Design And Electric Control Research On Hybrid Double Stator Bearingless Switched Reluctance Motor For Flywheel Batteries

In recent years,electric vehicles,aerospace,urban rail transit,regenerative energy braking and other fields have developed rapidly,and energy storage technology has become a hot topic in the world.As an emerging physical energy storage method,flywheel energy storage has the advantages of high energy density,fast charge and discharge speed and strong environmental friendliness,and has gradually attracted people’s attention.Bearingless switched reluctance motor(BSRM)is the energy conversion core of common flywheel batteries.Because of its simple and sturdy structure and good fault tolerance,it has a good application prospect.However,due to the natural coupling between the BSRM suspension system and the torque system,the control difficulty of the system is increased.Therefore,studying a new self-decoupled BSRM ontology topology has very important theoretical and practical value.Based on the in-depth analysis of the existing BSRM topology,a new hybrid double stator bearingless switched reluctance motor(Hybrid Double Stator BSRM,HDSBSRM)structure is proposed in this paper.Key technologies such as the operating principle,mathematical model,key dimension parameter optimization design,electromagnetic performance analysis,low torque ripple and low levitation force pulsation control strategy and digital system design of the new HDSBSRM are studied.The main research contents are as follows:(1)A new HDSBSRM structure is proposed,which not only retains the excellent decoupling characteristics of the traditional double stator bearingless switched reluctance motor(DSBSRM)structure,but also has better suspension output capability and reduces the suspension loss of the system.The basic composition and body structure of the motor are expounded.The connection mode of the motor winding is introduced.The principle of levitation force generation is analyzed in detail,and the mathematical model of the motor suspension system is established.(2)In order to obtain better performance index of the motor,the CQPSO-DE algorithm is used to optimize the key parameters of HDSBSRM.Starting from the structure and demand of the flywheel battery,aiming at improving the radial suspension output capacity,reducing the volume and reducing the axial length,the corresponding constraints are determined,and the multi-objective optimization function of the motor performance is established.A set of satisfactory solutions was chosen as the final size parameter of the HDSBSRM prototype.(3)Establish a three-dimensional finite element model of HDSBSRM and study the electromagnetic characteristics of the motor by finite element analysis.Firstly,the air gap magnetic density under static and dynamic is analyzed,and the principle of levitation force is verified.The coupling characteristics between the motor torque system and the suspension system and the two degrees of freedom of the suspension system are analyzed,which proves the weak coupling of HDSBSRM.Performance;compared with the traditional DSBSRM performance,verified its high floating output capability and low suspension power consumption.(4)For the problem of large torque and suspension force pulsation during motor operation,the direct torque and direct suspension force control strategies of HDSBSRM are proposed.The relationship between the flux linkage and torque of the motor is derived.The torque voltage space vector is given,and the hysteresis control of torque,flux linkage and suspension force is constructed.To further improve the dynamic response speed and robustness of the suspension system,HDSBSRM The suspension system adopts the second-order sliding mode direct suspension force control strategy,and the rotor displacement controller based on the second-order sliding mode is designed.The effectiveness of the proposed control strategy is verified by Simulink simulation.(5)The HDSBSRM high-speed digital system was established with DSP and CPLD as the main control chip.According to the resource characteristics of DSP and CPLD,the tasks are allocated reasonably.The power conversion,drive and detection circuits of the torque system and the suspension system are designed respectively,and the relevant device models are determined,which lays a foundation for the subsequent experimental research.