Simulation of the fuzzy direct torque control for induction motor drive in Simulink
Abstract
Simulation of the fuzzy direct torque control for induction motor drive in Simulink
Incoming article date: 02.07.2014Two different methods for direct torque control (DTC) of induction motor are analyzed. The first one is derived from well-known DTC strategy developed for voltage inverter drives. This type of control basically uses hysteresis type controllers for torque and flux. The decoupling of the torque and flux components is accomplished by using hysteresis comparators, which compares the actual and estimated values of the electromagnetic torque and stator flux. The torque and flux estimated values are calculated based on the sampled motor’s terminal variables, i.e. stator voltages and currents. Output of these comparators, together with the stator flux orientation, are used to select the appropriate voltage vectors of a three phase voltage source inverter. The other DTC method, proposed in the paper, is based on fuzzy logic concept , where fast torque response with low ripple in the torque of induction motor can be achieved. In this technique, the hysteresis comparators, used in basic DTC, are replaced by the fuzzy logic controllers. Takagi – Sugeno fuzzy algorithm are used to approximate nonlinear functions. In comparison with the conventional DTC simulation results clearly demonstrate a better dynamic and steady state performance with the fuzzy logic DTC. The performance of the proposed drive systems evaluated through digital simulation using MatLab package with Simulink blocksets. Also, MatLab/Fuzzy toolbox is used to implement the fuzzy logic controller. Both systems are simulated under the same conditions.
Keywords: асинхронный двигатель, прямое управление моментом, нечеткий регулятор, флуктуации,