DE102021129953B3 - Multi-compatible power converter, method of operating a power converter, drive system and electrically powered device - Google Patents

Abstract

The present invention relates to a multi-compatible power converter for a drive train of an at least partially electrically powered vehicle, a method for operating a multi-compatible power converter, a drive system and an at least partially electrically powered device. The power converter includes at least one control device, is coupled to at least one energy storage device and is set up to drive at least xi-electric machines of the vehicle, which are each yi-phase. At least xi is equal to or greater than 1. The energy storage device comprises a plurality of storage cells, each with associated cell switches. The control device is set up to switch the cell switches in such a way that at least ∑i=1nxiyi cell strands are formed. The power converter comprises at least ∑i=1nxiyi multi-selector switches. The control device is set up to variably couple the cell strings to a current phase of an electrical machine using the multiple selector switch.

Description

The present invention relates to a multi-compatible power converter for a drive train of an at least partially electrically powered vehicle, a method for operating a multi-compatible power converter for the drive train of an at least partially electrically powered vehicle, a drive system for an at least partially electrically powered vehicle and an at least partially electrically powered device with a propulsion system.

Electrically powered devices, particularly vehicles, typically include multi-phase electric machines coupled to energy storage devices having multiple cell strings. Individual cell strings are then coupled to different current phases of the electrical machine. Depending on the coupled current phase, the cell strings can be stressed to different extents, resulting in different states of charge and/or aging of the cell strings.

In addition, variations in the charge states and/or aging states of the cell strings can also result from a cell string being coupled to a peripheral circuit of the vehicle. The vehicle can include a secondary consumer (electrical machine is the primary consumer), for example vehicle lighting. The energy consumption of the electrical machine generally deviates (significantly) from the energy consumption of such secondary consumers. In addition, the electrical machine can be used for recuperation in a way that is different from the typical secondary consumers, so that the charge states of cell strings that are coupled to current phases of the electrical machine can also increase again. Such an effect cannot be achieved for cell strings coupled to secondary consumers.

The range of an electrified vehicle, generally the useful life of an electrified device, generally depends on the state of charge and/or the aging state of the entire energy storage device. Here, however, the sub-component that has the lowest state of charge represents the limiting component for the range or service life, although other sub-components may still have significant states of charge and/or sufficient aging states. Nevertheless, the range or the service life of the electrically driven device is then limited by the subcomponents that have the lowest charging state and/or the weakest aging state.

DE 10 2019 130 740 A1 , DE 10 2016 105 542 A1 , DE 10 2015 205 278 A1 DE 10 2017 110 708 A1 , DE 10 2010 064 311 A1 , DE 10 2010 041 059 A1 , DE 10 2019 130 741 A1 and DE 10 2019 130 739 A1 disclose generic power converters for electrically powered vehicles or methods of operating such a power converter. DE 10 2019 130 740 A1 discloses a power converter and a method for operating a power converter according to the preambles of the subject matter of claims 1 and 8.

The invention is therefore based on the object of providing a multicompatible power converter, a method for operating a multicompatible power converter, a drive system for an at least partially electrically powered vehicle and an at least partially electrically powered device with a drive system such that the range and/or service life of at least partially electrically driven devices, in particular vehicles, are or will be improved.

The object is solved by the subject matter of the independent patent claims. Advantageous configurations are specified in the dependent patent claims and the following description, each of which can represent aspects of the invention on its own or in (sub)combination.

x_iy_i Zellstränge gebildet sind. Der Stromrichter umfasst zumindest ${\displaystyle {\sum }_{i=1}^n}$

x_iy_i Mehrfachwahlschalter. Die Steuervorrichtung ist eingerichtet, die Zellstränge anhand der Mehrfachwahlschalter jeweils variabel mit einer Stromphase einer elektrischen Maschine zu koppeln.According to one aspect, a multi-compatible power converter for a drive train of an at least partially electrically powered vehicle is provided. The power converter includes at least one control device, is coupled to at least one energy storage device and is set up to drive at least x _i electrical machines in the vehicle. The x _i electric machines of the vehicle are each y _i -phase. In this case, at least x _i is equal to or greater than 1, in particular an integer number. The energy storage device includes a plurality of storage cells, each with associated cell switches. The control device is set up to switch the cell switch in such a way that at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i cell cords are formed. The power converter includes at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i Multiple selector switch. The control device is set up to variably couple the cell strings to a current phase of an electrical machine using the multiple selector switch.

