Electric machine unit, vehicle and method for operating electric machine unit

Abstract

The invention relates to an electric machine unit having an electric machine with two phase groups and a rectifier, the rectifier having a first switch and a second switch, the electric machine unit having a first DC charging contact, the DC-voltage-side connections of the half-bridges of the first half-bridge group are connected to each other and each electrically connected to one of the first DC charging contacts, and wherein the DC-voltage-side connections of the half-bridges of the second half-bridge group are connected to each other and each electrically connected to one of the second DC charging contacts. The motor unit is configured to: introduce the first switch and the second switch into the first switch position in each case in a motor operating mode; introducing the first switch into a first switching position and introducing the second switch into a second switching position in a first energy transfer mode; in the second energy transfer mode, the first switch is introduced into the second switching position, and the second switch is introduced into the first switching position.

Description

Field of the Invention

[0001] The present invention relates to an electric machine unit having an electric machine and a rectifier, a vehicle, and a method for operating such an electric machine unit. Background Art

[0002] In an electric machine unit, especially in an electric machine unit used as a motor and / or a generator, and especially also when used in a vehicle, an inverter (rectifier) is used to rectify the generated alternating current or invert the occurring direct current. For this purpose, especially an energy storage device such as a battery is also provided, which can also be charged or from which energy for operating the electric machine can be extracted. Especially, when the electric machine (also) serves as a traction drive of a vehicle, it is usually necessary to be able to charge the energy storage device from the outside, that is, for example, to charge from a (public or private) power grid. Summary of the Invention

[0003] According to the present invention, there are provided an electric machine unit, a vehicle, and a method for operating such an electric machine unit having the features described in the independent claims. The dependent claims and the subject matter described below are advantageous designs.

[0004] The present invention relates to an electric machine and a subordinate rectifier or inverter and their operation. Within the scope of the present invention, the combination of the electric machine and the subordinate rectifier shall be referred to as an electric machine unit. Usually, the rectifier is installed at the electric machine here. Here, the electric machine unit can be a part of a vehicle and especially can also be used as a traction drive. As the electric machine, for example, a synchronous motor, a synchronous reluctance motor, an induction motor, a permanent magnet motor, etc. can be considered. The electric machine unit and its operation will be described comprehensively below.

[0005] For example, a typical electric machine has three phases or a multiple of three phases; within the scope of the present invention, especially worthy of attention is an electric machine having at least two current-separated phase groups (each having three phases), that is, for example, having six, nine, twelve, or 15 phases. Typically, at this time, three phases respectively form a group (phase group); here, the three phases of a group are also connected to each other, for example, in a star or delta connection. Here, these phases (or phase windings) are installed in the stator of the electric machine (whereby these phases form a stator winding). In principle, however, the present invention can also be used in two current-separated phase groups each having at least one phase.

[0006] In addition, the electric machine has a rotor, which can be permanent magnet and / or externally excited. In addition, a preferred application is in a so-called high-voltage application, in which the electric machine operates at a voltage of, for example, 48 V or higher.

[0007] Here, the rectifier has a half-bridge provided for each phase connection terminal of the electric machine. In the case where there are three phases in a phase group, one phase connection terminal is assigned to each phase, while in the case where there is only one or two phases in a phase group, two phase connection terminals are provided. Here, a half-bridge group is assigned to each phase group. Thus, in the case of two phase groups each having three phases, there are two half-bridge groups, and each half-bridge group has three half-bridges respectively. A half-bridge further includes two switches or switching elements (such as MOSFETs or IGBTs), and its center tap (the tap between the two switches) is connected to the relevant phase connection terminal. The other two connection terminals of the half-bridge - the connection terminals on the DC voltage side - are generally commonly connected to the corresponding (positive or negative) DC voltage connection terminal. Thus, the rectifier has DC voltage connection terminals, and these DC voltage connection terminals are further configured to be connected to an energy storage device such as a battery. Usually, an intermediate circuit capacitor is also provided between the DC voltage connection terminals, and if necessary, an intermediate circuit capacitor is also provided for each half-bridge group. Preferably, this rectifier is bidirectional at this time, that is to say, the rectifier can not only convert DC voltage into an AC power supply (for the motor operation of the electric machine), but also vice versa (for the generator operation and possible regenerative operation of the electric machine).

[0008] Not only the half-bridge but also the rectifier can be designed as a so-called two-level half-bridge, but can also be designed as a multi-level half-bridge, and the multi-level half-bridge has more than two, that is, for example, three levels; thus, not only two voltage levels but also three or more voltage levels can be generated here.

[0009] Generally, the half-bridge is electrically (directly) connected to the relevant phase, precisely the phase connection terminal (via its center tap). In order to be able to charge an energy storage device arranged, for example, in a vehicle from the outside - and not only through the generator operation of the electric machine - a connection option for an external voltage source must be provided. In principle, in-vehicle (integrated in the vehicle) and off-vehicle (set independently of the vehicle) charging devices or charging equipment can be considered at this time. For reasons of cost savings and weight reduction in particular, in-vehicle charging devices are preferred.

