Change rate control of photovoltaic generation output and calculation of necessary capacitance

The photovoltaic (PV) generator changes its power output with the weather. If the photovoltaic generator output changes fast, the power system may require more load‐following capability and spinning reserve. This paper proposes a method of controlling the change rate of the photovoltaic generator output. The photovoltaic generator is combined with an electric double layer capacitor (EDLC). A moving average is used to eliminate short period fluctuations in the photovoltaic generator output. The output of the power conversion system (PCS) is determined by the moving average. The output changes within a limited rate. The capacitor voltage is maintained at a constant value to make the capacitor as small as possible. The necessary capacitance is theoretically derived. The effectiveness of this method is verified by experiments. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(4): 10–18, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20946