Research On Pmsm High Frequency Vibration Suppression Technology Based On SiC Inverter

Due to the characteristics of fast dynamic response and high power density,permanent magnet synchronous motors are widely used in occasions that require high drive control performance.In the motor control system,the chopping voltage generated by the inverter is often accompanied by harmonics,which in turn causes harmonic currents in the stator windings,thereby generating motor vibration noise.Based on the background of low-noise underwater submersible propulsion system,this paper studies the suppression strategy of high-frequency vibration and noise caused by high-frequency current harmonics.First,the mechanism and characteristics of high-frequency vibration noise of permanent magnet synchronous motors are studied.It is found that the voltage harmonics generated by the chopping voltage of the inverter are mainly concentrated near the switching frequency and multiples.The resulting current harmonics in the stator winding also have the same characteristics,which provides a further strategy for suppressing high-frequency vibration and noise.Necessary theoretical support.For the high-frequency harmonics around the switching frequency and its multiples,this paper uses a combination of increasing the switching frequency and random PWM modulation to suppress it.Firstly,the random PWM modulation is analyzed through the theory of power spectral density to verify its principle of suppressing high frequency noise.Through MATLAB simulation,the phase voltage,phase current spectrum and phase current power spectrum density waveforms before and after random pulse width modulation are obtained,and then the suppression effect of random pulse width modulation on high frequency harmonics is obtained.By changing the control conditions such as the switching frequency and the bandwidth,the influence of them on the characteristics of high-frequency noise is studied to reduce the noise amplitude in a wider frequency range.In order to solve the problem that random PWM modulation is difficult to realize random numbers in actual systems,the chaotic PWM modulation strategy is used.Analyze the voltage spectrum characteristics under different chaotic maps and different chaotic modulation strategies,establish the qualitative relationship between the chaotic parameters and the voltage spectrum characteristics,and compare with the random PWM modulation on the suppression effect of high frequency harmonics,compare the two modulation strategies Advantages and disadvantages.Finally,the air gap magnetic field and radial electromagnetic force models of permanent magnet synchronous motors are analyzed,and Maxwell is used toperform finite element simulation calculations on the motor air gap magnetic density and radial electromagnetic force under different modulation strategies,and the calculation results are imported into Workbench.Under the environment,conduct modal analysis and harmonious response analysis to verify the effectiveness of increasing the switching frequency and improving the PWM control strategy in suppressing high-frequency current harmonics and high-frequency motor vibration.In order to verify the effect of increasing the switching frequency and improving the PWM strategy on the suppression of high-frequency vibration,the Si C MOSFET power module was used to build a permanent magnet synchronous motor drive system experimental platform.