Research On Direct Torque Control Of Induction Motor

During the recent 20 years, induction motor Direct Torque Control (DTC) mothod has been developed rapidly for its concise system scheme, excellent dymamic and static performances. Its basic idea is: if the amplitude of magnetic flux of motor's gap is constant, we can adjust rotating speed of stator's magnetic flux to control torque and rotating speed of rotor. Compared with vector control technique, it has many adventages such as fast torque response, simple control structure, easy to be digitalized, etc.This paper is to design a Direct Torque Control system. Limited by time this paper focused on the basic DTC principal study and research.Stator flux observer is key part of DTC system. Classic U-I model is simple. However the integtator inevitably bring up the error accumulation on DC dirft at a low speed. So this paper present a new model based on the transform between low speed and high speed.This paper has carried on the simulation, the programming and the scene debugging work, in the simulation has established a complete DTC system.The simulation result has confirmed the system accuracy.Moreover the author with the assembly language programming, has developed the DTC control procedure on digital signal processor (DSP).The on-line experimental result indicated the real-time control system has achieved the anticipated goal.