Optimal ultracapacitor permutation and combination for voltage equalization using Rejected Monte Carlo algorithm

Abstract–Ultracapacitors are novel energy storage devices with high power density and long cycle life. For practical applications, numerous ultracapacitor monomers need to be connected in series or parallel to form modules, in which the voltage imbalance among monomers induced by technological parameter dispersion would damage ultracapacitors. It is an important issue to achieve the voltage balance with lower energy cost. Instead of designing cell balancing systems to minimize the voltage imbalance, this paper proposes a method for optimized ultracapacitor permutation and combination using Rejected Monte Carlo algorithm. This method not only reduces voltage difference, but also decreases balancing current and energy loss of the equalization circuit. Simulation results are provided to illustrate the effectiveness of the proposed method.