The scalable cascaded Z-source inverter is able to interface flexibly different distributed renewable energy sources or storages in wide voltage change range, such as wind power, solar power, battery, fuel cell, Ultra-capacitor and so on. The invention facilitates the AC 1 MHz frequency output; therefore high power density can be reached. Z-source network is integrated in each inverter module to wide system operation range, improve high system efficiency, and enhance high system reliability. The invention is applied for PV system to verify the performance.