A Post-Fault Modulation Strategy to Control the Matrix Converter under an Open-Switch Failure

In this paper, a new post-fault modulation strategy is proposed to operate the direct matrix converter (MC) as close as possible to its desired normal operating under an open-switch fault condition. The proposed strategy determines the switching states of the eight, out of the nine, remaining healthy switches of the converter, to generate the reference voltage. The corresponding duty cycles of the determined switching states are calculated by formulating a nonlinear optimization problem that aims at minimization of the error between the desired reference voltage and the voltage generated by the switching states. The solution to the nonlinear optimization problem is obtained based on the Karush-Khun-Tucker (KKT) conditions. Performance of the proposed modulation strategy, based on time-domain simulation studies in the MATLAB/Simulink software environment, is evaluated and experimentally verified. Compared to the existing strategies, the proposed strategy provides a superior performance in terms of the output power quality for the MC operating under an open-circuit switch fault condition.