Research On Electrical Propeller Based On Direct Torque Control Of AC Asynchronous Motor

As the prospect of the electrical propeller and the great progress of the relevant technology, ac propeller is in the leader position. The ac asynchronous motor ,ac permanent motor exist in the same time. The direct torque control was developed as the new technology in the eightieth of the last century, it has high performance of timing drive technology, followed as the vector technology and developed at the same time.Based on the traditional theory of the direct torque control, I researched the direct torque control system which used the circular flux on the low speed with the hexagon flux on the high speed, used the Matlab6.5/Simulink5.0 to build the model of the every part of the system and simulated the two instance which were the constant value as the speed offer and the variable value as the speed offer, then analyzed the simulation result.Followed with the front work, I did the more work and adopted the circular flux among the whole speed on the direct torque control system. It had the new observation of the flux, which designed the new stator observation of the flux based on the conditional u-i observation model, it introduced the closed loop of amplitude compensation to eliminated the error of the direct current integral. It not only improved the flux observated precision, but also effected the stator resistance hardly. The writer built the simulation model of the system, simulated the two instance which were the constant value as the speed offer and the variable value as the speed offer, then analyzed the simulation result. The result proved that the system had better performance of the dynamic and the static state.The dissertation also studied the speed sensorless system. The main speed observer methods were the direct account based on the motor model and the MRAS speed observer based on the no power.The dissertation combined the control theory and the motor characteristic...