DE102020203669A1 - Drive system with two electric machines - Google Patents

Abstract

The invention relates to a drive system (1), in particular for a vehicle (100), comprising a first electrical machine (EM1) with a first output shaft (2), a second electrical machine (EM2) with a second output shaft (3) and a transmission (10), which is connected to the first output shaft (2) and the second output shaft (3) and has at least one output shaft (11), the transmission (10) mechanically, the first output shaft (2) and the second output shaft (3) permanently coupled with each other. The invention further relates to the use of a drive system (1) as a drive system (1) for a vehicle (100) and a method for operating a drive system (1), in particular in a vehicle (100).

Description

The invention relates to a drive system, in particular for a vehicle, comprising a first electrical machine with a first output shaft, a second electrical machine with a second output shaft and a transmission which is connected to the first output shaft and the second output shaft and has at least one output shaft,
wherein the transmission mechanically permanently couples the first output shaft and the second output shaft to one another. The invention further relates to the use of a drive system as a drive system for a vehicle and a method for operating a drive system, in particular in a vehicle.

State of the art

Drive systems for electric drive trains with single-stage transmissions are known from the field of electrically operated vehicles. Multi-stage gears can also be used to spread the speed and torque of such drive systems. The disadvantage of transmissions with several fixed gear steps is that the driving electrical machines are usually not operated in the range of their optimal efficiency. To improve the efficiency of an electric drive for vehicles, it is known to use several different drive systems that drive different axles of a vehicle and work together in an optimized manner. Disadvantages of several drive systems in a vehicle, however, are the increased effort and greater complexity that results from the interaction of several drive systems.

DE102006057857B4 discloses an apparatus and a method for operating a motor vehicle with a plurality of electric drive units. The drive units are connected to one another via a differential which drives an axle of a vehicle. The drive units can be used for a common drive.

DE19841829A1 discloses a hybrid drive for vehicles. In addition to an internal combustion engine, this hybrid drive has two electrical machines that can be operated by motors. The rotors of the two machines are connected to one another via a superposition gear.

Disclosure of the invention

• - eine erste elektrische Maschine mit einer ersten Abtriebswelle,
• - eine zweite elektrische Maschine mit einer zweiten Abtriebswelle,
• - ein Getriebe, welches mit der ersten Abtriebswelle und der zweiten Abtriebswelle verbunden ist und zumindest eine Ausgangswelle aufweist,

