Arrangement for providing an output potential and vehicle with such an arrangement

Abstract

Arrangement (1) for providing an output potential, comprising: an electric machine (3) which has a stator (5), first conductor (7) each with one end (13) and one other end (15) which are wound around the stator (5) between one end (13) and the other end (15) and are connected at one end (13) to a first star point (21), and second conductor (9) which is wound around the stator (5); an inverter (35) which a first inverter component (37) which is connected to the other ends (15) of the first conductor (7), and a second inverter component (39) which is connected to the second conductors (9); and a driver circuit (51) configured to control switches (49) of the first inverter component (37) and the second inverter component (39) such that a maximum alternating voltage is supplied to the second conductors (9) and that an alternating voltage is supplied to the first conductors (7) which leads to the output potential at the first star point (21) and to a partial function of torque provision by the first conductors (7); where, when the electric machine (3) is operated, the output potential is provided at the first star point (21).

Description

[0001] The present invention relates to an arrangement for providing an output potential, in particular an output DC voltage, and further relates to a vehicle, in particular an electric vehicle, with such an arrangement.

[0002] Conventional dual-voltage or multi-voltage electrical systems can provide two or more voltages for different loads. For example, it may be necessary to provide two or more DC voltages. This is achieved by performing a voltage conversion, for example, using a converter (DC converter or similar device). This conversion, such as a transformation, generates a different voltage from one of the multiple voltages, which is required in the multi-voltage electrical system. This approach therefore requires a voltage converter, such as a DC converter, which incurs additional costs, weight, and space requirements.

[0003] German patent application DE 102 44 229 A1 discloses a power supply system and method in which energy from a high-voltage battery is supplied to a motor / generator via an inverter. A low-voltage battery is also connected to the neutral point of the motor / generator. The inverter is controlled such that the voltage follows a current distortion phenomenon in order to adjust the neutral point voltage to a desired charging voltage in the low-voltage battery. A dual power supply system with a voltage ratio of a low-voltage battery to a high-voltage battery between 1:2 and 1:4 is also described. The proposed solution has the disadvantage that the desired drive torque is not achieved by the motor under all circumstances for all desired low voltages, meaning that the voltage of the high-voltage battery cannot be used optimally to drive the electric motor.

[0004] German patent application DE 10 2013 205 869 A1 discloses a vehicle with a 2×N-phase electric machine, comprising a first partial power supply system with a first nominal DC voltage level, and a second partial power supply system with a second nominal DC voltage level. The electric machine has a rotor, a common stator system with a first N-phase winding system, and a second N-phase winding system.The first partial power supply network has an intermediate circuit capacitor, a first inverter and a second inverter, wherein the first winding system is assigned to the first inverter and the second winding system to the second inverter such that the first N-phase winding system is configured in a star connection, the second N-phase winding system is configured in a star connection, and at least one star point of a winding system can be electrically connected to the higher potential of the second partial power supply network by means of a transfer circuit.

[0005] European patent application EP 1 199 210 A2 discloses a control unit for a plurality of rotating electric machines, comprising a single current control unit with an inverter, a gate driver, and a motor controller. The motor controller provides each rotating electric machine with a control current, thus enabling control of the rotation in response to the rotational phase of the rotor. In this control unit, the current control unit determines the control current for each rotating electric machine based on the desired torques and angular velocities of all rotating electric machines and provides all rotating electric machines with a combined current resulting from the combination of the determined control currents for each rotating electric machine.In this control unit, the required voltage does not exceed the voltage of the power supply, and the peak value of the total current does not exceed the permissible range of the inverter.

[0006] The object of the present invention is to provide an arrangement for providing an output potential and a vehicle with such an arrangement which at least partially overcome the aforementioned disadvantages.

[0007] This problem is solved by an arrangement for providing an output potential according to independent claim 1 and by a vehicle according to independent claim 10.

[0008] Further advantageous aspects of the invention will become apparent from the dependent claims, the accompanying drawing and the following description of preferred embodiments.

