DC POWER SUPPLY INCLUDING SOLAR BATTERY AND METHOD OF CONTROLLING THE SAME

摘要

PROBLEM TO BE SOLVED: To effectively use a solar battery in a DC power supply including a solar battery. SOLUTION: This DC power supply incorporates a solar battery 4 to a DC power supply system which supplies electrical power of a commercial power supply 1 to a load 3 after converting it to a DC power and then converts this DC power to the predetermined constant voltage with a switching power supply circuit 6 including a control circuit 7 for limiting the input voltage with the dead time reference voltage 12. In this case, a means 33 for sequentially detecting the power input to the switching power supply circuit 6 from the solar battery 4, a means 36 for temporarily storing the detected power as a digital value and a means 35 for comparing the detected power being stored with the next detected power are made to output as the control voltage through the D/A conversion after adding or subtracting the predetermined digital value to or from the digital value temporarily stored depending on the comparison result in view of controlling the output power which makes minimum the input power from the solar battery by varying the operation time of the switching element 18 with such output voltage.