PROJECT TITLE :

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

ABSTRACT:

This paper presents the two-channel controller with inner current loops for dual bridge, DC/DC converter, based mostly on modular multilevel converter (MMC) technology. The DC/DC management strategy is based on two inner fast current control loops in dq rotating frame at each of the two MMC bridges. These current controls facilitate operation through dc faults at either dc bus. The active power management is shared by 2 MMCs, at the slower outer control level. The second outer control loop minimizes losses, that is achieved by feedback management of magnitude of both modulation indices at maximal price of zero.95 in the least loading levels. The controller is symmetrical, provides bidirectional power flow and responds equally to faults on either dc bus. Beneath dc fault conditions, one MMC actively controls the inner ac current, whereas 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 600 MW, 500-kV/640-kV take a look at dc/dc model. The controller can be used for control/stability studies with massive dc grids that contain dc/dc converters.