A
system for charging at least one energy reservoir
cell in a controllable energy reservoir serving to control / supply electrical energy to an n-phase electrical
machine (n≧2). The controllable energy reservoir has n parallel
energy supply branches each having at least two series connected energy reservoir modules, each encompassing at least one electrical energy reservoir
cell having an associated controllable
coupling unit, are connected to a reference
bus, and are connected to a respective phase of the
machine. As a function of control signals, the
coupling units interrupt the respective
energy supply branch or bypass the associated reservoir cells or switch the associated reservoir cells into the respective
energy supply branch. To charge at least one
cell, at least two phases of the
machine are connectable via at least one respective free-wheeling
diode to a negative pole of a charging device. The reference
bus is connectable to the negative pole of the device. Those energy supply branches connected to those phases which are connectable to the negative pole of the device each have a contact point disposed between two energy reservoir modules and is connectable via at least one free-wheeling
diode to a positive pole of the device.