The matrix converter input current formation in the case of unbalanced load

Abstract

The method of improving the quality of the matrix converter (MC) input current for the case of unbalanced load has been considered. This assumes that the supply voltages, as well as the generated MC output voltages, are symmetrical and sinusoidal (neglecting high-frequency components owing to the discrete nature with a pulse-width modulation frequency). The proposed and investigated method is based on a general algorithm for MC input reactive power control and dynamic modulation of the reactive component of the input current. The control parameter and the main lever of influence on the converter input current quality is the transfer ratio of the load current space vector in the reactive component of the input current space vector depending from the constant and variable components of the instantaneous power as well as from the degree of the load current unbalance and the output phase displacement. MC input current simulation at the proposed approach showed an improvement of its quality compared with the conventional control algorithm when a constant input phase displacement is set.