Common-mode voltage elimination in a three-to-seven phase dual matrix converter feeding a seven phase open-end induction motor drive

This work presents a novel seven-phase open-end winding induction motor drive supplied by the dual non-square matrix converter. The input to each of the matrix converter is three phase utility grid system and the output is seven phase voltages with variable voltage and frequency. The two matrix converters feeding a seven-phase induction motor are supplied from a common single three-phase utility source of 50 Hz. The multi-phase matrix converters are operated by space vector based PWM algorithm. The proposed control technique eliminates the common-mode voltage across the machine winding and hence no zero sequence currents will be produced and therefore no isolated supply is required for the dual three-to-seven phase matrix converter system. A detailed analytical approach is presented to derive the expression of duty cycles which are ultimately used to generate the switching pulses for the matrix converter. A seven phase open-end induction motor model is developed and simulated to support the idea of the proposed modulation scheme for dual matrix converter.