MAXIMUM POWER POINT FOLLOW-UP DEVICE AND SOLAR THERMAL POWER GENERATION SYSTEM USING THE FOLLOW-UP DEVICE

摘要

PROBLEM TO BE SOLVED: To accurately retrieve a maximum power point without reducing efficiency even when the output characteristics of a solar battery are largely changed by determining a direction of change of the output voltage of the solar battery based upon a change in generation power when output voltage is changed and a change in the generation power when the change of the output voltage is stopped for a fixed period. SOLUTION: A control means determines a direction for changing the output voltage of the solar battery based upon a change in generation power when the output voltage is changed and a change in the generation power when the change of the output voltage is stopped for a fixed period. Namely a change ΔAC in the generation power when the output voltage is changed to ΔV and generation power ΔPC due to an environmental change such as an illuminance change for a fixed period when the change of the output voltage is stopped are measured. Power variation removed with power variation due to the environmental change is calculated by subtracting the ΔPCD from the ΔPAC and optimum operation voltage is retrieved based upon the calculated power variation.