[0010] In addition, the electric machine has a first DC charging contact. In one embodiment, the electric machine also has a second DC charging contact. Here, the connection terminals on the DC voltage side of the half-bridges of the first half-bridge group are connected to each other and are respectively electrically connected to the first DC charging contact; the connection terminals on the DC voltage side of the half-bridges of the second half-bridge group are also connected to each other and, if provided, are respectively electrically connected to the second DC charging contact.

[0011] For example, the first DC charging contact can in turn be connected to or included in the first DC charging connection of the corresponding vehicle, where the first DC charging connection is configured to be connected to a mating part, in particular a charging plug or a charging socket. Similarly, if provided, for example, the second DC charging contact can be connected to or included in the second DC charging connection of the corresponding vehicle, where the second DC charging connection is configured to be connected to a mating part, in particular a charging plug or a charging socket.

[0012] Furthermore, the electric machine unit has a first switch and a second switch – for example, semiconductor switches such as MOSFETs or IGBTs can be used. However, for example, electromechanical switches or relays can also be considered, since they have low power losses. Here, each first switch and / or second switch can also include a plurality of independent semiconductor switches. Each first switch is designed such that, in the first switch position, the respective DC voltage side connection of the half-bridge of the first half-bridge group is electrically connected to the respective DC voltage connection via the respective first switch, and in the second switch position, the respective DC voltage side connection of the half-bridge of the first half-bridge group is separated from the respective DC voltage connection.

[0013] Similarly, each second switch is designed such that, in the first switch position, the respective DC voltage side connection of the half-bridge of the second half-bridge group is electrically connected to the respective DC voltage connection via the respective second switch, and in the second switch position, the respective DC voltage side connection of the half-bridge of the second half-bridge group is separated from the respective DC voltage connection.

[0014] Then, a (first) external DC voltage, more precisely a DC voltage source such as a current or energy supply network, can be connected to one first DC charging contact or a plurality of first DC charging contacts. Similarly, a (second) external DC voltage, more precisely a DC voltage source such as a current or energy supply network, can be connected to one second DC charging contact or a plurality of second DC charging contacts. For example, this can be done respectively by a plug inserted into a socket (or generally speaking, a DC charging connection). It is also conceivable to provide plugs at the vehicle respectively (for example, directly via a cable connection). During operation of the electric machine unit, the first switch and the second switch can be brought into the first switch position or the second switch position according to the operating mode (for example, by a corresponding control device) (in particular, all first switches and / or all second switches are always of the same type).

[0015] Here, the first switch and / or the second switch and the first DC charging contact and / or the second DC charging contact can be arranged or installed inside the rectifier (if there is sufficient additional space here) or outside the rectifier. For example, it is conceivable to arrange them on the housing.

[0016] To operate an electric machine, i.e., in particular for the operation of an electric motor and / or a generator (i.e., the electric machine operating mode), the first switch and the second switch are brought into the first switch position. Thereby, the half-bridges of the first half-bridge group and the second half-bridge group are electrically connected to the energy storage device. Although the first DC charging contact and, if necessary, the second DC charging contact are connected, they are inactive as long as an external DC voltage source is not connected. This allows for common operations such as electric driving of a vehicle or recuperation. In one embodiment, it can also be provided that there is a protection mechanism that prevents the connection of an external DC voltage source in such a case, i.e., in particular in the electric machine operating mode.

[0017] However, in one embodiment, it can also be provided that an external DC voltage source is still connected in the electric machine operating mode, for example, via an overhead line (Oberleitung), and energy is also provided for, for example, charging a battery and / or supplying the electric machine.

[0018] To transfer energy between the connected energy storage device and an external DC voltage system – i.e., for example, to charge the energy storage device externally from a DC voltage source as a DC voltage system, but alternatively to feed energy from the energy storage device into a load with a DC voltage supply as a DC voltage system – the first switch can be left in the first switch position or brought into the first switch position in a first energy transfer mode. Optionally, if a (second) external DC voltage system is connected to the second DC charging contact, if present, the second switch can be brought into the second switch position, for example, for safety reasons.

[0019] In this way, an external DC voltage system (e.g., a DC voltage source) can be connected to the first DC voltage connection terminal, for example, by means of a corresponding charging plug. In fact, it can also be envisaged that, in the case of use in a vehicle, when the charging plug is inserted (e.g., by means of a corresponding control device), the second switch is automatically brought into the second switch position. However, a (possibly manual) switch to an external charging or feeding mode can also be provided.

[0020] Thereby, current flows, for example, directly from the external DC voltage source via the first switch into the connected energy storage device. This variant allows the connection of a DC voltage source compatible with an energy storage device voltage level of, for example, 800V.

