Design And Research Of Double Stator Permanent Magnet Brushless DC Motor For Deep-sea Propulsion

The deep-sea thruster motor is considered as the power source of the underwater propulsion equipments,and the upper limit of deep-sea exploration and development work is directly affected by the development of the technology of the deep-sea thruster motor.In recent years,permanent magnet brushless DC motor has been widely applied in the underwater propulsion equipments because of the advantages of high efficiency,high power density and stable operation.The double stator permanent magnet brushless DC motor is a new structure motor,which has the advantages of high overload capacity,small inertia of the rotor,and flexible control mode.A great application value of the motor will be realized in the field of deep-sea propulsion.In this thesis,the basic structure and the principle of the double stator permanent magnet brushless DC motor are analyzed firstly.The magnetic circuit structure and the winding connection type of the motor are analyzed,and the equivalent magnetic circuit and the basic equations under the two phase conduction work mode are given.Secondly,the design method of the double stator motor is studied.Characteristics of small volume and light weight of the deep-sea motor are considered,and the design speed of the motor is improved.Then the design scheme of the structure with reducer is used.The design idea is that a single stator motor is designed firstly and then a double stator motor is designed based on the former design.The determination of the main dimension,the selection of the electromagnetic load,the design method of the stator and rotor,and the design method of the permanent magnet are studied based on the equivalent magnetic circuit method.The selection of the slot and pole cooperation is deeply studied.The preliminary design scheme is acquired by the calculation of the equivalent magnetic circuit.Then,the finite element model of the double stator permanent magnet brushless DC motor is built in ANSYS Maxwell.The magnetic filed under no-load mode and the operating performance of the motor in transient field are simulated and analyzed.The performance curves of the speed,torque,current and so on are acquired.Meanwhile,the operating performances of the motor in different winding connection modes are analyzed.The effects of performances of the back EMF,torque ripple,magnetic leakage and efficiency in different parameters of the motor are studied,and the corresponding parameters of the motor are adjusted.Finally,the influence factors of the torque ripple of the double stator permanent magnet brushless DC motor are analyzed.The method for reducing the cogging torque is studied.The change regulation of the cogging torque in different control methods is analyzed by the finite element method,and a reference to improve the steady operating state performance of the motor is provided.The results show that the double stator permanent magnet brushless DC motor improves the space utilization rate of the materials and it has higher power density and torque density.Because the different winding connection modes can be used,this motor also has a wider range of the running speed.The double stator permanent magnet brushless DC motor is very suitable for the deep-sea thruster motor and has a good application prospects.