Research On Vibration Noise Caused By Switching Frequency Modulation With Soft-switching Technology

Inverter with excellent speed performance is widely used in the field of motor control,while a new noise component is introduced into the motor powered by inverter,and the harmonic component is mainly in close proximity to the switching frequency and multiplied-frequency.With the development of power electronics technology,the application of soft switching technology has been widely concerned because of its excellent switching characteristics,which has become an important research direction.The research on soft-switching theory is mainly carried out currently in the improvement of efficiency,reduction of electromagnetic interference,suppression on harmonic pollution and decrease of voltage current stress,whereas the research on vibration noise is relatively insufficient.The effect of soft-switching technology on the vibration noise of the motor under the power supply of the inverter is studied in this thesis,which is divided into the following aspects:The cause of motor vibration noise caused by the power supply of the inverter is studied in this thesis firstly.Numerous domestic and foreign corresponding references on operating principle and application of soft-switch are researched and referenced,accordingly,the auxiliary diode resonator pole inverter(ADRPI)is selected as the objective of this thesis.Based on the detailed analysis on the operating principle and working process of ADRPI,the soft-switching circuit resonant inductance and capacitance parameters are calculated for a 45 kW induction motor.The single-phase topology of ADRPI inverter is simulated to verify the reliability of the topology secondly,and the dynamic IGBT model is constructed in this thesis subsequently,on this basis of which,vector control models of the induction motor comprised of hard switching control,soft-switching timing control and soft-switching time-variable control are modeled.The spectrum analysis of the obtained current data is analyzed.The switching frequency limit can be entirely improved combined with the advantages of soft-switching in eliminating the switch loss,therefore,it can be apparently implied that the soft-switch technology is feasible to diminish the current harmonics powered by the inverter.The adaptability between ADRPI inverter and the motor is studied in this thesis thirdly,and motors with different parameters are simulated through the ADRPI,and it can be seen from the obtained current spectrum analysis data that the topology is more obvious for the harmonic suppression of the motor with larger power,and the inverter is more conducive to reduce the high-power motor vibration noise.Considering the current of hard-switch and soft-switch as the excitation source,the radial electromagnetic excitation force of the motor is obtained by finite element method finally,and spectrum analysis of which is carried out subsequently.Simulation results illustrate that the radial electromagnetic force,caused by the switching frequency modulation,is weakened appropriately through soft-switching technology.In conclusion,the soft-switching technology features high feasibility and validity in reducing vibration noise of the motor powered by inverter.