POWER CONVERSION APPARATUS

A power conversion apparatus includes a direct current end, a positive direct current bus, a negative direct current bus, a positive bus capacitor, a negative bus capacitor, at least three inverter bridge arms, a switch unit, a controller, and filter inductors, filter capacitors, and alternating current ends that correspond to the at least three inverter bridge arms. A third end of each inverter bridge arm sequentially passes through a filter inductor, a filter capacitor, and a switch unit that correspond to each inverter bridge arm, and is connected to a bus midpoint. The controller is configured to: when a voltage of a power grid is less than or equal to a first voltage threshold, control the switch unit to be turned off or impedance of the switch unit to be increased; then control a amplitude of the modulated wave of each inverter bridge arm to increase.