Fuzzy logic energy management strategy for supercapacitor-based energy saving system for variable-speed motor drives

In recent years, problems in variable-speed motor drive systems have drawn more and more attention: the variable speed motor drive system will frequently absorb or regenerate large energy in short time when accelerating or decelerating respectively, which may lead to energy waste and voltage fluctuation. A solution can be easily found by using supercapacitor-based energy storage device to shave the power demand and absorb the braking energy. In order to control the bidirectional energy flow of the storage device accurately, an energy management strategy is required. In this paper, a fuzzy logic energy management strategy is presented. Using the voltage of the DC bus and its rate of changes, a set of rules are developed. It can not only enhance the ability of the energy saving but also reduce the peak power of power grid dramatically. Experimental results are presented to verify the design.