Adaptive Virtual Impedance-Based Reactive Power Sharing Approach for Multi Parallel Grid-Forming Converters

In the multi parallel grid-forming converters under the conventional Virtual Synchronous Generator (VSG) control strategy, it’s being challenging to achieve the precise reactive power sharing due to asymmetry of line impedance of each converter. To enhance the precision of reactive power sharing, this paper proposes an adaptive virtual impedance design method that integrates the reactive power sharing error and output voltage of inverters. The proposed reactive power sharing strategy can be simply integrated with conventional grid-forming control schemes, which helps to mitigate power coupling, achieve high-precision load power distribution, suppress circulating currents among inverters, and alleviate the inherent conflict between reactive power sharing accuracy and output voltage drop caused by virtual impedance. Finally, simulations under multiple operating conditions are conducted to verify the effectiveness of the proposed strategy.