Fuzzy Based Intelligent Voltage Balancing Scheme for Matrix Connected Ultracapacitor Bank

This paper presents an intelligent control using Fuzzy Logic for equalizing the voltages of Ultracapacitor (UC) cells in a matrix connected UC system with a coupled inductor as the energy transfer medium. This balancing topology has a lesser number of switches and inductor windings. The proposed control technique provides complementary pulses to switches whose duty ratio is determined by a Fuzzy Logic Controller based on the voltage difference of series UC cells. The duty ratio is adjusted such that the voltage difference keeps on reducing and finally reaches zero. This modification in the control technique is made without much addition to the components required, enabling faster balancing of cell voltages. The proposed control technique is experimentally validated using IF and 360F UC banks with four cells connected in matrix form.