HIGH VOLTAGE TRACTION SYSTEM FOR A VEHICLE

Abstract

A high voltage traction system for a vehicle includes two independently controllable power sub-systems being a powertrain power sub-system, PPS, and a vehicle power sub-system, VPS. The PPS comprising a plurality of PPS secondary power consumers and a PPS master controller being configured to arbitrate power limits among the PPS secondary power consumers by a first arbitration logic, and the VPS comprising a plurality of VPS secondary power consumers and a VPS master controller being configured to arbitrate power limits among the VPS secondary power consumers by a second arbitration logic, different to the first arbitration logic. A master interface is between the PPS master controller and the VPS master controller enabling communication exchange between the PPS and VPS including system-shared instructions of prioritization of the PPS and VPS secondary power consumers limiting the first arbitration logic and/or the second arbitration logic in a limited state.

Claims

1. A high voltage traction system for a vehicle, the high voltage traction system having an operating voltage of 48 V or higher and comprising: two independently controllable power sub-systems being a powertrain power sub-system, PPS, and a vehicle power sub-system, VPS, having the same operating voltage of 48 V or higher, the PPS comprising a plurality of PPS secondary power consumers and a PPS master controller being configured to arbitrate power limits among the PPS secondary power consumers by a first arbitration logic, and the VPS comprising a plurality of VPS secondary power consumers and a VPS master controller being configured to arbitrate power limits among the VPS secondary power consumers by a second arbitration logic, different to the first arbitration logic; a master interface between the PPS master controller and the VPS master controller enabling communication exchange between the PPS and VPS, wherein the high voltage traction system is operable in a limited state in which the requested power of the PPS secondary power consumers and VPS secondary power consumers exceeds the available power transfer in the high voltage traction system and wherein the communication exchange comprises system-shared instructions of prioritization of the PPS and VPS secondary power consumers limiting the first arbitration logic and/or the second arbitration logic in the limited state.

2. The high voltage traction system according to claim 1, wherein the PPS and the VPS are independently controlled by the PPS master controller and the VPS master controller, respectively.

3. The high voltage traction system according to claim 1, wherein the PPS master controller and the VPS master controller are on the same hierarchy level in the high voltage traction system.

4. The high voltage traction system according to claim 1, wherein each one of the PPS master controller and the VPS master controller is configured to perform high level system functions of power monitoring and power scheduling.

5. The high voltage traction system according to claim 1, wherein the PPS master controller is configured to handle a change in the plurality of PPS secondary power consumers by changing the first arbitration logic, and the VPS master controller is configured to handle a change in the plurality of VPS secondary power consumers by changing the second arbitration logic, wherein the communication exchange via the master interface is remained unaffected.

6. The high voltage traction system according to claim 1, wherein the master interface is configured to exchange information of intended power usage of the plurality of PPS secondary power consumers and VPS secondary power consumers, such that the PPS master controller is informed of the intended power usage of VPS secondary power consumers and the VPS master controller is informed of the intended power usage of the PPS secondary power consumers, and wherein the master interface is configured to use the exchanged information of intended power usage together with the system-shared instructions of prioritization to limit the first arbitration logic and/or the second arbitration logic and to decide when and which of the PPS and VPS secondary power consumers that is to be powered.

7. The high voltage traction system according to claim 1, wherein the limited state comprises a state in which the high voltage traction system is connected to the grid.

8. A method for operating a high voltage traction system of a vehicle, the high voltage traction system having an operating voltage of 48 V or higher and comprising two independent power sub-systems being a powertrain power sub-system, PPS, and vehicle power sub-system, VPS, having the same operating voltage of 48 V or higher, the PPS comprising a plurality of PPS secondary power consumers and a PPS master controller configured to arbitrate power limits among the PPS secondary power consumers by a first arbitration logic, the VPS comprising a plurality of VPS secondary power consumers and a VPS master controller configured to arbitrate power limits among the VPS secondary power consumers by a second arbitration logic different to the first arbitration logic, and a master interface between the PPS master controller and the VPS master controller enabling communication exchange between the PPS and VPS, the method comprising: operating the high voltage traction system in a limited state in which the requested power of the PPS secondary power consumers and VPS secondary power consumers exceeds the available power transfer in the high voltage traction system, exchanging communication via the master interface including system-shared instructions of prioritization of the PPS and VPS secondary power consumers limiting the first arbitration logic and/or the second arbitration logic in the limited state.

