A Novel DTC-ISVM for Induction Motor Drive System Fed by Indirect Matrix Converter Using 3-Level Voltage of DC-Link and ALM Estimator to Correct the Stator Resistance

摘要

In this paper, a novel Direct Torque Control (DTC) method based on Indirect Space Vector Modulation (ISVM) technique using Indirect Matrix Converters (IMC) is proposed. This method is characterized by simple structure, minimal torque ripple and unity input power factor. In order to improve the performance of the motor drive system, a suitable switching pattern in rectifier-bridge is proposed which allows to using all of the possible vectors of the indirect matrix converter. By selecting this switching pattern in rectifier-bridge, and controlling of the voltage level of intermediate dc link, it is possible to produce small, medium and large voltage vectors in the IMC. By this way, the electromagnetic torque ripples could be reduced. On the other hand, DTC method uses the stator resistance in its calculation. Variations of this resistance, due to changes in temperature, cause some difficulties at low speeds. Therefore to estimate the changes in stator resistance during the operation of the machine, an Active Learning Method (ALM) is implemented beside the DTC algorithm. The ALM uses its own modeling technique called Ink Drop Spread (IDS) method. The superiority of this method in comparison to conventional methods that uses IMC for DTC is proved by FFT and THD analysis and the simulation results confirm its effectiveness and accuracy.