Digital Simulation of Direct Torque Fuzzy Control of PMSM Servo System

Fuzzy logic is recently getting increasing emphasis in soft computing applications in the recent days. This paper presents an application of the fuzzy logic scheme to control the speed of an AC servo system & the same is proposed for a space vector pulse width modulation (SVPWM) inverter-fed permanent magnet synchronous motor (PMSM) drive. Based on the analysis of the PMSM transient response, a Direct Torque Fuzzy Control (DTFC) is developed. A high-performance AC servo motor system modeling and the designing simulation scheme of direct torque fuzzy control of a low speed permanent magnet synchronous motor is proposed. Direct torque control is known to produce quick and robust response in AC drive system. However, during steady state, torque, flux and current ripple occurs. Due to large torque ripples in low speed conditions, a permanent magnet synchronous motor, the PI-type speed controller in a conventional DTC is replaced by a fuzzy logic controller. The direct torque fuzzy control strategy of a permanent magnet synchronous motor drive system is simulated by using MATLAB-Simulink. This scheme integrates the direct torque fuzzy controller strategy, the time speed measurement algorithm, the fuzzy logic regulating technique and the space vector pulse width modulation principle. The simulation results indicate the DTFC provides satisfactory high dynamic and static performance compare to conventional DTC. The method presented in this paper shows the effectiveness of the scheme which is further verified through the simulation results.