A Fixed Switching Frequency Direct Torque Control Strategy for Induction Motor Drives Using Indirect Matrix Converter

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Direct torque control (DTC) is a very competitive control strategy because of its simple structure and good dynamic performance essentially in terms of torque response. However, there are some drawbacks which need to be eliminated or at least reduced, like the variable switching frequency and torque ripples. Matrix converters are the new generation of power converters which provide a very good quality of input and output waveforms with a controllability of input power factor, a bidirectional power flow and a compact sight structure. In this present paper, we propose a method used for a fixed switching frequency direct torque control (FSF-DTC) using an indirect matrix converter (IMC). This method is characterized by a simple structure, FSF-DTC which causes minimal torque ripple and unity input power factor. Using this strategy, we combine the IMCs advantages with those of DTC schemes. The technique used to obtain the constant frequency, based on a triangular waveform added to the reference of the torque to impose the dynamic of the torque slopes, is combined with the input current space vector to create the switching table for the IMC drives. The input current modulation allows the rectification stage control of the IMC, while the inverter stage is controlled using the classical DTC switching table. Simulation results clearly demonstrate a better dynamic and steady state performances of the proposed method.