Realization Of Starting Noise Suppression For Switched Reluctance Motor Of Electric Vehicle

Switched reluctance machine(SRM)has the advantages of simple structure,low manufacturing cost,good starting performance,strong system robustness and no rare earth resources,which makes it have a good development prospect in the field of electric vehicles.However,due to the particularity of its double salient structure,the vibration and noise during the start-up process is large,especially when the eccentric fault occurs,it will produce more noise,which limits its application in noise sensitive fields such as household appliances and electric vehicles.Therefore,it is very important to study the noise suppression method of switched reluctance motor under eccentric fault in the start-up stage for broadening its application field.In this thesis,the influence of SRM rotor static eccentricity fault on start-up vibration and noise is studied,and the suppression strategy is proposed.The main contents are as follows: 1)the causes of SRM start-up noise are analyzed.Based on the finite element analysis method,the influence of rotor static eccentricity on air gap flux density,radial force,torque and other parameters and performance is analyzed.It is revealed that rotor static eccentricity will produce radial force change and unbalanced force,and then cause vibration noise;2)In the startup phase,the motor works in current chopping mode.According to the characteristics of chopping current waveform,this thesis proposes a vibration suppression strategy based on the independent control of each pole current and the eccentric compensation of current partition,and establishes the analytical calculation relationship between radial force and winding current based on the complete magnetic circuit model.However,due to the complexity of the solution process,under the condition of ensuring the accuracy of the model,this thesis proposes a vibration suppression strategy based on the independent control of each pole current and the eccentric compensation of current partition,In this thesis,a simplified magnetic circuit model is proposed,and the analytical calculation relationship between the radial force and the winding current based on the simplified magnetic circuit model is established,so as to calculate the chopping current reference value and obtain the current control parameters.After that,the reference value of chopping current of each pole winding is controlled independently to control the current of each pole,and then the radial force of each pole is controlled to reduce the change of radial force and unbalanced force,so as to achieve the effect of eccentric compensation and realize the suppression of vibration and noise in the starting stage;3)For a 12 / 8-pole three-phase SRM,the simulation models of the traditional three-phase control mode and the proposed independent control mode of each pole current are built based on MATLAB / Simulink,which verify the effectiveness of the eccentric compensation and start-up noise suppression strategy;4)In this thesis,the software and hardware platform of SRM drive system is designed,and the vibration test platform is built for actual measurement and analysis.The experimental results also verify the effectiveness of the proposed method.The experimental results show that the peak value of additional vibration acceleration caused by eccentricity can be reduced by 68.8% by using the vibration suppression strategy based on the independent control of each pole current and the eccentricity compensation of current partition,which meets the design requirements.