[0009] In general, in some embodiments, the arrangement can provide an output potential that can assume various values, particularly for use in operating loads requiring different operating voltages. Furthermore, in some embodiments, it can generally provide a system for supplying power to two- or multi-voltage networks, where a plurality of voltage ratios of the two or more voltages can be provided, and simultaneously, a power supply device is effectively used to drive the motor, particularly to propel a vehicle. In some embodiments, a vehicle is also generally provided, which is designed to support the supply of loads requiring different operating voltages and which is furthermore effectively driven by an electric motor.

[0010] This arrangement can be used in various technical fields where two or more voltages (e.g., a higher voltage for power consumers or generators, lower voltage(s) for control) are required to supply different loads, particularly where two or more voltage levels are linked (indirectly connected to each other). The arrangement is especially suitable for use in technical fields where a rotating field machine is required or already present. In some embodiments, a rotating field machine is understood to be an electromechanical machine in which a rotor with electromagnets or permanent magnets is rotatably mounted relative to a stator, which has windings. For example, this arrangement can be used in vehicles, wind or hydroelectric power plants, emergency power generators, electric bicycles, or other drive machines.

[0011] The provided output potential can, for example, measure against a reference point (e.g., ground) and provide a voltage of one of two or more voltage levels. The provided output potential can, for example, provide a DC output voltage, which can be used for recharging, e.g., an electric accumulator or battery. The arrangement can be designed to generate and provide an output potential within certain limits. Therefore, a separate voltage converter is not necessarily required in some embodiments. This saves space and costs.

[0012] The electric machine can be used, for example, as a motor or generator in one operating mode; in particular, it can be designed as a synchronous machine. The stator can be ring-shaped and, in some embodiments, can be made of a ferromagnetic material with high magnetic permeability. The stator can, for example, have teeth that are directed radially inwards or radially outwards, with the first or second conductors passing through slots between the teeth. The first or second conductors are electrically conductive and can, for example, be made of a metal, in particular copper or an alloy. The conductors can be coated with an insulating layer. The conductors can be wound around the stator or the stator teeth according to various winding schemes. For example,Two, three, four, five, or even more first ladders may be provided. The same applies to the number of second ladders.

[0013] In operation, the arrangement allows, for example, the application or generation of a voltage to each of the first conductors at their respective other end (when the electric machine is operating as a motor or generator), each corresponding to one phase of an alternating voltage. If, for example, three first conductors are provided, the phases of the alternating voltages of the first conductors at the other end can be offset from each other by, for example, 120°.

[0014] The electric machine can be electrically driven and, for example, operated as a motor. In other embodiments, the electric machine can be mechanically driven and function or be operated as a generator. For example, the electric machine can be operated as a motor or generator in a vehicle, particularly an electric vehicle, and, for instance, it can be used in generator mode in a wind or hydroelectric power plant or in an emergency power generator. The voltage or terminal potential generated or supplied to the opposite end of each of the first conductors can be an alternating voltage and is, in particular, different from the output potential, especially the output DC voltage, provided by the arrangement. Thus, various high voltages are provided in the arrangement, in order to support, in particular, a dual-voltage or multi-voltage network.

[0015] At the first neutral point, one end of each of the first conductors is electrically connected. The first neutral point can be accessible from the outside to allow the output potential to be tapped. For example, an electrical conductor can be connected to the first neutral point to carry the output potential to the outside, so it can be tapped from outside the electric machine.

[0016] The number of second conductors can be the same as or different from the number of first conductors. In some embodiments, exactly three first conductors and exactly three second conductors are provided. Furthermore, third, fourth, fifth, or even more conductors may be provided, which are also wound around the (common) stator.

[0017] In some embodiments, exactly three first conductors, three second conductors and three third conductors are provided, each of which has one end and another end and which is electrically connected at one end to a respective star point.

[0018] For each of the first, second, third, fourth, ... nth conductors (n being a natural number), a first, second, ... nth inverter component can be provided, each connected to the other ends of the respective conductors. The other ends of each conductor can be connected to the respective AC terminals of the respective inverter component. The respective DC terminals of the inverter components can be interconnected and, in some embodiments, can be connected to a DC power supply, particularly in embodiments where the electric machine (or a system with multiple electric machines) is operated as a motor.

