Direct Torque Control for a Matrix Converter Based on Induction Motor Drive Systems

The paper proposes a direct torque control (DTC) scheme for a matrix-converter-fed induction motor drive system. DTC is a high performance motor control scheme with fast torque and flux responses. However, the main disadvantage of conventional DTC is electromagnetic torque ripple. Besides, the matrix converter is a single-stage ac-ac power conversion device without dc-link energy storage elements. Due to the properties of the matrix converter, the pseudo dc-link will provide with three different types of voltage: the high, middle, and low voltages. Therefore, based on space vector modulation generated by a matrix converter, there are three states on each space vector location. By suitably selecting switching pattern, the electromagnetic torque ripple of the motor is effectively reduced. Using this switching strategy, the advantages of the DTC schemes and the benefits of the matrix converters can be combined. As a result, a satisfactory servo drive can be achieved.