wobei das Getriebe die erste Abtriebswelle und die zweite Abtriebswelle mechanisch dauerhaft miteinander koppelt. Es ist vorgesehen, dass das Übersetzungsverhältnis zwischen der Rotorwelle der ersten elektrischen Maschine und dem Getriebeeingang sich von dem Übersetzungsverhältnis zwischen der Rotorwelle der zweiten elektrischen Maschine und dem Getriebeeingang unterscheidet und eine Steuerung vorgesehen ist, welche die beiden mechanisch miteinander gekoppelten elektrischen Maschinen unabhängig voneinander ansteuert, insbesondere aktiviert oder deaktiviert. Der Gegenstand der Erfindung ist ein elektrisches Antriebssystem für Fahrzeuge, bei dem eine erste elektrische Maschine und eine zweite elektrische Maschine gemeinsam eine Ausgangswelle eines Getriebes antreiben. Die beiden elektrischen Maschinen sind über ein Getriebe miteinander gekoppelt und laufen dauerhaft synchron. Zwischen der Rotorwelle der ersten elektrischen Maschine und dem Getriebeeingang besteht ein festes Übersetzungsverhältnis. Der Getriebeeingang wird durch das Element des Getriebes gebildet, welches in Wirkverbindung mit den Abtriebswellen der elektrischen Maschinen steht. Beispielsweise kann der Getriebeeingang durch einen Differenzialkorb eines als Differenzial ausgeführten Getriebes gebildet werden. In gleicher Weise besteht ein festes Übersetzungsverhältnis zwischen der Rotorwelle der zweiten elektrischen Maschine und dem Getriebeeingang. Erfindungsgemäß sind die beiden Übersetzungsverhältnisse der Rotorwelle der beiden elektrischen Maschinen zum Getriebeeingang unterschiedlich ausgeführt. Dabei kann das Übersetzungsverhältnis der ersten elektrischen Maschine länger als das Übersetzungsverhältnis der zweiten elektrischen Maschine ausgeführt sein. Auch der umgekehrte Fall gehört zur Erfindung. Erfindungsgemäß ist weiterhin eine Steuerung vorgesehen, die die beiden elektrischen Maschinen unabhängig voneinander, jedoch abhängig von der Betriebssituation ansteuert. Erfindungsgemäß sind zwei elektrische Maschinen durch ein Getriebe dauerhaft miteinander gekoppelt. Die Übersetzung von der Rotorwelle jeder elektrischen Maschine bis zur Ausgangswelle des Getriebes ist konstant und unveränderlich. Jedoch unterscheiden sich die Übersetzungen ausgehend von der Rotorwelle bis zur Ausgangswelle des Getriebes zwischen beiden elektrischen Maschinen. Die Rotorwelle der ersten elektrischen Maschine ist somit verglichen mit der Rotorwelle der zweiten elektrischen Maschine, bezogen auf die Ausgangswelle des Getriebes, unterschiedlich übersetzt. Die Kombination aus Ausführungsform oder Typ der beiden elektrischen Maschinen mit deren Übersetzungsverhältnissen zum Getriebeeingang ist so gewählt, dass die beiden elektrischen Maschinen zumindest in einem Drehzahlbereich der Ausgangswelle des Getriebes unterschiedliche Wirkungsgrade aufweisen. Die Steuerung ist dazu vorgesehen, abhängig von der gewünschten oder aktuell vorherrschenden Drehzahl der Ausgangswelle des Getriebes die elektrischen Maschinen so anzusteuern, dass diese gemittelt mit einem möglichst optimalen Wirkungsgrad betrieben werden. Die beiden mechanisch miteinander gekoppelten elektrischen Maschinen werden je nach Betriebssituation unterschiedlich angesteuert, so dass stets die elektrische Maschine mit dem aktuell besseren Wirkungsgrad einen größeren Anteil am Antrieb leistet. Die Maschine mit dem geringeren Wirkungsgrad treibt dann weniger an oder wird mitgeschleppt, sodass eine wirkungsgradgünstige Verteilung erreicht wird. Die elektrische Maschine mit dem im Betriebspunkt höheren Wirkungsgrad kann durchaus weniger Leistung beisteuern, bedingt dadurch, dass der hohe Wirkungsgrad nur bei geringer Last in diesem Punkt erreichbar ist. Die resultierende, gewichtete Summe der Wirkungsgrade ist entscheidend, $\frac{P_1}{P_{ges}}\ast \eta \left(M,n\right)+\frac{P_2}{P_{ges}}\ast \eta \left(M,n\right)={\eta }_{resultierend}.$

A drive system, in particular for a vehicle, is proposed comprising

• - a first electrical machine with a first output shaft,
• - a second electrical machine with a second output shaft,
• - a transmission which is connected to the first output shaft and the second output shaft and has at least one output shaft,

