Supplying auxiliary components with a stepped-up charging voltage in the case of a diode-protected connection of a charging connection

Abstract

A vehicle electrical system connection circuit (VS) is equipped with a booster output connection (IA), a battery connection (BA), a charging connection (LA), an auxiliary component connection (HA) connected to the booster output connection (IA), and at least one battery switch (B1, B2). The booster output connection (IA) and the battery connection (BA) are connected to one another via the battery switch (B1, B2). The connection circuit (VS) has a diode (D) via which the booster output connection (IA) is connected to the charging connection (LA). The forward direction of the diode (D) corresponds to the direction of a power flow from the booster output connection (IA) to the charging connection (LA). A corresponding vehicle electrical system branch is also described.

Description

[0001] Description

[0002] Supply of auxiliary components with boosted charging voltage with diode-protected connection of a charging port

[0003] It is known to equip electric vehicles with a high-voltage electrical system in order to operate the electric traction drive efficiently and powerfully at high voltage. On the one hand, in addition to the drive, there are other components (auxiliary components) which, due to their high power requirements, are also operated with high voltage. On the other hand, several voltage levels for DC charging have now been established, in particular 400 V DC charging, according to which numerous charging stations are designed, and more recently 800 V DC charging, which, due to the higher voltage, enables significantly higher charging power and thus significantly shortened charging times. Accordingly, there are vehicles with an 800 V electrical system that supplies 800 V auxiliary components, which gives rise to the task of charging such vehicles conveniently and safely using established 400 V charging stations.The challenge can be seen as making the on-board networks of vehicles with a high nominal voltage backward compatible so that they can be charged advantageously at existing charging stations with a lower nominal charging voltage.

[0004] This problem is solved by the subject matter of the independent claim. Further properties, features, embodiments, and advantages are revealed by the subordinate and dependent claims, as well as by the description and the figures.

[0005] It is proposed to equip a connecting circuit (in the sense of a vehicle power distributor) with a booster input and a booster output in order to be able to increase a charging voltage that is lower than the nominal voltage of a vehicle battery or the on-board electrical system. In order to be able to operate auxiliary components at the nominal voltage of the on-board electrical system during charging, an auxiliary component connection is connected to the booster output. To increase safety, the booster output (and thus the auxiliary component connection) is connected to the charging connection via a diode (which can be connected in series if necessary). When charging an 800 V vehicle battery at a 400 V charging station that has overvoltage protection against the ground potential (e.g. corresponding charging stations according to the CHAdeMO standard with a maximum charging voltage of 500 V), an insulation fault can lead to a potential shift and thus to the triggering of this overvoltage protection.In this case, the diode blocks, improving high-voltage safety until the resulting fault current has subsided. This allows a vehicle to be charged cost-effectively with a voltage lower than the nominal voltage of the vehicle's electrical system while maintaining a high level of safety.

[0006] In summary, the diode blocks when the voltage at the charging port needs to be boosted (boost mode due to a corresponding battery at the battery port), thus preventing the boosted voltage from triggering the charging station's overvoltage protection (Zener diode or functionally equivalent), which is not designed for the boosted voltage. This unwanted triggering (i.e., current flow through the overvoltage protection) can occur if an insulation fault shifts the potential position of the voltage relative to the ground potential and is no longer symmetrical. This allows a vehicle to be charged with a boosted voltage if it is connected to a charging station with a comparatively lower (non-boosted) voltage. At the same time, the procedure proposed here allows the operation of auxiliary components such as air conditioning compressors, etc.with the high nominal voltage of the vehicle's electrical system even during charging, which improves comfort without impairing the blocking effect of the diode.

[0007] An on-board electrical system connection circuit is proposed which is configured to suitably connect a charging connection and a battery connection to one another. To compensate for voltage differences between the charging connection and the battery connection (for example due to different nominal voltages), a booster, i.e. a step-up DC-DC converter, can be connected. For this purpose, the connection circuit has a booster output connection and a booster output connection to which an external booster (i.e. outside the connection circuit, preferably within the on-board electrical system) can be connected, which can increase the voltage of the charging connection to a suitable voltage for charging the batteries. The booster output connection is configured to be connected to a booster input and the booster input connection is configured to be connected to a booster output.This allows a booster to be connected that can increase the voltage at the booster input to a higher voltage at the booster output.

[0008] At least one battery switch is provided, via which the booster output terminal is connected to the battery terminal. Preferably, the connection between the booster output terminal and the battery terminal is switchable across all poles. Therefore, a first battery switch may be provided, which is located in a negative current path that connects a negative potential of the booster output terminal to a negative potential of the battery terminal. A second battery switch may be provided, which is located in a positive current path that connects a positive potential of the booster output terminal to a positive potential of the battery terminal.

