Operation of regenerative Cascade Multicell Converter under fault condition

Reliability and fault tolerant operation are key aspects in high power drives, specially when these drives are used to operate critical loads, as downhill conveyors. This paper presents a solution for the operation under internal fault of high power regenerative cascade multicell converter, which allows to operate temporally in normal conditions or to turn off the equipment in a controlled way. Previous works have shown that it is possible to reduce the effects on the load due to internal faults by modifying the phase- shift between the output voltages. The proposed method uses the additional degree of freedom given by the controlled dc-link voltage of the PWM rectifiers, to increase the operation range, even reaching non-fault operation.