[0021] However, to transfer energy between the connected energy storage device and an external DC voltage system – i.e., for example, to charge the energy storage device externally from a DC voltage source as a DC voltage system, but alternatively to feed energy from the energy storage device into a load with a DC voltage supply as a DC voltage system – the first switch can also be brought into the second switch position in a second energy transfer mode; the second switch can be left in the first switch position or brought into the first switch position.

[0022] In this way, an external DC voltage system (e.g., a DC voltage source) can be connected to the first DC voltage connection or the first charging contact, for example by means of a corresponding charging plug. In fact, it is also conceivable for this purpose that, in the case of use in a vehicle, when the charging plug is inserted (e.g., via a corresponding control device), the first switch is automatically introduced into the second switch position. However, it is also possible to provide a (possibly manual) switch to an external charging or feeding mode.

[0023] Thereby, for example, current flows from the external DC voltage source via the first half-bridge group of the electric motor, the first phase group and the second phase group, and continues to flow into the connected energy storage via the second half-bridge group. In this regard, it should be mentioned that in the case where the first phase group and the second phase group of the electric motor, more precisely its corresponding phase windings, have different numbers of turns, the second phase group acts as a transformer and can thus - depending on the ratio of the number of turns - increase or decrease the voltage.

[0024] This variant allows the connection of a DC voltage source that is not compatible with, for example, an energy storage voltage level of 400V.

[0025] In the electric motor, the phases of the first phase group are separated from the remaining phase currents (usually the three phases of each phase group are respectively separated from the remaining phase currents). In this way, a transformer is formed, so that the alternating voltage that appears at the phases or phase windings of the first phase group induces an alternating voltage correspondingly in the remaining phases - in a six-phase electric motor, these are the remaining three phases or phase windings. Thereby, the phase windings of the first phase group serve as the primary winding of the transformer, and the remaining phase windings serve as the secondary winding. Then, a transformed alternating voltage exists at the half-bridge of the second half-bridge group.

[0026] For this purpose, the two half-bridge groups and the two phase groups can be used as a DC-DC converter, a so-called active double bridge. However, it is also possible that (only) the half-bridges of the first half-bridge group are used as an inverter or a DC-AC converter for generating the mentioned alternating voltage. The second half-bridge group can remain passive, that is, serve as a passive rectifier.

[0027] However, in order to perform energy transfer between the first external DC voltage system and the second external DC voltage system - that is, for example, to perform energy transfer between two external DC voltage systems having, for example, two different voltage levels - the first switch and the second switch can also be respectively introduced into the second switch position in a third energy transfer mode.

[0028] In this way, the first external DC voltage system (e.g., a DC voltage source) can be connected to the first DC voltage connection, for example by means of a corresponding charging plug. The same applies to the second external DC voltage system.

[0029] Thus, the current flows, for example, from a first external DC voltage source via the first half-bridge group of the electric machine, the first phase group and the second phase group, and further via the second half-bridge group to a second external DC voltage source.

[0030] This variant allows the connection of two DC voltage sources with different voltage levels (e.g., 400 V and 800 V).

[0031] Here, the phases of the electric machine are used as transformers as in the second energy transfer mode. For this purpose, the two half-bridge groups and the two phase groups can be used as a DC-DC converter, a so-called active dual bridge. However, equally, only the half-bridges of the first half-bridge group can be used as an inverter or a DC-AC converter for generating the mentioned AC voltage. The second half-bridge group can remain passive, that is, used as a passive rectifier.

[0032] In one embodiment, the electric machine unit has a third switch, where the third switch is designed such that in the first switch position (closed), the first phase group and the second phase group (more precisely, the neutral points of the corresponding phase windings) are electrically connected to each other, and in the second switch position (open), the first phase group and the second phase group are electrically separated from each other. In the second switch position, the two phase groups are not connected, but can be used as transformers in the second energy transfer mode as described above, if necessary with different numbers of turns. Then, the second switch position (open) can be, for example, the standard position used in the electric machine operating mode.

[0033] Conversely, the fourth energy transfer mode and the fifth energy transfer mode are achieved by the first switch position (closed). Thus, in the fourth energy transfer mode and the fifth energy transfer mode, the phase groups are not used as transformers, but as series-connected inductors. The fourth energy transfer mode can correspond to the second energy transfer mode, and the fifth energy transfer mode can correspond to the third energy transfer mode, but the phase groups are not used as transformers. Instead, the corresponding half-bridges can be used together with the phase windings connected in series and used as inductors as a DC-DC converter, such as a buck or boost converter.

[0034] Furthermore, an object of the present invention is a vehicle having an electric machine unit according to the present invention. Here, the electric machine unit can be used as a traction drive, but - in the case of a smaller electric machine - other applications are also conceivable. As already mentioned, the vehicle can have a charging connection terminal that is configured to be connected to a mating part, in particular a charging plug or a charging socket, and thus the charging connection terminal also has an AC voltage connection terminal.

