Research On Flux Estimation In DTC System Of Asynchronous Motor

After direct torque control (DTC) technology was invented, it has been given wide concern and has got rapid development because of its original control notion, concise system structure and excellent capability on activity and immobility. In brief, using an analytical method on space vector, DTC technology directly calculates and controls the torque of AC motor under the stator coordinate. On the other hand, in order to get best capability on activity, adopting the stator-magnetic-field-oriented way, DTC technology directly applies optimum control on the switch conditions of inverter and generates PWM signal taking advantage of discrete Band-Band adjustment.Even though DTC technology has come to be ameliorated, the problem on flux observation haven't been perfectly solved all the time. Because of this reason, on the basis of dealing in details with the basic principle of induction motor direct-torque-control system, according to the faults of traditional direct-torque-control system and the requirement of induction motor with respect to changing speed, this paper presents a stator flux estimation model with connection between space-voltage-oriented and stator-flux-oriented vector control.To verify that the theory is right and practical, this paper achieves the simulating test of two stator-flux-oriented models with two different shapes in direct-torque-control system, and analyses the result of the test. At the other hand, after changing the parameters in direct connection with flux-regulation and torque-regulation, this paper gives the effect of changing parameters to motor ability.