Direct Torque Control Of Induction Motor Fed By Three-level Inverter

In recent years, multilevel technology has become an effective and practical solution for high-voltage high-power application field. Direct Torque Control (DTC) technology has been widely researched for the characteristics of briefness, robust, excellent dynamic response. This paper focuses on the study of direct torque control of induction motor drive based on diode-clamped three-level inverters.This paper analyzes the basic theory and the neutral-point-voltage balanced . Some simulations have been made by the MATLAB/SIMULINK software package.The three-level inverters and the two-level inverters are compared, on the basis of it, the simulation results tests advantages of three-level inverter.In this paper, the model of three-level inverters and induction motors had been analyzed firstly. A whole model was constructed inα-βtwo-phase stationary coordination for further research.For three-level NPC inverter, to keep the neutral-point-voltage balanced and simplify the complexity of vector selection, a virtual-vector method is applied. The phenomenon that a given voltage vector has a different effect on the drive behavior at high and low speed is analyzed. Taking these into considerations into account, a DTC algorithm for three-level NPC inverter, which is based on multilevel hysteresis comparator, is presented. Simulation results show the effectiveness of the algorithms.