WO2010149439A2

WO2010149439A2 - Device for supplying power to an electric drive for a motor vehicle

Info

Publication number: WO2010149439A2
Application number: PCT/EP2010/057023
Authority: WO
Inventors: Eckart Nipp; Thomas Schneider
Original assignee: Robert Bosch Gmbh
Priority date: 2009-06-26
Filing date: 2010-05-21
Publication date: 2010-12-29
Also published as: DE102009027220A1; WO2010149439A3

Abstract

The invention relates to a device for supplying power to an electric drive for a motor vehicle, comprising a power supply network that is connected to the drive and comprises a fuel cell unit and at least one energy storage, wherein the fuel cell unit and the energy storage are coupled. According to the invention, the power supply network comprises a first and a second power supply network. The first power supply network comprises a first converter, which is arranged between the fuel cell unit and the drive. The second power supply network comprises a second converter, which is arranged between the energy storage and the drive. The first converter is decoupled from the second converter.

Description

description

title

Device for supplying an electric drive for a motor vehicle

The invention relates to a device for supplying an electric drive for a motor vehicle with a power network which is connected to the drive and has a fuel cell unit and at least one energy store, wherein the fuel cell unit and the energy store are coupled according to the preamble of claim 1.

State of the art

From the document DE 102 23 1 17 A1 it is known that hybrid for the electrical supply of an electric drive for a motor vehicle

Energy supply systems consisting of a fuel cell unit and an energy storage can be used. In this case, an energy store is connected via a DC / DC converter in parallel with the active two-terminal of the fuel cell unit, which is responsible for the supply of an electric drive. Other circuit options are that the energy storage is connected directly to the electric drive of the motor vehicle. In this case, the fuel cell unit is connected via a DC / DC converter in parallel with the two-pole of the energy store. Another possibility is to precede each of the fuel cell unit and the energy storage a DC / DC converter, which then connected in parallel as an electrical supply of the

Drive serve. All illustrated supply concepts require at least one DC / DC converter to perform the desired energy exchange between the fuel cell unit and energy storage. This is because the fuel cell unit and the energy store have different voltage levels in hybridized operation. The disadvantage here is that both energy networks are electrically connected. Thereby can the two energy networks are not built and dimensioned independently of each other.

Disclosure of the invention

It is the object of the present invention to provide a simplified structure for supplying an electric drive for a motor vehicle, in order to achieve a cost reduction and at the same time functional advantages of the overall structure.

To solve this problem, a device with the features of claim 1 is proposed, in particular of the characterizing part. In the dependent claims preferred developments are carried out. The features mentioned in the claims and in the description may be essential to the invention, individually or in combination.

According to the invention, the energy network has a first and a second energy network, the first energy network has a first converter, which is arranged between the fuel cell unit and the drive, the second energy network has a second converter which is disposed between the second energy network

Energy storage and the drive is arranged, and the first inverter is decoupled from the second inverter.

It is particularly advantageous that energy is transferred from the first energy network to the second energy network via the drive, in particular during the

Drive of the motor vehicle. Thus, the fuel cell unit and the energy storage can be connected separately to the drive. A power DC / DC converter, which is normally required between the fuel cell unit and the energy storage for energy transfer, is eliminated. The fuel cell unit and the energy storage are connected directly to the drive.

It is likewise provided according to the invention that energy can be transferred from the first energy network to the second energy network via a magnetic alternating field. For a contactless inductive energy transfer is possible.

An electrical connection between the first power grid and the second Energy network can be omitted. In an extreme energy extraction of a strand of energy, which can lead to an undesirable and / or unexpected increase in temperature, in this case advantageously a thermal decoupling between the energy networks available. Accordingly, mechanical contacts between the energy strings can be dispensed with. This also gives a low-maintenance construction. In addition, the voltage levels of the two energy networks can largely be selected independently of one another, which means greater overall degrees of freedom in the design of the networks, without any further effort having to be operated.

Furthermore, it may be advantageous that the drive has a first and a second winding system, which are arranged on a common stator, wherein the first winding system is coupled to the first inverter and the second winding system to the second inverter. Through this

Arrangement, it is possible to integrate the two separate winding systems in the common electric drive. Thus, the electric machine can act either as a drive or generator and so exchange energy on the separate windings in the common stand. Another advantage of this arrangement is that, even when the drive is stationary, energy can be transmitted from the fuel cell unit to the energy store via the stator windings. The stator of the drive acts as a transformer. As a possible winding system, a three-phase system can be used, as is typically used in traction drives. Of course, the concept can also be applied to other phase numbers.

