Energy monitoring system for a vehicle

Abstract

The present disclosure relates to an energy monitoring system for a vehicle, a vehicle comprising such an energy monitoring system and a method for manufacturing such an energy monitoring system. The energy monitoring system comprises an on-board battery charging system, a traction voltage system and a control unit. The traction voltage system is connected to the on-board battery charging system, the control unit is configured to transfer energy stored in the traction voltage system to the on-board battery charging system in case the energy level of the traction voltage system exceeds a predetermined threshold.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an energy monitoring system for a vehicle, a vehicle comprising such an energy monitoring system, a method for manufacturing such an energy monitoring system, and a method for operating such an energy monitoring system. BACKGROUND

[0002] Electric vehicles use a power converter and a high voltage battery, which can be connected to a traction voltage system. After the traction voltage system is disconnected from the high voltage battery, the voltage of the traction voltage system (TVS) can not change from a high value (400V or 800V) to a low safety value (< 60V DC) due to a capacitor of the TVS, which is connected between the positive rail and the negative rail within the TVS. To reduce the voltage of the TVS to a safety value, a discharge system is generally applied to the traction voltage system to remove the energy stored in these capacitors.

[0003] Conventional discharge systems utilize additional components (e.g. switches and resistors) to remove and / or dissipate the energy stored in the traction voltage system. Alternatively, the electric drive (eDrive) and / or electric motor (eMotor) windings are used to consume the energy stored in the traction voltage system. The first approach requires more components, which accordingly increases the cost and weight of the system. But when applying the second approach, the discharge system connected to the eDrive and / or eMotor has to be arranged at the front or rear side of the vehicle, which can be damaged by a crash accident. SUMMARY

[0004] Therefore, there can be a need to provide an improved energy monitoring system, which facilitates an efficient discharge of energy from the traction voltage system.

[0005] This problem is solved by the subject matter of the present disclosure, wherein further embodiments are incorporated in the present disclosure. It should be noted that the aspects of the present disclosure described below apply to the energy monitoring system for a vehicle, the vehicle comprising such an energy monitoring system, the method for manufacturing such an energy monitoring system, and the method for operating such an energy monitoring system.

[0006] According to the present disclosure, an energy monitoring system for a vehicle is proposed. The energy monitoring system comprises an on-board battery charging system, a traction voltage system, and a control unit. The traction voltage system is connected to the on-board battery charging system, and the control unit is configured to transfer energy stored in the traction voltage system to the on-board battery charging system in case an energy level of the traction voltage system exceeds a predetermined threshold value.

[0007] The energy monitoring system according to the present disclosure allows for an efficient utilization of the energy stored in the traction voltage system. Thus, the energy monitoring system avoids unnecessary energy consumption and instead transfers energy to locations where it can be needed. Since the energy monitoring system uses existing components in the on-board battery charging system and the traction voltage system without any additional components, no additional costs and / or additional weight are generated. Furthermore, since the location of the on-board battery charging system is not limited, the energy monitoring system can be safely installed anywhere in the vehicle, for example, on the side of the vehicle. Thus, any damage of the energy monitoring system due to a vehicle accident can be reduced or even avoided.

[0008] The on-board battery charging system (OBC) can be configured to charge the battery system, preferably the high-voltage battery system of the vehicle, at any of a private or public charging station. The on-board battery charging system can be connected to an alternating current power source and it can convert the alternating current power into DC electrical power for charging the battery system. The on-board battery charging system can be configured to charge 400V batteries providing an output direct current (DC) voltage range of about 250V to 450V and / or 800V batteries providing an output DC voltage range of up to 850V.

[0009] The traction voltage system (TVS) can be configured for linking and distributing a high-voltage bus to a plurality of different electrical components. The traction voltage system can also be configured to balance fluctuating instantaneous power on the rails of the TVS and to stabilize the ripple current / voltage. In other words, the traction voltage system can store and / or release energy to maintain an energy balance between the electrical components. The traction voltage system can maintain the stored energy even if the TVS is disconnected from at least one electrical component.