[0035] Other advantages and design options of the present invention result from the description and the following drawings. Description of the Drawings

[0036] The present invention is schematically illustrated according to an embodiment in the figures and is described below with reference to the drawings.

[0037] Figure 1 A vehicle of one embodiment is schematically shown.

[0038] Figure 2 A motor unit of one embodiment is schematically shown.

[0039] Figure 3 Shown in another operating mode is Figure 2 the motor unit in

[0040] Figure 4 Shown in another operating mode is Figure 2 the motor unit in

[0041] Figure 5 Shown in another operating mode is Figure 2 the motor unit in

[0042] Figure 6 A motor unit of another embodiment is shown. Detailed Embodiment

[0043] In Figure 1 a vehicle 100 of one embodiment is generally schematically shown. The vehicle 100 has a front axle 110 with wheels 112 and 114, and a rear axle 120 with wheels 122 and 124. Here, the rear axle 120 is driven by a motor 130 with a stator 132 and a rotor 134. Thus, the motor 130 serves as a traction drive. It is understood that the front axle 110 can also be driven by the motor 130 instead of the rear axle 120, or both axles if necessary. Here, this is only for explanation.

[0044] The motor 130 is connected to a rectifier or inverter 140 (only schematically shown here, for a more detailed view refer to the subsequent figures). The rectifier 140 is in turn connected to an energy storage device 150 (such as a battery) via an intermediate circuit capacitor 142 (the intermediate circuit capacitor 142 can be part of the rectifier 140) if necessary. By the rectifier 140, the DC voltage provided by the battery 150 can be converted into an AC voltage for the generator operation of the motor 130. Similarly, conversely, in the generator operation of the motor 130, the AC voltage generated here can be converted into a DC voltage by the (thus bidirectional) rectifier 140 to charge the battery 150.

[0045] Here, the motor 130 and the rectifier 140 are part of a motor unit 160, as already mentioned at the beginning.

[0046] Supplementally, a first DC charging connection terminal 170.1 is provided at the vehicle 100. The first DC charging connection terminal can be connected, for example, via a charging cable 172.1 with a plug 174.1 and via a socket 176.1 to a (first) DC voltage source 178.1 (such as an electrical grid, an external power source) or another DC voltage system. Here, the DC voltage source can be a DC voltage source with corresponding plugs and sockets. In this way, the energy storage device or the battery 150 can be charged. Furthermore, it should be noted that the specific interconnection of the first DC charging connection terminal 170.1 to the electric machine unit 160 or the battery 150 is not shown here; reference should be made to the subsequent figures for this purpose.

[0047] Supplementally, a second DC charging connection terminal 170.2 is provided at the vehicle 100. The second DC charging connection terminal can be connected, for example, via a charging cable 172.2 with a plug 174.2 and via a socket 176.2 to a (second) DC voltage source 178.2 (such as an electrical grid, an external power source) or another DC voltage system. Here, the DC voltage source can be a DC voltage source with corresponding plugs and sockets. In this way, the energy storage device or the battery 150 can be charged. Furthermore, it should be noted that the specific interconnection of the second DC charging connection terminal 170.2 to the electric machine unit 160 or the battery 150 is not shown here; reference should be made to the subsequent figures for this purpose.

[0048] In Figure 2 a schematic illustration of an embodiment of the electric machine unit 160 is shown; here, the electric machine unit can be Figure 1 the electric machine unit 160 in Figure 1 . Furthermore, a rectifier 140 and a battery 150 are shown, which can also be

[0049] In the electric machine 130, six phases U1, V1, W1, U2, V2, and W2 are shown here, each of which includes a phase winding 136 (only labeled once). In this regard, it should be noted that the terms "phase" and "phase winding" can also be used as synonyms, where the phase winding mostly (only) refers to the winding or coil within the stator. Here, the phase winding 136 is part of the stator (see Figure 1 ); the rotor is not shown here. At this time, the phases U1, V1, W1 form a first phase group P1, and the phases U2, V2, W2 form a second phase group P2 (here, the numbering of the phase groups is ultimately only for illustration).

[0050] – For a six-phase electric machine – the rectifier 140 has 12 switching elements, such as transistors like MOSFETs or IGBTs, where respectively two switching elements form a half-bridge and are assigned to one phase. Exemplarily, for phase U1, they are T U1,H and T U1,LThe indicated switching elements (high-side and low-side), which form a half-bridge denoted by 144, where the center tap is connected to phase U1, more precisely to its phase winding or the corresponding phase connection terminal. For phase U2, the switching elements denoted by T U2,H and T U2,L form a half-bridge as well. The same applies to the switching elements and half-bridges for the remaining phases. The half-bridges for the first phase group P1 are combined into a first half-bridge group 146.1, and the half-bridges for the second phase group P2 are combined into a second half-bridge group 146.2. Here, each half-bridge group can also be referred to as an independent rectifier or inverter, and thus it only serves one of the corresponding phase groups.

