Comparative Evaluation of Three Z-Source/Quasi-Z-Source Indirect Matrix Converters

Abstract

Conventional matrix converters (MCs) have limited voltage gain that is less than 0.866, whether for direct MC (DMC) or indirect MC (IMC). Existing Z-source (ZS)/discontinuous quasi-Z-source (qZS) DMCs and ZS IMCs achieved larger than 0.866 voltage gain; however, the former inherited the complex commutation from DMC, and the latter involved a ZS network in dc link and led to non-all-silicon solution. In this paper, ZS and discontinuous qZS networks of existing ZS/qZS DMCs are used for an IMC topology for simplifying commutation and having high voltage gain, but they require extra input filter to reduce current harmonics. A new continuous qZS IMC is proposed, where a qZS network integrates the filtering function of the grid side; hence, additional input filter is avoided in the proposed continuous qZS IMC. Three new IMCs are compared in detail, in terms of voltage gain, current ripple, voltage ripple, inductor current and capacitor voltage stresses, ZS/qZS switch current and voltage stresses, filtering function, input current total harmonic distortion (THD), output voltage THD, and efficiency. Their control and modulation methods are presented to achieve the desired performances. Experimental comparisons verify the theoretical analysis and that the proposed continuous qZS IMC is a promising topology.