[0019] The inverter components can, for example, each have a half-bridge (controllable switches connected in pairs in series) per conductor. The controllable switches can be implemented, for example, by power transistors such as IGBTs or MOSFETs.

[0020] The controllable switches of the inverter component(s) can be controlled, for example, by pulse-width modulation signals from a driver circuit. For operation, field-oriented control or vector control can be implemented, for example, to provide a desired output potential (or output DC current) at the first star point.

[0021] According to field-oriented control, the (direct) current emanating from or flowing into the first star point can also be controlled by a controller receiving an error signal from a difference between a desired current and an actual current (e.g., in a DQ coordinate system) and calculating pulse width modulation signals from this to control the controllable switches of the inverter component(s), which ultimately result in the desired current (in particular, various current components in a DQ coordinate system, e.g., i). q , i d and i0).

[0022] The arrangement can further comprise an output terminal (which is particularly accessible from the outside to allow tapping of the output potential) and a first switch connected between the output terminal and the first star point. By closing the first switch, the output potential can be accessed at the output terminal, for example, to operate a load and / or to charge a battery. With the first switch open, in some embodiments, operation of the electric motor is not affected by tapping the output potential, so that the electric motor can be used optimally (i.e., at maximum voltage / power) in motor mode to propel a vehicle. This allows for either powering a load or optimal propulsion of a vehicle.

[0023] The arrangement can further include a DC power supply device (e.g., a high-voltage source providing 48 V or another voltage) connected to a first DC input and a second DC input of the inverter to supply a DC voltage to operate the electric machine as an electric motor (via the respective AC connections of the inverter components). An output DC voltage is provided between the first neutral point and the first DC input (or a connected electrical conductor). The first DC input can, for example, correspond to ground. Thus, the output DC voltage can be provided between the first neutral point and ground.It must be smaller than the DC supply voltage of the DC power supply unit. This allows for the simple support of a dual- or multi-voltage network.

[0024] The arrangement can further include a driver circuit (e.g., an integrated circuit) configured to control (controllable) switches (e.g., power transistors) of the first and second inverter components such that the second conductors are supplied with a maximum AC voltage (which is possible for a given DC supply voltage), and / or that the first conductors are supplied with an AC voltage (e.g., lower than the maximum AC voltage) that results in a desired DC output voltage or current at the first neutral point. Field-oriented control can be implemented for this purpose, which, for example, depends on a desired DC output current or current.a desired output DC voltage is generated at the first star point, a corresponding error signal is supplied to a controller, and voltages output by the controller are generated by controlling the controllable switches, which lead to the desired output DC current or the desired output DC voltage at the first star point.

[0025] By supplying a maximum alternating voltage to the second conductors (or essentially a maximum alternating voltage, within certain error tolerances), effective propulsion or the generation of optimal torque by the electric machine can be achieved due to the energizing of the second conductors. Simultaneously, the output DC voltage or current can be provided at the first neutral point to support a dual- or multi-voltage network, while at the same time ensuring sufficient drive power for the electric machine in motor mode or sufficient generator output in generator mode.

[0026] The driver circuit can, for example, be configured to control the switches of the first inverter component using pulse-width modulation signals such that the ratio of the supply DC voltage to the output DC voltage is between 1:1 and X:1, where X >= 1, e.g., between 2:1 and 10:1. This allows a wide voltage range of the output DC voltage to be provided for operating multiple loads. In other embodiments, the switches of the first inverter component are controlled such that the output DC current at the first star point has a desired value, particularly when an external voltage, e.g., the voltage of a battery to be charged (e.g., a 12 V battery), is applied to the output terminal.

[0027] The arrangement can further include an electric accumulator connected to the output terminal. When the first switch is closed, the accumulator is charged by the DC power supply via a current originating from the first neutral point. The electric accumulator, for example, can provide a lower voltage when fully charged than that supplied by the DC power supply. This allows, for example, a conventional car battery to be charged via the DC power supply (e.g., a traction power storage system) while still ensuring sufficient power for the vehicle.

