A power conversion system comprising: a first power conversion device connected between a DC generator and an electric power system, the DC generator configured to output a DC power, the first power conversion device configured to convert at least a portion of the DC power to an AC power to supply to the electric power system; a second power conversion device connected between a power storage device and the electric power system, the power storage device being possible to charge and discharge, the second power conversion device configured to supply power from the power storage device to the electric power system, the second power conversion device configured to supply a power from the electric power system to the power storage device; a third power conversion device connected between the DC generator and the power storage device, the third power conversion device configured to supply a power for charging the power storage device; and a control device configured to set operations of the first power conversion device, the second power conversion device and the third power conversion device based on a first data and a second data, the first data being amount of the DC power, the second data being a value of a DC power set point, the control device, when the first data is larger than the second data or is equal to the second data, configured to transmit a first command to the first power conversion device, the first command setting an AC power which the first power conversion device outputs based on the second data, configured to transmit a second command to the third power conversion device, the second command setting a power which the third power conversion device charges the power storage device based on a difference between the first data and the second data, when the first data is smaller than the second data, configured to transmit a third command to the first power conversion device, the third command setting an AC power which the first power conversion device outputs based on the first data, configured to transmit a fourth command to the second power conversion device, the fourth command setting an AC power which the second power conversion device outputs based on a difference between the second data and the first data, the second power conversion device outputting the AC power to convert a power supplied from the power storage device. a first power conversion device connected between a DC generator and an electric power system, the DC generator configured to output a DC power, the first power conversion device configured to convert at least a portion of the DC power to an AC power to supply to the electric power system; a second power conversion device connected between a power storage device and the electric power system, the power storage device being possible to charge and discharge, the second power conversion device configured to supply power from the power storage device to the electric power system, the second power conversion device configured to supply a power from the electric power system to the power storage device; a third power conversion device connected between the DC generator and the power storage device, the third power conversion device configured to supply a power for charging the power storage device; and a control device configured to set operations of the first power conversion device, the second power conversion device and the third power conversion device based on a first data and a second data, the first data being amount of the DC power, the second data being a value of a DC power set point, the control device, when the first data is larger than the second data or is equal to the second data, configured to transmit a first command to the first power conversion device, the first command setting an AC power which the first power conversion device outputs based on the second data, configured to transmit a second command to the third power conversion device, the second command setting a power which the third power conversion device charges the power storage device based on a difference between the first data and the second data, when the first data is smaller than the second data, configured to transmit a third command to the first power conversion device, the third command setting an AC power which the first power conversion device outputs based on the first data, configured to transmit a fourth command to the second power conversion device, the fourth command setting an AC power which the second power conversion device outputs based on a difference between the second data and the first data, the second power conversion device outputting the AC power to convert a power supplied from the power storage device.