Generalized Active Power Balancing in Multi-Terminal DC Systems

Abstract:
HVDC is an increasingly utilized technology which is able to help cope with regional power imbalances introduced by renewable energies. In particular, multi-terminal dc systems can be a technically and economically feasible solution for offshore and embedded applications. For these multi-terminal systems, a concept for active power balancing needs to be employed. This is traditionally done using piece-wise linear proportional control characteristics, that can achieve adequate voltage control and power sharing, but come with significant drawbacks. This work introduces a generalized active power balancing controller, which is able to implement arbitrarily parameterizable and continuous control characteristics. Furthermore, control concepts for multiterminal dc grids are proposed and demonstrated by a control design for an exemplary embedded system, which minimizes the stress on the surrounding ac network in case of a converter outage.