This article proposes a power adaptive compensated virtual impedance method (PACVI) for cascaded dc system. First, the instability problem of cascaded dc system with Boost-CPL is analyzed. Then, the power adaptive compensator and control parameters in PACVI are detailed designed. Compared with traditional virtual impedance (TVI) method, PACVI method has a larger stability margin. In addition, the compensator makes the proposed method adaptive to variable output power, providing a better dynamic performance, especially in light power condition. Finally, the advantages of PACVI method are verified on a 4kW, 48-60V cascaded system.
