Research On Electric Control Of Single Winding Bearingless Switched Reluctance Motor For Flywheel Batteries

Flywheel battery,as an electromechanical energy storage device,has many advantages,such as high power density,no need for periodic maintenance,environmental friendliness,long life and high cycle efficiency.It has broad application prospects in power peaking,distributed generation,electric vehicle,space vehicle and other vital science fields.As the core component of the flywheel battery,the motor is the key of its development and application.Bearingless switched reluctance motor combines the magnetic bearing with the switched reluctance motor as a whole to achieve the two degree of freedom suspension and rotation.This motor not only preserves the characteristics of the friction free and non wear of the magnetic bearing,but also shortens the axial length and improves the critical speed effectively.Single winding bearingless switched reluctance motor(SWBSRM)is less a set of suspended winding than double bearingless switched reluctance motor,which improves the operating efficiency of the motor and the utilization of the winding.In this dissertation,the operation mechanism of single winding and full angle mathematical modeling were analyzed.In order to solve the problem of SWBSRM nonlinear,strong coupling,high jitter and poor dynamic performance,the research of electric control has been carried out under the sponsorship of the National Natural Science Fund(51377074).The main research work and achievements of this paper are as follows:The electric/suspension mechanism of SWBSRM was analyzed,in addition,the magnetic stator flux and rotor pole two adjacent cross link was split.The SWBSRM full angle mathematical model was derived by virtual displacement method,and its accuracy was verified by the finite element simulation.In view of the problems of suspension force ripple,torque ripple and coupling in the operation of SWBSRM,the direct torque and direct suspension force control of SWBSRM was proposed.Due to the unique single winding operation mode,using a five-level power converter,combining the principles of Maxwell stress and electromechanical energy conversion,deriving the direct numerical analysis relation of SWBSRM flux linkage,voltage,torque and suspension force and constructing the voltage input module,finally torque and suspension force could be decoupled.In order to improve the robustness and reliability of the system and eliminate the speed jitter in steady state operation,the two order sliding mode speed controller was designed by using the super twising algorithm,and the two order sliding mode direct torque and direct suspension force control was put forward.Besides,aiming at the problem that the super twising algorithm was only is only applicable to the relative order of 1,the higher order derivative term was introduced to establish the sliding volume,and the two order sliding mode rotor displacement controller was designed.The direct torque and the two order sliding mode direct suspension force control was presented.For the sake of further improving the rotor suspension performance,the super twsing algorithm was optimized and the rotor displacement controller based on this algorithm was designed.Eventually,the prototype control system was constructed to verify the superiority of the proposed control method.The SWBSRM high speed digital control system was established by using the design scheme of DSP+CPLD as the main control chip.The task was reasonably allocated according to the running characteristics of DSP and CPLD.The circuits of Five level power converters,optocoupler drivers,quadrature encoders,voltage protection,current detection and current protection are designed,which will lay the foundation for subsequent experiments.