Abstract:
To overcome some shortcomings in current vector control (CVC) and basic direct torque control, a new speed and torque control strategy based on direct flux control (DFC) was presented. In this method, the flux and torque are controlled through directly controlling the trajectory of stator flux vector. It has some advantages such as fast dynamic response, constant switching frequency, reduced torque and flux ripple. The necessary condition for direct flux control to a permanent magnet synchronous motor (PMSM) was put forward. Simulation results show that the strategy not only operates well in the constant torque range, but also in the flux weakening range, and it improves fast dynamic response of speed and torque control over wide speed operation, better than the traditional current vector control.