CHARGING AND HEATING CIRCUIT AND VEHICLE ELECTRICAL SYSTEM HAVING A CHARGING AND HEATING CIRCUIT

Abstract

A charging and heating circuit is equipped with an AC voltage connection, a DC voltage connection and a rectifier. The rectifier is connected between the AC voltage connection and the DC voltage connection. The charging and heating circuit further includes a heating resistor which is connected to the rectifier and the rectifier is thereby set up to supply the heating resistor with current. Also described is a vehicle electrical system which includes the charging and heating circuit in addition to an accumulator.

Claims

1. A charging and heating circuit comprising: an AC voltage connection; a DC voltage connection; and a rectifier which is connected between the AC voltage connection and the DC voltage connection, wherein the charging and heating circuit further comprises a heating resistor which is connected to the rectifier and the rectifier is thereby set up to supply the heating resistor with current.

2. The charging and heating circuit as claimed in claim 1, wherein the heating resistor is connected to an input of the rectifier which is connected to the AC voltage connection, or the heating resistor is connected to an output of the rectifier which is connected to the DC voltage terminal, or the heating resistor connects an input of the rectifier to an output of the rectifier.

3. The charging and heating circuit as claimed in claim 1, wherein the heating resistor is connected to the rectifier via a switch.

4. The charging and heating circuit as claimed in claim 1, wherein the heating resistor is connected between different phases of the AC voltage connection, the heating resistor is connected between one phase of the AC voltage connection and a neutral conductor connection of the AC voltage connection, or the heating resistor is connected between a phase of the AC voltage connection and the DC voltage connection.

5. The charging and heating circuit as claimed in claim 1, wherein two capacitors and a configuration circuit are provided between the DC voltage connection and the rectifier, wherein the configuration circuit is set up to connect the capacitors either in parallel or in series with one another, and the heating resistor is connected between an AC voltage phase of a half-bridge of the rectifier and a configuration switch of the configuration circuit, or the heating resistor is connected directly or via a selection switch to a configuration switch of the configuration circuit, which configuration switch connects the capacitors to one another in a switchable manner and also connects said configuration circuit to a phase of the AC voltage connection.

6. The charging and heating circuit as claimed in claim 1, wherein the rectifier has a plurality of controllable half-bridges each having two switching elements which are connected to one another via a connecting point which forms the AC voltage phase of the relevant half-bridge, and series inductances are provided between the AC voltage phases of the half-bridges and the phases of the AC voltage connection.

7. The charging and heating circuit as claimed in claim 6, wherein the half-bridges connect a positive busbar and a negative busbar to one another.

8. The charging and heating circuit as claimed in claim 1, wherein the rectifier has a diode bridge which has two diodes connected to one another in series via a connecting point, wherein a neutral conductor contact of the AC voltage connection is directly connected to the connecting point of the diode bridge.

9. A vehicle electrical system having a charging and heating circuit as claimed in claim 1 and an accumulator which is connected directly or indirectly to the DC voltage connection of the charging and heating circuit.

10. The vehicle electrical system as claimed in claim 9, wherein the accumulator is connected to the DC voltage connection of the charging and heating circuit via two DC-DC converters, wherein the DC-DC converters comprise link circuit capacitors which are formed by capacitors in the charging and heating circuit and the charging and heating circuit comprises a configuration circuit which is set up to connect the link circuit capacitors or inputs of the DC-DC converters selectably in parallel or in series with one another.

11. The charging and heating circuit as claimed in claim 2, wherein the heating resistor is connected to the rectifier via a switch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The FIGURE serves to provide a more detailed explanation of examples of a charging and heating circuit and of a vehicle electrical system, as is described here.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The Figure shows a charging and heating circuit LS which comprises an AC voltage connection WA. Said AC voltage connection is connected to an external three-phase voltage source SN via phases P1 to P3. The voltage source SN is shown in a star configuration, with the star point being led out via a neutral conductor N. The AC voltage connection WA also comprises a neutral conductor connection which is connected to said neutral conductor of the voltage source SN. The voltage source SN can be formed by an AC voltage supply network, for example.

[0023] The circuit LS also comprises a DC voltage connection GA with a positive potential connection AN+ (corresponding to a positive potential V+) and a negative potential connection AN- (corresponding to a negative potential V-). The AC voltage connection is connected to a rectifier via isolating switches T1 to T4 (for the three phases individually and for the neutral conductor connection NK) and via series inductances L1 to L3. The rectifier comprises three half-bridges HB1 to HB3 which are each fully switchable. The relevant connecting points within the half-bridges HB1 to HB3 between the two switching elements of the half-bridges are connected to the AC voltage connection WA via the respective series inductance L1 and the isolating switches T1 to T4. Diode bridge DH has two diodes D1 and D2, which are connected in series via connecting point VD of the diode bridge DH and to positive potential connection AN+ and a negative potential connection AN-.

[0024] A configuration circuit with two switches S1, S2 is connected to two capacitors C1 and C2 in order to be able to set their configuration (series or parallel). A first switch S1 of the configuration circuit is connected to the first potential AN+ (positive potential) of the DC voltage connection. A second switch S2 is connected to the second potential, that is to say the negative potential AN- of the DC voltage connection GA. A first capacitor C1 is connected directly to the first potential V+ (that is to say to the first busbar) and via the second switch to the second potential V- (that is to say to the second busbar).

