VEHICLE CHARGING CIRCUIT AND VEHICLE ELECTRICAL SYSTEM HAVING THE VEHICLE CHARGING CIRCUIT

Abstract

A vehicle charging circuit includes an AC voltage connection that has a plurality of potentials, a switch device, a plurality of rectifiers that are each in the form of a bridge rectifier, a plurality of step-up converters, and a plurality of galvanically isolating DC-DC converters. Inputs of the rectifiers are connected to one other. The interconnected inputs of the rectifiers are connected to the AC voltage connection via the switch device. The rectifiers each have an output, downstream of each of which is connected one of the step-up converters. The step-up converters are connected to a rechargeable battery connection of the vehicle charging circuit.

Claims

1. A vehicle charging circuit, comprising: an AC voltage connection that has a plurality of potentials; a switch device; a plurality of rectifiers that are each in the form of a bridge rectifier; a plurality of step-up converters; and a plurality of galvanically isolating DC-DC converters, wherein inputs of the rectifiers are connected to one another and the interconnected inputs of the rectifiers are connected to the AC voltage connection via the switch device, and the rectifiers each have an output, downstream of each of which is connected one of the step-up converters, and the step-up converters are connected to a rechargeable battery connection of the vehicle charging circuit.

2. The vehicle charging circuit as claimed in claim 1, wherein the individual rectifiers are connected to the individual DC-DC converters via the individual step-up converters, wherein the DC-DC converters have outputs that are connected to one another and that are connected to an on-board electrical system connection.

3. The vehicle charging circuit as claimed in claim 1, wherein the step-up converters each have a diode, a load inductor, a DC link capacitor and a converter switch, wherein in each case the diode is connected to a first DC voltage potential of the connected rectifier via the load inductor and is connected to a second DC voltage potential of the connected rectifier via the converter switch, and the DC link capacitor is connected to the second DC voltage potential hand to that end of the diode that is opposite the converter switch.

4. The vehicle charging circuit as claimed in claim 1, which is equipped with two rectifiers and two DC-DC converters, wherein the DC-DC converters each have a first input potential and a second input potential, and the rechargeable battery connection is connected to the first input potential of the first DC-DC converter and to the second input potential of the second DC-DC converter.

5. The vehicle charging circuit as claimed in claim 1, wherein the AC voltage connection is configured to be connected to the outer conductors of a single-phase three-wire power supply network.

6. The vehicle charging circuit as claimed in claim 1, wherein the AC voltage connection is provided in the form of a plug-in connection element that is designed in accordance with the ANSI/NEMA WD 6-2002 standard, in particular in the form of a socket or plug connector in accordance with NEMA 6-15, NEMA L6-15, NEMA 6-20, NEMA L6-30, NEMA 6-30, NEMA 6-50, NEMA L6-50, NEMA 10-30 or NEMA 10-50.

7. The vehicle charging circuit as claimed in claim 1, which also has a DC voltage connection, wherein the rechargeable battery connection is connected to the DC voltage connection via rechargeable battery isolating switches of the vehicle charging circuit.

8. The vehicle charging circuit as claimed in claim 7, which also has connecting switches that connect the DC voltage connection to different potentials of the outputs of the different rectifiers in a switchable manner.

9. The vehicle charging circuit as claimed in claim 1, wherein the inputs of the rectifiers are connected to one another directly or are connected to one another in a switchable manner via an additional switch device.

10. A vehicle electrical system comprising a vehicle charging circuit as claimed in claim 1, a rechargeable battery and an on-board electrical system branch, wherein the rechargeable battery is connected to the rechargeable battery connection of the vehicle charging circuit and the on-board electrical system branch is connected to the on-board electrical system connection of the vehicle charging circuit.

11. The vehicle charging circuit as claimed in claim 2, wherein the step-up converters each have a diode, a load inductor, a DC link capacitor and a converter switch, wherein in each case the diode is connected to a first DC voltage potential of the connected rectifier via the load inductor and is connected to a second DC voltage potential of the connected rectifier via the converter switch, and the DC link capacitor is connected to the second DC voltage potential and to that end of the diode that is opposite the converter switch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The FIGURE is used to provide an exemplary explanation of the vehicle charging circuit described here and the vehicle electrical system described here.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The FIGURE shows a vehicle charging circuit comprising an AC voltage connection IF1 and a DC voltage connection IF2. Both connections are charging connections. The two phases of the AC voltage connection IF1 are connected to rectifiers GR1 and GR2 via a switch device S1.1 and S1.2. In this case, the inputs, that is to say the AC voltage connections of the rectifiers GR1 and GR2, are connected in parallel with one another, wherein this parallel connection is in turn connected in parallel with the AC voltage connection IF1. An additional switch device ZS can be provided that connects the inputs of the rectifiers GR1 and GR2 to one another in a switchable manner. In each case, a step-up converter B1, B2 is connected downstream of the rectifiers. In turn, two DC-DC converters W1, W2 are connected downstream of the step-up converters B1, B2. The outputs of the DC-DC converters W1, W2 are connected in parallel with one another. This parallel connection is in turn connected in parallel with the on-board electrical system connection BA. The on-board electrical system BN is connected to the on-board electrical system connection BA. The on-board electrical system BN is not part of the vehicle charging circuit, but rather is part of the vehicle electrical system shown in The FIGURE.

