A module comprising: - first and second module terminals (X1, X2), - a first, a second, a third and a fourth controllable switch (10, 30, 10a, 30a), and - a first storage two-pole, which comprises a first and a second two-pole terminal (Y1, Y2), an energy store (9, 9.1, 9.2) and a controllable switching device, wherein the controllable switching device • comprises a first controllable switching state, in which the first storage two-pole does not output any energy independently of a voltage which is present between the first and the second storage two-pole terminal (Y1, Y2), and • comprises a second controllable switching state, in which the store (9, 9.1, 9.2) of the storage two-pole can receive or output energy, wherein the module as a whole has a controllable conduction state, in which - the controllable switching device of the first storage two-pole assumes said first switching state, and - the first to fourth switches (10, 30, 10a, 30a) are connected such that a current flows through the module on two parallel branches, wherein the module further has one or more of the following four controllable power output or receiving states, in each of which the controllable switching device of the first storage two-pole assumes said second switching state, and 1. the voltage between the second and first module terminals (X2, X1) is positive and the storage (9, 9.1, 9.2) of the first storage two-pole is charged, or 2. the voltage between the second and first module terminals (X2, X1) is positive and the storage (9, 9.1, 9.2) of the first storage two-pole is discharged, or 3. the voltage between the second and first module terminals (X2, X1) is negative and the storage (9, 9.1, 9.2) of the first storage two-pole is discharged, or 4. the voltage between the second and first module terminals (X2, X1) is negative and the storage (9, 9.1, 9.2) of the first storage two-pole is charged. - first and second module terminals (X1, X2), - a first, a second, a third and a fourth controllable switch (10, 30, 10a, 30a), and - a first storage two-pole, which comprises a first and a second two-pole terminal (Y1, Y2), an energy store (9, 9.1, 9.2) and a controllable switching device, wherein the controllable switching device • comprises a first controllable switching state, in which the first storage two-pole does not output any energy independently of a voltage which is present between the first and the second storage two-pole terminal (Y1, Y2), and • comprises a second controllable switching state, in which the store (9, 9.1, 9.2) of the storage two-pole can receive or output energy, • comprises a first controllable switching state, in which the first storage two-pole does not output any energy independently of a voltage which is present between the first and the second storage two-pole terminal (Y1, Y2), and • comprises a second controllable switching state, in which the store (9, 9.1, 9.2) of the storage two-pole can receive or output energy, wherein the module as a whole has a controllable conduction state, in which - the controllable switching device of the first storage two-pole assumes said first switching state, and - the first to fourth switches (10, 30, 10a, 30a) are connected such that a current flows through the module on two parallel branches, - the controllable switching device of the first storage two-pole assumes said first switching state, and - the first to fourth switches (10, 30, 10a, 30a) are connected such that a current flows through the module on two parallel branches, wherein the module further has one or more of the following four controllable power output or receiving states, in each of which the controllable switching device of the first storage two-pole assumes said second switching state, and 1. the voltage between the second and first module terminals (X2, X1) is positive and the storage (9, 9.1, 9.2) of the first storage two-pole is charged, or 2. the voltage between the second and first module terminals (X2, X1) is positive and the storage (9, 9.1, 9.2) of the first storage two-pole is discharged, or 3. the voltage between the second and first module terminals (X2, X1) is negative and the storage (9, 9.1, 9.2) of the first storage two-pole is discharged, or 4. the voltage between the second and first module terminals (X2, X1) is negative and the storage (9, 9.1, 9.2) of the first storage two-pole is charged. 1. the voltage between the second and first module terminals (X2, X1) is positive and the storage (9, 9.1, 9.2) of the first storage two-pole is charged, or 2. the voltage between the second and first module terminals (X2, X1) is positive and the storage (9, 9.1, 9.2) of the first storage two-pole is discharged, or 3. the voltage between the second and first module terminals (X2, X1) is negative and the storage (9, 9.1, 9.2) of the first storage two-pole is discharged, or 4. the voltage between the second and first module terminals (X2, X1) is negative and the storage (9, 9.1, 9.2) of the first storage two-pole is charged.