PMSM Feedback Linearization-sliding Mode Direct Torque Control

Permanent magnet synchronous motor is the representative of modern industrial production of a tool,represented in the numerical control machine tool in mass production due to a smaller volume,the efficiency higher advantages and wide application of direct torque control is the main control mode,the motor using the conventional direct torque control is mainly using switch table and hysteresis comparator,but they can’t finish the size of torque to distinguish,so as to large torque ripple problem always exists in this kind of control mode,this article in view of the surface mounted permanent magnet synchronous motor,probe the causes of large torque ripple problem,eventually reduce the torque ripple.First of all in the form of direct torque control elaborates the research situation,and on the basis of the research on the current development trend are discussed,and established the mathematical model of permanent magnet synchronous motor,explores the hysteresis comparison method,established the simulink simulation diagram,it is concluded that the simulation results,analysis of causes of torque ripple,the reason is mainly because the hysteresis comparator can’t distinguish between the size of the torque.According to the nonlinear characteristics of permanent magnet synchronous motor and the characteristics of mathematical model,the analysis of the causes on the basis of the torque ripple,this dissertation designs an input-output feedback linearization method,the method is based on differential geometry theory,the motor to linearize the nonlinear coupling parts processing,in using the theory of some configuration,design a linear controller,this dissertation analyzes the feedback linearization theory,the relation between input and output was deduced,the simulink model,has carried on the simulation,the simulation results show that compared with hysteresis comparison,feedback linearization method can significantly reduce the torque ripple of motor.In motor parameter changes,the sliding mode control is not sensitive to this,on the basis of this feature,this dissertation design the sliding mode control into the speed adjustment part,to test and verify the effectiveness of two algorithm combining after,this simulation verification,the final results showed that the feedback linearization based on direct torque control of sliding mode control system,not only retain the advantages of the feedback linearization direct torque control,and make the system has good dynamic characteristic and robustness of the system output speed will be better able to track the given speed,and after add load torque,rotation speed drop is small,And speed recovery compared with PID control has a significant improvement.Finally,based on the two algorithms mentioned above,based on the background of mine hoist,this dissertation mainly introduces the implementation methods of the two algorithms from two aspects of software and hardware,and expounds the practical significance of the algorithms in engineering design.