Likewise, the wiring is in no way limited to a star connection, but can also be used with delta circuits and other phase connections. A solution of a winding system can be considered from a classic grooved stator with a two-layer winding. The two layers are then used for both winding systems. Of the

Manufacturing cost of such a winding arrangement is the same as in a classic two-layer winding, except that twice as many connections are led to the outside. This described winding arrangement is only one possible embodiment. Alternatively, z. B. four layers are used, the two winding systems are alternately inserted in each case. This increases the magnetic coupling. It is possible To arrange the winding systems in phase, so that many components of the motor control can be shared for both converters. In addition, a common sensor for the rotor angle position detection can be used. At a standstill of the vehicle and accordingly a stoppage of the drive, a pure

Alternate field are generated. This offers the advantage that the electrical machine generates no torque despite energization. To reduce rotor losses, the angular frequency ω can be chosen low. A particularly high angular frequency ω makes it possible to generate a high proportion of stray flux that does not penetrate the rotor.

It is also conceivable that the drive has a first stator and a second stator, which are coupled via a common rotor, wherein the first stator is arranged on the first inverter and the second stator on the second converter. In this case, the stator windings are arranged displaceably, so that any overlaps between the stator windings and the rotor are adjustable. It is also possible that both stator windings have different radii and can be moved into each other. So that the air gap in the stator with the larger radius does not become too large, special flux-conducting components are conceivable which minimize the resulting air gap. By this arrangement, the coupling of the two winding systems can be adjusted in the way it is needed for the energy exchange between the fuel cell unit and the energy storage.

It can be advantageous that at least one first electrical component is arranged on the fuel cell unit and a second electrical component is arranged on the energy store. This provides the ability to ensure the electrical supply of consumers with high power consumption, as z. B. in a compressor for the cathode air supply of

Fuel cell unit is needed. In addition, through the use of decoupled components with the same functionality, a redundancy of components of the overall system can be created in order to obtain the highest possible availability. These can then be attached separately to the fuel cell unit and the energy store. Likewise, it may be possible that the relevant electrical components to a first smaller variant and a second smaller variant are divided, wherein the first smaller variant arranged on the fuel cell unit and the second smaller variant can be arranged on the energy storage. This makes it possible to ensure the energy supply. Furthermore, it is conceivable to additionally mechanically couple the two smaller variants. This could for example be the case with two compressors, which are coupled by a pneumatic impeller.

It is also provided according to the invention that the drive has a first and a second electric machine, in particular that the first machine is separated from the second machine. For this purpose, advantageously, the first and the second electric machine have a common shaft. The first and the second electric machine can act as a motor or generator. Energy can be exchanged via the common wave. Due to the separation of the two electrical machines, it is thus possible that different electrical machines with different performance data are used. Also, the structure of the two electrical machines can be designed differently. Accordingly, the first and second inverters required for the electric machines can also be designed differently and based on different performance data, since these are decoupled from each other. This allows the greatest possible scope for the construction of the device for supplying an electric drive. For a motor vehicle, for example, it is possible to arrange the first electric machine to the front axle of the motor vehicle and to couple the second electric machine to the rear axle of the motor vehicle. The first electric machine could then be a motor which is supplied with energy via a first converter by a fuel cell unit and thus drives the motor vehicle. The second electric machine could in this case be a generator which supplies the energy store via a second converter with energy during the drive of the motor vehicle. Since the two electrical machines can be motor and / or generator, it goes without saying that the second electric machine on the rear axle of the vehicle can also act as a motor which is supplied with energy via the energy store. Advantageously, the first energy network is galvanically isolated from the second. This will allow the two energy grids to be designed and designed independently. This can bring cost advantages during the planning phase of the device for supplying an electric drive. In addition, a galvanic isolation allows that in the event of an electrical failure of one energy network, the other remains unaffected. Additional safety measures such as the attachment and assignment of electrical fuses between the two energy networks can be omitted.

