Generalized Pulse-Width-Modulation to Reduce Common-Mode Voltage in Matrix Converters

In this paper a simple pulse-width-modulation strategy for matrix converters is studied. It takes advantage of the fact that the space vector modulation switching sequences for a matrix converter are the same as those created by the carrier-based modulation when an adequate zero-sequence component is injected into the carrier system references. A generalized equation for the zero-sequence component, which is a function of a distribution ratio of zero voltage vectors allows the pulse widths to be easily calculated, avoiding the complicated derivation of similar relations for matrix converters. Such generalization is possible by using the two-stage direct power converter topology and an adaptation of the duty cycles for the matrix converter switches. In particular, a modulation technique for reducing the common-mode voltage of the matrix converter is proposed based on this concept and comparison results are exposed, demonstrating its efficacy without a significant degradation of the input currents quality in the matrix converter.