| 摘要 |
PROBLEM TO BE SOLVED: To reduce the capacity of a DC-to-DC converter and to prevent the charged state of sub-batteries from deteriorating by increasing the chances of fully charging them. SOLUTION: This power supply is provided with main batteries 3 for driving a drive motor 5, sub-batteries 8 for feeding power to low-voltage electric loads 9, and a DC-to-DC converter 7, which converts the voltage of the main batteries into voltages to be supplied to the sub-batteries and low-voltage electric loads. A current detector 10 detects the output current of the DCDC converter. As the output current increases, the output voltage of the DCDC converter is reduced continuously from a given maximum voltage capable of fully charging the sub-batteries to a given minimum voltage capable of operating the low- voltage electric loads. This design enables reduction in the capacity of the DCDC converter. When the output current of the DCDC converter becomes zero or small, its output voltage becomes high so that the sub-batteries are charged each time. Thus, a situation will not occur in which sub-batteries fall into an insufficiently charged state. |
