“…In [7], a comprehensive review of LVRT methods is done in two general categories: (a) high cost, using external devices; and (b) low cost, modifying control circuit of back-to-back converters and pitch angle. External devices that improve LVRT include FACTS devices [8], the braking chopper system [9,10], the fault current limiter (FCL) [11,12], and the energy storage system (ESS) [13] utilized at the common coupling point (PCC), dc-link, grid side, and dc-link, respectively. In addition, many studies have been performed in the field of improving back-to-back converter control circuits [14], including the use of active current droop in the MSC controller [9] as well as changing control functions between MSC and GSC [15].…”