Research On Adhesion Control Of Heavy-duty Locomotives Based On Improved Fuzzy PID

Good wheel-rail contact can not only improve the running performance of the locomotive,but also improve the service life of the locomotive and reduce the cost of line maintenance.Therefore,in-depth study of wheel-rail adhesion characteristics and locomotive adhesion control is conducive to improving wheel-rail adhesion performance,which is essential for improving locomotive transportation capacity and driving safety.Based on the relationship between the change of wheel-rail adhesion state and the stator current characteristics of traction motor,this paper further analyzes the optimal control of wheel-rail adhesion and adhesion of heavy-duty locomotives.The main research contents are as follows:(1)Aiming at the problem that the maximum torque-to-current ratio(MTPA)vector control of permanent magnet synchronous motor cannot continue to rise when the motor speed reaches the rated speed,this paper designs a leading angle weak magnetic control method based on MTPA,which uses the leading angle weak magnetic control module to compensate for the leading angle of MTPA control,changes the established trajectory of the current vector for field weakening control,and realizes high-efficiency control of the motor in a wide speed range.(2)The adhesion principle of heavy-duty locomotives was analyzed,and a simplified model of locomotive drive dynamics was built according to the analysis of the traction system and adhesion mechanism of heavy-duty locomotives.The self-excited vibration of the drive system when the locomotive is slipping is studied,and the influence of the gradient characteristics of the stick-slip characteristic curve on the vibration frequency of the drive system is analyzed.The results show that during the sliding process of locomotive,the negative slope characteristics of wheel-rail adhesion make the system unstable,and the vibration characteristics of the drive system are specifically manifested as self-excited torsional vibration,and the angular velocity frequency of self-excited torsional vibration of the drive system is similar to the inherent vibration frequency of the drive system.(3)MATLAB/Simulink is used to establish the single-wheelset motion model of the locomotive,and combines it with the traction motor control model,and the stator current characteristics of the traction motor when the wheel-rail adhesion state of the locomotive is changed is analyzed by fast Fourier transform(FFT).It is concluded that there are harmonic components in the stator current spectrogram that are similar to the natural frequency of the vibration of the drive system.When the amplitude of the harmonic component is greater than the threshold,the locomotive can be idled to idle.(4)Based on the optimization idea of differential evolution algorithm,the parameters of the fuzzy PI controller are optimized,and the PI control,fuzzy control and improved fuzzy PI control strategy are used to simulate and analyze the adhesion control,and the simulation results show that the improved fuzzy PI controller designed in this paper has certain stability and superiority compared with the traditional PI control and fuzzy control.