[0051] The connection terminals of the DC voltage sides of the half-bridges of the first half-bridge group 146.1 are interconnected or connected to each other, and are connected to the DC voltage connection terminals B+ and B- via the first switches 180.1, 182.1. A first intermediate circuit capacitor 142.1 is connected in parallel with the connection terminals of the DC voltage side. The phase connection terminals of the first phase group P1 are respectively connected to the subordinate half-bridges of the first half-bridge group 146.1 at the center taps of the corresponding half-bridges.

[0052] The half-bridges of the second half-bridge group 146.2 are interconnected or connected to each other, and are connected to the DC voltage connection terminals B+ and B- via the second switches 180.2, 182.2. A second intermediate circuit capacitor 142.2 is connected in parallel with the connection terminals of the DC voltage side. The phase connection terminals of the second phase group P2 are respectively connected to the subordinate half-bridges of the second half-bridge group 146.2 at the center taps of the corresponding half-bridges.

[0053] The rectifier can be connected to an energy storage device or battery 150 via the DC voltage connection terminals B+ and B-.

[0054] For example, the first switches 180.1, 182.1 and the second switches 180.2, 182.2 can respectively be devices with multiple transistors (such as MOSFETs or IGBTs), where each switch can be introduced into two different switch positions (to switch the type of switch). Thus, the switches can be bidirectional switches. Alternatively, for example, the first and / or second switches can also be configured as electromechanical switches.

[0055] Each of the first switches 180.1, 182.1 is designed such that, in the first switch position, the connection terminals of the respective DC voltage sides of the half-bridges of the first half-bridge group 146.1 are electrically connected via the respective first switches to the respective DC voltage connection terminals B+ and B-, and in the second switch position, the connection terminals of the respective DC voltage sides of the half-bridges of the first half-bridge group are separated from the respective DC voltage connection terminals. Similarly, each of the second switches 180.2, 182.2 is designed such that, in the first switch position, the connection terminals of the respective DC voltage sides of the half-bridges of the second half-bridge group 146.2 are electrically connected via the respective second switches to the respective DC voltage connection terminals B+ and B-, and in the second switch position, the connection terminals of the respective DC voltage sides of the half-bridges of the second half-bridge group are separated from the respective DC voltage connection terminals.

[0056] Furthermore, by way of example, the electric machine unit 160 has a control device 186 which is configured to selectively introduce the first switches into the first switch position or the second switch position, and to selectively introduce the second switches into the first switch position or the second switch position. By way of example, in Figure 2 the first switch position S1 (closed) is shown for the second switch 182.2. This also applies to the first switch and the other second switch.

[0057] By the situation shown in Figure 2 the electric machine operating mode is achieved, that is to say the first switches and the second switches are each in the first switch position. Thereby, normal operation of the electric machine 130 is achieved, specifically both generator operation and electric machine operation.

[0058] In Figure 3 the electric machine unit 160 in another operating mode is shown, specifically in a first energy transfer mode for energy transfer between the battery and the (first) DC voltage source, for example when charging the battery 150 from the outside. The electric machine unit 160 corresponds to Figure 2 the electric machine unit, such that not all components will be re-explained here; reference may be made in this regard to Figure 2 and the associated description. Figure 2 and the relevant description.

[0059] In contrast to Figure 2 the second switches 180.2, 182.2 are now in the second switch position S2 (open), while conversely the first switches 180.1, 182.1 remain in the first switch position S1 (closed). At this time, the (first) external DC voltage source 178.1 is now connected to the first DC charging connection terminal 170.1.

[0060] By the situation shown in Figure 3In the situation shown, energy transfer between the external DC voltage source 178.1 and the battery 150 is achieved. This can be charging of the battery or supplying the external DC voltage source 178.1 from the battery. Here, the current I bat flows directly between the battery and the external DC voltage source 178.1.

[0061] This first energy transfer mode can be used in particular if the voltage levels of the energy storage device and the external DC voltage source at least basically correspond to each other. For example, if a DC voltage source of 800 V (or a DC voltage source compatible with 800 V) is available, this is the case for a battery compatible with 800 V.

[0062] It should generally be mentioned at this point that especially in the case of a battery, the actual voltage level of, for example, 800 V may drop significantly during discharge, but nevertheless, such a battery can be supplied by the DC voltage source at, for example, 800 V.

[0063] In Figure 4 the motor unit 160 of Figure 2 is shown in another operating mode, namely in a second energy transfer mode for energy transfer between the battery and the (first) DC voltage source, for example when charging the battery 150 from the outside. The motor unit 160 corresponds to the motor unit of Figure 2 , so that not all components will be re-explained here; reference can be made to Figure 2 and the relevant description in this regard.

