TORQUE AND SPEED MODES SIMULATION OF A DTC- CONTROLLED INDUCTION MOTOR

摘要

Abstract By the huge advantages associated, induction motors drives are still justifying research and development. This paper presents the work developed in Direct Torque Control (DTC) based drives. With a growing importance in several applications, this method was object of a deep study, either in simulation environment and hardware implementation. The reached results confirm some weaknesses and several strengths, pointing out his worth in strength control, particularly in robotics. 1 Introduction In the past, AC drives were only used in small demanding applications, regardless the advantages of AC motors opposite to DC motors, since the high switching frequency inverters cost was rather competitive. With the developments in the power electronics area, the vector control methods, which use fast microprocessors and DSP’s, made possible the use of induction motors in typically DC motors dominated areas, since the current components producing torque and flux are decoupled, achieving the system separately excited DC motor similar features. The Direct Torque Control (DTC) method, developed by German and Japanese researchers [8], [3], allows direct and independent electromagnetic torque and flux control, selecting an optimal switching vector, making possible fast torque response, low inverter switching frequency and low harmonic losses. Figure 1 shows the usual block diagram of a DTC controller.