The multicompatible power converter set up in this way makes it possible to variably design the allocation between cell strings and current phases of the electrical machine during operation. Thus, the control device under couple different cell strings to different power phases of the electric machines at different points in time so as to improve operational efficiency. A redundancy is created with regard to the assignment, as a result of which the reliability and the service life of the at least partially electrically driven vehicle are improved.

The present power converter is not limited to use with a single electrical machine of the at least partially electrically powered vehicle. For example, the vehicle may also include multiple electrical machines. For example, several electric machines for driving the front axle and the rear axle or for driving individual wheels are conceivable. The electrical machines can also have different numbers of current phases. In this respect, the multi-compatible power converter is not limited to use with just one type of electrical machine. In this context, x _i is to be understood as meaning the number of electrical machines with a specific number of current phases y _i .

For example, if the vehicle includes a five-phase electrical machine (x ₁ = 1; y ₁ = 5), two three-phase electrical machines (x ₂ = 2; y ₂ = 3) and three four-phase electrical machines (x ₃ = 3; y ₃ = 4), the result for the number z of cell strings formed by the control device using the cell switches is: $$\mathrm{e.g}={\displaystyle {\sum }_{i=1}^n{x}_i{y}_i}=x_1{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="DE102021129953B3\_0017.png"\; state="\{\{state\}\}">y</figure-callout>}}_1+x_2{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="DE102021129953B3\_0017.png"\; state="\{\{state\}\}">y</figure-callout>}}_2+x_3{\mathrm{<figure-callout\; id="3"\; label="y"\; filenames="DE102021129953B3\_0017.png"\; state="\{\{state\}\}">y</figure-callout>}}_3=1\cdot 5+2\cdot 3+3\cdot 4=23$$

The control device thus forms at least 23 cell strands. x _i and y _i are therefore natural numbers (greater than zero).

Usually, the number of cell strings formed is not that high, this is just an example to illustrate the compatibility and flexibility of the power converter.

The multi-compatible power converter can be adapted to a wide variety of current phase topologies in a wide variety of devices.

The general concept of the power converter remains the same, so that the power converter provides a large number of possible applications. As a result, the power converter provides maximum scalability and interchangeability, both with regard to the cell strings and their subcomponents. The power converter also enables improved safety and reliability. Because the more cell strings are formed, the lower the impact on the overall performance of the energy storage device if, for example, a cell string or part of it fails and has to be bridged.

If the electrically driven vehicle (in general: the electrically driven device) comprises a plurality of electric machines, then the respective cell strings can also be independently coupled to the current phases of the electric machines. As a result, the electrical machines can be operated at different operating points, for example, so that different torques can be achieved at the same time. For example, this is necessary in all-wheel drive vehicles when cornering, where different drive torques are advantageous due to the asymmetrical weight distribution of the vehicle and the different track radii of the drive wheels.

In the present case, the multiple selection switches can be understood to mean switches (relays) with multistable states, which can each couple an individual current phase to different cell strings of the energy storage device depending on the switching state of a switching element. The respective switching state is determined by the control device. Examples of such multiple selector switches are mechanical rotary switches with at least one input and multiple outputs that can be coupled depending on the position of the switching element. Alternatively, the same functionality can also be achieved by a plurality of transistors that emulate the functionality of a rotary switch.

In the present case, the control device can be understood in particular as an electronic device with a processor which, on the basis of a plurality of input signals and output signals, enables corresponding switching sequences, both with regard to the cell switches and with regard to the multiple selection switches. The control device can in particular comprise a programmable logic controller. The switching sequences can be computer-implemented using appropriate software.

Optionally, the cell strings each include a plurality of storage cells. The cell switches assigned in each case can be switched by the control device in such a way that an alternating voltage can be provided between two cell string nodes of a cell string.

The storage cells form the basic units of the energy storage device. Each cell switch, which can assume different switching states, is assigned to the memory cells. The control device is set up to control the cell switches at least in such a way that a storage cell can provide a positive or negative voltage between memory cell nodes of the memory cell. The controller is then configured to apply a generally variable duty cycle (variable pulse width) to switching operations of the cell switches. As a result, through appropriate switching sequences, AC voltages (for example pseudo-sinusoidal AC voltages) can be provided by the control device at the cell string nodes of a cell string in order to operate an electrical machine.

