A Study On Asynchronous Motor Direct Torque Control Based On Intellectual Control Strategy

As a new control method, Direct Torque Control method has been developed greatly because of its simple system and excellent dynamic and static performance. However, the disadvantage of DTC is occurrence of torque ripple and flux ripple, especially torque ripple is very large.On the basis of conventional DTC system, the DTC system based on Fuzzy Logic Control Strategy is designed. A fuzzy logic controller is adopted, instead of two hysteresis controllers. In order to enhance the control performance of DTC much more, fuzzy neural network control algorithm is adopted. The DTC system based on Fuzzy Neural Network is designed. In this Fuzzy Neural Network ,Fuzzy Logic is combined with artificial Neural Network in series. It has the characteristic of self-learning ,self-adjusting and parallel processing.It is very easy to realize this Fuzzy Neural Network.In order to approve the validity of intellectual control strategy, the Simulation model of the DTC system based on Fuzzy Logic Control Strategy and the DTC system based on Fuzzy Neural Network Control Strategy are built in MATLAB/Simulink. By these models, simulation research is done. For the sake of approving the feasibility of intellectual control strategy sufficiently, an experiment is made based on TMS320F240 DSP.Simulation and experiment indicate that the control performance of the DTC system based on Fuzzy Neural Network is enhanced evidently compared with the conventional DTC system. Especially, torque ripple and flux ripple are diminish evidently. Compared with Fuzzy Logic Control Strategy, its control performance is improved evidently in torque ripple. It provides feasible scheme for developing the DTC system and other AC drive system which have high control performance.