Modularized grid-connected inverter and double-voltage-loop control method thereof

The invention relates to a modularized grid-connected inverter and a double-voltage-loop control method thereof. The method includes: a central controller generates a system grid-connected current given value through a system voltage control loop according to a direct-current bus voltage sampling value and a direct-current bus voltage given value and transmits the direct-current bus voltage given value and the system grid-connected current given value to each grid-connected inverter module through a communication bus, each grid-connected inverter module generates a module grid-connected current given value through a module voltage control loop according to a module direct-current bus voltage sampling value and the direct-current bus voltage given value transmitted by the central controller and combines the system grid-connected current given value transmitted by the central controller to generate the final grid-connected current given value. By the method, good steady-state performance of the modularized grid-connected inverter is kept, system dynamic performance is improved, adverse effects of the communication bus on the system dynamic performance is reduced, and direct-current bus voltage fluctuation is reduced greatly when system input power changes fiercely.