DC-to-DC converter for converting a DC input voltage (U E) present between two input lines (6 and 7) at an input side of the DC-to-DC converter into a DC output voltage (U Z) present between two output lines (8 and 9) at an output side of the DC-to-DC converter, the DC-to-DC converter comprising: - at least one alternating-current forward path, which is connected at its input side via electrical components to the input lines (6 and 7) and at its output side to the output lines (8 and 9), wherein the electrical components between the alternating-current forward path and at least one of the input lines (6 and 7) and at least one of the output lines (8 and 9) are electrical switching components of which at least one is driven; and - at least one alternating-current return path for a return flow of current flowing via the alternating-current forward path, which alternating-current return path is connected at its input side via connections to at least one of the input lines (6 and 7) and at its output side to at least one of the output lines (8 and 9), wherein the input-side and output-side connections are either permanent electrically conductive connections or electrical switching connections; - wherein the input lines (6 and 7) are galvanically isolated from the output lines (8 and 9) by capacitors (C r1, C r2) in all alternating-current paths (16, 13), characterized by - an auxiliary converter for compensating a total current via all alternating-current forward paths and alternating-current return paths, which transmits no more than 10% of the present current flowing via all of the alternating-current forward paths, and which electrically conductively connects an additional compensation current path, which runs parallel to all of the alternating-current forward paths and alternating-current return paths, at its one end via two driven switches (S 7, S 8 or S 9, S 10) alternately to two lines on the same side of the DC-to-DC converter which are selected from the group of lines which comprises - the input lines (6, 7), - intermediate potential input lines which conduct intermediate potentials lying between the potentials of the input lines, - the output lines (8 and 9), and - intermediate potential output lines which conduct intermediate potentials lying between the potentials of the output lines, wherein the compensation current path is permanently electrically conductively connected at its other end via at least one connecting capacitor (C e) to at least one line on the side opposite to the same side of the DC-to-DC converter, which line is selected from the group of lines. - at least one alternating-current forward path, which is connected at its input side via electrical components to the input lines (6 and 7) and at its output side to the output lines (8 and 9), wherein the electrical components between the alternating-current forward path and at least one of the input lines (6 and 7) and at least one of the output lines (8 and 9) are electrical switching components of which at least one is driven; and - at least one alternating-current return path for a return flow of current flowing via the alternating-current forward path, which alternating-current return path is connected at its input side via connections to at least one of the input lines (6 and 7) and at its output side to at least one of the output lines (8 and 9), wherein the input-side and output-side connections are either permanent electrically conductive connections or electrical switching connections; - wherein the input lines (6 and 7) are galvanically isolated from the output lines (8 and 9) by capacitors (C r1, C r2) in all alternating-current paths (16, 13), characterized by - an auxiliary converter for compensating a total current via all alternating-current forward paths and alternating-current return paths, which transmits no more than 10% of the present current flowing via all of the alternating-current forward paths, and which electrically conductively connects an additional compensation current path, which runs parallel to all of the alternating-current forward paths and alternating-current return paths, at its one end via two driven switches (S 7, S 8 or S 9, S 10) alternately to two lines on the same side of the DC-to-DC converter which are selected from the group of lines which comprises - the input lines (6, 7), - intermediate potential input lines which conduct intermediate potentials lying between the potentials of the input lines, - the output lines (8 and 9), and - intermediate potential output lines which conduct intermediate potentials lying between the potentials of the output lines, wherein the compensation current path is permanently electrically conductively connected at its other end via at least one connecting capacitor (C e) to at least one line on the side opposite to the same side of the DC-to-DC converter, which line is selected from the group of lines. - the input lines (6, 7), - intermediate potential input lines which conduct intermediate potentials lying between the potentials of the input lines, - the output lines (8 and 9), and - intermediate potential output lines which conduct intermediate potentials lying between the potentials of the output lines,