Abstract: Permanent magnet synchronous motor (PMSM) is a multivariable nonlinear system with strong coupling. It is sensitive to the load and parameter disturbances. In order to improve the robustness of this system, a fractional calculus control strategy is applied to the PMSM drive system. Compared with integer order proportional-integral-derivative (PID) controllers, the fractional order PID controllers are expected that better control performance can be achieved due to the extra tuning knobs. The PMSM speed drive system is designed based on the fractional order controller, and simulation results show that the behavior of fractional order PID controller is much better than the integer order PID controllers.