Composite charging system and method

A composite charging system, comprising:

• a hydrogen charger for charging hydrogen to a vehicle;
• a hydrogen-based power supply system for generating and supplying power based on hydrogen;
• a power grid-based supply system for supplying power from a power grid;
• an electrical charger for charging an electric vehicle;
• and
• a battery power supply system for storing power supplied from the hydrogen-based power supply system and the power grid-based supply system, and supplying the stored power to the electrical charger,
• wherein the battery power supply system includes:
• an energy storage system (ESS) for storing power and discharging the stored power;
• and a DC-DC converter for storing power supplied from the hydrogen-based power supply system and the power grid-based supply system, and converting a DC voltage outputted from the ESS to a DC voltage required for input to the electrical charger,
• wherein time zones comprise an off-peak time, a peak time, and a high-peak time, based on a cost of the power supplied from the power grid,
• wherein the off-peak time is a time zone where an electricity rate is the cheapest, and the high-peak time is a time zone where the cost of the power supplied is the highest, and the peak time is a time zone which is located between the off-peak time and the high-peak time,
• wherein the ESS is charged through the power grid-based supply system during the off-peak time, and the ESS is charged through the hydrogen-based power supply system during the peak time and the high-peak time,
• wherein, in the off-peak time, as a result of comparison between a charging cost through the power grid-based supply system during the off-peak time and the charging cost through the hydrogen-based power supply system, when the charging cost through the power grid-based supply system during the off-peak time is lower than the charging cost through the hydrogen-based power supply system, and when a residual capacity of hydrogen stored in a hydrogen tank is bigger than a predetermined level, power is charged from the power grid-based supply system, and when a second charging cost is lower than a first charging cost, power is charged from the hydrogen-based power supply system,
• wherein in the peak time, as a result of comparison between the charging cost through the power grid-based supply system during the peak time and the charging cost through the hydrogen-based power supply system, when the charging cost through the power grid-based supply system during the peak time is lower than the charging cost through the hydrogen-based power supply system, and when the residual capacity of hydrogen stored in the hydrogen tank is bigger than the predetermined level, power is charged from the power grid-based supply system, and when the second charging cost is lower than the first charging cost, power is charged from the hydrogen-based power supply system,
• wherein in the high-peak time, as a result of comparison between the charging cost through the power grid-based supply system during the high-peak time and the charging cost through the hydrogen-based power supply system, when the charging cost through the power grid-based supply system during the high-peak time is lower than the charging cost through the hydrogen-based power supply system, and when the residual capacity of hydrogen stored in the hydrogen tank is bigger than the predetermined level, power is charged from the power grid-based supply system, and when the second charging cost is lower than the first charging cost, power is charged from the hydrogen-based power supply system,
• wherein, regardless of when the charging cost through the hydrogen-based power supply system is lower than the charging cost through the power grid-based supply system, charging is performed through the power grid-based supply system when the residual capacity of hydrogen stored in the hydrogen tank is less than the predetermined level,
• wherein the charging cost through the hydrogen-based power supply system is differently set depending on a unit price of purchasing hydrogen when the hydrogen is charged in the hydrogen tank, or periodically updated.