A Hybrid Power Sharing Strategy For Parallel Inverters With Interconnect Lines Fault Ride-through

Abstract

Conventional power sharing strategies for parallel inverters are mainly divided into two categories. One is based on interconnect lines (ILs) for power information exchange, where the whole system would be subjected to paralysis once a fault hits ILs. Another approach is droop control, where no communication mechanism is required but has uneven power sharing due to the mismatched output impedance. To address this issue, a hybrid power sharing strategy based on adaptive virtual impedance is proposed for low-voltage parallel inverters, which reduces the number of ILs and achieves power sharing evenly. Besides, since the mismatch in output impedance among inverters is compensated by virtual impedance, the system can maintain normal operation even if the ILs fail, which shows superior fault ride-through capability. Simulation results verify the effectiveness of the proposed strategy.