Power conversion system suppressing reduction in conversion efficiency

A power conversion system comprising:

• a DC-DC converter electrically connected to an electrical load and a power storage apparatus, the power storage apparatus supplying power to the electrical load, the DC-DC converter converting a voltage of a DC power supplied to the DC-DC converter with a conversion efficiency and outputting power to the electrical load and the power storage apparatus;
• a voltage detector that detects an output voltage of the power storage apparatus as a voltage detection value;
• a current detector that detects an output current of the DC-DC converter as a current detection value;
• and
• a controller that controls the DC-DC converter such that the DC-DC converter starts outputting the power when the voltage detection value detected by the voltage detector is below a predetermined voltage and stops outputting the power when the current detection value detected by the current detector is below a reference current that corresponds to the conversion efficiency being larger than or equal to a predetermined conversion efficiency,
• wherein
• the reference current is determined as a current value at which the conversion efficiency is decreased to be lower than the predetermined conversion efficiency when the output current exceeds the current value in response to an increase in the output current and the controller includes a limiting means configured to limit the output current not to exceed the reference current while the DC-DC converter is outputting the power.