[0028] The second conductors can have a (first) end and another (second) end, with the second conductors being wound around the stator between the first and second ends and each connected (i.e., electrically connected) to a second star point at the first end. The arrangement can further include a second switch located between the output terminal and the second star point. When the second switch is closed, a higher DC output current can be provided at the output terminal than if only the first switch were closed. This allows for effective charging, for example, of a low-voltage battery.

[0029] In an exemplary, non-limiting embodiment, the supply DC voltage can be between 45 V and 50 V (in particular, essentially 48 V), and the output DC voltage can be between 10 V and 15 V. Other values ​​are possible. The rated power of the first and / or second conductors can be between 3 kW and 5 kW. This allows for the support of dual-voltage electrical systems in conventional vehicles, especially electric vehicles.

[0030] The arrangement can further include a rotor having at least one magnet (e.g., electromagnet and / or permanent magnet) and being rotatably mounted relative to the stator. The rotor and stator are arranged relative to each other such that when the rotor rotates relative to the stator, electrical voltages are induced in the first conductors and the second conductors (or further conductors).

[0031] The rotor can be driven mechanically, for example, when the electric machine is used in generator mode. Alternatively, the rotor can be driven electrically or magnetically by magnetic fields generated by the first and second conductors, respectively, when the electric machine is used in motor mode.

[0032] Some embodiments relate to a vehicle, in particular an electric vehicle, with an arrangement for providing an output potential as described above. This arrangement can perform a dual function. On the one hand, it serves to propel the vehicle; on the other hand, it serves to supply electrical energy to a component of the vehicle, whereby the component may require a voltage which, in some embodiments, is lower than the DC supply voltage used for propulsion.

[0033] Embodiments of the present invention will now be explained with reference to the accompanying drawings. The invention is not limited to the illustrated or described embodiments. Fig. Figure 1 schematically illustrates an arrangement for providing an output potential according to an embodiment of the present invention, which may, for example, be included in a vehicle according to an embodiment of the present invention; and Fig. 2 illustrates graphs to explain operating modes of the in Fig. 1 illustrated arrangement.

[0034] The in Fig. 1 Schematically illustrated arrangement 1 for providing an output potential comprises an electric machine 3, which has a schematically illustrated stator 5, first conductor 7, second conductor 9 and third conductor 11.

[0035] The schematically illustrated stator 5 is, for example, ring-shaped, in particular circular, and is made of ferromagnetic material. It also has teeth, with the first conductor 7, the second conductor 9, and the third conductor 11 being laid (wound) in the spaces between the teeth. The stator 5 can be a single stator used for all conductors 7, 9, and 11, or it can be formed by separate stators 5a, 5b, and 5c, around which the conductors 7, 9, and 11 are laid separately, as shown in Fig. 1 is indicated.

[0036] The first conductors 7 each have one end 13 and another end 15, being wound around the stator between the first end 13 and the second end 15, thus forming an inductance 17 and an ohmic resistance 19. At the first end 13, the first conductors 7 are electrically connected to each other at a first star point 21. The output potential is provided at the first star point 21.

[0037] An inductor 62 is connected between the neutral point 21 or the neutral points 31 and 33 of the electric motor(s) and the output terminal 59 (the "low-voltage electrical system"), which can decouple the (true) DC voltage on the low-voltage battery side from the neutral point potential. The neutral point potential can correspond to a DC voltage, but especially when the traction system voltage is optimally utilized by the electric motor, it can be superimposed with an AC component and thus only correspond to the low voltage on average.

[0038] The second conductors 9 and the third conductors 11 are configured analogously to the first conductors 7 and also have a (first) end 23 and 25 respectively, as well as a different (second) end 27 and 29 respectively. At one (first) end 23, the second conductors 9 are electrically connected to each other at a second star point 31. At one (first) end 25, the third conductors 11 are electrically connected to each other at a third star point 33.

[0039] The arrangement 1 further comprises an inverter 35, which includes a first inverter component 37, a second inverter component 39, and a third inverter component 41. The AC terminals 43 of the first inverter component 37 are each electrically connected to the other (second) ends 15 of the first conductors 7, with the connection points being oriented with U1, V1, and W1. Fig. are marked 1. During operation, alternating voltages are present at points U1, V1 and W1, which are controlled by the first inverter component 37.

