System for charging at least one energy storage cell in a controllable energy store used for controlling and supplying electric power to an n-phase electrical machine, where n ≥ 1, wherein - the controllable energy store has n parallel energy supply parts (3-1, 3-2, 3-3) that • each have at least two series-connected energy storage modules that each comprise at least one electrical energy storage cell having an associated controllable coupling unit, • are firstly connected to a reference rail (T-) and • are secondly connectable to a respective phase (U, V, W) of the electrical machine, - the coupling units take control signals as a basis for opening a first switching element (7-311, 7-3m1) and a second switching element (7-312, 7-31m) of the associated controllable coupling unit (6, 6-31, 6-3m) to interrupt the respective energy supply path (3-1, 3-2, 3-3) or decouple the respective associated energy storage cells by opening the second switching element (7-312, 7-3m2) of the associated controllable coupling unit (6, 6-11, 6-3m), and this second switching element (7-312, 7-3m2) and the associated energy storage cells in the respective energy supply path (3-1, 3-2, 3-3) are bypassed by closing the first switching element (7-311, 7-3m1), or open the first switching element (7-311, 7-3m1) and close the second switching element (7-312, 7-3m2) of the associated controllable coupling unit (6, 6-31, 6-3m) to connect the respectively associated energy storage cells into the respective energy supply path (3-1, 3-2; 3-3), - the energy supply paths (3-1, 3-2, 3-3) of the controllable energy store and the phases (U, V, W) of the electrical machine are connected to a DC link circuit via a controllable n-phase bidirectional rectifier unit, - the reference rail (T-) of the controllable energy store is connected to a reference rail of the DC link circuit, and - the DC link circuit is electrically connected to a charging device, characterized in that the controllable bidirectional rectifier unit is a controllable n-phase bridge rectifier that has at least one controllable high-side switch arranged in a rectifier path connected to an energy supply path (3-1, 3-2, 3-3) of the controllable energy store that has no energy storage cells to be charged, wherein the at least one high-side switch of the ' bridge rectifier, together with the stator windings of the electrical machine, are operable analogously to a step-down converter during a charging process and/or the coupling units associated with energy storage cells to be charged, together with the stator windings of the electrical machine, are operable analogously to a step-up converter during a charging process, wherein energy is supplyable to and storable in the stator windings of the electrical machine. - the controllable energy store has n parallel energy supply parts (3-1, 3-2, 3-3) that • each have at least two series-connected energy storage modules that each comprise at least one electrical energy storage cell having an associated controllable coupling unit, • are firstly connected to a reference rail (T-) and • are secondly connectable to a respective phase (U, V, W) of the electrical machine, • each have at least two series-connected energy storage modules that each comprise at least one electrical energy storage cell having an associated controllable coupling unit, • are firstly connected to a reference rail (T-) and • are secondly connectable to a respective phase (U, V, W) of the electrical machine, - the coupling units take control signals as a basis for opening a first switching element (7-311, 7-3m1) and a second switching element (7-312, 7-31m) of the associated controllable coupling unit (6, 6-31, 6-3m) to interrupt the respective energy supply path (3-1, 3-2, 3-3) or decouple the respective associated energy storage cells by opening the second switching element (7-312, 7-3m2) of the associated controllable coupling unit (6, 6-11, 6-3m), and this second switching element (7-312, 7-3m2) and the associated energy storage cells in the respective energy supply path (3-1, 3-2, 3-3) are bypassed by closing the first switching element (7-311, 7-3m1), or open the first switching element (7-311, 7-3m1) and close the second switching element (7-312, 7-3m2) of the associated controllable coupling unit (6, 6-31, 6-3m) to connect the respectively associated energy storage cells into the respective energy supply path (3-1, 3-2; 3-3), - the energy supply paths (3-1, 3-2, 3-3) of the controllable energy store and the phases (U, V, W) of the electrical machine are connected to a DC link circuit via a controllable n-phase bidirectional rectifier unit, - the reference rail (T-) of the controllable energy store is connected to a reference rail of the DC link circuit, and - the DC link circuit is electrically connected to a charging device, characterized in that the controllable bidirectional rectifier unit is a controllable n-phase bridge rectifier that has at least one controllable high-side switch arranged in a rectifier path connected to an energy supply path (3-1, 3-2, 3-3) of the controllable energy store that has no energy storage cells to be charged, wherein the at least one high-side switch of the ' bridge rectifier, together with the stator windings of the electrical machine, are operable analogously to a step-down converter during a charging process and/or the coupling units associated with energy storage cells to be charged, together with the stator windings of the electrical machine, are operable analogously to a step-up converter during a charging process, wherein energy is supplyable to and storable in the stator windings of the electrical machine.