A power conversion apparatus including a first direct current conversion module, a second direct current conversion module, and a control module. The control module is configured to: in response to an output voltage of the first photovoltaic string being greater than an output voltage of the second photovoltaic string and a comparison value between the two output voltages being greater than a first threshold: control a switching transistor in the first direct current conversion module to be turned on or off to decrease the output voltage of the first photovoltaic string and control a switching transistor in the second direct current conversion module to be turned on or off to increase the output voltage of the second photovoltaic string, so that a comparison value between the output voltage of the second photovoltaic string and a bus voltage of the direct current bus is less than a second threshold.