[0040] Similarly, the other ends 27 of the second conductor 9 are connected to AC terminals 45 of the second inverter component 39 and the other ends 29 of the third conductor 11 are electrically connected to AC terminals 47 of the third inverter component 41.

[0041] All inverter components 37, 39 and 41 each comprise six controllable switches 49 (e.g. IGBTs), which are controlled by means of a driver circuit 51 with control signals 53, 55 or 57 (each comprising individual control signals for all six switches 49 of the respective inverter component) for the first, second or third inverter component 37, 39 or 41.

[0042] The arrangement 1 further comprises an output terminal 59 and a first switch 61, which is arranged between the output terminal 59 and the first star point 21. The arrangement 1 further comprises a DC supply device 63, which is connected to a first DC input 65 of the inverter 35 and to a second DC input 67 of the inverter 35 for supplying a DC supply voltage u TN is connected to operate the electric machine 3 as an electric motor. An output DC voltage u is present between the first star point 21 and the first DC voltage input 65. N provided.

[0043] By controlling the six controllable switches 49 of the first inverter component 37 by means of the control signals 53, which are generated by the driver circuit 51, the output DC voltage u can be Nto be set to a desired value, in particular so that a ratio of the supply DC voltage u TN to the output DC voltage u n between 1:1 and X:1, where X >= 1, e.g. between 2:1 and 10:1.

[0044] The arrangement 1 further comprises an electric accumulator 69, which is connected to the output terminal 59 and, when the first switch 61 is closed, is supplied by the DC power supply unit 63 via a current i emanating from the first star point 21 N1 is charged. In addition, the arrangement 1 has a rotor with magnets (not shown), which is rotatably mounted relative to the stator 5 and induces voltages in the first conductors 7, the second conductors 9 and the third conductors 11 when rotating.

[0045] When integrating the in Fig. The arrangement shown in 1 can be installed in a vehicle to produce a desired DC output voltage u. Ne.g., to charge a conventional car battery, 69 can be generated.

[0046] Arrangement 1 for providing the output potential or an output DC voltage u N It can also be considered a complex implementation of an electric machine with an inverter in a dual-voltage electrical system of 12 V / 48 V. The electric machine 3 can be viewed as consisting of several (e.g., three) "sub-machines," each with at least three phase windings U1, ..., 3, V1, ..., 3, W1, ..., 3 (a higher number of phases per sub-machine is also possible), each controlled by an inverter 37, 39, or 41, respectively.

[0047] The first electric machine (the first conductors 7) with winding connections U1, V1, W1 is connected to the (switchable) star point tap N1, via which the voltage conversion function can be implemented. Thus, sub-machines 9 and 11 (or up to n, where n is a natural number) can operate at full electric machine performance, and sub-machine 1 (the conductors 7) can perform the voltage conversion function and the (partial) torque supply function by utilizing half the traction network voltage.

[0048] By switching off the star point connection (the first switch S1 is open) the full electric machine power of the first sub-machine or the first conductor 7 can be accessed, however, in this case the voltage conversion function is not available in this embodiment.

[0049] The in Fig. 1. An illustrated arrangement for providing an electrical potential can show different voltage ratios between the supply DC voltage and the supply voltage. TN and the output DC voltage u N Provide, for example, a voltage ratio of 2:1 or 4:1, or even a higher voltage ratio. At the same time, the drive performance can be sufficient or optimal.

[0050] Optionally, a second switch 71 can be provided between the second star point 31 and the output terminal 59 and / or a third switch 73 between the third star point 33 and the output terminal 59.

[0051] The additional switches 71 and 73 allow for increased flexibility. For example, a higher charging current (with switches 61, 71, and 73 closed) can be provided to charge the accumulator 69.

[0052] Furthermore, some embodiments provide for an increase in the number of sub-machines (or an increase in the number of conductor groups) as well as an increase in the number of phases per sub-machine. For example, in some embodiments it may be sufficient to provide only two sub-machines (i.e., first conductor 7 and second conductor 9), each with, for example, three conductors to support three phases. However, some embodiments support even more phases and also provide for more than three sub-machines.

