Fault Ride-through Control of Wind Turbines-based DC Microgrid

DC microgrid has become an important development direction microgrid, and its fault ride-through (FRT) control needs to be investigated. DC microgrid using wind turbines-based is studied and designed in this paper, and its FRT technology research is different from general grid-connection wind farm systems, the situation that AC grid cannot transmit power to the DC microgrid also needs to be considered. The configuration and operation performances are described firstly. Based on different system operation situations under AC grid fault, various FRT strategies are proposed which is depended on the DC voltage variation range. Under every working condition, there must be at least one DC terminal converter to control the DC voltage. Without communicating with different DC terminal converter, each microgrid unit can implement independent control. Therefore, the control structure is simplified and the control flexibility is increased. Simulation results of the proposed control strategy show that the system has quick respond to the AC grid fault, and the FRT ability can improve the power supply quality of the DC microgrid system.