9. The method according to claim 8, comprising: independently controlling the PPS and VPS by the PPS master controller and the VPS master controller, respectively.

10. The method according to claim 8, comprising: performing a change in the plurality of PPS secondary power consumers by changing the first arbitration logic by means of the PPS master controller, performing a change in the plurality of VPS secondary power consumers by changing second arbitration logic by means of the VPS master controller, wherein the step of exchanging communication via the master interface is remained unaffected.

11. The method according to claim 8, wherein operating the high voltage traction system in a limited state comprises operating the high voltage traction system in a state in which the high voltage traction system is connected to the grid.

12. A vehicle comprising a high voltage traction system according to claim 1.

13. A control unit for operating a high voltage traction system of a vehicle, the control unit being configured to perform the method according to claim 8.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples. In the drawings:

[0056] FIG. 1 is a schematic side view of a vehicle comprising a high voltage traction system in accordance with example embodiments of the invention,

[0057] FIG. 2 is a schematic view of a high voltage traction system in accordance with an example embodiment of the invention, and

[0058] FIG. 3 is a flowchart illustrating the steps of a method in accordance with example embodiments of the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

[0059] With reference to FIG. 1, a vehicle 1, here embodied as a heavy duty truck 1, is disclosed for which a method and a high voltage traction system 30 of a kind disclosed in the present invention is advantageous. However, the method, and a high voltage traction system 30 may as well be implemented in other types of vehicles, such as in busses, light-weight trucks, passenger cars, marine applications (e.g. a vessel) etc. The vehicle 1 is an electric vehicle, such as a full electric vehicle or a hybrid, comprising at least one electric machine 10, a powertrain power subsystem, PPS, 40 comprising energy storage or energy transformation devices, typically batteries or fuel cells, 41, 42, 43 arranged and configured to power the electric machine 10. The vehicle 1 further comprises at least one electrically driven auxiliary equipment 52, e.g. being a heater or a tool, powered by a vehicle power subsystem VPS, 50. The vehicle 1 typically further comprises other parts of the powertrain such as transmission, drive shafts and wheels (not shown in detail in FIG. 1). The electric machine 10 is typically controlled by a control unit, e.g. being comprised in an ECU of the vehicle 1.

[0060] FIG. 2 schematically illustrates a high voltage traction system 130 for a vehicle, such as e.g. vehicle 1 of FIG. 1. The high voltage traction system 130 comprises two independently controllable power sub-systems 140, 150 being a powertrain power sub-system, PPS, 140 and vehicle power sub-system, VPS, 150. Typically, the PPS 140 and VPS 150 have the same operating voltage, e.g. 600 V. Moreover the PPS 140 comprises a plurality of PPS secondary power consumers 142, 144, 146 and a PPS master controller 148 being configured to arbitrate power limits among the PPS secondary power consumers 142, 144, 146 by a first arbitration logic. Correspondingly, the VPS 150 comprises a plurality of VPS secondary power consumers 152, 154, 156 and a VPS master controller 158 being configured to arbitrate power limits among the VPS secondary power consumers 152, 154, 156 by a second arbitration logic, different to the first arbitration logic. Thus, the PPS 140 and the VPS 150 are independently controlled by the PPS master controller 148 and the VPS master controller 158, respectively. Each one of the PPS master controller 148 and the VPS master controller 158 is configured to perform high level system functions of power monitoring and power scheduling related to their respective secondary power consumers. Moreover, the high voltage traction system 130 comprises a master interface 160 between the PPS master controller 148 and the VPS master controller 158 enabling communication exchange between the PPS 140 and VPS 150. As also shown in FIG. 2, the PPS master controller 148 is configured to control a charging system 149 connected to the grid 120 for providing power transfer to the high voltage traction system 130. For example, at least one of the PPS secondary power consumers 142, 144, 146 is a battery 146 or a battery pack 146, being chargeable by the grid 120. According to another example, at least one of the VPS secondary power consumers 152, 154, 156 is an auxiliary equipment 156, configured to be powered by the battery 146 or the grid 120.