wherein the transmission mechanically permanently couples the first output shaft and the second output shaft to one another. It is provided that the transmission ratio between the rotor shaft of the first electrical machine and the transmission input differs from the transmission ratio between the rotor shaft of the second electrical machine and the transmission input and a control is provided which controls the two electrical machines mechanically coupled to one another independently of one another. in particular activated or deactivated. The subject matter of the invention is an electrical drive system for vehicles, in which a first electrical machine and a second electrical machine jointly drive an output shaft of a transmission. The two electric machines are coupled to one another via a gearbox and run permanently synchronously. There is a fixed transmission ratio between the rotor shaft of the first electrical machine and the transmission input. The transmission input is formed by the element of the transmission, which is in operative connection with the output shafts of the electrical machines. For example, the transmission input can be formed by a differential basket of a transmission designed as a differential. In the same way, there is a fixed transmission ratio between the rotor shaft of the second electrical machine and the transmission input. According to the invention, the two transmission ratios of the rotor shaft of the two electrical machines to the transmission input are designed differently. The transmission ratio of the first electrical machine can be designed to be longer than the transmission ratio of the second electrical machine. The reverse case is also part of the invention. According to the invention, a control is also provided which controls the two electrical machines independently of one another, but depending on the operating situation. According to the invention, two electrical machines are permanently coupled to one another by means of a transmission. The translation from the rotor shaft of each electrical machine to the output shaft of the gearbox is constant and unchangeable. However, the gear ratios differ from the rotor shaft to the output shaft of the gearbox between the two electrical machines. The rotor shaft of the first electrical machine is thus compared to the rotor shaft of the second electrical machine, based on the output shaft of the gearbox, translated differently. The combination of the embodiment or type of the two electrical machines with their transmission ratios to the transmission input is selected such that the two electrical machines have different efficiencies at least in one speed range of the output shaft of the transmission. The control is provided to control the electrical machines as a function of the desired or currently prevailing speed of the output shaft of the transmission in such a way that, averaged, they are operated with the best possible efficiency. The two mechanically coupled electrical machines are controlled differently depending on the operating situation, so that the electrical machine with the currently better efficiency always makes a larger share of the drive. The machine with the lower efficiency then drives less or is dragged along, so that an efficient distribution is achieved. The electrical machine with the higher efficiency at the operating point can certainly contribute less power, due to the fact that the high efficiency can only be achieved at this point with a low load. The resulting, weighted sum of the efficiencies is decisive, $\frac{{\mathrm{P.}}_1}{{\mathrm{P.}}_{Ges}}\ast \eta \left(\mathrm{M.},n\right)+\frac{{\mathrm{P.}}_2}{{\mathrm{P.}}_{Ges}}\ast \eta \left(\mathrm{M.},n\right)={\eta }_{resultierend}.$

In one embodiment it is provided that the transmission is designed as a differential, in particular as an open bevel gear differential, and the first output shaft and the second output shaft are in a fixed transmission with a differential cage in operative connection. In this embodiment, the transmission is designed as a differential, which has two output shafts, which are each provided for driving a wheel on the same axle of a vehicle. The two output shafts of the two electrical machines are firmly coupled to one another by a differential cage, which is part of the differential. An open bevel gear differential is particularly suitable as a transmission in a drive system. However, the invention is not restricted to this embodiment; rather, different types of transmissions can be used in connection with the two electrical machines that are firmly coupled to one another.

In a further embodiment it is provided that the first electrical machine and the second electrical machine are formed by different types of electrical machines and have different efficiency maps. The two electrical machines are preferably designed differently from one another and are formed by different types. The type of electrical machine can be understood to mean, for example, its functional principle, for example asynchronous machine or synchronous machine. However, different types of electrical machines can also be understood to mean machines with the same functional principle but different performance or size. The different types of electrical machines have different efficiency maps. This means that the first electrical machine has its optimal efficiency in a different range than the second electrical machine. Alternatively, the efficiency maps can also differ from one another according to the gear ratios of the electrical machines to the transmission input. These efficiency maps, which differ from one another, make it possible to use the electrical machine that currently has the better efficiency to drive the at least one output shaft of the transmission, depending on the current operating state of this output shaft. Depending on the situation, however, both electrical machines can be used simultaneously to drive the output shaft. Compared with the provision of a single electrical machine, in the present drive system it is possible to choose between two electrical machines when driving, whereby a significantly higher degree of efficiency can be achieved than with known drive systems. Alternatively, it is also possible to use two identical electrical machines of the same type. Different efficiency maps can also be achieved when using two identical electrical machines through different transmission ratios to the transmission input.

It is also provided that the first electrical machine is designed as a permanently excited synchronous machine and the second electrical machine is designed as an asynchronous machine. In this embodiment, the two electrical machines are based on different functional principles. An asynchronous machine has high efficiencies at medium to high speeds in combination with low to medium torque loads. A permanent magnet synchronous machine has high levels of efficiency at low and medium speeds in combination with a high torque load. The efficiency maps of the electrical machines therefore differ significantly from one another.