[0025] A second capacitor C2 is connected to the second potential V- directly and to the first potential V+ (that is to say to the positive potential) via the first switch S1. The two capacitors are thus alternately connected to the different potentials V+, V- via the two switches S1, S2. A third switch S3 connects the two capacitors together (in series) in a switchable manner. The switches S1 to S3 permit a parallel or a series configuration to be set selectively. The switches S1 and S2 on the one hand and the switch S3 on the other hand are alternately closed and opened. If the switches S1, S2 are closed, the switch S3 is open. If the switch S3 is closed, the switches S1 and S2 are open.

[0026] Other options for connecting heating resistors H1 to H7 are also shown. Said heating resistors can be provided individually or in any desired combination with one another.

[0027] A first option is to connect a heating element H1 to the phases P1 and P2, that is to say to different phases of the AC voltage connection WA, in particular via a switch H1 via which the heating element can be activated or deactivated. In this case, the heating element H1 and the associated switch A1 are not connected directly to the phases P1 and P2 of the AC voltage connection, but via the isolating switches T1 and T2. Another example of such a configuration is the heating resistor H2 connected between the first phase P1 and the third phase P3. It is also possible to connect a heating element to the second or third phase, preferably via an associated switch, with the second heating resistor H2 being connected to the third phase P3 (via the isolating switch T3) via an associated switch A2. Switches K1, K2 provide a switchable connection of phases P1 and P2, respectively, with phase P3 between the isolating switches T1 - T3 and the series inductances L1 to L3. This allows to use only one phase as input for the half-bridges HB1-HB3, DH.

[0028] A further option is the connection of a heating resistor H3 between the neutral conductor connection NK (via an isolating switch T4) of the AC voltage connection WA and one of the phases, in particular the third phase P3, as shown here using switch A3. The isolating switches T1 to T3 are basically optional, but are preferably implemented in order to enable disconnection of the AC voltage connection in the event of a fault. The heating resistor H3 receives the single root mean square voltage of the voltage source SN, while the heating resistors H1 and H2 receive the line-to-line voltage.

[0029] Another option is shown with the heating resistor H4 which is connected between one phase of the AC voltage connection (here: the first phase P1 and the DC voltage connection GA, in particular a busbar or a potential AN+ of the DC voltage connection). The fourth switch H4 is also connected via its own switch A4 and can therefore be switched. The switches via which the heating resistors are connected are also optional.

[0030] The heating resistors H5 and H6 are connected (via the third isolating switch T3) between one phase (here: third phase P3) of the AC voltage connection and the configuration circuit. In this case, the heating resistor H5 is connected between the third phase P3 and one side of the third switch S3 of the configuration circuit. Switch A5 is connected in series to heating resistor H5 and can be used to switch the heating resistor H5, depending on the selection provided by selection switches W1 and W2. The selection switches W1 and W2 can be used to select whether the heating resistor H5 is connected to the side of the third switch that is connected to the positive potential V+ (corresponding to the first busbar AN+) of the DC voltage connection via the first capacitor C1, or via the changeover switch W2 and is thus connected via the second capacitor C2 to the negative potential V- or AN- of the DC voltage connection. The selection switches W1 and W2 are alternately closed, but never simultaneously. However, the two switches could both be open.

[0031] The heating resistor H6 is not connected via selection switches W1, W2, but rather directly (in particular only via the switch A6) to a specific side of the switch S3, namely to the side which is connected to the negative potential V- or AN- of the DC voltage connection via the second capacitor. It is even possible that this connection cannot be selected with the first capacitor C1 which connects the relevant heating resistor to the positive potential V+ or AN+ of the DC voltage connection GA.

[0032] Another option is to connect the heating resistor, in this case heating resistor H7, between a connecting point VP3 of a half-bridge HB3 and one side of the third switch S3 or the configuration circuit. Switch A7 is connected in series with heating resistor H7 and connects heating resistor H7 to the AC voltage phase VP3 of the half-bridge HB3. Instead of connecting the heating resistor between a connecting point VP3 or an AC voltage phase of a half-bridge and the configuration circuit, as shown with the heating resistor H7, a heating resistor can also be connected between another AC voltage phase (connecting point VP1 or VP2) of another half-bridge HB1, HB2 and the configuration circuit. In addition, it is possible to connect such a heating resistor to the side of the third switch S3 which is connected to the positive potential AN+ of the DC voltage connection GA via the first capacitor C1.

[0033] An accumulator, or a vehicle electrical system or also DC-DC converters which lead to an accumulator, can be connected directly to the DC voltage connection GA. A working inductance and a working switch of a DC-DC converter can be provided in each case in parallel with the capacitances C1 and C2 which together with the respective capacitors C1, C2 form a DC-DC converter. The DC-DC converter can be DC-isolating or DC-conducting. The relevant DC-DC converters are preferably designed in the same way, but can also be designed differently, with the capacitors C1 and C2 preferably being the link circuit capacitors of different converters, which can be configured in parallel or in series with one another using the configuration circuit. This configuration refers to the inputs of the DC-DC converters. The capacitors C1 and C2 can also be designed in the same way and in particular have the same rated capacitance value.