[0010] The control unit can communicate with at least one of a vehicle electronic control unit and / or a measuring equipment inside the OBC, so that the control unit can receive a signal of the current energy level of the TVS. The control unit can then compare whether the energy stored in the traction voltage system exceeds a predetermined threshold. The predetermined threshold can be a safe energy level of the TVS. The predetermined threshold can be a predetermined safe voltage of the traction voltage system. Thus, if the detected energy level, in other words, the detected voltage of the TVS, is higher than the predetermined threshold, the control unit can initiate an energy transfer from the TVS to the on-board battery charging system to reduce the energy level of the TVS below the predetermined safe level and to utilize the excess energy.

[0011] In one embodiment, the energy monitoring system further includes an energy storage system. A traction voltage system is positioned between the on-board battery charging system and the energy storage system. The energy storage system may be a high-voltage battery pack that provides traction energy to the motor for electric vehicle propulsion. The energy storage system may be coupled to the on-board battery charging system via the traction voltage system. The traction voltage system may be connected to the energy storage system when charging the energy storage system or driving the vehicle.

[0012] However, when the energy storage system is disconnected from the traction voltage system—for example, when neither the energy storage system is being charged nor the vehicle is being driven—no energy flow may occur between the traction voltage system and the energy storage system. However, the traction voltage system may still contain electrical energy. In this case, if the voltage of the traction voltage system is higher than a predetermined voltage, the control unit can command the energy stored in the TVS to be transferred to the onboard battery charging system.

[0013] For example, the energy storage system can be powered by 400V or 800V. Even if the energy storage system is disconnected from the traction voltage system, the TVS may still contain energy. If the voltage of the traction TVS exceeds a predefined threshold, such as 60V, the control unit can transfer the energy stored in the traction voltage system to the on-board battery charging system.

[0014] In one embodiment, the control unit is configured to transfer energy from the traction voltage system to the on-board battery charging system only when the energy storage system is disconnected from the traction voltage system. In other words, energy transfer can only be performed when the traction voltage system is operatively disconnected from the energy storage system. The traction voltage system can be operatively disconnected from the energy storage system if it is not being charged or is not receiving power from it.

[0015] In one embodiment, the traction voltage system includes at least one traction capacitor. The traction capacitor can be configured to store electrical energy to balance fluctuating instantaneous power on the rails of the traction voltage system and stabilize ripple current / voltage. Therefore, the traction capacitor can store energy retained after being separated from the energy storage system.

[0016] In one embodiment, the control unit is also configured to monitor the energy level of the traction capacitor. In other words, the control unit can monitor and control the energy level of the energy stored in the traction capacitor. The energy level of the traction capacitor can be expressed as a voltage value, and it can be the same as the energy level of the traction voltage system. Therefore, the control unit can continuously monitor whether the voltage of the traction voltage system exceeds a safe energy level (i.e., a predetermined threshold).

[0017] The control unit can also communicate with the on-board battery charging system regarding the energy level of the traction capacitor and / or traction voltage system. In one embodiment, the control unit can be integrated into the on-board battery charging system. If the control unit receives information that the voltage value of the traction capacitor and / or traction voltage system is higher than a predetermined threshold and the TVS is disconnected from the energy storage system, the control unit can control the TVS to reduce its energy level below the predetermined threshold by transferring electrical energy to the on-board battery charging system.

[0018] In one embodiment, the on-board battery charging system includes a bidirectional converter unit through which energy stored in the traction voltage system is transferred to the on-board battery charging system. The bidirectional converter unit can be configured to transfer energy from the on-board battery charging system in the direction of the traction voltage system and vice versa. Therefore, the bidirectional converter unit allows the on-board battery charging system to not only charge the energy storage system from an external energy source but also receive excess energy from the traction voltage system.

[0019] In one embodiment, the bidirectional converter unit is a bidirectional DC / DC converter unit. The bidirectional DC / DC converter unit can provide energy flow in both buck and boost directions and a safe energy interface between an external energy source and an energy storage system. The bidirectional DC / DC converter unit allows traction voltage systems and / or traction capacitors to transfer energy to an on-board battery charging system by applying the boost function of the bidirectional DC / DC converter unit.

[0020] In one embodiment, the bidirectional DC / DC converter unit may include an isolated DC-DC converter. The isolated DC-DC converter may be current-isolated.