[0009] Furthermore, an auxiliary component connection is provided which is connected to the booster output connection. This allows components that are connected to the auxiliary component connection to be supplied directly with the boosted voltage of the booster output connection. The auxiliary component connection is connected to the battery connection via the at least one battery switch, so that supply using the voltage at the battery connection is also possible. When the battery switch is closed, voltage can be supplied to the battery connection for charging (the connectable battery) and, at the same time, a voltage can be supplied to the auxiliary component connection which can be used to supply at least one auxiliary component that can be connected to the auxiliary component connection. The booster output connection is connected to the charging connection via a diode in the connecting circuit. Due to the (preferably switch-free and, if necessary,In the (fuse-free) connection of the auxiliary component terminal to the booster output terminal, the auxiliary component terminal is connected to the charging terminal via the diode. The diode is preferably provided in a negative current path that connects the booster output terminal (or a negative potential thereof) to the charging terminal (or a negative potential thereof). The flow direction of the diode corresponds to the direction of power flow from the booster output terminal to the charging terminal. In particular, the flow direction of the diode points towards the charging terminal (preferably towards a negative potential of the charging terminal). In other words, the flow direction of the diode points away from the booster output terminal or from the auxiliary component terminal or from the battery switch (preferably away from a negative potential of the terminals or from a battery switch in a negative current path).The diode reduces at high speed a current that can flow through overvoltage protection elements of a charging station (connected to the charging port) due to an earth-related insulation fault, which then become conductive when the high voltage of the battery terminal or the booster output terminal is partially or completely between an earth potential and a potential of the charging port due to a potential shift.

[0010] Especially in CHAdeMO charging stations that comply with a CHAdeMO standard whose maximum charging voltage does not exceed 500 V, appropriately designed surge protection diodes are connected between the ground potential and the charging voltage potentials. If an insulation fault causes the voltage level of the battery connection / booster output connection to shift relative to the ground potential, one of the charging station's surge diodes becomes conductive. The diode very quickly reduces the current flow due to its forward or reverse conduction.

[0011] The diode is provided in a connection in a (negative) current path between the charging connection on the one hand and the booster output connection or auxiliary component connection on the other hand (as a component connected in series in the connection). This is particularly the case for the negative potentials of the connections in question. This connection or current path is preferably switchable. A diode switch is preferably provided which is connected in series with the diode. The booster output connection or the auxiliary component connection (in particular a negative potential thereof) is connected to the charging connection (in particular a negative potential thereof) via the diode switch. A series circuit comprising a diode and diode switch connects the side of the battery switch facing away from the battery connection to the charging connection or to a path leading to the charging connection, which path may have a filter and / or a charging switch and / or a fuse.The diode switch can be provided between the charging port and the diode. Alternatively, the diode can be provided between the charging port and the diode switch. The diode switch relates to the same potential as the diode, in particular a negative potential. The diode switch and / or the diode are preferably provided in only one potential connection, not in connections of both potentials of the connecting circuit.

[0012] A combination of an inverter and an electrical machine, or a dedicated boost converter module (charging booster module), can be considered as a booster or boost converter. In such embodiments, the on-board electrical system connection circuit preferably has a booster input terminal. The booster input terminal is configured to be connected to an AC side of an inverter or to a winding or star point of an electrical machine connected to the AC side of the inverter. In particular, it can be provided to connect the booster input terminal to a center tap of a half-bridge or part of the half-bridges of an inverter, wherein this half-bridge or this part of the half-bridges remains in the open state.As a result, the booster input terminal is separated from the inverter, except for a current path that runs through at least one winding of the electrical machine (and is used for voltage conversion). The at least one remaining half-bridge of the inverter is controlled in a clocked manner to produce a boost converter in which the working switching unit is formed by the at least one fading half-bridge, and the working inductance is formed by at least one winding of the electrical machine. A control device can be provided that controls the inverter and, in addition to the mode for motor and / or generator operation of the electrical machine, has a corresponding converter mode in which the inverter is operated for DC voltage conversion (together with at least one winding of the electrical machine) as described above.The booster output terminal is configured to be connected to a DC side of the same inverter. The DC side of the inverter is formed by the ends of the inverter's half-bridges. The inverter can be designed as a BnC bridge, where n is twice the number of phases of the inverter (twice the number of all connected half-bridges of the inverter). Instead of windings of the electric machine, a dedicated working inductance (working choke) can also be used. The booster input terminal can be provided by a phase terminal configured to be connected to at least one phase terminal of an inverter. The booster output terminal corresponds in particular to a DC voltage supply terminal of an inverter, i.e., a terminal for the DC voltage side of the inverter. The inverter is in particular a high-voltage traction inverter.

[0013] In addition to the previously described possibility of providing an inverter and an electrical machine (or a dedicated working inductance) to form a boost converter, for the connection of which the connecting circuit is designed, a dedicated boost converter module can also be used. The boost converter module has its own (clocked-controlled) switching unit and its own dedicated working inductance. The boost converter module has an input side and an output side and is configured to boost electrical voltage starting from the input side and to output the boosted input voltage at the output side. The on-board electrical system connection circuit can have a booster input terminal configured to be connected to an input side of such a boost converter module.The booster output terminal is preferably configured to be connected to an output side of the same boost converter module. For this purpose, switches can be provided, in particular, in the connecting circuit, which can disconnect a phase connection and establish a connection between the boost converter module and the connecting circuit.

