DIRECT TORQUE AND FLUX CONTROL OF INDUCTION MACHINE AND FUZZY CONTROLLER

Milan Žalman - Ivica Kuric

   In this paper we describe the control of an induction machine (IM) using the principle of direct torque and flux control (DTFC). This method is designed by means of fuzzy logic with three inputs and three outputs and contains 180 rules. For improvement of this method a fuzzy duty ratio controller is added. This controller prepares an optimum voltage vector (output from fuzzy DTFC control). In this control the selected inverter switching state is applied for a portion of the switching period, defined as duty ratio δ, and the zero switching state is applied for the rest of the period. The duty ratio is chosen to give an average voltage vector for a change of torque with decreasing ripples. The control is verified by simulation.

Keywords: induction machine, servo system, direct torque and flux control, fuzzy controller, speed control

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