Research Of A High Performance Direct Torque Control System

The direct torque control(DTC) theory as a kind of new method in the field of AC drive system. It calculates and controls the torque of AC motor in stator coordinate using the space vector analysis and stator-flux-oriented method. And optimal controls the switch state of the inverter to get the high dynamic performance. It is dynamic response fastly,simple and easy to realize the advantages. However, There are still some imperfections and areas for improvement.The basic theory of the direct torque control was introduced in this paper, large ripple exists in motor torque in the conventional direct torque control was analysed detaily, especially at low speed performance deficiencies. Aiming at the improvement of the ripple large defects of motor torque, a solution to excessive torque ripple of new control methods is provided in this paper. As in the conventional direct torque control system, the voltage vector selection table has some defects or errors in the case. This article made use of voltage vector subdivision, will be available for selection the number of non-zero voltage space vector to 12, and stator flux subdivided into 12 sectors, in order to optimize the voltage space vector selection, inhibition of excessive motor pulse. Meanwhile, the fuzzy control technology to further optimize the voltage vector selection, with the voltage vector selection fuzzy controller to replace the traditional voltage selection table, and thus further improve the performance of the system.A new program on the computer simulation and experimental validation was proposed.in this paper. Under the proposed new program, the MATLAB/SIMULINK software in the computer simulation results prove the effectiveness of the algorithm. Finally, the design and construction of the use of TMS320F2812 DSP chip to control the core of the direct torque control experimental platform, and the experimental test platform. Experimental results show that the proposed new scheme is fast torque response, good robust and dynamic and static performance, the motor is running when the problem of excessive torque ripple better solution to improve the control accuracy.