It is also conceivable that a power transmission from the first power grid to the second power grid via an electrical connection. This creates the opportunity to use known electrical and electronic methods for coupling the two energy networks. Also, a coupling of the fuel cell unit and the energy storage via a

Three-phase system can be made possible. Also, the installation of a bidirectional DC / DC converter between the two energy networks allows energy transfer from the fuel cell unit to the energy storage even when the drive is stopped. High-power electrical components can be connected to the energy storage so that they can be powered by an inactive drive. It is also possible to form the DC / DC converter unidirectionally, so that only energy can be transmitted from the fuel cell unit to the energy store. According to the invention it is further provided that the periphery for the operation of a fuel cell system optionally of the energy storage and / or the

Fuel cell unit is supplied. This makes it possible that in each operating state of the device for supplying an electric drive, the periphery is optimally supplied with energy. In addition, any failures of the energy storage or the fuel cell unit can be bridged by the other intact unit.

Further advantages, features and details of the invention will become apparent from the following description in which several embodiments of the invention are described in detail with reference to the drawings. In this case, those mentioned in the claims and in the description Characteristics individually individually or in any combination essential to the invention. Show it:

1 shows a schematic structure of two energy networks for the energetic supply of a drive,

FIG. 2 shows a schematic structure of a winding system,

FIG. 3 shows a schematic view of two separate stands with a rotor,

Figure 4 shows a schematic structure for supplying an electrical

Drive with two components to be supplied,

Figure 5 shows a schematic structure of two separate electrical

Machinery,

Figure 6 shows a schematic structure of two electrical with a

Shaft connected machines,

Figure 7 shows a schematic structure of a supply of an electric drive to be supplied with peripherals and attached DC / DC converter.

FIG. 1 shows a first energy network 20 with a fuel cell unit 21 and a first converter 22, wherein the first energy network 20 is connected to a drive 10. A second energy network 30 with an energy store 31 and a second converter 32 is also electrically connected to the drive 10. The first converter 22 and the second converter 32 can work on separate winding systems in the electric drive 10. This allows energy to be exchanged via the separate windings in a common stand. In addition, the first inverter 22 is decoupled from the second inverter 32.

FIG. 2 shows a schematic structure of a winding system. A first

Power network 20 with a fuel cell unit and a first inverter 22nd is coupled to a first winding system 23. A second energy network 30 with a second converter 32 and an energy store 31 is coupled to a second winding system 33. It is shown here a three-phase system as it can be used in the drive 10. Of course, the concept can also be applied to other phase numbers. Likewise, it is in no way limited to the illustrated star connection, but can also be used with delta circuits and other phase connections. The first winding system 23 is galvanically isolated from the second winding system 33. By decoupling the converters 22, 32, which allow a conversion from DC to AC voltages and vice versa, the structure of the two converters 22, 32 can be different, since they can be dimensioned independently of each other.

Figure 3 shows a schematic structure of a first stator 24 and a second stator 34, which are energetically coupled to each other by a common rotor 40. The first stator 24 is in this case connected to the first converter 22, which in turn is coupled to the fuel cell unit 21, which thus form the first energy network 20. The second stator 34 is connected to the second converter 32, which in turn is coupled to the energy store 31 and form the second energy network 30. The two separate stands 24, 34 are galvanically separated from the rotor 40. There are thus arbitrary overlaps between the individual uprights 24, 34 and the rotor 40 adjustable. It is also possible that both stands have 24.34 different radii and can be moved into each other. So that the air gap in the stator with the larger radius does not become too large, if it covers only the rotor 40 and not the other stator, special flux-conducting components are possible, which minimize the resulting air gap.

FIG. 4 shows a schematic structure of the first energy network 20 and the second energy network 30, both of which are arranged on the drive 10. In this case, the first energy network 20 has the fuel cell unit 21 and the first converter 22. This also applies to the second energy network 30, which has the energy store 31 and the second converter 32. A first electrical component 25 is arranged directly on the fuel cell unit 21. A second electrical component 35 is connected to the energy store 31 connected. Thus, both electrical components 25, 35 can be supplied independently with electrical energy. Even if the two electrical components 25,35 have the same function within the device for supplying an electric drive 10, they can be constructed differently and dimensioned. This makes it possible to take into account the individual specific output parameters of the fuel cell unit 21 and / or the energy store 31. In addition, both electrical components 25, 35 are electrically isolated from each other, which can lead to a cost reduction compared to electrically bonded components.

