A DC conversion system includes a power-generating device, a power storage device, and a DC boost circuit. The power-generating device transforms power from natural resources such as solar power and wind force into a direct current power source. The direct current voltage output from the power-generating device can be stepped up directly from 6-12 volts to high voltage of 200-680 volts by the DC boost circuit and thereby obviate the need to perform a DC to AC conversion.