Analysis of non-idealities in direct and indirect matrix converters

This paper compares the voltage transfer characteristics of direct and indirect matrix converter topologies. Knowledge of the real voltage transfer capability of a converter is essential, especially in sensorless motor drives in low speed region. The comparison is based on the analysis of non-idealities caused by real semiconductor devices and safe commutation methods. The effects of on-state voltage losses and commutation methods are modelled with equations. The analysis is verified in measurements and simulations. The direct matrix converter follows the reference more accurately than the indirect matrix converter. Thus direct topology is also found to be a more suitable converter solution for sensorless motor drives if no compensation methods of voltage inaccuracies are used. The results show that analysis of voltage transfer inaccuracies in direct and indirect matrix converter topologies can be used as a basis to develop the compensation methods needed in high performance motor drives without speed sensors