A Parameter Compensation FCS-MPC-based Temperature Balance Control Method For Rectifier

As an important part of the traction drive system of high-speed train,the reliability of single-phase three level neutral point clamp rectifier is of great significance to the safe and stable operation of high-speed train.During the operation of single-phase three-level rectifier,due to the differences in the manufacturing process of IGBT and the asymmetry of working state,uneven thermal stress is generated between IGBTs at different positions on each bridge arm,resulting in temperature imbalance,which eventually leads to inconsistent service life of each IGBT.In addition,due to the aging of single-phase three-level rectifier due to fatigue accumulation during long-term operation,the system parameters change,which seriously affects the normal operation of single-phase three-level rectifier.Therefore,balancing the uneven temperature distribution between IGBTs and compensating the parameter mismatch in the system in real time,so as to improve the service life of single-phase three-level rectifier and improve the control performance of single-phase three-level rectifier,which has very important theoretical research significance and engineering application value to ensure the safe operation of high-speed train.The main research contents and innovative work of this thesis are as follows:(1)For the problem of uneven temperature distribution between IGBTs at different positions on each bridge arm of single-phase three-level rectifier,a FCS-MPC-based temperature balance control method for rectifier is proposed.This method constructs the active power and reactive power prediction model,neutral point potential balance prediction model and IGBT energy loss prediction model,designs the objective function corresponding to the prediction model,the evaluation function and optimization based on temperature balance control,and realizes the temperature balance control between IGBTs.Real time simulation results verify the effectiveness of the proposed method.(2)For the problem that the temperature balance control performance is reduced due to the change of resistance or inductance parameters in the process of system aging,a parameter estimation FCS-MPC-based temperature balance control method for rectifier is proposed.This method constructs the observer model related to the corresponding model parameters,studies the influence of parameter mismatch on the active power and reactive power of the system,realizes the parameter compensation of parameter online identification,and improves the performance of temperature balance control.Real time simulation results verify the effectiveness of the proposed method.(3)For the problem that the observed parameters of the above method are single and there may be multiple parameters changing at the same time in the process of actual system degradation,a parameter compensation FCS-MPC-based temperature balance control method for rectifier is proposed.In this method,a sliding mode disturbance observer is constructed to identify different disturbance parameters by using one observer.This method realizes the parameter on-line compensation under the condition of uncertain model parameters,improves the unit power factor,and alleviates the degradation of system temperature balance control performance caused by uncertain model parameters on the basis of ensuring the control performance of single-phase three-level rectifier.Real time simulation results verify the effectiveness of the proposed method.