改进下垂控制下的中压直流配电系统双时间尺度分层调控方法OA北大核心CSTPCD

In the medium-voltage DC distribution system(MVDC-DS),there are some moments when the loads surge or the renewable energy sources(RESs)fluctuate greatly.Under these conditions,the conventional regulation and control strategies have the problems that the scheduling plan is not economically optimal and the DC bus voltages are easy to violate.To solve these issues,a dual-time-scale hierarchical regulation and control method based on the improved droop control is proposed for the MVDC-DS in this paper.First,a±10 kV three-terminal hybrid modular multilevel converter(MMC)-based ring MVDC-DS is constructed with DC fault ride-through capability.This system integrates electric vehicle(EV)charging stations,energy storage system(ESS),distributed photovoltaic and wind turbines.Next,in order to improve the system stability under load surging,this paper improves the conventional droop control based on the tan-function.Then,a dual-time-scale hierarchical regulation and control method is proposed.In the long time-scale scheduling layer,the reference power of MMC is optimized to minimize the total operating cost.In the short time-scale control layer between converters,the droop control is improved and the control parameters are optimized to make a compromise between the economy and voltage quality.Finally,a case verifying the effectiveness of the proposed method is given as follows:By optimizing the scheduling of flexible resources,the total operating cost can be reduced by about 11%;when the load of a data center increases by 100%,all DC bus voltages can be bounded within the allowable range of±3%UN(rated voltage).