[0025] External voltage sources WQ and GQ can be connected to the connections IF1 and IF2, which are part of the vehicle charging circuit and the vehicle electrical system (WQ is an AC voltage source and GQ is a DC voltage source). The voltage sources are not part of the vehicle electrical system and also not part of the vehicle charging circuit.

[0026] The rectifiers GR1 and GR2 are implemented in the form of a Graetz bridge, as shown by way of example using the rectifier GR2. In this case, there are two diode bridges, namely a first diode bridge D1, D2 and a second diode bridge D3 and D4. The two phases of the AC voltage connection IF1 are connected to the connecting points of the respective diode bridges (via the switches S1.1 and S1.2). The connecting points of the diode half-bridges D1, D2 on the one hand and D3, D4 on the other hand form the input of the rectifiers GR1, GR2. Each diode half-bridge has a first end toward which the conducting directions of the diodes point, wherein these ends of the diode half-bridges are connected to one another. The opposite ends of the two diode half-bridges are also connected to one another. The two ends form the output of the rectifiers GR1 and GR2 and are each connected individually to the step-up converters B1, B2 or to the inputs thereof.

[0027] The DC-DC converters 131, B2 each have a series-connected load inductor at the input, which load inductors are connected to the opposite potential in a switchable manner via a converter switch. The load inductors are shown here in the positive branch, wherein the converter switches make a connection from the inductors to the negative potential in a switchable manner. In each step-up converter 131, B2, a diode is connected downstream of the load inductor, the forward direction of which diode points away from the load inductor. A capacitor is connected downstream of the diode and connects the diode in parallel with the opposite potential. In the embodiment shown, this therefore results in a series connection, which comprises the load inductor and the diode, in the positive potential. The converter switch is provided a connecting point between these components and connects the connecting point to the negative potential. The capacitor is located at the output of the step-up converter, while the load inductor is located at the input. At the output of the step-up converter, the capacitor connects the positive potential to the negative potential and is therefore used for smoothing.

[0028] An optional switch AS is connected between the negative potential of the step-up converter B1 and the positive potential of the second step-up converter B2. As mentioned, this switch is optional and can also be omitted. If said switch is omitted, then a series connection is created by the rectifiers GR1 and GR2 or by the diodes D1 to D4 of the diode bridge, with the result that the capacitors of the step-up converters are connected in series with one another. The positive potential of the DC voltage connection IF2 is connected to the positive potential between the first step-up converter B1 and the first DC-DC converter W1. The negative potential of the DC voltage connection GF2 is connected to the negative potential of the connection between the second step-up converter B2 and the second DC-DC converter W2. The connection between the DC voltage connection IF2 and the DC-DC converter W1, W2 or the step-up converters 131, B2 is routed via a connecting switch. Said connecting switch is configured to break the connection to the DC voltage connection IF2 at all poles. It should be noted that the DC voltage connection IF2 has two potentials that are connected to different converters W1, W2 or to the inputs thereof. If a voltage of, for example, 800 volts is thus applied to the DC voltage connection IF2, this voltage is divided between the two capacitors of the step-up converters 131, B2 or between capacitors that are provided on the input side in the DC voltage converter W1, W2 (not shown), since these are connected to the AC voltage inputs of the rectifiers GR1, GR2 via the rectifier bridges and the parallel connection of the rectifiers GR1, GR2. The connection can also be provided by the optional switch AS.

[0029] Between the DC voltage connection IF2 and the rechargeable battery AK, there are rechargeable battery isolating switches S5.1 and S5.2 that allow the rechargeable battery AK to be disconnected at all poles. In particular, said rechargeable battery isolating switches enable all-pole disconnection of the rechargeable battery connection AA to which the rechargeable battery AK is connected. The connection of the connecting switches S2.1, S2.2 is not routed via the rechargeable battery isolating switches S5.1, S5.2, but rather is routed directly to the DC voltage connection IF2.

[0030] There can also be a further connection, which can be switched by means of the switches S4.1 and S4.2, between the rechargeable battery AK and an on-board electrical system branch BN that is connected to the on-board electrical system connection BA. The on-board electrical system can therefore be fed directly by the rechargeable battery, can be fed by the on-board electrical system connection BA and therefore by the converters W1, W2, or by both.

[0031] Due to the voltage division of the voltage that is applied to IF2, the capacitors of the step-up converters W1, W2 or of the converters W1, W2 can be dimensioned to have a relatively low nominal voltage or maximum voltage. The voltage division results from the series connection of these capacitors, which is provided by the diodes, the diode full-bridge D1 to D4, the rectifiers GR1, GR2, and from the parallel connection thereof on the input side.