Modularized cascade type multi-level alternating current converter and working method thereof

The invention relates to a modularized cascade type multi-level alternating current converter and a working method thereof, and belongs to the field of power electronic conversion technology and power system power electronization. The modularized cascade type multi-level alternating current converter comprises a single-phase multi-winding transformer which comprises a primary side winding and a plurality of secondary side windings which are in mutual inductance with the primary side winding; the modularized cascade type multi-level alternating current conversion circuit module comprises a plurality of modularized cascade type multi-level alternating current conversion sub-modules, and the input ends of the plurality of modularized cascade type multi-level alternating current conversion sub-modules are connected with the plurality of secondary side windings in a one-to-one correspondence manner; each modularized cascade type multi-level alternating current conversion sub-module is provided with an input end an