In a further embodiment it is provided that the optimum efficiency of the first electrical machine is at a lower speed and a higher torque than the optimum efficiency of the second electrical machine. In this embodiment, the areas of high or optimal efficiency of the two electrical machines are arranged in different operating situations. Accordingly, the two electrical machines can be controlled according to the requirement of the operating state of the output shaft of the transmission so that the electrical machine always takes over the entire drive or at least a larger part of the drive with the better efficiency for this operating state.

In one embodiment it is provided that the two electrical machines are designed identically, the transmission ratios of the electrical machines to the transmission input differing. In this embodiment, two identical electrical machines are used, which, however, differ in their transmission ratio to the transmission input. In this way, a combination of different efficiency chain fields can be implemented in a cost-effective manner using two electrical machines designed as lightweight parts.

A vehicle with at least one drive system according to one of the previously described embodiments is also proposed, the drive system driving a drive axle via its output shaft. A vehicle according to the invention comprises a drive system for driving a vehicle axle. It is particularly advantageous in a vehicle according to the invention that an efficiency-optimized electric drive takes place via only one drive axle and the second axle of the vehicle, in particular the steering of the axle of the vehicle, is not provided with a drive, which reduces the effort and complexity compared to one over two Axles driven vehicle significantly reduced.

In addition, the use of a drive system according to one of the embodiments described above is proposed as a drive system for a vehicle, in particular in a purely electrically driven vehicle or a hybrid vehicle. A drive system according to one of the embodiments described above is particularly suitable for use in a vehicle, in particular in a road vehicle. Thanks to the compact design of the drive system, it can be easily integrated into vehicles and, thanks to its optimized efficiency compared to the state of the art, results in a more energy-efficient operation of a purely electrically powered vehicle or a hybrid vehicle. This more energy-efficient operation can increase the range of the vehicle.

• - Ermitteln der aktueller Betriebssituation, wobei zumindest die IST-Drehzahl und das IST-Drehmoment der Ausgangswelle ermittelt werden;
• - Ermitteln der gewünschte Betriebssituation, wobei zumindest die SOLL-Drehzahl und das SOLL-Drehmoment der Ausgangswelle ermittelt werden;
• - Ansteuerung der ersten elektrischen Maschine und der zweiten elektrischen Maschine, wobei die Differenz aus gewünschter Betriebssituation und aktueller Betriebssituation mit den Wirkungsgradkennfeldern der der elektrischen Maschinen verglichen wird und die Parameter zur Ansteuerung jeder der beiden elektrischen Maschinen so eingestellt werden, dass die beiden elektrischen Maschinen zusammen die gewünschte Betriebssituation an der Ausgangswelle bewirken und gleichzeitig beide elektrischen Maschinen in einem über beide Maschinen gemittelt optimalen Wirkungsgrad, betrieben werden.

Finally, a method for operating a drive system according to one of the embodiments described above, in particular in a vehicle, is proposed, comprising the steps

• - Determination of the current operating situation, with at least the ACTUAL speed and the ACTUAL torque of the output shaft being determined;
• - Determining the desired operating situation, with at least the target speed and the target torque of the output shaft being determined;
• - Control of the first electrical machine and the second electrical machine, the difference between the desired operating situation and the current operating situation is compared with the efficiency maps of the electrical machines and the parameters for controlling each of the two electrical machines are set so that the two electrical machines together bring about the desired operating situation on the output shaft and at the same time both electrical machines are operated with an optimal efficiency averaged over both machines.

A method according to the invention is provided for operating a drive system. The method is described in detail in connection with the operation of a drive system in a vehicle. However, the method according to the invention is not restricted to use in a vehicle, but can also be used, for example, to operate a drive system in a stationary work machine.

