| Energy issues in the 21 st century have been became one of the major problems in the world.The development of renewable energy is imminent.The flywheel battery has a high research value in the application of renewable energy as a high-performance energy storage device.Bearingless brushless DC motor is suitable for flywheel batteries because of its characteristics.Aiming at some drawbacks of the motor in the flywheel battery,a bearingless brushless DC motor for flywheel battery is presented,namely outer-rotor bearingless brushless DC motor(OBBDM).There are a high power density and a low degree of coupling between the suspension force and the torque in the motor.The design of the structure can greatly reduce the size of the flywheel battery to achieve a high degree of integration of the flywheel battery.The principle of suspension force generation makes it have stronger suspension force adjustment performanceFirst,the basic composition of the OBBDM system is briefly introduced,the basic structure of the OBBDM motor body is presented,and the structure of the motor body including the connection of the torque winding and the suspension winding is explained.According to the energizing characteristics of the motor,it is proposed that the torque winding and the suspension winding of the same tooth are not energized at the same time to reduce the coupling.The torque principle and suspension principle of the motor are explained,and the mathematical model of the torque and the mathematical model of the radial suspension force are given.Secondly,the OBBDM is designed and optimized based on the structure and requirements of the flywheel battery.The design method of the motor parameters of the OBBDM was studied with reference to the design method of the BLDC motor and the initial values were calculated.In order to make the motor performance more superior,optimizing single parameter of motor parameters under conditions of multiple constraints on the motor.The constraints are to achieve suspension,torque ripple and eddy current,and hysteresis loss at the same time under the premise of satisfying torque and suspension force.Determine the optimal parameters in consideration of constraints.Thirdly,Using Maxwell,an Ansys finite element analysis software,to study the electromagnetic properties of a motor.An OBBDM finite element model was established to simulate and analyze the motor performance parameters.Firstly,the magnetic field of the motor is analyzed,including the magnetic field distribution,the back-EMF of the torque winding and the suspension winding,and the air gap magnetic field density.It is verified that the principle of the suspension force is due to the imbalance of the air gap magnetic field density.Then the motor torque characteristics were analyzed and the results of the torque mathematical model were verified.Then the characteristics of the suspension force were analyzed,the mathematical model of the suspension force was verified,and the regulating performance of the suspension force of the motor was proved.Finally,the coupling characteristics of the motor are analyzed,and the coupling relationship between torque and suspension,suspension and suspension is obtained,and the weak coupling of OBBDM is proved.Finally,for the test of the OBBDM prototype,a digital control system for the prototype was designed.Start with the control method to understand the amount of control and control required for control.A digital control system based on TMS320F28335 digital signal processor was designed.Firstly,the main circuit of the torque winding and suspension winding was designed.Then,the drive circuit,signal conditioning circuit and protection circuit were designed respectively,and the physical object was made,and the real object was tested in part.At the end of the article,we summarized the work done in this paper and the results achieved,and introduced the work that needs to be completed. |