[0053] When switches 71 and 73 are open (or when the second star point 31 and the third star point 33 are not connected to the output terminal 59), sub-machines 9 and 11 can be operated at full power (for example, to drive a vehicle), while the first sub-machine 7 can only be operated at a maximum of half voltage to represent the voltage conversion function.

[0054] It is possible to divide the stator 5 of the machine into several stators. According to embodiments of the invention, the concept of "sub-machines" can allow for various configurations: a. Division of the electric machine into sub-machines containing separate windings 7, 9, 11, which are housed in a stator (possibly distributed around the circumference) and act on a (single) rotor (corresponds to an addition of the magnetic fluxes within the machine). b. Distribution of the separate windings 7, 9, 11 to separate stators 5a, 5b and 5c respectively (see Fig. 1) acting on a rotor. For example, an axial division of the (partial) stators 5a, 5b and 5c is possible with a common rotor (corresponding to an addition of the magnetic fluxes within the rotor). c. Distribution of the separate windings 7, 9, 11 to separate stators 5a, 5b and 5c respectively, which act on separate rotors arranged on a common shaft. For example, an axial distribution is possible (corresponding to an addition of the mechanical torques of each sub-machine). d. Distribution of the windings 7, 9, 11 to separate complete machines, whose outputs are mechanically coupled, e.g. by a friction wheel stage / gear stage (corresponds to an addition of the mechanical power of each sub-machine).

[0055] This allows for the support of various electric machine concepts.

[0056] In some embodiments, arrangement 1 is operated by field-oriented control or vector control.

[0057] In this process, the field-oriented control of a synchronous machine uses the so-called Clarke transformation to convert the three (linked) phase currents i U , i V , i Wto be transformed as a space vector into the two-dimensional stator-fixed coordinate system with components α and β, as described in Equation 1 below. A control described below can be applied to each of the sub-machines 7, 9, 11 (separately). In fact, transformed voltages ud, uq, u0 can be supplied to the driver circuit 51 for each of the sub-machines 7, 9, 11 (separately). For clarity, indices for the sub-machines in connection with the driver circuit 51 and in connection with the following equations are suppressed. (iαiβi0)=23(1−12−12032−32121212)(iUiViW)

[0058] The zero component i0 (for each of the sub-machines 7, 9, 11) describes the degree of imbalance in the three-phase system U, V, W (for each of the sub-machines 7, 9, 11). The stator-fixed representation can be transformed by means of a rotation by the rotor angle φ (see Equation 2 below) into the rotor-fixed coordinate system with the components d (orientation equal to the pole position of the rotor permanent magnet) and q (rotated 90° relative to the d-axis) (so-called Park transformation) (for each of the sub-machines 7, 9, 11). (idiqi0)=(cos φsin φ0−sin φcos φ0001)(iαiβi0)

[0059] Since the currents i d , i q (For each of the sub-machines 7, 9, 11) rotating at synchronous speed ω = dφ / dt in the steady state, these are DC quantities, i.e., not AC quantities. These are the controlled variables of the current controller, which adjusts the manipulated variables u d , u q, u0 (for each of the sub-machines 7, 9, 11) is calculated. The inverse transformation of u d , u q , u0 leads to the phase voltages u U , u V , u W (for each of the sub-machines 7, 9, 11) according to the following equations 3 and 4. (uαuβu0)=(cos φ−sin φ0sin φcos φ00001)(uduqu0) (uUuVuW)=(101−12321−12−321)(uαuβu0)

[0060] To operate the arrangement 1, for example, target current values ​​id, iq (target currents in rotor coordinates) and i0 ("zero component") (for each of the sub-machines 7, 9, 11) are specified in this embodiment, as shown in Fig. 1 is schematically illustrated.

