A Fault-Tolerant 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 as close as possible to its desired normal operation under an open-switch fault condition. The proposed strategy determines appropriate switching states associated with eight, out of the nine, remaining healthy switches of the converter, to synthesize the reference voltages. 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 voltages and the voltages generated by the switching states. The solution to the nonlinear optimization problem is obtained based on the Karush-Kuhn-Tucker conditions. The performance of the proposed modulation strategy is evaluated based on time-domain simulation studies in the MATLAB/Simulink software environment and also experimentally verified.