Based On The Fuzzy Control Of Permanent Magnet Synchronous Motor Direct Torque Control System

The Permanents magnet synchronous machine (PMSM) has come to the drive system developers' attentions for their merits such as low volume, high power density, high efficiency and simple maintenance. The direct torque control has the advantage such as simple structure, clear concept and fast response. Therefore, the permanent magnet synchronous direct torque control becomes the research focus recently.Researches on the direct torque control system of permanent magnet synchronous motor have been done in this paper. Firstly the background and significance of the research are showed, and then the recent research achievements of the direct torque control system of permanent magnet synchronous motor are summarized. Take the Three-phase AC PMSM as the research object, the basic principle of PMSM DTC method is discussed particularly. Depend on the analysis the configuration and characteristic of PMSM, the mathematical model and movement equation is put forward, and the application theory foundation of PMSM DTC is discussed deeply.The reason of DTC torque ripple in PMSM is concretely analyzed, and the special effect of the zero voltage vector on the motor torque is discussed. Based on it a method of direct torque control using double fuzzy logic has been proposed. Fuzzy controller and fuzzy PI controller is used to improve the system's performance instead of hysteresis adjusting controller and PI speed adjusting controller. By mapping the symmetry characteristic of flux angle, an improved fuzzy control rule table has been proposed, decreasing the number of fuzzy control rules and making the controller easily realized and been better real-time action.Depend on the analysis of the PMSM DTC theory, by dint of the MATLAB/SIMULINK tools, the simulation experiment of double fuzzy control of PMSM is built and the result is coincident with theory analysis, validating the feasibility of double fuzzy control strategy. By comparing with the conventional direct torque control system, the results of Simulink show that the double fuzzy DTC is more effective than the conventional DTC and it reduces the torque ripples and improves the system control performance.