Induction Motor Direct Torque Control System Based On Matrix Converter Powered Studies

Direct Torque Control technology is developed as a kind of AC DriveTechnology in the1980's. It's a mathematics model for analysis of electricalmachines based on stator coordinate system. In the model, Stator Flux SpaceVector and Electromagnetic Torque are directly used as the controlled variables,to realize the direct control of the Electromagnetic Torque. The method is moresimple and rapid, so the dynamic and static performance of system has beenfurther improved. But the harmonic pollution problems had been caused byAC-DC-AC voltage type inverter.Matrix converter is of bi-directional powerflow, the input power factor1, the input and output sinusoidal current, withoutthe need for DC energy storage capacitors and other, these advantages made itapplicable to AC applications.Based on matrix converter fed induction motor direct torque control,firstly,we simply elaborated the basic principle and the mathematical model ofdirect torque control. On this basis,we detailedly analyzed the controlmethods, the direct torque control of hexagonal and approximate circle fluxlinkage locus, and made research of simulation on the second strategy.Secondly, considering the large number of power devices, and the complexfeatures of the control methods of the matrix converter, we modeled the matrixconverter based on its topology and working principle, put forward theAC-DC-AC virtual equivalent circuit and indirect space vector modulationstrategy, detailedly analyzed the modulation algorithm of direct and indirectspace vector, and then simulated the indirect space vector modulation model.Finally, we used the matrix converter in direct torque control system, inorder to combine the advantages of the matrix converter and direct torquecontrol, and constitute a high performance AC speed regulation system with nopollution to electric network. Based on the DTC principle analyzation, we gavethe block diagram of the control system, and then set up the simulation modelusing MATLAB/SIMULINK. The results showed that the combined controlstrategy is a kind of control system with high performance.