The Simulation Research On The Impact Of Flux On The Direct Torque Control System Of Induction 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, the present paper in the introduction asynchronous machine direct torque control system basic principle foundation, the method which in the thorough discussion direct torque control the flux estimates, and the flaw as well as to the asynchronous machine velocity modulation performance request which exists according to the traditional direct torque control system in, this article uses one kind of entire step closed loop flux sight, take decides, the rotor flux as the state variable, directly carries on the observation to it, thus will observe the obtained flux to use in the direct torque control realizing directly to the stator flux accurate observation.A simulation system of model reference adaptive adopted speedsensorless DTC system is developed by usingMATLABISIMULINK software package.The simulation resultsshow that,compared with the traditional model flux sight,model,thissystem using full order flux server has better reliable stator anddynamic stator when it running in the course that the systemstarts and runs loading with and without load,high speed and lowspeed etc.In speedsensorless DTC system,calculate speed is inosculatingto motor's actual speed under all of the running states ofmotor.It also have good efects even when staor resistace or rotorresistance has changed.So we can draw a conclusion as:using thestrengthen the robustness of system,and widen the range of drivesystem.