[0061] The setpoint values ​​are compared with actual values ​​of the currents in the d,q coordinate system (for each of the sub-machines 7, 9, 11), and an error (vector) signal 77 (for each of the sub-machines 7, 9, 11) is calculated using a subtraction element 75 (for each of the sub-machines 7, 9, 11). This error vector signal 77 is fed to a respective controller (e.g., PI controller 79) (for each of the sub-machines 7, 9, 11), which calculates voltages ud, uq, u0 (for each of the sub-machines 7, 9, 11). From these voltages, the driver circuit 51 calculates pulse width modulation signals 53, 55, and 57 for the sub-machines 7, 9, 11, which are then fed to the respective controllable switches 49 of the various inverter components 37, 39, and 41. The zero component i0 (for each of the sub-machines 7, 9, 11) determines the neutral point current, e.g. the current i N1, which originates from or is directed towards the first star point 21, the second star point 31 or the third star point 33.

[0062] The calculated voltages ud, uq, u0 (for each of the sub-machines 7, 9, 11) are transformed into the phase voltages uu, uv, uw (for each of the sub-machines 7, 9, 11) using equations 3 and 4 (transformer element 80) and sent to the driver circuit 51 for the calculation and output of the pulse width signals 53, 55 and 57 for the sub-machines 7, 9, 11. The actual currents id, iq, i0 (for each of the sub-machines 7, 9, 11) are determined by transformation 82 from the measured phase currents iu, iv, iw (for each of the sub-machines 7, 9, 11) using equations 1 and 2.

[0063] Fig. Figure 2 illustrates curves 81 and 83 in a coordinate system, where the abscissa 85 represents a phase angle φ and where an ordinate 87 represents a voltage.

[0064] Curve 81 illustrates a sinusoidal voltage waveform with maximum output of the pulse inverter between points u1 and N1, i.e., between points 15 and 21 in Fig. 1. It is assumed that the supply DC voltage u TN The voltage is 48 V. Between points u1 and N1, space vector modulation then results in a maximum voltage amplitude u. max from 48 V / √3: umax=23⋅uTN⋅cos(30°)=13uTN

[0065] At the first star point 21, exactly half the voltage of the supply DC voltage u is present. TN Provided, i.e., 24 V. Should the star point 21 now be set to a fixed potential of u? N' = u TN When / 4 is placed, restrictions arise in the voltage amplitude; in the space vector representation, it can only be u max 'as described in the following equation, amount to: umax†=123uTN

[0066] Curve 83 shows that only half the traction network voltage can be utilized. However, this limitation only applies to the first sub-machine 7, while the second sub-machine 9 and the third sub-machine 11 can be operated at full output and thus full power, because their star points 31 and 33 respectively are not connected to the output terminal 59.

[0067] In this embodiment, without limiting the present invention in this respect, arrangement 1 is dimensioned as follows: 3 × 4 kW = 12 kW rated power of the machine for full operation would correspond to (4 + 4 + 1) kW = 9 kW machine power for converter operation with 1 kW converter power. The precise design of the machine in relation to motor / generator power requirements and the power requirements of the low-voltage electrical system can be adapted as needed. The operating strategy and the driving cycle can also be influencing factors for the design of arrangement 1.

[0068] Some designs allow for DC conversion in the "downward direction" (Buck Mode) and (depending on the operating situation) an upward conversion, e.g. from 12V to 48V (Boost Mode).

[0069] A voltage conversion function described here can encompass the control concept of the machine (and thus the converter function), which is based on regulating the current i0. The current setpoint (i 0, soll ) can be calculated by a higher-level instance (charge controller or similar) that monitors the voltages and / or charge levels of the storage devices in the two vehicle electrical systems.

[0070] The DC / DC conversion function can be provided independently of the electric machine function (the electric machine's torque can also be 0 Nm). This allows the electric machine to operate simultaneously as a motor or generator while converting voltage.

