Indirect Space-Vector PWM Technique for Three to Nine Phase Matrix Converters

This paper develops indirect space vector modulation technique for a three-to nine-phase matrix converter. The proposed technique is based on the double-stage configuration in which the matrix converter is modeled as three-phase rectifier followed by a nine-phase inverter. Both rectifier and inverter stages are controlled using space-vector modulation technique. In the rectifier stage, the modulation is based on input currents space-vectors. However, the modulation of the inverter stage is based on output voltages space-vectors. Two different schemes are suggested to control the inverter stage. In the first scheme, only largest space vectors are used in order to achieve maximum voltage transfer ratio of the inverter stage. In the second scheme, eight active vectors are used in each sector in order to minimize the switching stresses and to give a sinusoidal output voltage. It is observed that, using the first scheme results in achieving a higher value of the maximum overall voltage transfer ratio. However, the output voltages contain a significant amount of lower order harmonics. On the other hand, sinusoidal output voltages with a reduced value are obtained by second scheme. A sample of the obtained simulation results is presented to support the viability the proposed technique.