DC / DC converter

Abstract

The invention relates to a DC / DC converter (1) for converting a high-voltage voltage (U_HV) into a low-voltage voltage (U_LV), comprising a primary side (P) and a secondary side (S), wherein the primary side (P) has an inverter (2) connected to a primary winding (3.1) of a transformer (3), wherein the transformer (3) further has a secondary winding (3.2) connected to a rectifier (7) arranged on the secondary side (S), wherein a changeover switch (8) is also provided, wherein either - the secondary winding (3.2) has two end taps (4, 5) and one intermediate tap (6) and the rectifier (7) is connected on the input side to one of the end taps (4) and via the changeover switch (8) depending on its switching position either to the other end tap (5) or to the intermediate tap (6), or - the primary winding (3.1) has two end taps (4, 5) and one intermediate tap (6), and the inverter (2) is connected on the output side to one of the end taps (4) and via the changeover switch (8), depending on its switching position, either to the other end tap (5) or to the intermediate tap (6), wherein the changeover switch (8) is permanently preset or presettable in order to set a low voltage (U_LV) to be generated at the output of the DC / DC converter (1) depending on a range of the high voltage (U_HV) at the input.

Description

The invention relates to a DC / DC converter according to the preamble of claim 1.In vehicles of one or more series, different high-voltage batteries having different voltage ranges can be used. However, for converting the high-voltage voltage into a low-voltage voltage, preferably only one DC / DC converter per series of construction should be used. This means that the DC / DC converter must cover the various voltage ranges of the high-voltage batteries. An additional DC / DC converter stage is frequently used for this purpose. This additional converter stage causes additional installation space, costs and weight.DE 10 2021 129 235 A1 describes a DC-DC converter comprising a first switching network which receives an input DC voltage and outputs a first AC voltage, a transformer and a secondary-side converter circuit. The first switching network receives an input DC voltage. The transformer includes a primary coil center tap such that when the DC input voltage is in a low voltage range, the center tap of the transformer primary side is connected to the DC input voltage causing current to flow through the first plurality of primary windings in parallel with current flowing through the second plurality of primary windings, and when the DC input voltage is in a high voltage range, the center tap is disconnected from the DC input voltage causing current to flow through the first plurality of primary windings in series with current flowing through the second plurality of primary windings.The invention is based on the object of specifying a novel DC / DC converter.The object is achieved according to the invention by a DC / DC converter having the features of claim 1.Advantageous embodiments of the invention are the subject matter of the dependent claims.A DC / DC converter for converting a high-voltage voltage into a low-voltage voltage is proposed, having a primary side and a secondary side, wherein the primary side has an inverter which is connected to a primary winding of a transformer, wherein the transformer furthermore has a secondary winding which is connected to a rectifier arranged on the secondary side, wherein a changeover switch is furthermore provided, wherein eitherthe secondary winding has two end taps and one intermediate tap, and the rectifier is connected on the input side to one of the end taps and, via the changeover switch, either to the other end tap or the intermediate tap, depending on the switching position of the latter, orthe primary winding has two end taps and one intermediate tap, and the inverter is connected on the output side to one of the end taps and, via the changeover switch, either to the other end tap or to the intermediate tap, depending on the switching position of the latter.According to the invention, the changeover switch is permanently preset or preset in order to set a low voltage to be generated at the output of the DC / DC converter as a function of a range of the high voltage at the input. In particular, the changeover switch should remain permanently set during operation of the DC / DC converter.The solution according to the invention proposes the use of a transformer with additional voltage taps on the primary or secondary side and the use of a changeover switch for switching between the voltage taps on the transformer in order to increase the voltage range of the DC / DC converter. An additional DC / DC converter stage can thus be dispensed with, thus saving costs, weight and installation space.Exemplary embodiments of the invention are explained in more detail below with reference to drawings.The following are shown: FIG. 1 shows a schematic view of an embodiment of a DC / DC converter for converting a high voltage voltage into a low voltage, and FIG. 2 shows a schematic view of a further embodiment of a DC / DC converter for converting a high-voltage voltage into a low-voltage voltage.Corresponding parts are provided with the same reference numerals in all figures.FIG. 1 is a schematic view of an embodiment of a DC / DC converter 1 for converting a high voltage U_DC into a low voltage U_LV.The DC / DC converter 1 has a primary side P and a secondary side S. The primary side P has power electronics 2, in particular an inverter 2. The power electronics 2 can be designed, for example, as a half bridge or full bridge. The power electronics 2 have phase conductors, by means of which it is connected to a primary winding 3.1 of a transformer 3. The transformer 3 also has a secondary winding 3.2 with two end taps 4, 5 and an intermediate tap 6. The secondary side S has a rectifier 7, for example an active or passive rectifier 7, having two inputs and two outputs. One of the inputs of the rectifier 7 is connected to one of the end taps 4 of the secondary winding 3.2. The other input of the rectifier 7 is connected via a changeover switch 8, depending on its switching position, either to the other end tap 5 or to the intermediate tap 6. The changeover switch 8 can be designed, for example, as a mechanical switch, relay or semiconductor arrangement. The intermediate tap 6 is a tap of the secondary winding 3.2 between the two end taps 4, 5, which does not necessarily have to lie exactly in the middle between the two end taps 4, 5, but can.Depending on whether the input of the rectifier 7 is connected to both end taps 4, 5 or to an end tap 4 and the intermediate tap 6, a higher or lower AC voltage is present at the inputs. The alternating voltages are proportional to the turns ratio between the respective taps. Thus, the voltage range of the DC / DC converter 1 can be increased, that is, the DC / DC converter 1 covers a larger range of the high voltage U_DC and a larger range of the low voltage U_LV. This offers great advantages, since the DC / DC converter 1 can be used for different high-voltage batteries with different voltage ranges.FIG. 2 is a schematic view of another embodiment of a DC / DC converter 1 for converting a high voltage U_DC into a low voltage U_LV.The DC / DC converter 1 has a primary side P and a secondary side S. The primary side P has power electronics 2, in particular an inverter 2. The power electronics 2 can be designed, for example, as a half bridge or full bridge. The power electronics 2 have outputs with which it is connected to a primary winding 3.1 of a transformer 3. The primary winding 3.1 has two end taps 4, 5 and an intermediate tap 6. One of the outputs of the power electronics 2 is connected to one of the end taps 4. The other output of the power electronics 2 is connected via a changeover switch 8, depending on its switching position, either to the other end tap 5 or to the intermediate tap 6. The changeover switch 8 can be designed, for example, as a mechanical switch, relay or semiconductor arrangement. The intermediate tap 6 is a tap of the primary winding 3.1 between the two end taps 4, 5, which does not necessarily have to lie exactly in the middle between the two end taps 4, 5, but can.The transformer 3 also has a secondary winding 3.2. The secondary side S has a rectifier 7, for example an active or passive rectifier 7, having two inputs and two outputs. The inputs of the rectifier 7 are connected to the secondary winding 3.2.Depending on whether the output of the power electronics 2 is connected to both end taps 4, 5 or to an end tap 4 and the intermediate tap 6, a higher or lower AC voltage is present at the secondary winding 3.2 and the inputs of the rectifier 7. The alternating voltages are proportional to the turns ratio between the respective taps. Thus, the voltage range of the DC / DC converter 1 can be increased, that is, the DC / DC converter 1 covers a larger range of the high voltage U_DC and a larger range of the low voltage U_LV. This offers great advantages, since the DC / DC converter 1 can be used for different high-voltage batteries with different voltage ranges.For universal applicability of a DC / DC converter 1 according to FIG. 1 or FIG. 2 with different voltage sources, for example batteries, in particular in a vehicle, for example an electrically driven vehicle, the voltage position can be preselected by means of the changeover switch 8 depending on the range of the high voltage U_DC at the input and / or the low voltage U_LV to be generated at the output of the DC / DC converter 1. In particular, it can be provided that the changeover switch 8 is not switched or does not have to be switched during operation of the DC / DC converter 1, but rather is preselected depending on the field of application and is then fixed during operation. The changeover switch 8 can therefore be configured as a hardware parameterization, on the basis of which a selection of the corresponding voltage levels can be set, which can then be changed or is not to be changed at least substantially during operation of the DC / DC converter 1.List of reference characters1 DC / DC converter 2 power electronics, inverter 3 transformer 3.1 primary winding 3.2 secondary winding 4 end tap 5 end tap 6 intermediate tap 7 rectifier 8 changeover switch P primary side S secondary side U_DC high-voltage voltage U_LV low-voltage voltageReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 129 235 A1