Alternatively, the cell switches can also be controlled in such a way that a DC voltage is provided between the cell string nodes of a cell string. As a result, the power converter provides optimal compatibility depending on the voltage signal to be provided for the respective consumer. The multi-compatible power converter achieves maximum flexibility. It can therefore be used in combination with a wide variety of electrical devices. As a result, complex specialized development work for different types of electrical devices can be avoided.

Optionally, the control device is set up to vary a pulse width during switching processes of the cell switch assigned to the storage cell, or the signal applied to the cell switch, depending on a state of charge and/or an aging state of a storage cell in a cell string. This further improves the flexibility of the power converter. Individual sections of an energy storage device can be optimally used according to their individual properties in order to increase the service life of the underlying electric vehicle (the device), which also increases the service life. If the control device determines, for example, that the state of charge and/or aging state of a specific storage cell is particularly poor, the control device can adapt the switching sequence accordingly. As a result, the uniformity of the charge states and/or aging states for the storage cells within a cell string can be ensured.

In the present case, the aging state of an energy storage component is understood to mean the ability to absorb or release electrical charge with as little loss as possible between a minimum charging state and a nominal maximum charging state of the energy storage component. For example, the internal resistance of the energy storage component changes so that the charging speed or discharging speed decreases. The maximum state of charge that can still be reached can also vary during the operating period compared to the nominal maximum state of charge.

In addition, depending on a state of charge and/or an aging state of the cell strings, the control device can be set up to variably couple the cell strings to different current phases of electrical machines. So if it is determined that the state of charge and/or the aging state of a cell string coupled to it is particularly stressed by the coupling to a certain current phase of the electrical machine, the coupling can be switched variably during operation, so that other cell strings with this current phase of the electrical machine to be coupled. Consequently, uniformity of the charge states and/or aging states of the individual cell strings of the energy storage device relative to one another can be ensured. This improves the range and the service life of the at least partially electrically powered vehicle.

Since the power converter can be used both in the motor operating mode and in the recuperation operating mode, the uniformity of the states of charge and/or aging states of the cell strings and the storage cells they include can be ensured both with increasing and falling states of charge and/or aging states.

In a special configuration, storage cells of a cell string can be bypassed by the cell switches assigned in each case, so that a cell string voltage is essentially zero. In particular, the control device can control the cell switches in such a way that a cell string voltage is zero before the respective cell string is coupled to another current phase. The cell string voltage is understood here as meaning the voltage output by a respective cell string between two cell string nodes associated with the cell string. An AC voltage or DC voltage is usually output at the cell string nodes or applied to them (recuperation).

The cell switches assigned to the storage cells can have particularly short switching times between different switching states. If the cell switches are switched in such a way that no voltage is output from the storage cells and consequently the cell string voltage is zero, the multi-selector switch can be switched from a first switching configuration to a second switching configuration without the risk of a voltage spike. Multiple selector switches are known in the prior art that have particularly short switching times and can avoid voltage peaks. Such multiple selector switch but are expensive and require complex secondary circuitry. Since the cell switches have short switching times anyway, more cost-effective multiple selector switches can be used here that do not require secondary circuits if the respective cell string voltage is zero during the switching process of the multiple selector switch. This can avoid the risk of damage to parts of the underlying electronic circuitry that can result from voltage spikes. In addition, the cell switches then enable particularly short switching times for a reassignment of the coupling, even in conjunction with conventional multiple selection switches. The switching times can be further shortened if the multiple selector switches are each formed by combined transistors.

Depending on the performance/energy requirements of the individual electric machines, the control device can ensure that the cell strings can be connected/disconnected to the different power phases very quickly in order to minimize state of charge variations and/or state of health variations between the cell strings and the energy storage device and the electric machines during of operation to the fullest.

