A power management system may employ a power source, a distribution system between the power source and electrical loads and an energy accumulator. The accumulator may comprise a plurality of energy processing blocks. Each block may have a limited number of energy storage cells connected in series to produce first voltage. A second higher output voltage from the accumulator may be achieved though integrated DC-DC, DC-AC and AC-DC conversion with intermediate boost of AC voltage through high frequency transformers. Bidirectional power flow may be achieved with high efficiency during charge and discharge of the accumulator. Secondary windings of the transformers may be connected with one another in series so that the accumulator can transfer energy between the distribution system and any one or all of the energy processing units in a fault-tolerant and efficient manner.