[0021] In one embodiment, the on-board battery charging system further includes at least one internal capacitor configured to store energy transferred from the traction voltage system. The energy transferred from the traction voltage system can be stored in the internal capacitor of the on-board battery charging system instead of being dissipated or unnecessarily consumed. Therefore, efficient energy use can be achieved.

[0022] In one embodiment, an internal capacitor is integrated into the power factor correction unit. The power factor correction unit can be connected to an external AC charging interface and is configured to vary the output voltage within a predetermined range. The power factor correction unit may include an internal capacitor that can store energy transferred from the traction voltage system. Typically, the internal capacitor of the power factor correction unit is large enough to eliminate or reduce voltage ripple caused by the AC power supply. Therefore, the internal capacitor arranged in the power factor correction unit can store energy transferred from the traction voltage system without the need for any additional active or passive components (e.g., switching circuits and / or resistors) to dissipate excess energy from the TVS.

[0023] In one embodiment, the power factor correction unit is configured to utilize energy stored in an internal capacitor before initiating AC charging. Before full rectification of the AC power supply begins, the energy stored in the internal capacitor of the power factor correction unit can raise the potential of the bidirectional converter unit to the rated voltage level. Additionally or alternatively, once the traction voltage system and the energy storage system are connected, the energy stored in the internal capacitor can be transferred back to the energy storage system.

[0024] In one embodiment, the on-board battery charging system is always powered. In other words, even if the energy storage system is disconnected and / or no energy is transferred to the traction voltage system when the energy level of the TVS exceeds a predetermined safe energy level, the on-board battery charging system can remain powered.

[0025] According to this disclosure, a vehicle is proposed. The vehicle includes the energy monitoring system described above. The vehicle is a battery electric vehicle or a hybrid electric vehicle.

[0026] In one embodiment, the control unit is configured to initiate energy transfer from the traction voltage system to the on-board battery charging system only when the vehicle is outside of driving and charging modes. Reverse energy transfer may be impossible if the energy storage system supplies power to or charges the motor used for electric vehicle propulsion via the on-board battery charging system. In other words, energy transfer from the traction capacitor and / or the traction voltage system to the internal capacitors of the on-board battery charging system can only be performed if the TVS is operatively disconnected from the energy storage system and the energy level of the traction voltage system exceeds a predefined threshold of a safe energy level.

[0027] According to this disclosure, a method for manufacturing an energy monitoring system is proposed. This method does not necessarily include the following in this order:

[0028] - Provide traction voltage system

[0029] - Provides onboard battery charging systems, and

[0030] - Connects the on-board battery charging system and the traction voltage system.

[0031] The control unit is configured to transfer energy stored in the traction voltage system to the on-board battery charging system when the voltage of the traction voltage system exceeds a predetermined threshold.

[0032] According to this disclosure, a method for operating an energy monitoring system in a vehicle is proposed. This method does not necessarily include, in this order:

[0033] - Receive information about the energy level of the traction voltage system.

[0034] - Disconnect the traction voltage system from the energy storage system.

[0035] - Determine whether the energy level of the traction voltage system exceeds a predetermined threshold, and

[0036] - When the energy level of the traction voltage system exceeds a predetermined threshold, the energy stored in the traction voltage system will be transferred to the on-board battery charging system.

[0037] Therefore, the energy monitoring system avoids unnecessary energy consumption and instead redirects energy to where it might be needed. Because the energy monitoring system uses existing components of the onboard battery charging system and traction voltage system without any additional components, it incurs no additional cost and / or weight.

[0038] It should be noted that, regardless of the aspects involved, the above embodiments can be combined with each other. Therefore, the method can be combined with structural features, and similarly, the system can be combined with the features described above concerning the method.

[0039] These and other aspects of this embodiment will become apparent and explained with reference to the embodiments described below. Attached Figure Description

[0040] Exemplary embodiments will now be described with reference to the accompanying drawings.

[0041] Figure 1 An embodiment of an energy monitoring system according to this disclosure is illustrated schematically and exemplary.

[0042] Figure 2 A flowchart illustrating, and exemplarily demonstrating, a method for operating an energy monitoring system according to the present disclosure is shown. Detailed Implementation

[0043] Figure 1An energy monitoring system 1 for a vehicle is shown. The vehicle may be an electric vehicle, such as a battery electric vehicle (EBV), a plug-in hybrid electric vehicle (PHEV), and / or a hybrid electric vehicle (HEV).

