The sparse matrix converter is an indirect matrix converter that converts AC input voltages directly into AC output voltages without the use of an intermediate DC energy storage link. The sparse matrix converter has a total of 15 switches compared to 18 that are required for a conventional matrix converter. 

The output voltages are generated with a conventional 6-switch inverter. The output inverter is switched into the free-wheeling state when the input stage is required to commutate between line-line voltages and this can be viewed from the switching pattern time plot. This switching action results in no current flow between the input and out stage and therefore no switching losses occur in the input stage. The output stage although requires a switching frequency that is twice the input stage frequency. 

The modulation of the input stage results in an input current that is in-phase with the input phase voltage. The output stage is able to produce a variable output frequency, magnitude (although it is limited to 0.86 of the input voltage) and phase compared to the input voltage.

• Move the red timeline on the input and output waveform plots and observe how the sector numbers and the switching pattern change.
• Move the red timeline over one switching period to observe the various current paths .
• Adjust the output frequency by moving the red dot positioned at zero volts on the output voltage waveform.
• Change the output current phase angle by moving the red dot on the output current waveform.
• Adjust the magnitude and phase of the output voltage waveform by moving the red dot positioned at the peak of the output voltage waveform.