In the present case, the cell switches can be understood to mean so-called H-bridge switches. Four switching elements are then arranged relative to the capacitor of the memory cell in such a way that both positive and negative voltages can be output by the memory cell. In addition, the capacitor of the memory cell is bypassable so that no voltage is output by the memory cell (the output voltage can be considered zero). The switching elements of the memory cells can be realized, for example, by transistors (e.g. metal oxide field effect transistors) whose gate voltages can be switched accordingly by the control device. This also creates the possibility of putting defective memory cells out of operation without causing a failure of the energy storage device as a whole. The corresponding storage cell can then be bridged, so that the functionality of the energy storage device is essentially retained.

The control device can also be set up to switch the cell switches of a cell string in such a way that a plurality of sub-cell strings are formed in a parallel circuit between cell string nodes of the cell string. The amplitude of the current emitted by this cell string can be increased by connecting several sub-cell strings in parallel between the cell string nodes of a cell string. This can be advantageous for certain applications, for example particularly high torques to be achieved by the electric machine (for example a “sports mode”). Overall, this again improves the flexibility and compatibility of the power converter. It is then also not necessary for the memory cells to have the same storage capacities. Rather, for example, a sub-cell string with storage cells that enable a particularly high power output can be provided for such special applications, which is added if necessary in order to adapt the power output at the cell string node.

Overall, the control device can therefore be set up to implement cell strings consisting of a plurality of storage cells arranged in a series connection between two cell string nodes. In this case, sub-cell strings can be arranged in parallel circuits. Series and parallel circuits of storage cells can also be combined as desired in order to be able to provide desired voltage profiles at the cell string nodes.

Due to the switching configurations that can be implemented by the control devices, additional contactors in the power converter to protect the energy storage device are not required. The conventional connection and/or disconnection sequences commonly used in such arrangements can be considered. Naturally, contactors, in particular high-voltage contactors, can optionally be considered, which are then preferably arranged between the individual cell strings and the multiple selector switches.

The control device is optionally set up to form at least one additional cell line. The power converter then includes at least one additional multiple selector switch and the control device is set up to couple the additional cell string to at least one peripheral device of the at least partially powered electric vehicle (the device) at least using the additional multiple selector switch. Electrical machines of today's electrical vehicles are usually subjected to high voltages, for example voltage amplitudes equal to or greater than 100V, in particular equal to or greater than 200V, more particularly equal to or greater than 400V, in particular up to 800V. As a rule, however, electric vehicles also have many peripheral devices (auxiliary consumers, secondary consumers) that require significantly lower supply voltages. Typically, the voltage amplitudes of secondary consumers are in the range of a few volts, for example 5V, 12V or in the range of a few 10V, for example 36V or 40V. The result of this is that a cell string that is coupled to an electrical machine (primary consumer) generally has a different state of charge profile and/or aging state profile than is the case for a cell string that is coupled to secondary consumers. The power converter according to the invention makes it possible to variably assign the individual cell strings during operation, so that the uniformity of the charge states and/or the aging states of the cell strings relative to one another is ensured. In addition, the power converter also provides compatibility with regard to the voltage signal required in each case. For example, a specific cell string can then apply a DC voltage to auxiliary consumers, whereas the same cell string can also be used to output an AC voltage at a different point in time, for example after the assignment of cell strings to consumers in the vehicle has been changed using the multiple selector switch.

x_iy_i Zellstränge gebildet sind. Das Verfahren umfasst ferner den Schritt des variablen Koppelns, durch die Steuervorrichtung anhand von zumindest ${\displaystyle {\sum }_{i=1}^n}$

