Battery energy storage systems(BESSs)need to comply with grid code and fault ride through(FRT)requirements during disturbances whether they are in charging or discharging mode.Previous literature has shown that consta...Battery energy storage systems(BESSs)need to comply with grid code and fault ride through(FRT)requirements during disturbances whether they are in charging or discharging mode.Previous literature has shown that constant charging current control of BESSs in charging mode can prevent BESSs from complying with emerging grid codes such as the German grid code under stringent unbalanced fault conditions.To address this challenge,this paper proposes a new FRTactivated dual control strategy that consists of switching from constant battery current control to constant DC-link voltage control through a positive droop structure.The results show that the strategy ensures proper DC-link voltage and current management as well as adequate control of the positive-and negative-sequence active and reactive currents according to the grid code priority.It is also shown that the proposed FRT control strategy is tolerant to initial operating conditions of BESS plant,grid code requirements,and fault severity.展开更多
The three-phase dual active bridge(3 p-DAB)converter is widely considered in next-generation DC grid applications.As for traditional AC grids,the successful integration of power electronic converters in DC grids requi...The three-phase dual active bridge(3 p-DAB)converter is widely considered in next-generation DC grid applications.As for traditional AC grids,the successful integration of power electronic converters in DC grids requires accurate time-domain system-level studies.As demonstrated in the existing literature,the development and efficient implementation of large-signal models of 3 pDAB converters are not trivial.In this paper,a generalized average model is developed,which enables system-level simulation of DC grids with 3 p-DAB converters in electromagnetic transient type(EMT-type)programs.The proposed model is rigorously compared with alternative modeling techniques:ideal-model,switching-function and state-space averaging.It is concluded that the generalized average model provides an optimal solution when accuracy of transient response,reduction in computation time,and wideband response factors are considered.展开更多
文摘Battery energy storage systems(BESSs)need to comply with grid code and fault ride through(FRT)requirements during disturbances whether they are in charging or discharging mode.Previous literature has shown that constant charging current control of BESSs in charging mode can prevent BESSs from complying with emerging grid codes such as the German grid code under stringent unbalanced fault conditions.To address this challenge,this paper proposes a new FRTactivated dual control strategy that consists of switching from constant battery current control to constant DC-link voltage control through a positive droop structure.The results show that the strategy ensures proper DC-link voltage and current management as well as adequate control of the positive-and negative-sequence active and reactive currents according to the grid code priority.It is also shown that the proposed FRT control strategy is tolerant to initial operating conditions of BESS plant,grid code requirements,and fault severity.
文摘The three-phase dual active bridge(3 p-DAB)converter is widely considered in next-generation DC grid applications.As for traditional AC grids,the successful integration of power electronic converters in DC grids requires accurate time-domain system-level studies.As demonstrated in the existing literature,the development and efficient implementation of large-signal models of 3 pDAB converters are not trivial.In this paper,a generalized average model is developed,which enables system-level simulation of DC grids with 3 p-DAB converters in electromagnetic transient type(EMT-type)programs.The proposed model is rigorously compared with alternative modeling techniques:ideal-model,switching-function and state-space averaging.It is concluded that the generalized average model provides an optimal solution when accuracy of transient response,reduction in computation time,and wideband response factors are considered.
