Permanent Magnet Synchronous Motor Control For Vibration Reduction Based On Sawtooth Carrier

As the main driving force of the unmanned submarine propulsion system,permanent magnet synchronous motor(PMSM)has the advantages of high power density,high efficiency,simple structure and high reliability.Underwater propulsion systems have high requirements for both low and high frequency vibration and noise.The current research on control methods focuses on the solution of high frequency vibration and noise problems.In order to achieve the goal of low vibration and noise in the full band of underwater propulsion motors,this paper proposes a new control method using sawtooth carrier for PMSM.The details are as follows:Firstly,the mathematical model of the three-phase inverter bridge based on the switch function is used,the expression of the switching function in the sawtooth carrier mode is derived,and the phase current harmonics of PMSM are analyzed and calculated.Analytic calculations show that there are sideband harmonic currents with large amplitudes on both sides of the phase current fundamental wave,and these sideband harmonic currents affect the low frequency vibration characteristics of PMSM.Secondly,buliding the co-simulation model of PMSM using Matlab/Simulink and ANSYS software.The simulation verified the accuracy of the analytical calculation of the phase current harmonics using sawtooth carrier mode.Besides that,simulating the phase current harmonics of PMSM using the sawtooth and the triangle carrier modes.Simulation results of a 1100 W PMSM show that the sawtooth carrier can reduce the sideband harmonic current peaks which are on both sides of the phase current fundamental wave by 40.9% compared with using the triangular carrier wave.Thirdly,a sawtooth carrier dual-random control method combining random switching frequency and random zero vector is proposed.The effect of the proposed method on the dispersion of high-frequency harmonics is verified by using the co-simulation model.The simulation results of 1100 W PMSM show that the double-random method has the best effect of high frequency harmonic dispersion of phase currents.Finally,sawtooth carrier double-random control method is used to verify the effectiveness of suppressing motor vibration in the entire frequency range.The 1100 W PMSM experiments show that the use of saw-tooth carrier can reduce the vibration amplitude of the low-frequency vibration by 60% compared with the triangular carrier.Compared with the random switching frequency method of sawtooth carrier,the amplitude of the high-frequency vibration acceleration nearby the switching frequency can be reduced by 50% using the double-random method.