent magnet.Secondly,the driving force performance of the active vibration absorber was tested,and the relationship between the driving force and the current was analyzed.The results showed that the natural frequency of the absorber met the design goal,and the relationship between driving force and the current was linear.In addition,the measured electrodynamic force was compared with the calculated,which validated the modeling method and calculation method.In order to further enhance the actuator's performance,this paper proposed a new structure actuator.Another orthogonal test was arranged,with structural parameters of magnetizer and the number of permanent magnets as test factors.Its purpose was to investigate the influence of these parameters on average strength of magnetic induction in the center of air gap.Compared with the previous actuator,the electrodynamic force increased about by 12% under the same current input,which providing a guidance for the development and design of high performance actuator.