A hierarchical-hybrid system for balancing a series of cells, said system being divided into m modules, each module having k cells, the system comprising: - one or two central cells and additional two neighboring cells in each module, each neighboring cell being adjacent to one of said central cells; - a local capacitor (C sw ) for each neighboring cell, within a section of each module located at a primary side of a transformer associated with that module; - one global capacitor (C bus ) which is common to all said modules and is located at secondary sides of all modules' transformers; - a plurality of controlled switches (S) configured to form a balancing circuit at the primary side of each module's transformer and a full bridge rectifier at the secondary side; - a controller which is configured to periodically, repeatedly, and alternately open and close certain switches (S)from said plurality of controlled switches (S) to: (a) within each module, connect each local capacitor (C sw ) in parallel to a respective one of said neighboring cells; (b) within each module, connect each said local capacitors (C sw ) in parallel to the central cell if one central cell exists, or to connect each local capacitor (C sw ) to another central cell, respectively, if two central cells exist; (c) within the system, connect all said central cells of all modules separately or simultaneously to said global capacitor (C bus ) through the modules' transformers wherein the primary side of each module's transformer is connected to the balancing circuit via a series resonant-type circuit and the secondary side is connected to the global capacitor via the full bridge rectifier; wherein each module further comprising a capacitor (Cr) and inductor (L) at said primary-side section of the module, that are configured to form the series resonant-type circuit. - one or two central cells and additional two neighboring cells in each module, each neighboring cell being adjacent to one of said central cells; - a local capacitor (C sw ) for each neighboring cell, within a section of each module located at a primary side of a transformer associated with that module; - one global capacitor (C bus ) which is common to all said modules and is located at secondary sides of all modules' transformers; - a plurality of controlled switches (S) configured to form a balancing circuit at the primary side of each module's transformer and a full bridge rectifier at the secondary side; - a controller which is configured to periodically, repeatedly, and alternately open and close certain switches (S)from said plurality of controlled switches (S) to: (a) within each module, connect each local capacitor (C sw ) in parallel to a respective one of said neighboring cells; (b) within each module, connect each said local capacitors (C sw ) in parallel to the central cell if one central cell exists, or to connect each local capacitor (C sw ) to another central cell, respectively, if two central cells exist; (c) within the system, connect all said central cells of all modules separately or simultaneously to said global capacitor (C bus ) through the modules' transformers wherein the primary side of each module's transformer is connected to the balancing circuit via a series resonant-type circuit and the secondary side is connected to the global capacitor via the full bridge rectifier; <EOS>