| Direct Torque Control (DTC) technology is a AC regulation speed which has rapiddevelopment after Vector Control. This strategy has got wide attention with advantages suchas new thoughts, simple control scheme and excellent performance. DTC technology uses thestator flux orientation and directly makes the flux and electromagnetic torque as the controlvolume, so it has rapid torque response and perfect dynamic and static performance.In this article, we carried on a research on Induction Machine which uses DTC, first froma mathematical model of induction Machine we introduced the basic theory of DTCtechnology and analyzed the basic principles. Then based on this, we module the DTCalgorithm. In the MATLAB/Simulink environment, the Induction Machine direct torquecontrol system of quasi-circular flux simulation model is established. From the simulationresults we can see that control method of DTC is simple and system performance is superior,but low-speed performance is poor, such as torque ripple is too large in low speed state andthe stator current distortion is serious.In order to improve the low-speed performance of the Induction Machine direct torquecontrol system, we use adaptive fuzzy PI controller take place of traditional PI controller andadopt expected voltage vector control technology to synthesize space voltage vector. Throughthese , we overcome the impact of relay regulator. Also we establish the simulation model inthe MATLAB/Simulink environment, simulation results show that torque ripple and currentdistortion is decreased by use improved programs.The speed estimation without speed sensor is an important trend of modern AC drive.Based on the analysis of several commonly used speed-sensor technology, we use modelreference adaptive system to estimate speed and make simulation research. Simulation resultsshow that model reference adaptive system can estimate speed effectively and Speedidentification error is small, can prove the effectiveness of this strategy. |
PDF Full Text Request