x_iy_i Mehrfachwahlschalter des Stromrichters, von zumindest jeder Stromphase einer elektrischen Maschine der elektrisch angetriebenen Vorrichtung bzw. des Fahrzeugs mit einem Zellstrang. Insofern ist zu jedem Zeitpunkt gewährleistet, dass für jede elektrische Maschine der Vorrichtung bzw. des Fahrzeugs jede Stromphase mit einem gebildeten Zellstrang der Energiespeichervorrichtung gekoppelt ist. Durch die Variabilität der Zuordnung zwischen den Zellsträngen und den damit gekoppelten Stromphasen der elektrischen Maschinen werden die zuvor erläuterten Vorteile bezüglich der Lebensdauer und/oder der Reichweite der Vorrichtung bzw. des Fahrzeugs erzielt.According to a further aspect, a method for operating a multi-compatible power converter for the drive train of an at least partially electrically powered vehicle. In general, however, the method can also be provided for the operation of a multi-compatible power converter for the drive train of an at least partially electrically driven device in general. The device or the vehicle comprises at least x _i electrical machines, which are each y _i -phase. The number of electrical machines x _i is equal to or greater than 1. The method comprises at least the step of switching, by a control device of the power converter, cell switches that are each assigned to a storage cell of an energy storage device of the electrically driven device. The cell switches are switched in such a way that at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i cell cords are formed. The method further includes the step of variable coupling, by the control device based on at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i multiple selector switch of the converter, of at least each current phase of an electrical machine of the electrically driven device or of the vehicle with a cell string. In this respect, it is ensured at all times that for each electrical machine of the device or of the vehicle, each current phase is coupled to a cell string formed in the energy storage device. The previously explained advantages with regard to the service life and/or the range of the device or vehicle are achieved through the variability of the association between the cell strings and the current phases of the electrical machines coupled thereto.

According to yet another aspect, a drive system for an at least partially electrically powered vehicle is also provided. In principle, the drive system can generally be provided for an at least partially electrically driven device. The drive system includes a drive train with x _i electrical machines that are each y _i -phase, an energy storage device with a plurality of storage cells and respectively associated cell switches and a multi-compatible power converter as previously described. Alternatively, the drive system includes a power converter that is operated according to the method described above.

In addition, according to a further aspect, an at least partially electrically powered device is also provided, in particular an at least partially electrically powered vehicle. The device includes a drive system as previously described.

Within the meaning of the present invention, at least partially electrically powered vehicles include at least one electric machine. Such vehicles can in particular include land vehicles, namely electric scooters, e-scooters, two-wheelers, motorcycles, three-wheelers, trikes, quads, off-road and road vehicles such as cars, buses, trucks, tractors and other commercial vehicles, rail vehicles (trains), but also watercraft (Boats) and aircraft such as helicopters, multicopters, propeller aircraft and jet aircraft, which have at least one electric motor used to propel the vehicle. Vehicles can be manned or unmanned. In addition to pure electric vehicles (BEV), plug-in hybrids (PHEV) and fuel cell vehicles (FCEV) can also be included.

In this respect, at least partially electrically powered vehicles correspond to at least partially electrically powered devices.

All of the features explained with regard to the various aspects can be combined individually or in (sub)combination with other aspects.

• - 1 eine vereinfachte schematische Darstellung einer Speicherzelle in verschiedenen Schaltzuständen des zugeordneten Zellschalters und den resultierenden Spannungsverlauf gemäß dem Stand der Technik;
• - 2 eine vereinfachte schematische Darstellung eines Zellstrangs gemäß dem Stand der Technik;
• - 3 eine vereinfachte schematische Darstellung eines Zellstrangs mit Unterzellsträngen gemäß dem Stand der Technik;
• - 4 eine vereinfachte schematische Darstellung eines multikompatiblen Stromrichters, der mit zwei elektrischen Maschinen und einer Energiespeichervorrichtung gekoppelt ist;
• - 5 eine vereinfachte schematische Darstellung eines Verfahrens zum Betrieb eines multikompatiblen Stromrichters; und
• - 6 eine vereinfachte schematische Darstellung eines elektrisch angetriebenen Fahrzeugs mit einem Antriebssystem umfassend einen multikompatiblen Stromrichter.

The invention and other advantageous embodiments and developments thereof are described and explained in more detail below with reference to the examples shown in the drawings. Show it:

• - 1 a simplified schematic representation of a memory cell in different switching states of the associated cell switch and the resulting voltage profile according to the prior art;
• - 2 a simplified schematic representation of a cell line according to the prior art;
• - 3 a simplified schematic representation of a cell string with sub-cell strings according to the prior art;
• - 4 a simplified schematic representation of a multi-compatible power converter, which is coupled to two electrical machines and an energy storage device;
• - 5 a simplified schematic representation of a method for operating a multi-compatible power converter; and
• - 6 a simplified schematic representation of an electrically powered vehicle with a drive system comprising a multi-compatible power converter.

All features disclosed below in relation to the exemplary embodiments and/or the accompanying figures can be combined alone or in any sub-combination with features of the aspects of the present disclosure, including features of preferred embodiments, provided that the resulting combination of features is for a person skilled in the art field of technology makes sense.

