Simplified models to calculate the change of torque and flux of surface permanent magnet synchronous motor (PMSM) on stator flux coordinate system are proposed. In order to solve the problem of high torque ripple in direct torque control (DTC) system, dead-beat (DB) control of flux and torque is proposed. The calculation of ideal voltage vector for the DB control of flux and torque using simplified models is given and model predictive control (MPC) is used to implement the DB control. In order to improve the control performance of the system, the method to extend voltage vectors set is proposed, which can increase the number of candidate voltage vectors from 7 to 37. According to the angle of ideal voltage vectors, extended voltage vectors set does not add calculation burden. Look-up table is used to output voltage vector instead of space vector modulation (SVM) to improve the real-time performance. Simulation results show that extended voltage vectors set can decrease torque ripple. In order to further suppress flux and torque ripple, a novel method to expand voltage vectors is proposed. The angle and amplitude of ideal voltage vector are used to evaluate the angle and amplitude of the output voltage vector and look-up table is still used to output voltage vector with arbitrary value. Simulation results show that the novel method can effectively decrease flux and torque ripple.