Soft Switched Hybrid Energy Storage Module for Power and Energy Management of a DC Bus

A hybrid energy storage module based around two strings consistent of battery cells as an energy optimized string, and super-capacitors as a power surge optimized string, is presented. The energy transfer between the two strings is carried out using a series resonant link, that connects one battery to two super capacitors. The rest of the cells are equalized by series resonant balancers that shuttle the energy along each of the strings. The serial resonant link between the strings results in faster energy transfer, operates more efficiently than previous options, and reduces component count compared to the latest available solutions. Hybrid energy storage connection to a common DC bus options are outlined, and three setups that provide added value for dual string architecture are shown. Dual voltage source management methods are summarized, along with their advantages and down sides. The system is analyzed analytically, evaluated in simulation, and verified by an experimental prototype. The simulation and experimental results are in good agreement with theoretical predictions.