[0014] In some versions of the connecting circuit, this has a fuse device. The booster input connection is connected to the battery connection via this. The fuse device is preferably designed as an electronic fuse in order to be able to switch off quickly in the event of high currents. Alternatively, the fuse device can be designed as a fast-acting fuse. The fuse device and the diode are provided in current paths of different polarity. The fuse device is preferably provided in a positive current path. The fuse device is connected in series in the current path. The entire current of the current path in which the fuse device is provided flows through the fuse device. The fuse device is provided in a current path that connects the booster input connection on the one hand with the battery connection or the charging connection on the other.The fuse device is connected to one side of the battery switch, which is connected (switchlessly) to the battery terminal. The fuse device and the diode are connected to different battery switches. In embodiments with the diode and the fuse device, two battery switches are provided. The fuse device is provided between the booster input terminal and the battery terminal, in particular between the booster input terminal and the positive potential of the battery terminal. The fuse device is connected between the booster input terminal and the side of a first of the battery switches that faces the battery terminal (or its positive potential). The fuse device is connected between the booster input terminal and the charging terminal (or its positive potential).The diode is connected between the booster output terminal / auxiliary component terminal and the side of a first of the battery switches facing the battery terminal (or its positive potential). The fuse device is connected between the booster input terminal and the side of a second of the battery switches facing the battery terminal (or its positive potential). The current path connecting the booster input terminal to the battery terminal (positive potential) via the fuse device is preferably switchable, for example, by means of a fuse device switch.

[0015] The connecting circuit may include a safety device switch. This is connected in series to the safety device. The booster input terminal is connected to the battery terminal via the safety device switch. The safety device switch preferably connects the safety device to the battery terminal. The safety device (which is preferably connected to the booster input terminal without a switch) is connected to the battery terminal (preferably to its positive potential) and to the (first) battery switch via the safety device switch, in particular to the side of the battery switch facing the battery terminal. The safety device is connected to the charging terminal, in particular to its positive potential, via the safety device switch. This connection is preferably switchable (by means of a charging terminal switch).

[0016] According to further embodiments, the diode connects the booster output terminal to the charging terminal without a switch or via a charging terminal switch. In particular, the diode connects a potential, for example the negative potential, of the booster output terminal to a potential (negative potential) of the charging terminal without a switch or via a (first) charging terminal switch. The booster output terminal is preferably connected to the battery terminal via a first switching element and a battery switch provided in series therewith (in particular in this order). A negative potential of the booster output terminal can be connected to a negative potential of the battery terminal via a first battery switch, in particular without a switch or via a first switching element.A positive potential of the booster output connection can be connected to a positive potential of the battery connection via a second battery switch, in particular without a switch or via a second switching element. If the first and / or second switching element is provided in addition to the at least one battery switch, then the first or second switching element can be provided between the booster output connection and the respective battery switch that leads to the battery connection. The charging connection is connected to the connection point between the first or second switching element and the respective at least one battery switch, preferably directly, or via a (preferably all-pole) switching unit, a (preferably all-pole) filter and / or a fuse in one or both current paths. The switching unit can have one or both charging switches, which can be connected upstream of the charging connection.The booster input terminal can be connected to the charging terminal or the relevant potential thereof (e.g., the positive potential) via the fuse device (single-pole) via a (single-pole) charging switch, optionally via a fuse element between the charging switch and the battery terminal. The booster input terminal can be connected to the fuse device via a fuse switch, which is preferably connected to the charging terminal without a switch. The booster input terminal can be connected to the fuse element via a fuse device and a subsequent fuse switch, which leads (via a charging switch) to the charging terminal. The end of the fuse element facing away from the charging terminal is connected to the battery terminal, either directly or via a battery switch.The booster input terminal can alternatively be connected to the charging terminal via a fuse device and a downstream fuse switch, and optionally to one end of a charging switch facing the charging terminal. The charging switch can be provided between the fuse switch and the battery terminal or the auxiliary component terminal or the booster output terminal. The path leading from the booster input terminal (via the fuse device and, if applicable, the fuse switch) to the charging terminal can be connected directly, i.e., not via a charging switch, to the charging terminal, while the charging switch leads from the charging terminal or from this path to the battery terminal. Viewed from the booster input terminal, the fuse device can follow first, followed by the fuse switch, or vice versa.This series connection connects in particular the booster input connection to the charging connection (directly) or via a charging switch. The positive potential of the booster output connection can be connected to the battery connection (or a positive potential thereof) via a first switching element and a first battery switch provided in series therewith. The negative potential of the booster output connection can be connected to the battery connection (or a negative potential thereof) via a second switching element and a second battery switch provided in series therewith. The connection point between the first or second switching element on the one hand and the first or second battery switch on the other hand is connected (via a charging switch) to the charging connection. The booster input connection is connected (via the fuse device) to the resulting current path between the connection point (orThe booster output terminal or a negative potential thereof is connected to the connection point (or negative potential thereof) via the diode, in particular without a switch.

[0017] The connecting circuit can have at least one charging connection switch. This switch connects the charging connection to the battery connection. The negative potential of the charging connection can be connected to the negative potential of the battery connection via a first charging connection switch. The positive potential of the charging connection can be connected to the positive potential of the battery connection via a second charging connection switch.

[0018] The diode can be connected to the charging port (or a positive potential thereof) via the charging port switch. Furthermore, the diode can be connected to the battery port via the (first) charging port switch, in particular to a positive potential of the battery port.

