Comparison of decomposition levels for wavelet transform based energy management in multi-fuel cell system

Abstract

In a hybrid energy storage system consisting of multi-fuel cell systems and super-capacitors, the wavelet transform is adopted to decompose the load power into multiple levels and assign the low-frequency component for fuel cell (FC) systems to reduce the impact caused by frequent variations in power demand. Two strategies—wavelet-based direct strategy and wavelet-quadratic strategy—are simulated in order to explore the system output characteristics with an increasing decomposition level. It is shown that the wavelet-quadratic strategy decreases the frequency of FC fluctuations as the decomposition level increases, which facilitates delayed degradation. The direct strategy improves the efficiency but sacrifices the FC stack health due to frequent load changes.