[0064] Different from Figure 2 , the first switches 180.1, 182.1 are in the second switch position S2 (open) at this time, and conversely, the second switches 180.2, 182.2 are still in the first switch position S1 (closed). At this time, the (first) external DC voltage source 178.1 is now connected to the first DC charging connection terminal 170.1 (see also Figure 1 ).

[0065] Through the situation shown in Figure 4 , energy transfer between the external DC voltage source 178.1 and the battery 150 is achieved. This can be charging of the battery or supplying the external DC voltage source 178.1 from the battery.

[0066] But different from that in Figure 3Differently in , the current does not flow directly between the battery and the external DC voltage source 178.1 at this time. Instead, the current flows through the first half-bridge group 146.1, the first phase group P1, the second phase group P2, and the second half-bridge group 146.2. Here, the second phase groups P1, P2 function as transformers. For example, the first half-bridge group 146.1 can operate as a DC-AC converter. Similarly, the two half-bridge groups can operate as a DC-DC converter together with the phase groups. Thus, as shown in the figure, the current I U1 , I V1 , I W1 , I U2 , I V2 , I W2 , and the current I bat flows to or from the battery.

[0067] As already mentioned, the number of turns of the phases or phase windings of the first phase group P1 and the second phase group P2 can be different, so that the voltage can be increased or decreased to a higher or lower voltage level according to the ratio of the number of turns. The specific number of turns can be selected according to requirements, for example, one to two or two to one.

[0068] In Figure 5 the motor unit 160 of Figure 2 is shown in another operating mode, specifically in the third energy transfer mode for energy transfer between a (first) DC voltage source and another (second) DC voltage source. The motor unit 160 corresponds to the motor unit of Figure 2 , so all components will not be re-explained here; reference can be made to Figure 2 and the related description for this.

[0069] Differently from Figure 2 , the first switches 180.1, 182.1 and the second switches 180.2, 182.2 are in the second switch position S2 (open) at this time. At this time, the (first) external DC voltage source 178.1 is connected to the first DC charging connection terminal 170.1, and at this time, the (second) external DC voltage source 178.2 is connected to the second DC charging connection terminal 170.2 (also see Figure 1 ).

[0070] Through the situation shown in Figure 5 , energy transfer between the external DC voltage source 178.1 and the external DC voltage source 178.2 is achieved. Here, in particular, the two DC voltage sources can have different voltage levels, such as 400V and 800V.

[0071] Differently from Figure 4Similarly, at this time, current flows through the first half-bridge group 146.1, the first phase group P1, the second phase group P2, and the second half-bridge group 146.2, and then flows to the second DC voltage source 178.2. Here, the two phase groups P1, P2 are used as transformers. The first half-bridge group 146.1 can operate as a DC-AC converter, for example. Similarly, the two half-bridge groups can operate as a DC-DC converter together with the phase groups. Thus, the current I as shown in the figure U1 , I V1 , I W1 , I U2 , I V2 , I W2 and the current I DC1 flows to or flows out from the DC voltage source 178.1, and the current I DC2 flows to or flows out from the DC voltage source 178.2.

[0072] As already mentioned, here the number of turns of the phases or phase windings of the first phase group P1 and the second phase group P2 can also be different, so that a higher or lower voltage level can be achieved for the voltage, according to the ratio of the number of turns. The specific number of turns can be selected according to requirements, for example, one to two or two to one.

[0073] In Figure 6 a motor unit 160' of another embodiment is shown. The motor unit 160' corresponds to the motor unit 160 according to Figures 2 to 5 , but the difference is that a third switch 184 is provided in the motor 130'. By means of the third switch, the first phase group P1 and the second phase group P2, precisely the corresponding phases, can be connected via their respective neutral points. The third switch 184 can be part of the motor or can also be provided externally, but in this case it can be part of the motor unit 160'.

[0074] If the third switch 184 is open (second switch position), then operationally it remains the same as explained in Figures 2 to 5 . That is, thus, for example, the motor operation mode and the first, second, and third energy transfer modes can be used.

[0075] Conversely, if the third switch 184 is closed (first switch position), then the fourth and fifth energy transfer modes can be used.

[0076] The fourth energy transfer mode corresponds to the second energy transfer mode shown in Figure 4 (by the switch positions of the first switch and the second switch shown here), but the third switch 184 is closed, that is, the phase windings of the two phase groups are connected, and the two phase groups are used as inductors in series. As in Figure 4It is also shown that an (first) external DC voltage source 178.1 can be connected to the first DC charging connection terminal 170.1.

[0077] At this time, current flows through the first half-bridge group 146.1, the first phase group P1, the second phase group P2, and the second half-bridge group 146.2. However, here, the two phase groups P1, P2 are not used as transformers at this time, but as (common) inductors. Here, the phase windings and the half-bridges are used together as a DC-DC converter, specifically, for example, as a buck or boost converter.