[0019] Further embodiments provide for the charging port to be connected to the booster output port via at least one battery switch. This connection is preferably all-pole and has a battery switch for each potential. Furthermore, the charging port can be connected to the battery port via at least one battery switch. This connection is preferably all-pole and has a battery switch for each potential. Thus, the at least one battery switch can be located on the side leading to the booster output port or on the side leading to the battery port, as viewed from the charging port.

[0020] A control device may be provided that is connected to the switches described here for control purposes and is preferably configured to output signals to an inverter (external to the connection circuit). The control device may be part of the connection circuit or may be part of a charging system branch that includes the connection circuit and the inverter (and, if applicable, an electrical machine connected to it).

[0021] The procedure described here can be implemented using a charging electrical system branch. A corresponding charging electrical system branch is equipped with an on-board electrical system connection circuit (as described herein) and an inverter (as described herein). The DC side of the inverter is connected to the booster output terminal. The AC side of the inverter is configured for connection to an electrical machine. Alternatively, an electrical machine can be provided that is part of the charging electrical system branch, for example if its inductances are used as working inductances in a boost converter. The AC side of the inverter is connected to a booster input terminal of the on-board electrical system connection circuit (directly or via a switch, such as a star switch of the electrical machine). Alternatively, the charging electrical system branch has a (dedicated) boost converter, such as a boost converter as described herein.The output side of the boost converter is connected to the booster output terminal. The input side of the boost converter is connected to a booster input terminal of the vehicle electrical system connection circuit.

[0022] In one embodiment in which the charging electrical system branch has the inverter and in particular also uses the inverter for boost conversion, the charging electrical system branch can have a control device that is configured to directly or indirectly control the inverter in a driving state according to a pulse pattern for generating a rotating field in an electrical machine connected to it. The control device can further be configured to directly or indirectly place the inverter and switches of the electrical system connection circuit in a fault state into a permanently open state. In a preferred embodiment, the control device directly or indirectly controls the inverter to place some of the half-bridges or advantageously all of the half-bridges into a closed state.In other words, the control device is preferably configured to control the inverter to generate a bridge short circuit (active short circuit), in particular by putting the half-bridges (some or all of them) into a conductive state. A bridge short circuit means the ON state, i.e. the conductive state of the series-connected transistors of a half-bridge, in which the inverter or the half-bridge(s) are. The bridge short circuit acts on the input voltage of the inverter, i.e. on the potentials of the booster output terminal, and short-circuits them. If a dedicated boost converter is connected to the booster output terminal, the control device is configured to close switches of the boost converter accordingly to cause the boost converter to actively generate the short circuit. This accelerates and ensures the triggering of any fuse that may be present.The control device is configured to output such a signal to the inverter and in particular has a corresponding control output.

[0023] The control device is also configured to control the inverter in a boost state in a clocked manner as a switch of a boost converter for boost conversion, wherein the inverter together with at least one winding of the electrical machine connected to the inverter form the boost converter.

[0024] The on-board electrical system can also have batteries that have a fixed nominal voltage or that have different nominal voltages due to a parallel / serial configuration of battery strings. The batteries are in particular high-voltage batteries with a fixed or configurable nominal voltage of 800 V (including a variation range of +- 5, 10 or 20%). If the battery is not configurable, the booster input connection (if necessary via a fuse) and the booster output connection (or a negative potential thereof) are connected to the charging connection, whereby this connection does not lead via charging switches. Rather, the current paths leading to the booster input and output connections, as well as the current paths leading to the battery connection, lead from the charging connection, whereby only the latter current paths have battery switches. If the battery is configurable, the booster input connection (if necessary via a fuse) and the booster output connection (or a negative potential thereof) are connected to the charging connection.via a fuse) and the booster output terminal (or a negative potential thereof) are connected to the battery terminal. This connection does not pass through a charging switch. Rather, the current paths leading away from the charging terminal first pass through charging switches, which are connected to the battery terminal and the diode or fuse on their side facing away from the charging terminal.

[0025] The components described here, in particular the diode, the fuse device and the fuse element as well as the connections, are high-voltage components with a nominal voltage of more than 60 V, in particular of at least 200 V, 400 V or 800 V. The connections described here are preferably high-power connections with a current-carrying capacity of at least 10 A, 50 A or 100 A. The battery connection, the auxiliary component connection, the charging connection and the booster output connection are preferably two-pole and each have a negative potential and a positive potential. These connections are direct current connections. The booster output connection is preferably single-pole. The switches described here are preferably electromechanical switches such as relays, but can also be designed as semiconductor switches.

[0026] Unless otherwise stated, the switches described here are single-pole switches or on / off switches. The fuse device is provided in a current path between the booster input connection and the rest of the circuit. The fuse element is connected upstream of the charging connection, in particular between the charging connection on the one hand and the battery connection or booster input connection on the other. The fuse element is preferably a fuse, but can also be designed as an electronic fuse. The fuse device is preferably an electronic fuse, but can also be designed as a quick-acting fuse. The charging connection can be designed according to a charging standard for charging electric vehicles or can be connected to a plug-in connection element that is designed according to a charging standard.The vehicle electrical system connection circuit is preferably housed in one housing; the inverter, the electric motor, and any batteries are preferably provided in another housing. Other embodiments provide for the vehicle electrical system connection circuit and the inverter to be provided in the same housing. The connections mentioned here are, in particular, recessed into the housing wall. The connections mentioned here can be plug-in connections or are implemented by connections resulting from a continuous conductor track or continuous busbar, or by other connected busbars.