5 shows a schematic structure of two separate electrical machines 1 1, 12. The first electric machine 1 1 is connected via the first inverter 22 to the fuel cell unit 21, which form the first power network 20. The second electric machine 12 is above the second

Inverter 32 electrically connected to the energy storage 31, which form the second power network 30. In this case, the first 1 1 of the second electric machine 12 is electrically isolated. Again, the electrical machines 1 1, 12 can be constructed differently and dimensioned. Thus, the two electric machines 1 1, 12 act on different axes of the vehicle. In this case, the first 1 1 and the second electric machine 12 may be a synchronous machine and / or an asynchronous machine.

FIG. 6 shows a schematic structure of a first electric machine 11 and a second electric machine 12, which are connected to one another via a common shaft 13. The energetic supply of the first electric machine 1 1 via a fuel cell unit 21, which is connected via a first inverter 22 to the first electric machine 1 1, which form the first power network 20. The energetic supply takes place for the second electric machine 12 via a

Energy storage 31, which is connected via a second inverter 32 to the second electric machine 12 and the second power network 30 form.

FIG. 7 shows a schematic structure in which the first energy network 20 is connected to the second energy network 30 by a DC / DC converter 50. In this case, the fuel cell unit 21 is connected via a DC / DC Transducer 50 is electrically connected to the energy storage 31. The fuel cell unit 21 feeds the first electric machine 1 1 via the first converter 22. The energy store 31 is connected to the second electric machine 12 via a second converter 32. Schematically, the periphery 60 is connected to the energy storage 31 here. Of course, it is also possible to connect the periphery 60 to the fuel cell unit 21. The periphery 60 may consist of, for example, a compressor, a blower, a pressure regulator, a cooling circuit, a system control, a safety monitoring and / or power electronics.

It can be seen from FIGS. 1 to 7 that a separation of a first converter from a second converter in the energy networks is provided for supplying an electric drive.

Claims

claims

1.) Device for supplying an electric drive (10) for a

Motor vehicle with an energy network, which is connected to the drive (10) and has a fuel cell unit (21) and at least one energy store (31), wherein the fuel cell unit (21) and the energy store (31) are coupled, characterized in that the power grid a first (20) and a second energy network (30), the first energy network (20) having a first converter (22) which is arranged between the fuel cell unit (21) and the drive (10), the second energy network (30) a second converter (32) which is arranged between the energy store (31) and the drive (10) and the first converter (22) is decoupled from the second converter (32).

2.) Device according to claim 1, characterized in that a

Energy transfer from the first power grid (20) to the second power grid (30) via the drive (10) takes place, in particular takes place during the drive of the motor vehicle.

3.) Device according to claim 1, characterized in that a

Energy transfer from the first energy network (20) to the second energy network (30) takes place via a magnetic alternating field.

4.) Device according to claim 1 or 3, characterized in that the

Drive (10) via a first (23) and a second winding system (33) which are arranged on a common stator, wherein the first winding system (23) on the first inverter (22) and the second winding system (33) on the second inverter (32) is coupled.

5.) Device according to one of the preceding claims, characterized in that the drive (10) via a first stator winding (24) and a second stator winding (34) which are coupled via a common rotor (40), wherein the first stator winding (24) on the first inverter (22) and the second stator winding (34) on the second converter (32) is arranged.

6.) Device according to one of the preceding claims, characterized in that at least one first electrical component (25) on the fuel cell unit (21) and a second electrical

Component (35) is arranged on the energy store (31).

7.) Device according to one of the preceding claims, characterized in that the drive (10) has a first (1 1) and a second electric machine (12), in particular that the first machine

(1 1) is separated from the second machine (12).

8.) Device according to claim 6, characterized in that the first (1 1) and the second electric machine (12) have a common shaft (13).

9.) Device according to one of the preceding claims, characterized in that the first power network (20) from the second (30) is electrically isolated.

10.) Device according to one of the preceding claims, characterized in that a transfer of energy from the first power grid (20) to the second power grid (30) via an electrical connection.

1 1). Apparatus according to claim 10, characterized in that the electrical connection via a DC / DC converter (50) between the fuel cell unit (21) and energy storage (31).

12.) Device according to claim 1 1, characterized in that the DC / DC

Transducer (50) has a uni- or bidirectional orientation.

13.) Device according to one of the preceding claims, characterized in that the periphery (60) for the operation of a fuel cell system optionally from the energy storage (31) and / or the fuel cell unit (21) can be supplied.

14.) Motor vehicle with a device for supplying an electric drive (10) according to one of the preceding claims.