For purposes of this disclosure, the phrase “at least one of A, B, and C” means, for example, (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C), including all other possible combinations if more than three items are listed. In other words, the term "at least one of A and B" generally means "A and/or B", namely "A" alone, "B" alone or "A and B".

1 shows a simplified schematic representation of a memory cell 10 in different switching states 12A to 12D of the associated cell switch 14 and the resulting voltage profile 16 according to the prior art.

The storage cell 10 includes a capacitor 18 which is set up to store and release electrical charge. In the present case, the cell switch 14 (H-bridge switch) assigned to the memory cell 10 comprises four separate switching elements 20A to 20D. The switching elements 20A to 20D can be implemented by transistors, for example. The switching elements 20A to 20D are configured to be controlled by a controller of the multi-compatible power converter. For example, switching positions of the switching elements 20A to 20D can be varied using gate voltages of the transistors.

Based on the switching positions of the switching elements 20A to 20D, the memory cell 10 is set up to output positive voltages or negative voltages, or to be bypassed.

The voltage profile 16 shows an example of the output voltage of the memory cell 10 in relation to the various switching positions of the associated cell switch 14. The amplitude of the voltage V output by the memory cell 10 is plotted on the x-axis 24 versus the time t plotted on the x-axis 24 shown.

During switching interval t1, corresponding to switching state 12A, memory cell 10 is bypassed since switching elements 20C and 20D are closed and switching elements 20A and 20B are open. Consequently, no voltage is output from the memory cell 10. During the switching interval t2, corresponding to the switching state 12B, a positive voltage V-cell+ is output by the memory cell 10 due to the switching positions of the switching elements 20A to 20D. During switching interval t3, memory cell 10 is again bypassed, whereas during switching interval t4 memory cell 10 outputs a negative voltage V-cell-.

Thus, the memory cell 10 can be controlled in such a way that any output voltage topologies can be generated. In particular, the duty cycle (the pulse width) underlying the switching operations of the cell switch 14 can be adjusted. Consequently, the time intervals t1 to t4 do not have to be uniform, but can deviate from one another.

2 FIG. 12 shows a simplified schematic representation of a cell line 26 according to the prior art. In its simplest form, the cell string 26 comprises a plurality of storage cells 10 which are arranged in a series connection 28 . The cell switches 14 assigned to the storage cells 10 can be controlled separately by a control device. Consequently, the voltage amplitudes output from the memory cells 10 can be added. In this way, typical cell string voltage amplitudes V string of up to 800 V can be achieved at cell string nodes 30A, 30B of the cell string 26 . The cell switches 14 of the individual storage cells 10 can be switched by the control device in such a way that charge states and/or aging states of the individual storage cells 10 of the cell string 26 have developments (current states) that are as homogeneous as possible. The uniformity of the charge states and/or aging states of the individual storage cells 10 can therefore be ensured within the entire cell string 26 . For example, the duty cycle to Switching of the memory cells 10 associated cell switches 14 are adjusted accordingly.

3 12 shows a simplified schematic representation of a cell string 26 with sub-cell strings 32A to 32C according to the prior art. The cell string 26 here has a plurality of sub-cell strings 32A to 32C which are arranged in a parallel connection 34 relative to one another. Each sub-cell string 32A here comprises a plurality of storage cells 10 which are arranged in a series connection 28 . The resulting total voltage of the cell string 26 is tapped at the cell string nodes 30A, 30B. In particular, the parallel connection 34 allows the amplitudes of the currents output at the cell string nodes 30A, 30B to be increased.

Parallel circuits 34 and series circuits 28 can be adjusted as needed to provide desired voltage topologies at cell string nodes 30A, 30B.

The cell switches 14 assigned to the storage cells 10 can in particular be switched by the control device in such a way that states of charge and/or aging states of the individual sub-cell strings are stressed uniformly, ie have uniform course characteristics.

4 1 shows a simplified schematic of a multi-compatible power converter 36 coupled to two electric machines 38A, 38B and an energy storage device 40. FIG. The electrical machines 38A, 38B are each three-phase in the present case.