[0027] The diode and any fuse device present can be designed with a maximum current load (pulse current load, continuous current load) that is lower than the corresponding current load rating of the battery switches (or charging switches). This also applies to switching elements between the booster output terminal and the battery switches, i.e., switching elements that are in the same current path as the diode and any fuse device present. In particular, the diode and any fuse device present are designed for the (lower) load power of auxiliary components for which the auxiliary component terminal is also designed, whereby this rating is lower than the rating of the components located between the booster output terminal and the battery terminal (or between the load terminal and the battery terminal).

[0028] As a diode, a diode component (with exactly one PN junction or Schottky junction) can be used or a switch (semiconductor switch or electromechanical switch) can be used, which opens when the current flows through the power path in one direction and is closed when the voltage across the switch is reversed, ie a switch with the function of a diode.

[0029] Figures 1 and 2 serve to explain numerous embodiments of the connecting circuits and on-board branches described here. First, the elements that are identical in the figures and thus bear the same reference numerals are described. Figures 1 and 2 each show a connecting circuit VS that has a booster output terminal IA, a battery terminal BA, and a charging terminal LA. Furthermore, the connecting circuit VS has an auxiliary component terminal HA. These terminals each have a negative potential - and a positive potential +. A booster input terminal PA is single-pole and has a positive potential.

[0030] Components external to the connection circuit VS are connected to the booster input terminal PA and the pool booster output terminal IA, whereby these components comprise an inverter INV and an electrical machine EM. The inverter INV has an AC side which is connected to the electrical machine EM. The booster input terminal PA is also connected to the AC side. The DC side of the inverter INV is connected to the booster output terminal IA. This allows voltage to be applied to the AC side of the inverter INV via the booster input terminal PA, in particular to windings of the electrical machine EM which is connected to it. By clocking the inverter INV, the inductances of the electrical machine EM can be operated together with the inverter INV as a boost converter. The examples shown relate to a solution in which the inverter and the electrical machine act as a boost converter orHigh seat controllers work, but instead of these two components a dedicated boost converter can also be used.

[0031] Within the connection circuit VS, the booster output connection IA is connected via two poles to the auxiliary component connection HA. This connection is switchless, but can be fused and / or provided with a filter. Furthermore, the booster output connection IA is connected to the battery connection BA via two battery switches B1, B2 (one switch per potential, i.e. a two-pole arrangement of the two switches). The first battery switch B1 connects the positive potential of the booster output connection lA to the positive potential of the battery connection BA. The second battery switch B2 connects the negative potential of the booster output connection lA to the negative potential of the battery connection BA. If a (stepped up) voltage is present at the booster output connection lA, this can be passed on to the auxiliary component connection HA and to the battery connection BA.This can be used to supply auxiliary components via the auxiliary component connection HA or to charge the battery via the battery connection BA.

[0032] The charging connection LA is connected to the battery connection BA via two poles. Two-pole (i.e. one switch per potential) charging switches C1, C2 are provided in this connection. This results in a first connection point V1 between the negative potential of the charging connection LA and the first battery switch C1. This results in a second connection point V2 between the positive potential of the charging connection LA and the second battery switch C2. Both Figures 1 and 2 have this in common, although in Figure 1 the connection point V1 and the connection point V2 of the battery switches C1, C2 are connected on the side facing the charging connection LA, and in Figure 2 they are connected on the side facing the battery connection BA. What both Figures have in common is that the first connection point V1 is connected via a diode D to the booster output connection IA, in particular to its negative potential.

[0033] This results in a third connection point V3, at which the negative potential of the booster output terminal IA, the negative potential of the auxiliary component terminal HA, and the diode D are connected to one another. The forward direction of the diode D points away from the third connection point V3 and points in particular towards the charging terminal LA. The reverse direction of the diode D thus points away from the charging terminal LA and points in particular towards the third connection point or the booster output terminal IA. The connection between the first and third connection points V1, V3 includes not only a diode D, but also a diode switch M2 (connected in series to the diode). The diode D and the diode switch M2 are connected in series and are both arranged between the points V3 and V1. In the illustrated embodiments, the third connection point V3 is followed by the diode D, with the diode switch M2 connecting the diode D to the first connection point V1.The diode switch and the diode can also be connected in reverse order. If diode D is not connected between the negative potentials of the charging terminal LA and the booster output terminal IA, but between the positive potentials, then the diode can be connected in reverse order.

[0034] The booster input connection PA is connected to the charging connection LA via an electronic fuse EF (generally: safety device EF). In Figure 1, this connection is direct and leads to the charging connection LA simply via a safety switch M1. In Figure 2, this connection leads from the booster input connection PA via the electrical fuse EF, the subsequent safety switch M1 to the second connection point V2. This point V2 is connected to the charging connection LA via the second charging switch C2. The illustration shows that the booster input connection PA is first connected to the safety switch M1 via the electronic fuse EF, although this order can also be reversed. The safety switch M1 shown leads to the charging connection LA directly (Figure 1) or via the second charging switch C2 (Figure 2).

