Permanent Magnet Synchronous Motor Control For Vibration Reduction Based On Random Asymmetrical Carrier

Permanent magnet synchronous motor(PMSM)has the advantages of high efficiency,high torque density and high reliability.Space vector pulse width modulation(SVPWM)technology is widely used in PMSM for variable frequency speed control.In order to effectively reduce the high and low frequency vibration noise of the underwater propulsion PMSM,this dissertation proposes a new control method using random slope asymmetric carrier for PMSM.The details are as follows:Firstly,based on the mathematical relationship between asymmetric carrier and modulation wave to generate PWM pulse sequence,the mathematical expressions of phase current and line voltage under asymmetric carrier pulse width modulation(ACPWM)control mode of PMSM are deduced and analyzed.The results show that compared with the traditional SVPWM control method,the ACPWM control method can significantly reduce the phase current low frequency harmonics and help to suppress low frequency vibration.Secondly,aiming at the problem of high frequency harmonic peak of motor phase current under ACPWM control mode,a new random slope asymmetric carrier(RAC)control method is proposed,that is,the slope of asymmetric carrier changes randomly,and the carrier amplitude and period remain unchanged.The results show that,compared with the traditional random switching frequency(RSF)control,the RAC control method has a more obvious effect on the suppression of the high frequency harmonic peak at the motor switching frequency and its multiples,which is helpful to suppress the high frequency vibration.Thirdly,using Matlab/Simulink and ANSYS software to construct the cosimulation model of PMSM,and simulate the four control methods of SVPWM,ACPWM,RSF and RAC respectively.The results show that the RAC control method can reduce both the high frequency and low frequency harmonic peaks of the phase current,and help to suppress the high frequency and low frequency vibration of the propulsion motor at the same time.Finally,a motor test bench is constructed,and the ACPWM and RAC control methods proposed in this dissertation are realized.The corresponding experimental results are given and compared with the theoretical analysis and simulation results.The results show that the method of RAC control can effectively reduce the high and low frequency vibration of PMSM.