In a first method step, the current operating situation, using the example of the use of the method in a vehicle, the current driving situation is determined. At least the current speed and the torque applied to the output shaft are determined. In a second process step, the desired operating situation, using the vehicle as an example, the desired driving situation is determined. This determination can take place, for example, by reading out input elements such as an electronic accelerator pedal in a vehicle. The desired operating situation determined results, for example, in the desire to increase the speed and / or torque of the output shaft compared to the current operating situation. In a third method step, the difference between the parameters of the desired operating situation and the parameters of the current operating situation is determined. The result is whether the speed or torque is to be increased or reduced and the amount of such an increase or reduction. The difference formed between the desired and current operating situation is then compared with the efficiency maps of the two electrical machines. The two electrical machines are now based on this comparison with the Efficiency maps controlled. Based on this comparison, the two electrical machines can be controlled either individually or together, until the desired operating situation occurs on the output shaft. The method according to the invention is operated like a control loop, the individual method steps being repeated iteratively at very short time intervals. As a result of this repetitive processing of the individual method steps, the method according to the invention is also able to take into account external influences, for example when the vehicle drives into an incline, when operating the drive system. If the comparison of the desired operating situation with the current operating situation shows, for example, that the vehicle is to be accelerated from slow driving, this results in the requirement to provide a high torque on the output shaft at low speed. The efficiency maps now show, for example, that the first electric machine achieves its optimal efficiency at high speeds and low torques, the second electric machine achieves its optimal efficiency at low speeds and high torques, so the second electric machine is controlled according to the method according to the invention, to transfer the vehicle from the current to the desired operating state. The first electrical machine, the efficiency of which is not in the optimum range in the current driving situation or operating situation, is not or only to a small extent actuated or is dragged passively by the transmission via the coupling with the second electrical machine. In other driving situations, for example when driving at a constant speed at high speeds, the controller will control the first electrical machine either alone or for the most part after a comparison with the efficiency characteristic maps. In the case of a particularly high power requirement, which results from high speed and / or torque requirements, both electrical machines can also be activated at the same time. At least one of the two electrical machines is then not operated in an optimal efficiency range, but a greater output power is provided on the output shaft.

In one embodiment of the method it is provided that when the first electrical machine and the second electrical machine are controlled, the first electrical machine and the second electrical machine are operated simultaneously by a motor or only one of the two electrical machines is operated by a motor, the other being the electrical machines are dragged along deactivated; the first electrical machine and the second electrical machine are operated as a generator at the same time or only one of the two electrical machines is operated as a generator, the other of the electrical machines being dragged along in a deactivated manner; or one of the two electrical machines is operated as a motor and the other of the electrical machines is operated as a generator. In this embodiment, various options for controlling the two electrical machines are provided. In general, the first and the second electrical machine can be used either as a motor as a drive or as a generator to generate electricity. The two electrical machines can still be dragged passively without current, whereby neither torque nor current is generated. According to the embodiment of the method, any combinations of motor operation, generator operation and passive towing of the two electrical machines are possible. The advantages of motorized operation of one or both electrical machines according to the method have already been described above. The same advantages apply to generator operation in an analogous manner, since there are also different efficiencies of the two electrical machines with different operating parameters in generator operation. In certain operating states, the motor operation of an electrical machine in combination with a generator operation of the other electrical machine can lead to an increase in efficiency. If one of the electrical machines is switched to generator operation, torque is required for this generator operation, which must be provided by the other electrical machine in motor operation via the coupling through the transmission. A resulting increased torque requirement for the motor-operated electrical machine can lead to the efficiency of the motor-operated electrical machine being better than without the additional load that is generated by the generator operation of the other electrical machine. In addition, the electric machine operated as a generator generates electricity, which can be stored in a battery in the vehicle and used again. The generator operation of an electrical machine thus leads to an increase in the load point of the second motor-operated electrical machine.

Advantages of the invention

A drive system according to the invention has an improved efficiency compared to a drive system with only one electric machine and is mechanically much simpler than a drive system with a multi-stage gear or as a combination of several drive systems. In a drive system according to the invention, different types of electrical machines can be optimally adapted to the application in combination to be selected. The transmission ratios between the rotor shafts and the gearbox input can also be individually adapted to different applications with little effort. Furthermore, compared to a drive system with only a single electrical machine, there is increased failure safety, since there are two electrical machines and if one of these machines fails, the other machine still provides drive power. In addition, a drive system according to the invention has a small number of components. A single gear is used to translate two electrical machines to one output shaft. The drive system according to the invention can integrate different types of transmissions and can therefore also be easily adapted to different requirements. The described advantages of the invention also apply in an analogous manner to the vehicle according to the invention, the use and the method.

