Hybrid Fuzzy-PI controller and Novel Switching Functions Using Speed Control technology of Surface Mounted Permanent Magnet Synchronous Motor

Vector control is one of the standard techniques used for the control of a permanent magnet synchronous motor (PMSM). The outer speed loop in vector controlled PMSM drive greatly affects the drive performance. In order to combine the advantages of proportional plus integral (PI) and fuzzy controllers, hybrid fuzzy-PI controllers are used in which the output can either be the outputs of the two, i.e. the PI or fuzzy units being switched as per the predetermined speed errors or be a combination of the two outputs with separate weights assigned to them with online calculations for the weights from the speed errors. The former method based on switching often causes chattering effects, and later method demands larger execution time because of inclusion of separate switching algorithms. This paper reports the vector control of PMSM with hybrid fuzzy-PI speed controller with switching functions calculated based on the weightsfor both the controller outputs using the output of (a) only the fuzzy controller, (b) only the PI controller and (c) a combination of the outputs of both the controllers. These switching functions are very simple and effective and do not demand any extra computations to arrive at the hybrid fuzzy-PI controller outputs. These control algorithms have been simulated and also implemented on hardware with TMS320F2812 digital signal processor, and it is observed that the performance of the vector controlled PMSM drive with these hybrid fuzzy-PI speed controllers in terms of the response and torque ripples is very promising.