| At this stage,the energy structure dominated by fossil energy has many disadvantages,and the development of new energy technology is the key to energy transformation.As an important means of new energy development,energy storage technology has attracted increasing attention.Compared with other energy storage methods,the flywheel energy storage system has no obvious shortcomings.It has the advantages of high energy density,wide operating temperature range,and low environmental pollution.It has outstanding application advantages in the field of new energy.The motor/generator is the core of the flywheel energy storage system,and its performance significantly affects the operation of the flywheel energy storage system.The bearingless switched reluctance motor(BSRM)has a simple structure and high reliability,and is suitable for high-speed and ultra-high-speed operation.It has obvious advantages in the flywheel energy storage system.While BSRM is a nonlinear strongly coupled system,and realizing the stable suspension of the motor has important research significance for the smooth operation of the flywheel energy storage system.This thesis chooses the new 12/14 hybrid stator bearingless switched reluctance motor(HSBSRM)as the research object.The key technologies of the 12/14 HSBSRM,such as structural composition,operating principle,operating characteristic analysis,suspension force modeling,and time Invariant control of the suspension system were studied,and relevant experimental verification was designed.The specific work is as follows:(1)The 12/14 HSBSRM structure and the principles of torque and suspension force generation are described in detail,and its operating characteristics are analyzed through the finite element model,including torque characteristics,suspension characteristics,and coupling characteristics of the motor.(2)Based on the equivalent magnetic circuit method,the traditional mathematical model of time-invariant suspension force is derived,which shows that the traditional mathematical model of suspension force ignores the pulsation of suspension force caused by the rotor salient pole effect,resulting in inaccurate estimation of suspension force.Aiming at this problem,based on the results of motor coupling analysis,a main-side magnetic circuit modeling method is proposed,and a mathematical model considering suspension force fluctuations is derived.Compared with the suspension force finite element simulation data,the accuracy of the mathematical model is verified.(3)Aiming at the shortcomings of the time-varying characteristics of the suspension force that make it difficult to improve the robustness of the traditional suspension control system,and based on the mathematical model of the suspension force established in this thesis,a suspension system control strategy considering the time-varying characteristics of the suspension force is proposed.The time-varying component of the suspension force is regarded as the external disturbance of the suspension system,and the anti-disturbance performance and suspension control accuracy of the suspension system are improved by designing a sliding model observer(SMO)to observe and feed forward compensation.And for the buffet of the sliding mode observer,improve its switching function and approach rate.The effectiveness of the control method is verified by MATLAB/Simulink.(4)In order to further verify the effectiveness of the control strategy mentioned in this thesis,based on the d SPACE system,related experiments were designed to verify the control strategy of the suspension system considering the time-varying characteristics of the suspension force,mainly include the design of the power conversion circuit,isolation drive circuit,and rotor position detection circuit.On this basis,the 12/14 HSBSRM suspension start experiment,stable suspension experiment,suspension percussion experiment and load percussion experiment were completed to verify the performance of the control strategy. |
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