The embodiment shown in combination with two three-phase electrical machines 38A, 38B is merely an example. The multicompatible power converter 36 is basically also set up for coupling to a different number of electrical machines 38A or to electrical machines 38A that have a different number of current phases.

The multi-compatible power converter 36 includes a controller 42 and a plurality of multiple selector switches 44A through 44F. Controller 42 is coupled to energy storage device 40 and multiple selector switches 44A-44F. The energy storage device 40 comprises a plurality of storage cells 10, each with associated cell switches 14.

The control device 42 switches the cell switches 14 in such a way that cell strings 26 are formed. The number of cell strings 26 formed corresponds at least to the total number of current phases 46A to 46F of the electrical machines 38A, 38B to be acted upon. At least six cell strands 26A to 26F are formed here.

The control device 42 controls the multiple selector switches 44A to 44F in such a way that a cell string 26 is coupled to a current phase 46A to 46F of the electrical machines 38A, 38B. In the present case, for reasons of clarity, this is only shown for three cell strands 26A to 26C.

Due to a different operating behavior of the electrical machines 38A, 38B, it can happen that the states of charge of the cell strings 26A to 26F differ from one another. For example, it is shown here that the average states of charge (avg. LZ) of the storage cells 10 of the cell strings 26A to 26C are greater than those of the remaining cell strings 26D to 26F. The control device 42 is set up to make the coupling between the cell strings 26A to 26F and the current phases 46A to 46F variable in such a way that a reassignment can take place during operation.

Before switching over the multiple selector switches 44A to 44F, the storage cells 10 of the cell string 26A to be switched over are bypassed using the cell switches 14 assigned in each case. Then the respective multiple selector switch 44A can be toggled by the controller 42 without the risk of voltage spikes (arcing) since the resulting cell string voltage is then zero. After switching, there is a different switching configuration 48B of the multiple selector switches 44A to 44F. While the cell strings 26A to 26C are coupled to the power phases 46A to 46C of the first electrical machine 38A in the original switching configuration 48A, they are coupled to the power phases 46D to 46F of the second electrical machine 38B in the changed switching configuration 48B.

Thus, the multicompatible power converter 36 is set up not only to switch the storage cells 10 of a cell string 26A in such a way that uniform developments in the states of charge and/or aging states within the cell string 26A are ensured, but also the uniformity of the states of charge and/or aging states between the different cell lines 26A to 26F can be ensured.

Optionally, additional contactors 50, in particular high-voltage contactors, can be provided between energy storage device 40 and multiple selector switches 44A to 44F.

5 shows a simplified schematic representation of a method 52 for operating a multi-compatible power converter 36.

x_iy_i Zellstränge 26 gebildet sind.The method 52 includes at least the step 54 of switching, by a control device 42 of the power converter 36, of cell switches 14, each of which is assigned to a storage cell 10 of an energy storage device 40 of the electrically driven device, such that at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i cell strands 26 are formed.

x_iy_i Mehrfachwahlschalter 44 des Stromrichters 36, von zumindest jeder Stromphase 46 einer elektrischen Maschine 38 der elektrisch angetriebenen Vorrichtung mit einem Zellstrang 26.Furthermore, the method 52 includes the step 56 of variable coupling, by the control device 42 based on at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i multiple selector switch 44 of the converter 36, of at least each current phase 46 of an electrical machine 38 of the electrically driven device with a cell string 26.

6 1 shows a simplified schematic representation of an electrically powered vehicle 60 having a drive system 62 comprising a multi-compatible power converter 36. The electrically powered vehicle 60 is here an exemplary embodiment of a general electrically powered device 64.

The vehicle 60 includes four wheels 64A through 64D. The front wheels 64A, 64B are driven by a first electric machine 38A and the rear wheels 64C, 64D are driven by a second electric machine 38B. The electric machines 38A, 38B are part of the drive system 62, which also includes an energy storage device 40. The energy storage device 40 has, in a known manner, storage cells 10 with respectively associated cell switches 14 . The power converter 36 is set up by means of the control device 42 to form cell strings 26 and to variably couple them to the current phases 46 of the electrical machines 38A, 38B.

