An adaptive PI controller schema based on fuzzy logic controller for speed control of permanent magnet synchronous motors

In speed control systems, which is desirable is that the speed of a controlled object should track the reference speed as fast as possible and at the same time should provide good robustness to load variations. As far as conventional PI controllers are concerned, once their parameters are tuned for solely one operating condition, they remain constant during the whole operational cycle and therefore, a poor controller performance may arise unexpectedly when the operating condition is changed. To overcome this problem, a PI controller incorporated by fuzzy logic controller (FLC) is introduced in this paper for the speed control of a permanent magnet synchronous motor (PMSM). In the proposed control schema, the parameters of the PI controller are determined online based on the error signal and its time derivative by means of a PD-type FLC, which has separate two rule bases, the former of which is responsible for P gain and the latter is for I gain. According to the computer simulations performed under the same conditions, the obtained results based on the proposed method are more promising than those obtained by the conventional PI controller with fixed parameters.