Design And Research On Tubular Permanent Magnet Linear Synchronous Motor Of Electromagnetic Active Suspension

An active force of real-time control is input into the active suspension system through the actuator according to the vehicle state and road condition,which can improve the ride comfort as well as handling stability.Excessive energy consumption and costs of the active suspension prevent its large-scale application.The electromagnetic suspension,a brand new suspension system using electromagnetic reaction principle,has the following advantages: quick response,high control precision,and vibration energy recovery which can make up for some deficiencies of active suspension like high energy consumption and complex structure.Therefore,the study of electromagnetic active suspension is of great significance.Based on the research status of electromagnetic suspension and linear motor at home and abroad,a tubular permanent magnet synchronous linear motor with compact structure and stable thrust is designed.The main research contents are as follows:1.Based on the understanding of structure and working principle of tubular permanent magnet synchronous linear motor,the mathematical model is established.Then the motor equation is changed from a-b-c into d-q coordinate through coordinate transformation of constant power.Finally,the stator current is decoupled by voltage feedforward.The thrust of the motor is controlled precisely by vector control.2.The thrust is mainly used to restrain the low frequency vibration.The rated parameters of the linear motor is estimated on consideration of factors like sensor delay and so on.Then the electromagnetic load is chosen.After that,structure and size of the primary section are calculated,which contains ratio of the pole to slot,the slot shape,the winding form and coil space factor.Next,the selection of permanent magnetic material and calculation of permanent magnet size are involved in secondary design.According to equivalent circuit,the electromagnetic parameters of the motor are calculated.Finally,design parameters of motor is determined and the initial design of tubular linear motor is given in form of 3D drawing.3.The tubular permanent magnet synchronous linear motor is modeled in ANSYS Maxwell.The finite element model is verified in two methods: contrast between simulation and analytic calculation on magnetic density in air gap,and the comparison between simulation and theoretical calculation on thrust constant.Furthermore,the effect of the structure form,structure parameters and other factors of linear motor exerted on electromagnetic thrust is studied carefully.4.The optimal controller is designed for the electromagnetic suspension of quarter car in Matlab/Simulink.When the vehicle with the electromagnetic suspension travels at velocity of 30m/s on B class road,the result shows that it can improve the ride comfort of the vehicle obviously.Also,the electromagnetic suspension composed of linear motor can improve the ride comfort for various vehicles on E class road.At last,the structure design scheme of electromagnetic suspension is proposed.