[0078] For example, at this time, the high-side switches of the first half-bridge group 146.1 (only one or two, or also three – or more, if any – depending on the current intensity and / or the required inductance) can be closed. Then, current flows from the DC voltage source into the first phase group P1 and the second phase group P2 connected in series therewith via the closed high-side switches. Subsequently, the current can flow from here into the energy storage via the second half-bridge group 146.2. At this time, the switches of the second half-bridge group 146.2 can be controlled accordingly (for example, as a boost converter) to increase the voltage of the DC voltage source.

[0079] But alternatively, for example, only the first half-bridge group 146.1 can be controlled accordingly, while the switches of the second half-bridge group 146.2 remain passive, so that the first half-bridge group 146.1, specifically its switches, together with the inductance of the phase windings, are used as a buck converter to reduce the voltage of the DC voltage source.

[0080] The fifth energy transfer mode corresponds to the third energy transfer mode shown in Figure 4 (by the switch positions of the first switch and the second switch shown here), but the third switch 184 is closed, that is, the phase windings of the two phase groups are connected, and the two phase groups are used as inductors connected in series. As shown in Figure 5 It is also shown that an (first) external DC voltage source 178.1 can be connected to the first DC charging connection terminal 170.1, and a (second) external DC voltage source 178.2 can be connected to the second DC charging connection terminal 170.2.

[0081] At this time, current flows through the first half-bridge group 146.1, the first phase group P1, the second phase group P2, and the second half-bridge group 146.2. However, here, the two phase groups P1, P2 are not used as transformers at this time, but as (common) inductors. Here, the phase windings and the half-bridges are used together as a DC-DC converter, specifically, for example, as a buck or boost converter.

[0082] For example, at this time, the high-side switch of the first half-bridge group 146.1 (only one or two of them, or also three - or more, if present - depending on the current intensity and / or the required inductance) can be closed, and then the current flows from the first DC voltage source into the first phase group P1 and the second phase group P2 connected in series therewith via the closed high-side switch. Subsequently, the current can flow from here into the second DC voltage source via the second half-bridge group 146.2. At this time, the switches of the second half-bridge group 146.2 can be correspondingly controlled (for example, as a boost converter) to increase the voltage of the first DC voltage source.

[0083] However, alternatively, for example, only the first half-bridge group 146.1 can be correspondingly controlled, while the switches of the second half-bridge group 146.2 remain passive, so that the first half-bridge group 146.1, specifically its switches, together with the inductance of the phase winding, are used as a buck converter to reduce the voltage of the first DC voltage source.

Claims

1. A motor unit (160), comprising a motor (130) and a rectifier (140), wherein the motor has two phase groups (P1, P2) each having at least one phase (U1, V1, W1; U2, V2, W2), in, The rectifier has two half-bridge groups, each of which has at least one half-bridge, wherein a half-bridge group is assigned to each phase group, so that a half-bridge (144) is provided for each phase connection of the electric machine, wherein the rectifier has DC voltage connections (B+, B-) configured for connection to an energy storage device (150), The rectifier has a first switch (180.1, 182.1) and a second switch (180.2, 182.2), The motor unit has a first DC charging contact (190.1, 192.1), The phase connection ends (U1, V1, W1) of the first phase group (P1) of the two phase groups in the motor are respectively connected to the slave half bridge (144) of the first half bridge group (146.1) of the two half bridge groups at the center tap of the corresponding half bridge. The phase connection ends (U2, V2, W2) of the second phase group (P2) of the two phase groups are respectively connected to the slave half bridges of the second half bridge group (146.2) of the two half bridge groups at the center taps of the corresponding half bridges. The connection ends on the DC voltage side of the half bridges of the first half bridge group (146.1) are connected to each other and are respectively electrically connected to one of the first DC charging contacts (190.1, 192.1), The connection ends of the DC voltage side of the half bridges of the second half bridge group (146.2) are connected to each other. Each first switch (180.1, 182.1) is designed such that, in a first switch position (S1), the corresponding DC voltage side connection end of the half bridge of the first half bridge group is electrically connected to the corresponding DC voltage connection end (B+, B-) via the corresponding first switch, and in a second switch position (S2), the corresponding DC voltage side connection end of the half bridge of the first half bridge group is separated from the corresponding DC voltage connection end (B+, B-), Each second switch (180.2, 182.2) is designed such that, in a first switch position (S1), the connection end on the DC voltage side of the corresponding half bridge of the second half bridge group is electrically connected to the corresponding DC voltage connection end (B+, B-) via the corresponding second switch, and in a second switch position (S2), the connection end on the DC voltage side of the half bridge of the second half bridge group is separated from the corresponding DC voltage connection end, and Wherein, the motor unit is configured as follows: In the motor operating mode, the first switch and the second switch are each moved into the first switch position (S1), In a first energy transmission mode, the first switch is moved into the first switch position (S1) and the second switch is moved into the second switch position (S2), and In a second energy transmission mode, the first switch is moved into the second switch position ( S2 ), and the second switch is moved into the first switch position.

