Abstract:In the multi-inverter parallel system of micro-grid, due to the mismatch between output impedance and feeder impedance between inverters in micro-grid, it is difficult to realize a rational reactive power distribution according to the sag coefficient by using the traditional droop control method, with even the problem of reactive power circulation to be generated. For an improvement of the accuracy of reactive power balance, a control strategy based on adaptive virtual impedance control has thus been proposed. With an integral link added on the basis of a fixed virtual impedance, the proposed method combines the improved reactive power demand value from the adaptively adjusted Distributed Generation (DG) unit, and compensates the impedance mismatch of the feeder, thus accurately dividing the reactive power evenly. Free of the dependence on the prediction of the impedance of feeders in advance, as well as on the participation of communication platform, this control strategy is applicable in the microgrid with complex structure. The results show that the proposed method is characterized with a better adaptive ability and reactive power balance than the traditional ones.