Electromagnetic Structure Design Optimization Of Variable AC Synchronous Electro-hydraulic Coupler

Automotive and energy,transportation,information and communication and other fields accelerate the integration of material field,energy field,AI field and more and more cutting-edge technology into the new energy vehicle,as one of the new energy vehicle core drive system,its performance directly affects the vehicle’s power,economy and comfort.The characteristics of electromechanical and hydraulic power have their own advantages,and better energy saving effect can be achieved by complementing each other.The variable AC synchronous electromechanical hydraulic coupler integrates the electric drive system and the hydraulic drive system highly,and forms the powertrain of the electromechanical hydraulic coupling electric vehicle after loading,taking into account the advantages of pure electric drive and hybrid drive.Electromagnetic structure of electromechanical hydraulic coupler is the core of energy conversion of the whole system.Good electromagnetic performance and taking into account the stability of hydraulic system is the key to design electromechanical hydraulic coupler.In this paper,the electromechanical hydraulic coupler electromagnetic structure design,through the finite element simulation analysis of electromechanical hydraulic coupler electromagnetic structure design feasibility,finally through the Taguchi method to optimize the rotor structure to improve the electromechanical hydraulic coupler electromagnetic performance.Combined with the structural characteristics and performance requirements of the electromechanical hydraulic coupler,the material selection and electromagnetic structure design of the electromechanical hydraulic coupler were carried out according to the stator and rotor structure of the permanent magnet synchronous motor,and the electromagnetic structure parameters of the electromechanical hydraulic coupler with rated power of 18k W were determined.The rotor material of the electromechanical hydraulic coupler needs to meet the working requirements of the electric drive system and the hydraulic system at the same time.Through the comparison of the material properties,the silicon steel sheet rolling holes and embedded brass sleeve are selected as the rotor structure of the electromechanical hydraulic coupler.Finite element simulation software Maxwell was used to analyze the two-dimensional electromagnetic structure of electromechanical hydraulic coupler in static and transient fields to verify its rationality.Research the influence of plunger hole on electromagnetic performance of electromechanical hydraulic coupler is studied.The output torque characteristics of the two rotor structures with and without the plunger cavity were compared under the control of MTPA,and the influence of the plunger cavity on the performance of the electromechanical hydraulic coupler was explained by the transient magnetic field cloud image and the Q-axis flux linkage Angle.The inductance L_q and L_d of AC-D axis are solved considering the cross-coupling of AC-D axis.The influence of plunger cavity on magnetic circuit is analyzed through the change trend of AC-D axis inductance with current.The results show that plunger has influence on the inductance of D axis and Q axis at the same time.In order to make the mechanical and electrical hydraulic coupler has better torque output capacity and improve the utilization rate of permanent magnets to minimize plunger effect on magnetic circuit,the use of taguchi method of arrangement and analysis of permanent magnet rotor permanent magnet width,thickness effect on the stability of output torque size and the degree,to choose the appropriate parameter combination according to the proportion of impact simulation.The results show that compared with the original model,the average torque increases,the torque fluctuation decreases,the utilization rate of permanent magnet increases,and the optimization effect is remarkable.