RIPPLE CONTROL METHOD FOR MODULAR CASCADED POWER CONVERSION DEVICE

A ripple control method for a modular cascaded power conversion device is provided. The method obtains, according to a grid voltage vector of three-phase AC power, a second-order fluctuating voltage superposition vector representing the total amount of second-order fluctuating voltages on respective floating DC sides of the three phases; determines a single-phase power control amount of each phase to be transferred from the floating DC sides to a low-voltage DC side; determines a single-module power control amount of each power module to be transferred to a low-voltage DC side thereof; and generates a single-module control signal for controlling the power module, so as to transfer a second-order fluctuating voltage on a floating DC side of the power module to the low-voltage DC side thereof. A modular cascaded power conversion device is also provided.