[0035] In Figure 1, diode D is connected to the negative potential of charging terminal LA via diode switch M2, without this connection going through one of the charging switches C1, C2. Rather, diode D and the diode switch M2 connected in series with it lead via the first charging switch C1 to battery terminal BA (more precisely: to its negative potential -). The path leading from phase terminal PA, which leads via electronic fuse EF and fuse switch M1, also leads to charging terminal (or to its positive potential +), without this path going through one of the battery switches C1, C2. In Figure 1, electronic fuse EF and diode D therefore lead directly to charging terminal LA and via the (two-pole) charging switches C1, C2 to battery terminal BA.In Figure 2 it is the other way around: There the diode D and the electronic fuse EF are connected via the charging switches C1, C2 to the charging connection LA in a two-pole manner, while the connection to the battery connection BA in many embodiments runs directly (in particular without a switch) (or via alternatively placed battery switches B1', B2'). In Figure 1 the second charging switch C2 is connected to the battery connection BA (or to its positive potential +) via a fuse element in the form of a fuse S1. Furthermore the connection between the charging switches C1, C2 leads via a filter F to the battery connection BA. In Figure 2 the connection starts from the diode D or the electrical fuse EF and goes via a fuse S1 (in the positive current path) and via a filter F to the charging switches C1, C2. These lead directly (in particular without a switch) to the charging connection LA.

[0036] In addition to the third connection point V3, from which the current path including diode D originates, there is a fourth connection point V4 in Figures 1 and 2, which connects the positive potential of the booster output terminal IA to both the auxiliary component terminal HA and the first battery switch B1. Thus, the third and fourth connection points V3 and V4 are connected switchlessly to the booster output terminal IA and, via the battery switches B1 and B2, to the battery terminal PA. This connection is two-pole.

[0037] Both figures show a fifth and sixth connection point V5, V6, which is located on the side of the battery switches B1, B2 facing the battery terminal BA. A two-pole current path (+ and -) branches off from this connection point, which leads via the charging switches C1, C2 to the charging terminal LA. The diode D and the electronic fuse EF, respectively, are connected to this current path via the connection points V1, V2.

[0038] In a first embodiment, apart from switches B1, B2, no further switches are provided between the booster output terminal IA and the battery terminal BA. A path leads from the battery terminal to the charging terminal LA, which path, in addition to the charging switches C1, C2 and the filter F, only has a single-pole fuse S1. This fuse S1 is a fuse element or a safety fuse. In this embodiment, it is possible for a battery whose nominal voltage is greater than the charging voltage at the terminal LA to be connected to the battery terminal BA. For example, an 800 V battery can be connected to the battery terminal BA, while a charging station with, for example, 400 V is connected to the charging terminal LA. To adjust the voltage, switches C1, C2 are opened, and a charging voltage is applied to the booster input terminal PA via the electronic fuse EF and the fuse switch M1.The electric machine EM (outside the connecting circuit) and the corresponding inverter INV operate as a boost converter, so that the higher voltage, corresponding to the higher nominal voltage of the batteries, is available at the battery terminal BA at the booster output terminal lA connected to it. In addition, the auxiliary component terminal HA in Figure 1 is connected to the booster output terminal IA, so that the boosted voltage is available there during charging. This can supply the auxiliary components connected to terminal HA. To charge the battery connected to terminal BA, switches B1 and B2 are closed. In the event of an insulation fault that shifts the potential level of the 800 V battery at terminal BA relative to the ground potential, diode D can prevent a current that would result from overvoltage elements in the charging station (between a high-voltage potential +, - on the one hand and the ground potential).

[0039] Switches C1 and C2 are closed to enable direct charging when the charging station at terminal LA is in the same voltage range as the batteries BA. This is the case when the 800 V batteries BA at terminal BA are to be charged with an 800 V charging station connected to terminal LA. Thus, the circuit shown in Figure 1 is also upward compatible.

[0040] Figure 2 shows embodiments for connecting configurable batteries to the BA terminal, the nominal voltage of which, depending on the battery configuration, can correspond either to the nominal voltage of the charging terminal LA (even if this is only 400 V) or to a higher voltage level, for example 800 V. A first embodiment of this provides that the battery switches B1, B2 are connected to the battery terminal BA without a switch. In this embodiment, the diode D is connected to the battery terminal BA via a switch M1, and the electrical fuse EF is also connected to the battery terminal BA via a switch M2. The switch M2 is also referred to as a diode switch, and the switch M1 is also referred to as a fuse switch.The first embodiment of Figure 2 thus provides a switch-free connection between the battery switches B1, B2 and the battery terminal BA, while switches in the form of switches M1, M2 are provided in the direction of the booster input terminals and booster output terminals IA, PA (two-pole).

