Direct Torque Control Of PMSM Using Twelve Voltage Space Vectors

In recent years, permanent magnet synchronous motor (PMSM) have developed rapidly, it has been used in various fields because of its excellent performance, and gradually replaces the DC motor and induction asynchronous motor. However, with the rapid development of modern industry, it is no longer satisfied with simple control of permanent magnet synchronous motor, and it is extremely important to research high-performance control strategy.For the purpose of decreasing the torque ripple problem of ordinary direct torque control system, this paper proposes a novel direct torque control scheme based twelve voltage space vectors. Two phase conduction and three phase conduction are both utilized. Because pure integral observer output contains a DC component, a first-order filter is used to filter out it, and anti-saturation links is designed for the speed PI regulator to improve the system’s rapid ability to regulate.In this proposed system, it also constructs an adaptive observer which uses the stator flux and stator current as the state variables. Based on Lyapunov stability theory, the observer gain matrix is obtained to ensure its stability. The stator flux can be measured precisely by the adaptive observer, and speed identification rate can be deduced by torque equation and observations, it achieves the speed sensor-less control of the system.Finally, MATLAB/SIMULINK platform is used to build a simulation model of this system, and the results show that this proposed method is feasible and effective.