[0071] The invention is not limited to application in a PM-excited synchronous machine. All rotating field machines (externally excited, asynchronous) are suitable for implementing the invention. Reference symbol list 1 Arrangement for providing an output potential 3 Electric machine 5 Stator 5a, 5b, 5c sub-stators 7 first ladder 9 second ladder 11 third ladder 13 first ends 15 other ends 17 Inductance 19 ohmic resistance 21 first star point 23 one end of the second ladder 25 one end of the third ladder 27 other ends of the second ladder 29 other ends of the third ladder 31 second star point 33 third star point 35 inverters 37, 39, 41 Inverter components 43, 45, 47 AC connections 49 controllable switches 51 Driver circuit 53, 55, 57 Pulse width modulation signals 59 Output port 61 first switch 62 Inductance 63 DC power supply unit 65 first DC input 67 second DC input 69 Electric accumulator 71 second switch 73 third switch 75 Addition element 77 Error (vector) signal 79 PL controllers 80, 82 Transformer element 81, 83 Voltage curves 85 Abscissa 87 ordinates i N1 Current emanating from the first star point id, iq, i0 Actual currents iu, iv, iw measured phase currents ud, uq, u0 calculated voltages u TN DC supply voltage u N Output DC voltage u max Voltage amplitude U1, V1, W1 connection points

Claims

[1] Arrangement (1) for providing an output potential, comprising: an electric machine (3) which has a stator (5), first conductor (7) each with one end (13) and one other end (15) which are wound around the stator (5) between one end (13) and the other end (15) and are connected at one end (13) to a first star point (21), and second conductor (9) which is wound around the stator (5); an inverter (35) which a first inverter component (37) which is connected to the other ends (15) of the first conductor (7), and a second inverter component (39) which is connected to the second conductors (9); and a driver circuit (51) configured to control switches (49) of the first inverter component (37) and the second inverter component (39) such that a maximum alternating voltage is supplied to the second conductors (9) and that an alternating voltage is supplied to the first conductors (7) which leads to the output potential at the first star point (21) and to a partial function of torque provision by the first conductors (7); where, when the electric machine (3) is operated, the output potential is provided at the first star point (21). [2] Arrangement (1) according to claim 1, further comprising: an output port (59); and a first switch (61) which is connected between the output terminal (59) and the first star point (21). [3] Arrangement (1) in accordance with the preceding claim, further comprising: a DC power supply device (63) which is connected to a first DC input (65) of the inverter (35) and to a second DC input (67) of the inverter (35) for supplying a DC voltage to operate the electric machine (3) as an electric motor, wherein an output DC voltage (u) is provided between the first star point (21) and the first DC input (65). N ) is provided. [4] Arrangement (1) according to the preceding claim, wherein the driver circuit (51) is configured to control the switches (49) of the first inverter component (37) and the second inverter component (39) in order to supply an alternating voltage to the first conductors (7) which results in a desired output DC voltage (u N ) leads. [5] Arrangement (1) according to claim 4, wherein the driver circuit (51) is configured to control the switches (49) of the first inverter component (37) by means of pulse width modulation signals (53) such that a ratio of the supply DC voltage (u TN ) to the output DC voltage (u N ) lies between 1:1 and X:1, where X >= 1. [6] Arrangement (1) according to any one of the preceding claims 3 to 5, further comprising: an electric accumulator (69) which is connected to the output terminal (59) and, when the first switch (61) is closed, is supplied by the DC power supply unit (63) via a current (i) emanating from the first star point (21). N1 ) is being loaded. [7] Arrangement (1) according to any one of the preceding claims 2 to 6, wherein the second conductors (9) have one end (23) and another end (27), wherein the second conductors (9) are wound around the stator (5) between one end (23) and the other end (27) of the second conductor (9) and are connected at one end (23) to a second star point (31), wherein the arrangement (1) further comprises a second switch (71) which is arranged between the output terminal (59) and the second star point (31). [8] Arrangement (1) according to any one of the preceding claims 3 to 7, where the DC supply voltage (u TN ) is between 45 V and 50 V and where the output DC voltage (u N ) between 10 V and 15 V, and / or where the rated power of the first and / or second conductors (7, 9) is between 3 kW and 5 kW. [9] Arrangement (1) according to any one of the preceding claims, further comprising: a rotor having at least one magnet and being rotatably mounted relative to the stator (5), wherein the rotor and the stator (5) are arranged relative to each other such that when the rotor is rotated relative to the stator (5) electrical voltages are induced in the first conductors (7) and the second conductors (9). [10] Vehicle with an arrangement (1) according to one of the preceding claims.

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