A fault tolerant modulation strategy for matrix converters

This work focuses on the operational behavior of an adjustable drive system, consisting mainly of a matrix converter and an induction machine, in the case of faults that occur either on the MC or the induction machine. In detail, faults that lead to the open-circuit of a single bidirectional switch of the MC or an entire MC leg are considered. It is confirmed that these faulty conditions deteriorate severely the operation of the examined drive system resulting in no fault tolerance of the drive. The possibility the drive system´s operation to be continued after such a fault is diagnosed, and until repairing becomes potential, is examined. The cases of adding a redundant switch to connect the source´s neutral to the load´s neutral and the case of a 4-leg MC are evaluated. A remedial MC control algorithm realizing a carrier based modulation method for the case of a 4-leg MC is proposed resulting in a significant improvement of the matrix converter´s fault tolerance and reliability.