In the present case, an additional cell string 26 is formed by the control device 42, so that the number of cell strings 26 formed is greater than the number of current phases 46 of the electrical machines 38 of the device 64. The additional cell string 26 is controlled by the control device 42 of the power converter 36 with at least one Peripheral device 66 of device 64 coupled. The consumption characteristics with regard to the state of charge and/or the aging state of the cell string 26 coupled to the peripheral device 66 will generally deviate from that of the cell strings 26 coupled to the current phases 46 of the electrical machines 38 . Due to the variable coupling or the reassignment during operation, which is ensured by the control device 42 of the power converter 36, the charge states and/or aging states of the different cell strings 26 can nevertheless be stressed evenly.

Claims (10)

Multi-compatible power converter (36) for a drive train of an at least partially electrically powered vehicle (60), the power converter (36) comprising at least one control device (42), being coupled to at least one energy storage device (40) and for driving at least x _i electric machines (38) of the vehicle (60) is set up, each of which is y _i -phase, with at least x _i being equal to or greater than 1, the energy storage device (40) comprising a plurality of storage cells (10) each with associated cell switches (14), wherein the control device (42) is set up to switch the cell switch (14) in such a way that at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i cell strings (26) are formed, wherein the multi-compatible power converter (36) is characterized in that the power converter (36) at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i multiple selector switch (44), and the control device (42) is set up to couple the cell strings (26) using the multiple selector switch (44) in each case variably with a current phase (46) of an electrical machine (38). Multi-compatible power converter (36) according to claim 1 , the cell strings (26) each comprising a plurality of storage cells (10), the cell switches (14) assigned in each case being switchable by the control device (42) in such a way that an AC voltage is provided between two cell string nodes (30A, 30B) of a cell string (26). is. Multi-compatible power converter (36) according to claim 2 , wherein the control device (42) is set up to vary a pulse width of the cell switch (14) assigned to the storage cell (10) depending on a state of charge and/or an aging state of a storage cell converter (10) of a cell string (26). Multicompatible power converter (36) according to one of the preceding claims, wherein the control device (42) is set up as a function of a state of charge and/or an aging state of the cell strings (26), the cell strings (26) variably to different current phases (46) of electrical machines ( 38) to pair. Multicompatible power converter (36) according to one of the preceding claims, wherein storage cells (10) of a cell string (26) can be bridged by the respectively assigned cell switch (14), such that a cell string voltage is essentially zero, in particular wherein the controller controls the cell switches such that a cell string voltage is zero before the respective cell string is coupled to another power phase. Multicompatible power converter (36) according to one of the preceding claims, wherein the control device (42) is set up to switch the cell switch (14) of a cell string (26) in such a way that between cell string nodes (30A, 30B) of the cell string (26) a plurality of sub-cell strings ( 32) are formed in a parallel circuit (34). Multicompatible power converter (36) according to one of the preceding claims, wherein the control device (42) is set up to form at least one additional cell string (26), wherein the power converter (36) comprises at least one additional multiple selector switch (44), and wherein the control device ( 42) is set up to couple the additional cell string (26) to at least one peripheral device (66) of the at least partially powered electric vehicle (60) at least by means of the additional multiple selector switch (44). Method (52) for operating a multi-compatible power converter (36) for the drive train of an at least partially electrically powered device (64), in particular an at least partially electrically powered vehicle (60), having at least x _i electrical machines (38), each of which has y _i -phase, where at least x _i is equal to or greater than 1, the method at least comprising: - switching, by a control device (42) of the power converter (36), of cell switches (14), each of which is a storage cell (10) of an energy storage device ( 40) of the electrically driven device (64) are assigned such that at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i cell strings (26) are formed, the method (52) being characterized in that it further comprises: - Variable coupling, by the control device (42) based on at least ${\displaystyle {\sum }_{i=1}^n}$

x _i y _i multiple selector switches (44) of the converter (36), of at least each current phase (46) of an electrical machine (38) of the electrically driven device (64) with a cell string (26). Drive system (62) for an at least partially electrically driven vehicle (60), wherein the drive system (62) has a drive train with x _i electrical machines (38), each of which is y _i -phase, an energy storage device (40) with a plurality of storage cells (10 ) and respectively associated cell switches (14) and a multi-compatible power converter (36) according to one of Claims 1 until 7 comprises or a multi-compatible power converter (36) according to the method (52). claim 8 is operated. Device (64) which is at least partially electrically driven and a drive system (62). claim 9 includes.

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