PROJECT TITLE :

Dual Channel Control with DC Fault Ride Through for MMC-based, Isolated DC/DC Converter - 2017

ABSTRACT:

This paper presents the 2-channel controller with inner current loops for dual bridge, DC/DC converter, based on modular multilevel converter (MMC) technology. The DC/DC control strategy is based on two inner quick current control loops in dq rotating frame at every of the two MMC bridges. These current controls facilitate operation through dc faults at either dc bus. The active power control is shared by two MMCs, at the slower outer management level. The second outer control loop minimizes losses, which is achieved by feedback management of magnitude of both modulation indices at maximal worth of 0.ninety five in the slightest degree loading levels. The controller is symmetrical, provides bidirectional power flow and responds equally to faults on either dc bus. Below dc fault conditions, one MMC actively controls the inner ac current, while temporary blocking of MMC on faulted aspect is needed to stop cell capacitor discharge. The validity of the proposed management is verified on PSCAD using a 60zero MW, 500-kV/640-kV test dc/dc model. The controller will be used for control/stability studies with massive dc grids that contain dc/dc converters.