  The existing decentralized control for cascaded inverters is based on the
assumption that all modules have same capacities, and a local
fixed-amplitude-varied-phase voltage control is adopted for each inverter
module. However, available source power capacities of cascaded inverters may be
different in some practical applications. To address this issue, this letter
proposes an improved decentralized control scheme, in which the voltage
amplitudes are varied according to their individual available powers. Moreover,
a power factor consistency control is proposed to achieve autonomous voltage
phase synchronization. The steady-state analysis and synchronization mechanism
of cascaded inverters are illustrated. In addition, the proposed strategy has
other advantages, such as adjustable grid power factor and immune to the grid
voltage fault. The effectiveness of the proposed control is tested by
experiments.