[0061] Typically, during operation of the vehicle, the high voltage traction system 130 is subject to external and internal power transfer. For example, in a vehicle condition or vehicle operation in which the battery 146 is to be charged, the PPS master controller 148 controls the power transfer from the grid 120, via the charging system 149 to the battery 146. In another vehicle condition or vehicle operation in which an auxiliary action is to be performed, the VPS master controller 158 controls the power transfer from the grid 120, or the battery 146, to the auxiliary equipment 156. In operating states with sufficient power transfer for satisfying the secondary power consumers of the PPS 140 and the VPS 150, the high voltage tractions system 130 may be referred to as being operated in an unlimited state. Thus, in such state, there is enough power, or sufficient power transfer possibilities, for satisfying the need of the PPS 140 and VPS 150. Thus, each one of the PPS 140 and VPS 150 may be operated based on the first and second arbitration logic, respectively, without any external restrictions. However, in operating states with insufficient power transfer for satisfying the secondary power consumers of the PPS 140 and the VPS 150, the high voltage traction system 130 may be referred to as being operated in a limited state. Thus, in the limited state, the requested power of the PPS secondary power consumers 142, 144, 146 and the VPS secondary power consumers 152, 154, 156 exceeds the available power transfer in the high voltage traction system 130. The limited state may e.g. be a state in which the high voltage traction system 130 is connected to the grid 120.

[0062] The communication exchange between the PPS 140 and VPS 150, or between the PPS master controller 148 and the VPS master controller 158, via the master interface 160 comprises system-shared instructions of prioritization of the PPS and VPS secondary power consumers 142, 144, 146, 152, 154, 156. The system-shared instructions of prioritization limits the first arbitration logic and/or the second arbitration logic in the limited state. That is, in the limited state in which the requested power of the PPS secondary power consumers 142, 144, 146 and the VPS secondary power consumers 152, 154, 156 exceeds the available power transfer in the high voltage traction system 130, the system-shared instructions of prioritization decides which of the PPS and VPS secondary power consumers 142, 144, 146, 152, 154, 156 that is to be prioritised. Thus, the PPS master controller 148 and the VPS master controller 158 are typically on the same hierarchy level in the high voltage traction system 130, and the system-shared instructions of prioritization governs the power transfer to and from the PPS and VPS secondary power consumers 142, 144, 146, 152, 154, 156 in the limited state.

[0063] As the PPS 140 and VPS 150 are independently controlled by their respective master controller 148, 158, the PPS 140 and VPS 150 may be designed and developed independently of each other and still being able to operate in the limited state without being adapted to be controlled by a separate master controller (such as an overall master controller). For example, the PPS master controller 148 may be configured to handle a change in the plurality of PPS secondary power consumers 142, 144, 146 (for example the disconnection of a battery 146, or the addition of a new battery) by changing the first arbitration logic. Correspondingly, the VPS master controller 158 is configured to handle a change in the plurality of VPS secondary power consumers 152, 154, 156 (for example the disconnection of an auxiliary equipment, or the addition of a new auxiliary equipment) by changing the second arbitration logic. Thus, the communication exchange via the master interface 160 may remained unaffected of the individual changes of the PPS 140 and VPS 150.

[0064] The master interface 160 may for example be configured to exchange information of intended power usage of the plurality of PPS secondary power consumers 142, 144, 146 and VPS secondary power consumers 152, 154, 156, such that the PPS master controller 148 is informed of the intended power usage of VPS secondary power consumers 152, 154, 156 and the VPS master controller 158 is informed of the intended power usage of the PPS secondary power consumers 142, 144, 146. For example, the VPS master controller 158 may receive power information of the battery or batteries of the PPS 140. Moreover, the master interface 160 may be configured to use the exchanged information of intended power usage together with the system-shared instructions of prioritization to limit the first arbitration logic and/or the second arbitration logic and to decide when and which of the PPS and VPS secondary power consumers 142, 144, 146, 152, 154, 156 that is to be prioritised or powered.

