Droop Control Strategy for AC/DC Distribution Network Based on Virtual Voltage Drop
In the multi-port AC/DC distribution network with a large number of DC side source loads,due to the differences in transformer loads and line impedences in different AC distribution stations,the traditional droop control cannot realize the reasonable allocation of DC power to multiple different AC/DC converters.To solve this problem,an adaptive droop control strategy based on virtual voltage drop is proposed,which can eliminate the influence of line impedance on power allocation without obtaining impedance information while ensuring reasonable power allocation.Firstly,an adaptive power controller is designed to dynamically adjust the droop coefficient to realize the adaptive DC side power allocation according to the load difference of the AC/DC converter in the AC distribution transformer.Then,for the inconsistency of DC line impedance between multiple converters,an impedance compensator based on the virtual voltage drop is designed to eliminate the influence of line impedance inconsistency,and the DC voltage deviation is reduced by the voltage compensator.Then,the stability analysis provides theoretical support for the proposed control strategy.Finally,simulation results show that the proposed strategy can adaptively allocate DC side power,eliminate the influence of line impedance on power allocation,and reduce the DC bus voltage deviation.
AC/DC distribution networkAC/DC converteradaptive droop controlvirtual voltage drop