Research On Direct Torque Control For Permanent Magnet Synchronous Motor Based On Cloud Model

Permanent Magnet Synchronous Motor(PMSM)is a kind of Synchronous Motor whose synchronous rotational magnetic field is generated by permanent magnet.It has been widely applied in industrial,transportation and home appliances field for merits such as simple structure,high efficiency and low heat,etc..PMSM-DTC theory is a kind of control theory based on torque direct control,it has the benefits of simple control method,fast response and high robustness,it has became a hotspot of research in PMSM control field.Traditional PMSM-DTC theory is based on the linear system.But in actual condition,when the motor is running,the complex environment may make the system to a nonlinear system.Cloud Model theory is a new subject focusing on fuzziness and randomness,it has high practical value for intelligent control.Cloud Model theory does not need the exact mathematical model,it can transform the qualitative concept to quantitative value through interface rule,which can realize the control of nonlinear system.Due to the above problems of traditional DTC theory,this paper creatively uses Slide Mode Observer,Stator Resistance Estimation and Cloud Model theory in Traditional PMSM DTC theory,aim to solve the problems in traditional theory.This paper includes:Firstly,this paper analyzed the mathematical model of PMSM,and introduced the traditional Direct Torque Control(DTC)based on this model.Secondly,focus on the weakness of Traditional DTC,this paper presented the improvements.In order to decrease the cost of PMSM and improve the stability of PMSM in actual running condition on electric automobile,the paper used Sliding Mode Observer(SMO)in speed loop instead of traditional speed sensor to realize sensor-less control.In order to solve the problem of stator resistance changing when the motor is running,this paper uses stator resistance estimation to realize the stator resistance parameters updating.To solve the problem of nonlinear in actual condition,his paper presents a self-tuning PI regulator based on Cloud model to replace traditional PI controller in speed loop.Lastly,this paper established the simulation model of PMSM DTC control based on Cloud Model,The simulation verified the validity of the PMSM DTC based on Cloud model.