[0003]

Claims

DC / DC converter (1) for converting a high-voltage voltage (U_DC) into a low-voltage voltage (U_LV), having a primary side (P) and a secondary side (S), wherein the primary side (P) has an inverter (2) which is connected to a primary winding (3.1) of a transformer (3), wherein the transformer (3) furthermore has a secondary winding (3.2) which is connected to a rectifier (7) arranged on the secondary side (S), wherein a changeover switch (8) is furthermore provided, wherein either - the secondary winding (3.2) has two end taps (4, 5) and an intermediate tap (6), and the rectifier (7) is connected on the input side to one of the end taps (4) and, via the changeover switch (8), either to the other end tap (5) or the intermediate tap (6) depending on its switching position, or - the primary winding (3.1) has two end taps (4, 5) and an intermediate tap (6), and the inverter (2) is connected on the output side to one of the end taps (4) and, via the changeover switch (8), depending on its switching position, to either the other end tap (5) or the intermediate tap (6), characterized in that the changeover switch (8) is fixedly preset or can be preset, in order to set a low voltage voltage (U_LV) to be generated at the output of the DC / DC converter ( 1) as a function of a range of the high voltage (U_VL) at the input.The DC / DC converter (1) according to claim 1, characterized in that the changeover switch (8) is configured and / or provided to remain fixedly set during operation of the DC / DC converter (1).DC / DC converter (1) according to Claim 1 or 2, characterized in that the changeover switch (8) is designed as a mechanical switch, a relay or a semiconductor arrangement.DC / DC converter (1) according to one of the preceding claims, characterized in that the inverter (2) is designed as a half bridge or full bridge.Use of the DC / DC converter (1) according to one of the preceding claims in an electrically driven vehicle for converting a high-voltage voltage (U_DC) of a high-voltage battery into a low-voltage voltage (U_LV).

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