Design Of Permanent Magnet Synchronous Motor Controller For Underwater Noise Reduction

The permanent magnet synchronous motor(PMSM)is applied to the area of electric propulsion because of simple structure,small volume,high power density and good speed performance.It is very important to reduce the vibration noise of PMSM because vibration and noise directly determine the stealth and safety of unmanned underwater vehicle(UUV).This dissertation designed an UUV motor controller for reducing noise.Related work were as follows:Firstly,vector control system of current and speed double closed-loop was designed according to the performance requirements of PMSM.SVPWM and random modulation control methods were analyzed in theory.The expression of phase current in time and frequency domain were derived in the control method of SVPWM.The composition and harmonic distribution of phase current were analyzed.The simulation model was constructed to verify the accuracy of theoretical analysis.Secondly,the influence between rotor position error of magnetic encoder and vibration noise were studied.Working principle of magnetic encoder was analyzed.The rule of rotor position error in different installation position was analyzed by finite element method.A BP neural network system for magnetic encoder error compensation was constructed.The effect of rotor position error in current harmonic and the effectiveness of compensation method were verified by simulation.Thirdly,a motor controller based on dual closed-loop SVPWM method and random switching frequency modulation were designed.The correctness of phase current harmonic distribution and the validity of rotor position compensation and random switching frequency modulation were verified by experiments on motor test platform...