Convergence analysis for wireless parallel inverter systems with power sharing in proportion to capacity

For wireless parallel connected inverters with different capacity, it's a must that system load should be shared proportionally since the equally sharing scheme may cause failure for the inverters with smaller capacity. And this is a hot spot in the research of micro-grid. In this paper, sufficient conditions for the proportional load sharing of inventers are deduced by the convergence analysis for inverter output voltage magnitude and frequency, which are helpful for determining droop control coefficients. Then, with virtual impedances and dual-loop regulators, a micro-grid system is built comprised of two invertors with different capacities. At last, the effectiveness of the analysis is verified through simulations and experiments.