Grid fault ride-through of an LCC-VSC tandem converter, used as a grid interface for a multi-MW wind turbine

A tandem converter, consisting of a line-commutated converter in parallel with a voltage source active filter, is proposed as a grid interface for a 10 and 20MW superconducting wind turbine generator. A commutation assistance scheme is introduced which allows the active filter to regulate the commutation of the LCC thyristors. This can allow ride through of grid faults by enabling the LCC thyristors to continue commutating with reduced grid voltage, which enables the use of tandem converters as a grid interface for renewable energy sources. The commutation assistance scheme is verified using simulation.