Study Of The Key Technologies Of High Performance Servo PMSM

The existing permanent magnet synchronous servo motors are mostly surface-mounted rotor structures,which are difficult to meet the requirements of high-speed servo motors.This paper studies the high-performance inner-buried rotor structure permanent magnet synchronous servo motor.The inner-buried rotor of this servo motor can run at high speed with safe and reliable structure,and the processing cost of magnetic steel is low.However,the inner-buried rotor structure has a high harmonic content of magnetic field.The asymmetric magnetic circuit of the direct and quadrature axis makes the electromagnetic torque and vibration and noise performance of the motor worse.Therefore,it is of great theoretical and practical significance to study the inner-buried rotor structure of high performance servo motor in this paper.Chapter 1 summarizes the research status of PMSM rotor pole shift and rotor slotting to reduce cogging and ripple torque and to improve the electromagnetic vibration and noise of PMSM.Chapter 2 of this paper studies the inner-buried rotor structure of permanent magnet synchronous servo motor which reduces cogging torque by pole shift and its field-circuit combination analysis method.Establishing the surface-equivalent model of inner-buried rotor structure by equivalent idea.The function expression of the equivalent model cogging torque with the magnetic pole shift angle is solved,and then the magnetic pole shift angle of the equivalent model is determined,which is the magnetic pole shift angle of the inner-buried rotor structure cogging torque weakening.and the rationality of the equivalent model of the surface-mounted rotor is verified by finite element simulation.In chapter 3,the internal tangential slitting of the inner-buried permanent magnet synchronous servo motor is studied to improve the no-load magnetic field harmonics to weaken the motor ripple torque and reduce the motor torque ripple.The effects of width,length and position of tangential slitting on ripple torque are analyzed by analytical and finite element simulation respectively.The structural stress of tangential slitting rotor is analyzed by equivalent sheath method and the simulation verification of finite element method is carried out.In chapter 4,the electromagnetic vibration and noise of high performance permanent magnet synchronous servo motor are studied.Comparing the natural modes of two shapes of casing motors.The effects of different pole shift angles and tangential slitting lengths of rotor poles on the amplitude of low-order force wave and magnetopolar multiple force wave amplitude are discussed.The electromagnetic vibration and noise of circular and square case motors with different pole shift angles and tangential slot lengths are simulated and analyzed.In chapter 5,the prototype of inner-buried permanent magnet synchronous servo motor is introduced.Two prototypes of rotor with rated power of 3.7 kW magnetic pole shift and tangential slitting have been manufactured respectively.No-load back EMF experiment,electric operation experiments and cogging torque measurement experiments.A modal test was conducted using the hammer method to measure the natural modal frequency of the motor and vibration and noise experiments.Compared with the simulation results,the correctness of the finite element simulation method is verified.Chapter 6 summarizes the whole paper.