Figure list

Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

• 1 eine schematische Ansicht einer Ausführungsform eines erfindungsgemäßen Antriebssystems,
• 2 eine schematische Ansicht eines erfindungsgemäßen Fahrzeuges mit einer Ausführungsform eines erfindungsgemäßen Antriebssystems,
• 3 ein Wirkungsgradkennfeld eines ersten Typs einer elektrischen Maschine,
• 4 ein Wirkungsgradkennfeld eines zweiten Typs eine elektrischen Maschine.

Show it:

• 1 a schematic view of an embodiment of a drive system according to the invention,
• 2 a schematic view of a vehicle according to the invention with an embodiment of a drive system according to the invention,
• 3 an efficiency map of a first type of electrical machine,
• 4th an efficiency map of a second type an electrical machine.

Embodiments of the invention

In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference numerals, a repeated description of these elements being dispensed with in individual cases. The figures represent the subject matter of the invention only schematically.

1 shows a schematic view of an embodiment of a drive system according to the invention 1 . At the top of 1 is a first electric machine EM1 with a first output shaft 2 , at the bottom of 1 is a second electrical machine EM2 with a second output shaft 3 shown. The two output shafts 2 , 3 are fixed ratios with the gearbox 10 in operative connection. The gear 10 is designed here as an open bevel gear differential. The two output shafts 2 , 3 are permanently in engagement with the differential cage 101 of the transmission 10 . Between the rotor shaft of the first electrical machine EM1 and the differential basket 101 there is a fixed transmission ratio i1. The differential basket 101 represents the gearbox input of the gearbox here 10 between the rotor shaft of the second electrical machine EM2 and the differential basket 101 there is a fixed gear ratio i2. The gear ratios i1 and i2 differ from one another. The translation of the rotor shaft of an electrical machine EM1 , EM2 to the differential basket 101 of the transmission 10 is thus greater than the translation of the rotor shaft of the other electrical machine EM1 , EM2 to the differential basket 101 . In the embodiment shown, the ratio i1 / i2 = 0.5. The transmission ratio i2 is therefore twice as long as the transmission ratio i1. It has been found that a ratio of i1 / i2 between 0.2 and 5 is particularly suitable for good energy efficiency of a drive system according to the invention 1 is. Of course, other ratios between the transmission ratios i1 and i2 can also be selected. In the embodiment in 1 illustrated gear 10 has two output shafts 11 which extend to the left and to the right. To the left of 1 is symbolically a control S. shown, which via control lines with the first electrical machine EM1 and the second electric machine EM2 connected is. The control S. controls the two electrical machines EM1 and EM2 at. The control S. is still connected to the signal lines that the control S. Information on the operating status of the drive system 1 respectively. These signal lines are in 1 not shown.

2 shows a schematic view of a vehicle according to the invention 100 with an embodiment of a drive system according to the invention 1 . In 2 is a schematic plan view of a vehicle according to the invention 100 to see. The vehicle 100 has two axes A1 and A2 on which two wheels each R. wear. The axis shown on the left A1 represents the drive axle of the vehicle 100 represents which of a drive system according to the invention 1 is driven. The drive system 1 corresponds to the in 1 embodiment shown, the two output shafts 11 each with one wheel R. the axis A1 are connected. The second axis A2 has no drive system 1 and is provided here to steer the vehicle. Thus, in the embodiment shown, there is a vehicle 100 none from the drive system 1 resulting disturbances for the steering of the vehicle 100 . Furthermore, by providing a single drive system 1 Cost savings compared to a multi-axis drive.

3 shows an efficiency map of a first type of electrical machine EM1 , EM2 . The speed n is plotted on the horizontally aligned axis of the map shown. The torque M is plotted on the vertical axis of the characteristic diagram. The areas shown in gray levels, which show the efficiency as a function of speed n and torque M in combination with one another, are shown in different brightnesses. The darker the area shown in the map, the greater the efficiency. An operating point A in a range of very high efficiency and an operating point are exemplary B. drawn in an area of low efficiency. 3 shows a typical efficiency map of a permanently excited synchronous machine, which is a type of an electrical machine EM1 , EM2 is.

