4. Optimum Sizing of Ultracapacitors

The batteries cannot get an immediate response to the load requirement when sudden clouds or no wind occur. The batteries are often deep discharged, which damages the battery and shortens its useful life. It is not possible to ensure an optimum charge/discharge cycle. Undercharging of the battery leads to sulfating and stratification; both of which shorten the lifetime of the battery. Another cause of reduced battery life is gassing, which results from battery overcharging. For avoiding all previous problems, new storage devices should be used, one of these devices is ultracapacitor (UC). This chapter exposes ultracapacitors composition, theory, and characteristics. Also, advantages, the equivalent circuits, temperature effect, and voltage variation effect of ultracapacitors are displayed. This chapter also addressed the methods of ultracapacitors sizing. ANN technique is used to determine the optimum UC type for a certain load. Application and results of applied sizing methods and ANN techniques on different loads are displayed.