Sliding mode speed control of direct torque fuzzy controlled IPM synchronous motor drive

This paper presents a fuzzy logic based direct torque and flux controlled interior permanent magnet synchronous motor drive using variable structure speed regulation. The closed loop control over stator flux and torque error values are performed by two separate fuzzy logic controllers. A Mamdani type of fuzzy controller is employed to produce the amplitude of the reference voltage vectors, while a Sugeno type calculates the desired displacement angle for the reference voltage vectors in the stationary reference frame. The resultant voltage vectors are generated by means of inverter switching based on space vector modulation technique. In terms of the outer closed loop control, a variable structure speed controller is utilized where the induced chattering effect has also been suppressed by using PI controller within the specified boundary layer of switching surface. The proposed scheme features highly smooth steady state response, excellent dynamic performance, superior disturbance rejection capability as well as the robustness to uncertainties and parameters variations due to presence of a combination of fuzzy and sliding mode controllers. The claimed performance improvements are also demonstrated through the presented simulation results.