Based on the analysis of the mathematical model of permanent magnet synchronous motor (PMSM), a new direct torque control system based on space vector pulse width modulation technique (SVM-DTC) is proposed. The stator flux and torque were regulated by PI controllers to decouple motor space vector in the two components of stator flux and torque. Meanwhile, a stator flux estimation method based on rotor position and stator current was used and sensorless was designed to estimate the rotor position. Simulation and experiment results have shown that the proposed method can effectively estimate the stator flux and reduce the electromagnetic torque and stator flux ripple, so the system has good static and dynamic performances.