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 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 from said plurality of controlled switches 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 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 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 from said plurality of controlled switches 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;