针对永磁同步电机常规直接转矩控制系统涉及到的问题,例如磁链的准确观测、定子电阻的变化、电压矢量开关表的改进以及滞环控制器的改进等等,本文都作了详细的分析,并提出了改进方案。为了提高系统的性能,本文将空间矢量调制的方法引入了常规直接转矩控制中,并在此基础上,对永磁同步电机无速度传感器问题作了详细的分析,总结了国内外的研究热点,提出了采用转子磁链矢量为基础的永磁同步电机直接转矩控制速度估计方法。仿真结果表明,该方案具有很好的动、静态特性。-Firstly, the paper analyzes the principle of direct torque control of permanent magnet synchronous motor and elaborates the impact of space voltage vector of the stator flux and the electromagnetic torque.Secondly, the paper introduces direct torque control of permanent magnet synchronous motor SVPWM technology.Under the same　hardware conditions,the system can obtain More continuous voltage space vector by taking advantage of SVPWM.The simulation results show the program not only keeps the direct torque control fast dynamic response, but also reduce the motor torque ripple.