[0041] A second embodiment of Figure 2 provides a switch-free connection between the diode D or the electronic fuse EF on the one hand and the battery switch on the other hand; here the switches M1, M2 are not present (i.e. replaced by a fixed connection). Instead, the battery switches B1, B2 are located directly in front of the battery connection BA at the points B1', B2'. The diode or the electrical fuse D, EF are connected to the booster output connection IA via (two-pole switches) at the points M1', M2'. In the second embodiment of Figure 2 the switches M1, M2 are therefore located at the points M1', M2'. The battery switches B1, B2 are located at the points B1', B2'. In this embodiment the battery switches are therefore provided between connection points V5, V6 and the battery connection BA.Between the booster output connection 1A and the connection points V5, V6, (two-pole) switching elements are provided at the points M1', M2'. The battery switches B1, B2 shown in Fig. 2 are not located to the left of the connection points V5, V6 (due to the shift to the points B1', B2'), but to the right of them. In contrast to the first embodiment, the battery switches in the second embodiment are connected directly upstream of the battery connection BA, see points B1', B2', i.e., viewed from the battery connection BA, they are located upstream of the current path leading to the charging connection LA. Furthermore, in contrast to the first embodiment, in the second embodiment the switches M1, M2 are not connected directly downstream of the diode or the electronic fuse D, EF, but are located between the battery switches B1, B2 or the charging connection LA on the one hand and the booster output connection IA on the other.In particular, the diode switch is connected between the negative potential of the booster output terminal IA and point V5, to which the diode and (via a charging switch) the charging terminal are also connected. In this embodiment, the diode D thus connects the negative potential of the booster output terminal IA to the point to which the negative potential of the charging terminal is connected (via a charging terminal switch C1). The battery terminal (or its negative potential) is also connected to this point V5 (via a battery switch at point B2'), as is the booster output terminal IA (or its negative potential) via a switch at point M2'. The diode bridges the switch at point M2' (without an additional switch); the battery switch is provided at point B2' (directly in front of the battery terminal BA).In this embodiment, the switch M2 is not present at the location shown, but at point B2' between terminal BA and point V5.

[0042] With the embodiments shown in Figure 2, charging is possible with 800 V if the switches C1, C2 are closed and if the battery connected to the BA terminal also has a nominal voltage of 800 V (or is configured accordingly). The same applies to a 400 V charging station with a battery configured for a nominal voltage of 400 V. Adaptation to the voltage level of the charging station can thus be carried out by configuring the battery that is connected or connectable to the battery terminal BA. However, the circuit in Figure 2 enables the auxiliary components to be supplied with a boosted voltage via the auxiliary component terminal HA if the voltage at the charging terminal LA is too low, by virtue of the inverter and the electric machine (or a dedicated boost converter module) connected to the booster terminals IA, PA being able to boost the voltage via switch M1 and fuse EF.However, if a high voltage is already present at the charging terminal LA (i.e. corresponding to the nominal voltage of the auxiliary components), for example 800 V, then the switches provided at points M1', M2' can be closed in order to provide the high voltage present at the charging terminal LA at the auxiliary component terminal HA. Thus, with the circuit in Figure 2, a high voltage or boosted voltage can always be provided at the auxiliary component terminal HA, either by directly passing a high voltage or by boosting a lower voltage present at the charging terminal LA. This enables an auxiliary component supply at 800 V - charging a battery configured for 800 V - as well as an auxiliary component supply at 400 V - charging a battery configured for 400 V, in both cases with a high or boosted voltage that corresponds to the nominal voltage of the auxiliary components.Both figures show a control device C which controls both the inverter and the switches of the connecting circuit VS. This is shown schematically, with particular hierarchical aspects of the control system being omitted for the sake of clarity. The control device C can open all switches in the event of a fault, can control inverters for recuperation and in particular for driving, and can also control the inverter in a clocked manner such that, together with an inductance of the electric machine EM, a boost converter is produced. In Figure 1, this boost converter is used to boost the charging voltage of an 800 V battery when charging is to be carried out at 400 V, and in Figure 1 it is also used to supply the auxiliary components with an 800 V voltage (boosted).In Figure 2, the boost converter provided in this way serves to provide 800 V at the HA terminal when 400 V are present at the LA charging terminal and the battery connected to the BA terminal is configured to a nominal voltage of 400 V.

[0043] The control device C is preferably configured to output a signal that represents a desired configuration of the battery. This applies in particular to embodiments of Figure 2 or embodiments in which the diode D is connected to the charging connection LA via a charging switch C1 (and the safety device EF is connected to the charging connection LA via a further charging switch C2). The control device C is preferably configured to output a desired configuration in a low-voltage charging mode (for charging with, for example, 400 V), which corresponds to a parallel configuration (of battery strings of the battery). In this mode, the control device C is preferably configured to provide the switches between the connection points V1, V2 (or V5, V6) on the one hand and the auxiliary component connection HA in the open state (in particular switches B1, B2 orSwitches at points M1' and M2'), and to output a boost signal which provides the boost converter (EM+INV or a dedicated converter module) in the active state. The control device C is preferably designed to output a target configuration which corresponds to a series configuration (of battery strings of the battery) in a high-voltage charging mode (for charging with, for example, 800 V, i.e. a voltage greater than the charging voltage provided in the low-voltage charging mode). The control device C is preferably designed to provide the switches between the connection points V1, V2 (or V5, V6) on the one hand and the auxiliary component connection HA in the closed state (in particular switches B1, B2 or switches at points M1' and M2') in this high-voltage charging mode, and to output a switch-inactive signal which provides the boost converter (EM+INV or a dedicated converter module) in the open, inactive state.In low-voltage charging mode, switches M1 and M2, if present, are closed. In high-voltage charging mode, switch M1, in particular, is open.