4th shows an efficiency map of a second type of electrical machine EM1 , EM2 . The map with its axes and degrees of efficiency, symbolized by different gray levels, is analogous to the map in 3 built up. Even 4th shows an operating point A in a high efficiency range and an operating point B. is in a range of low efficiency. 4th shows a typical efficiency map of an asynchronous machine, which is also a type of electrical machine EM1 , EM2 .

The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, a large number of modifications are possible within the range specified by the claims, which are within the scope of expert action.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102006057857 B4 [0003]
• DE 19841829 A1 [0004]

Claims (9)

Drive system (1), in particular for a vehicle (100), comprising - a first electrical machine (EM1) with a first output shaft (2), - a second electrical machine (EM2) with a second output shaft (3), - a transmission ( 10), which is connected to the first output shaft (2) and the second output shaft (3) and has at least one output shaft (11), the transmission (10), the first output shaft (2) and the second output shaft (3) being mechanically permanent couples with each other, characterized in that the transmission ratio (i1) between the rotor shaft of the first electrical machine (EM1) and the transmission input differs from the transmission ratio (i2) between the rotor shaft of the second electrical machine (EM2) and the transmission input and a controller ( S) is provided, which controls the two mechanically coupled electrical machines (EM1, EM2) independently of one another, in particular activated or deactivated. Drive system (1) Claim 1 , characterized in that the transmission (10) is designed as a differential, in particular as an open bevel gear differential, and the first output shaft (2) and the second output shaft (3) are in fixed transmission with a differential cage (101) in operative connection. Drive system (1) one of the preceding claims, characterized in that the first electrical machine (EM1) and the second electrical machine (EM2) are formed by different types of electrical machines and have different efficiency maps. Drive system (1) according to one of the preceding claims, characterized in that the first electrical machine (EM1) is designed as an asynchronous machine and the second electrical machine (EM2) is designed as a permanent-magnet synchronous machine. Drive system (1) according to one of the preceding claims, characterized in that the optimal efficiency of the first electric machine (EM1) is at a lower speed and a higher torque than the optimal efficiency of the second electric machine (EM2). Drive system (1) according to one of the Claim 1 or 2 , characterized in that the two electrical machines (EM1, EM2) are designed identically, the transmission ratios (i1, i2) of the electrical machines (EM1, EM2) differing from the transmission input. Vehicle (100) with at least one drive system (1) according to one of the preceding claims, wherein the drive system (1) drives a drive axle (A1, A2) via its output shaft (11). Method for operating a drive system (1) according to one of the Claims 1 until 6th , in particular in a vehicle (100), comprising the steps of determining the current operating situation, at least the ACTUAL speed and the ACTUAL torque of the output shaft (11) being determined; - Determining the desired operating situation, with at least the target speed and the target torque of the output shaft (11) being determined; - Control of the first electrical machine (EM1) and the second electrical machine (EM2), the difference between the desired operating situation and the current operating situation being compared with the efficiency maps of the electrical machines (EM1, EM2) and the parameters for controlling each of the two electrical machines (EM1, EM2) can be set so that the two electrical machines (EM1, EM2) together bring about the desired operating situation on the output shaft (11) and at the same time both electrical machines (EM1, EM2) in one over both electrical machines (EM1, EM2 ) averaged optimum efficiency. Procedure according to Claim 8 , characterized in that when the first electrical machine (EM1) and the second electrical machine (EM2) are controlled, the first electrical machine (EM1) and the second electrical machine (EM2) are operated simultaneously as a motor or only one of the two electrical machines (EM1, EM2) is operated by a motor, the other of the electrical machines (EM1, EM2) being dragged along in a deactivated manner; the first electrical machine (EM1) and the second electrical machine (EM2) are operated as a generator at the same time or only one of the two electrical machines (EM1, EM2) is operated as a generator, the other of the electrical machines (EM1, EM2) being dragged along in a deactivated manner; or one of the two electrical machines (EM1, EM2) is operated as a motor and the other of the electrical machines (EM1, EM2) as a generator.

Images