Permanent Magnet Synchronous Motor Model Predictive Control Based On Maximum Torque-to-current Ratio

Interior permanent magnet synchronous motor with high reliability,high power density and other characteristics in the industrial manufacturing,rail transportation,aerospace and other fields of application has been widely favored.In the maximum torque per ampere control method interior permanent magnet synchronous motor can provide higher torque density.Space vector control and direct torque control are two classical control strategies.Among them,the direct torque control strategy has the advantages of simple control structure,fast torque dynamic response and high parameter robustness.However,due to the direct torque control strategy using torque and flux hysteresis controller,resulting poor modulation vectors,so the motor output larger torque ripple.The finite control set model predictive control strategy has the advantages of fast dynamic response,flexible target function configuration and easy to handle constrained optimization problems.In recent years,it has been widely used in electric drive.And the finite control set model predicts torque control compared to the direct torque control,which uses an accurate internal model to replace the traditional hysteresis controller so that the problem of torque ripple can be effectively suppressed.However,this method still have many shortages,such as the weight factor is difficult to set,too much calculation and the modulation vector is too small.In response to the above problems,this paper carried out the following research work.In this paper,the interior permanent magnet synchronous motor basic ideas and methods of vector control,direct torque control and predictive control are introduced first,and the establishment of the mathematical model of the interior permanent magnet synchronous motor is analyzed.Then,the problems of weight factor and large torque ripple in traditional predictive torque control are analyzed.At the same time,some existing improvement schemes are introduced and discussed.Aiming at the problem of less modulation voltage vector and weight factor setting with heavy workload in traditional predictive torque control,the discrete space vector modulation strategy and an improved method which can eliminate the weight factor in the model predictive torque control.The improved method analysis of the torque generated by the motor under the control of the maximum torque per ampere,a cost function with uniform torque dimension is designed.At the same time,the method of flux vector control is used to improve the shortcoming of the designed cost function under light load.Compared with the method of fliux vector cost function,this method can make the motor have better torque control effect under heavy load.Finally,the traditional methods and improved methods simulation and experimental analysis are carried out based on the two-level inverter feed interior permanent magnet synchronous motor control system.In the simulation and experiment,the motor speed,torque and flux of the waveform data analysis that:the improved method compared to the traditional method eliminates the weight factor.And compared with the flux vector method,the proposed method has less torque ripple when the motor is overloaded...