2. The motor unit (160) according to claim 1, further comprising a second DC charging contact, wherein: The connection ends of the DC voltage side of the half bridges of the second half bridge group are also electrically connected to one of the second DC charging contacts (190.2, 192.2), respectively, and Wherein, the motor unit is configured as follows: In a third energy transmission mode, the first switch and the second switch are each moved into the second switch position (S2).

3. The motor unit (160) according to claim 1 or 2, wherein: The phases of the first phase group (P1) are electrically decoupled from the phases of the second phase group (P2).

4. The motor unit (160) according to any one of the preceding claims, wherein: The half bridges are each designed as a two-level half bridge or as a multi-level half bridge having more than two levels.

5. The motor unit (160) according to any one of the preceding claims, wherein: The rectifier (140) is designed to be bidirectional.

6. The motor unit (160) according to any one of the preceding claims, further comprising a control device, which is configured to selectively introduce the first switch (180.1, 182.1) into the first switch position (S1) or into the second switch position (S2), and to selectively introduce the second switch (180.2, 182.2) into the first switch position (S1) or into the second switch position (S2).

7. The motor unit (160) according to any one of the preceding claims, wherein: The number of turns of the phases of the first phase group (P1) and the number of turns of the phases of the second phase group are different from each other.

8. The motor unit (160') according to any one of the preceding claims, comprising a third switch (184), wherein: The third switch (184) is designed such that, in a first switch position, the first phase group (P1) and the second phase group (P2) are electrically connected to each other, the first phase group (P1) and the second phase group (P2) are electrically separated from each other, and Wherein, the motor unit is configured as follows: In a fourth energy transmission mode, the first switch is moved into the second switch position (S2), the second switch is moved into the first switch position (S1), and the third switch (184) is moved into the first switch position, and With reference to claim 2, in a fifth energy transmission mode, the first switch is moved into the second switch position (S2), the second switch is moved into the second switch position (S2), and the third switch (184) is moved into the first switch position.

9. The motor unit (160) according to any one of the preceding claims, which is designed as a traction drive of a vehicle (100).

10. A vehicle (100) having an electric motor unit (160) according to any of the preceding claims and an energy storage device (150), in particular a battery, which is electrically connected to the DC voltage terminals (B+, B-) of the rectifier (140).

11. The vehicle (100) according to claim 10, wherein: The vehicle also has a first DC charging connection terminal (170.1), which is configured to be connected to a mating piece, in particular a charging plug or a charging socket, and is connected to the first DC charging contact or has a first DC charging contact, and / or with reference to claim 2, the vehicle has a second DC charging connection terminal (170.2), which is configured to be connected to a mating piece, in particular a charging plug or a charging socket, and is connected to the second DC charging contact or has a second DC charging contact.

12. A method for operating, the method being suitable for operating a motor unit (160) according to any one of claims 1 to 9 or a vehicle according to claim 10 or 11, in, The first switch and the second switch are moved into the first switch position (S1) or the second switch position (S2) depending on the operating mode, and, in particular with reference to claim 8, the third switch is moved into the first switch position (S1) or the second switch position (S2) depending on the operating mode.

13. The method according to claim 12, wherein: The motor operating mode is used for operating the electrical machine (130), in particular for operating the electrical machine (130) as an electric motor and / or a generator.

14. The method according to claim 13, wherein: During the motor operating mode, energy is also provided for the connected energy storage device (150) and / or the motor (130) from an external DC voltage system which is or will be connected to the first DC charging contact.

15. The method according to any one of claims 12 to 14, wherein: The first energy transfer mode is used for energy transfer between the connected energy storage device (150) and an external direct current voltage system which is or is to be connected to the first DC charging contact.

16. The method according to any one of claims 12 to 15, wherein: The second energy transfer mode is used for energy transfer between the connected energy storage device (150) and an external DC voltage system which is or will be connected to the first DC charging contact, and Therein, the rectifier is controlled to convert the voltage.

17. A method according to any one of claims 12 to 16, with reference to claim 2, wherein: The third energy transfer mode is used for energy transfer between a first external DC voltage system connected or to be connected to the first DC charging contact and a second external DC voltage system connected or to be connected to the second DC charging contact, and Therein, the rectifier is controlled to convert the voltage.

18. A method according to any one of claims 12 to 17, with reference to claim 8, wherein: The fourth energy transfer mode is used for energy transfer between the connected energy storage device (150) and an external direct current voltage system which is or will be connected to the first DC charging contact, and Therein, the rectifier is controlled to convert the voltage.

19. A method according to any one of claims 12 to 18, with reference to claims 2 and 8, wherein: The fifth energy transfer mode is used for energy transfer between a first external DC voltage system connected or to be connected to the first DC charging contact and a second external DC voltage system connected or to be connected to the second DC charging contact, and Therein, the rectifier is controlled to convert the voltage.

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