Direct Torque Control System Of Permanent Magnet Synchronous Motor Application Research On Hybrid Electric Vehicle

Recently,permanent magnet synchronous motor has been widely used in hybrid vehicle as it's easy to control.At the same time,it has a variety of advantages such as simple structure,less noise,small proportion of the whole vehicle,and so on.Direct torque control scheme has a sample control method,it can control torque and speed through changing the torque angle.Moreover,it has small demand for parameters,and doesn't require complex decoupling operations.It has been widely used and become a mature application on permanent magnet synchronous motor at the same time.The direct torque control system still can be improved,and it is very important for the development of hybrid electric vehicle.In the first part,the paper introduced the development history and the situation of the hybrid power vehicle.Then introduces the necessity of its researching and improvement,and summarizes the situation of the development of hybrid power vehicles.In the second part,the motor and its control method are selected according to the operation of the hybrid electric vehicle.In the third part,the mathematical model of the motor and the control variables are analyzed,and then SVPWM method is used to replace the traditional control method to improve the control accuracy.In this way the accuracy of the system is improved,and the fluctuation of the system is reduced.In the traditional flux observation,due to the influence of the integral saturation and the salient pole property of the motor,the error of flux observation is larger when the motor is running.Considering the motor dynamic performance and static performance is poor,this paper has improved the flux observation method.Firstly,due to the existence of salient pole property of permanent magnet synchronous motor,the actual value of the induction motor and the reference of the motor will have a certain deviation,which will affect the observation of the flux linkage.In order to reduce the error,this paper proposes a direct torque control system based on the concept of “active flux”,and the effect of the salient pole property on the control system of the permanent magnet synchronous motor is reduced by it.Secondly,considering the influence of temperature and other variables on the flux,the active flux is estimated using the hyperstability criterion for model reference adaptive control system.In Mtalab/Simulink,the model of direct torque control of permanent magnetsynchronous motor is built,and the simulation is carried out.Based on the analysis of the simulation results,the adaptive method based on the concept of the active flux has been proved to be effective in improving the performance of the system.