[0065] In FIG. 2, the double pointing arrows are referring to communication exchange between the components of the high voltage traction system 130, rather than power transfer. Power transfer is typically carried out directly between a PPS secondary power consumers, such as e.g. a battery 146, and a PPS or VPS secondary power consumer, such as e.g. an auxiliary equipment.

[0066] A method for operating a high voltage traction, such as the high voltage traction system 130 of FIG. 2, will now be described in more general terms with additional reference to FIG. 3. FIG. 3 is a flowchart describing the steps of such method. The method may e.g. be implemented in a control unit, or ECU, of the vehicle. The high voltage traction system being subject to the method described with reference to FIG. 3 comprises two independent power sub-systems being a powertrain power sub-system, PPS, and a vehicle power sub-system, VPS, the PPS comprising a plurality of PPS secondary power consumers and a PPS master controller configured to arbitrate power limits among the PPS secondary power consumers by a first arbitration logic. Correspondingly, the VPS comprises a plurality of VPS secondary power consumers and a VPS master controller configured to arbitrate power limits among the VPS secondary power consumers by a second arbitration logic different to the first arbitration logic. The high voltage traction system further comprises a master interface between the PPS master controller and the VPS master controller enabling communication exchange between the PPS and VPS.

[0067] In a first step S10, the high voltage traction system is operated in a limited state in which the requested power of the PPS secondary power consumers and VPS secondary power consumers exceeds the available power transfer in the high voltage traction system. The limited state may e.g. be a state in which the high voltage traction system is connected to the grid. Thus the limitation in the available power transfer may be originating from power limitations from and to the grid, power limitations from and to the PPS, and power limitations to and from the VPS. Typically, the first step comprises operating the PPS and VPS at the same operating voltage.

[0068] In a second step S20, exchanging communication via the master interface is performed, the exchanged information includes system-shared instructions of prioritization of the PPS and VPS secondary power consumers limiting the first arbitration logic and/or the second arbitration logic in the limited state. Thus, the PPS and the VPS are independently controlled by the PPS master controller and the VPS master controller, respectively, and only the system-shared instructions of prioritization may influence the operation of the PPS and VPS by means of their respective master controller. That is, the PPS is not controlled by the VPS master controller, and the VPS is not controlled by the PPS master controller. Typically each one of the PPS master controller and the VPS master controller is performing high level system functions of power monitoring and power scheduling.

[0069] In a third step S30, a change in the plurality of PPS secondary power consumers is performed by changing the first arbitration logic by means of the PPS master controller. For example, an additional PPS secondary power consumer may be added to the PPS.

[0070] In a fourth step S40, a change in the plurality of VPS secondary power consumers is performed by changing the second arbitration logic by means of the VPS master controller. For example, an additional VPS secondary power consumer may be added to the VPS, or a VPS secondary power consumers is replaced with another VPS secondary power consumer.

[0071] Thus, as the change of PPS secondary power consumers and/or VPS secondary power consumers are handled by the PPS master controller and the VPS master controller, respectively, the communication exchange via the master interface may remained unaffected. Only the system-shared instructions of prioritization may be updated based on the changes.

[0072] It should be noted that the naming of the steps not necessarily, but might according to at least one example embodiment, relate to the order in which the steps are carried out, unless explicitly stated otherwise. One or more of the steps may be combined and carried out simultaneously and/or one or more of the steps may be omitted.

[0073] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

[0074] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed inventive concept, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0075] It should be understood that the master controller, or control units, may refer to a combination of analog and digital circuits, and/or one or more processors configured with program software and/or firmware, e.g. stored in a memory, that when executed by the one or more processors perform the one or more of the steps described in conjunction with FIG. 3. One or more of these processors, as well as the other digital hardware, may be included in a single ASIC (Application-Specific Integrated Circuitry), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a SoC (System-on-a-Chip).