[0044] 1 and 2, it is provided in particular that the control device C provides the diode switch (switch M1) in the closed state when a battery with high voltage (e.g. 800 V) is connected to the battery terminal BA or the battery provided there is configurable and is configured in a series configuration. In this case, the control device C preferably provides at least one switch in a path running parallel to the diode in the open state. This applies in particular to the charging switch C1, to which the diode D is connected (via the diode switch) when the charging switch C1 leads from the diode to the battery terminal BA, and to the switch B2 or a switch at the point M2' when the diode D is connected to the charging terminal LA via the first charging switch C1.As a result, the diode can have a blocking effect in the event of an insulation fault, as described, since when the diode is open, there is no closed parallel path through which the current resulting from potential shift and overvoltage protection on the charging station side could flow. Preferably, the control device C is configured to provide at least one switch state of said switches such that a charging current must be conducted through this diode (when charging with a voltage lower than the nominal battery voltage, i.e., with an active boost converter), and that a current path that would bypass the diode in a closed state (by means of a switch) is open.

[0045] In embodiments of Figure 2, or in embodiments in which the diode D is connected to the charging terminal LA via a charging switch C1 (and the safety device EF is connected to the charging terminal LA via another charging switch C2), the connection points V1 and V5 are identical, and the connection points V2 and V6 are identical. If identical, the potentials and, in particular, the features (such as the position) are identical and transferable.

[0046] The connection circuit is transformer-free, i.e. not galvanically isolating.

Claims

Patent claims 1. On-board network connection circuit (VS) with a booster output connection (IA), a battery connection (BA), a charging connection (LA), an auxiliary component connection (HA) connected to the booster output connection (IA) and with at least one battery switch (B1, B2) via which the booster output connection (IA) and the battery connection (BA) are connected to one another, wherein the connection circuit (VS) has a diode (D) via which the booster output connection (IA) is connected to the charging connection (LA) and whose flow direction corresponds to the direction of a power flow from the booster output connection (IA) to the charging connection (LA).

2. On-board network connection circuit (VS) according to claim 1, further comprising a diode switch (M2) which is connected in series to the diode (D) and via which the booster output terminal (IA) is connected to the charging terminal (LA).

3. The on-board network connection circuit (VS) according to claim 1 or 2, further comprising a booster input terminal (PA) configured to be connected to an AC side of an inverter (INV), wherein the booster output terminal (IA) is configured to be connected to a DC side of the same inverter (INV), or wherein the on-board network connection circuit (VS) comprises a booster input terminal (PA) configured to be connected to an input side of a boost converter module, wherein the booster output terminal (IA) is configured to be connected to an output side of the same boost converter module.

4. On-board network connection circuit (VS) according to claim 3, wherein the booster input terminal (PA) is connected to the battery terminal (BA) via a safety device (EF), wherein the safety device (EF) is designed as a fast-acting fuse or as an electronic fuse.

5. On-board network connection circuit (VS) according to claim 4, further comprising a fuse device switch (M1) which is connected in series to the fuse device (EF) and via which the booster input terminal (PA) is connected to the battery terminal (BA).

6. On-board network connection circuit (VS) according to claim 1, wherein the diode (D) connects the booster output terminal (IA) to the charging terminal (LA) without a switch or via a charging terminal switch (C1), wherein the booster output terminal (IA) is connected to the battery terminal (BA) via a first switching element (M1 ') and via a battery switch (B1 ') provided in series therewith.

7. On-board network connection circuit (VS) according to one of the preceding claims with at least one charging connection switch (C1, C2) via which the battery connection (BA) is connected to the charging connection (LA).

8. On-board network connection circuit (VS) according to claim 7, wherein the diode (D) is connected to the charging connection (LA) via the charging connection switch (C1), or the diode (D) is connected to the battery connection (BA) via the charging connection switch (C1).

9. On-board network connection circuit (VS) according to one of the preceding claims, wherein the charging connection (LA) is connected to the booster output connection (IA) via at least one battery switch (B1, B2), or the charging connection (LA) is connected to the battery connection (BA) via at least one battery switch (B1', B2').

10. Charging on-board network branch with an on-board network connection circuit (VS) according to one of the preceding claims, wherein the charging on-board network branch has an inverter (INV) whose DC side is connected to the Booster output terminal (IA) is connected, and whose AC side is set up for connection to an electrical machine (EM) and is connected to a booster input terminal (PA) of the on-board network connection circuit (VS), or wherein the charging on-board network branch has a step-up converter, the output side of which is connected to the booster output terminal (IA) and the input side of which is connected to a booster input terminal (PA) of the on-board network connection circuit (VS).

11. Charging on-board network branch according to claim 10, wherein the charging on-board network branch comprises the inverter (INV) and further comprises a control device (C) which is arranged - in a driving state, to directly or indirectly control the inverter (INV) according to a pulse pattern to generate a rotating field in an electrical machine (EM) connected to it, - in a fault condition, to set the inverter (INV) and the switch of the on-board network connection circuit (VS) directly or indirectly into a permanently open state and - in a boost state, to control the inverter (INV) in a clocked manner as a switch of a boost converter for boost conversion, wherein the inverter together with at least one winding of the electrical machine (EM) connected to the inverter forms the boost converter.

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