[0044] The energy monitoring system 1 includes an on-board battery charging system (OBC) 20, a traction voltage system (TVS) 30, an energy storage system 40, and a control unit 21. The traction voltage system 30 is connected to the on-board battery charging system 20 and may also be coupled to the energy storage system 40. The energy storage system 40 may be a high-voltage battery pack that can provide electrical energy to the motor used for propulsion of the electric vehicle and auxiliary loads connected to the TVS 30.

[0045] The on-board battery charging system 20 can be configured to charge the energy storage system 40. The on-board battery charging system 20 includes a power factor correction unit 22. The power factor correction unit 22 is connected to an external AC power source 10 and is configured to change the output voltage within a predetermined range. The power factor correction unit 22 includes at least one internal capacitor 24, which is large enough to eliminate or reduce voltage ripple caused by oscillations of the external AC power source 10.

[0046] The on-board battery charging system 20 also includes a bidirectional converter unit 23, preferably a bidirectional DC / DC converter unit. The bidirectional DC / DC converter unit 23 can provide energy flow in both buck and boost directions, as well as a safe energy interface between the external AC power supply 10 and the energy storage system 40.

[0047] The traction voltage system 30 includes at least one traction capacitor 31 configured to store electrical energy to balance fluctuating instantaneous power on the track of the TVS and to stabilize ripple current / voltage between the various electrical components connected thereto. The traction voltage system 30 is connected to the energy storage system 40 during charging or supplying power to the energy storage system 40. The traction capacitor 31 may contain electrical energy even after the traction voltage system 30 is operatively disconnected from the energy storage system 40, for example, after charging the energy storage system or driving the vehicle.

[0048] The control unit 21 of the energy monitoring system 1 monitors the energy level of electrical energy stored in the traction capacitor 31, especially when the traction voltage system 30 is disconnected from the energy storage system 40. The control unit 21 is integrated into the on-board battery charging system 20 and communicates with at least one of the vehicle electronic control unit and / or measuring equipment within the OBC to receive signals indicating whether the energy stored in the traction voltage system 30 exceeds a predetermined threshold. The energy level of the traction voltage system 30 can be expressed as a voltage value. The predetermined threshold can be a safe energy level for the traction voltage system 30.

[0049] If the energy level of the traction capacitor 31 or the traction voltage system 30 exceeds a predetermined threshold, the control unit 21 prompts the on-board battery charging system 20 to transfer the energy stored in the traction voltage system 30 to the OBC 20. Therefore, even if the energy storage system 40 is inactive, the bidirectional DC / DC converter unit 23, and thus the on-board battery charging system 20, is always powered.

[0050] The bidirectional DC / DC converter unit 23 allows energy to flow in either the buck or boost direction, enabling excess energy stored in the traction capacitor 31 to be transferred to the internal capacitor 24 of the power factor correction unit 22. Due to the large size of the internal capacitor 24, it can store energy transferred from the traction voltage system 30 without requiring any additional active or passive components (e.g., switching circuits and / or resistors) to dissipate excess energy in the TVS 30. The power factor correction unit 22 can utilize the energy stored in the internal capacitor 24 before initiating AC charging.

[0051] Figure 2 A flowchart of a method for operating energy monitoring system 1 is shown. The method includes:

[0052] -S1: Start;

[0053] -S2: Receive information about the energy level of the traction voltage system 30;

[0054] -S3: Disconnect the traction voltage system 30 from the energy storage system 40;

[0055] -S4: Determine whether the energy level of the traction voltage system 30 exceeds a predetermined threshold.

[0056] -S5: When the energy level of the traction voltage system 30 exceeds a predetermined threshold, the energy stored in the traction voltage system 30 is transferred to the on-board battery charging system 20; and

[0057] -S6: Stop.

[0058] Preferably, in step S2, the state of the energy storage system 40 can also be measured, and in step S5, the traction capacitor 31 is discharged and the internal capacitor 24 is charged.

[0059] It should be noted that embodiments of this disclosure are described with reference to different subject matter. In particular, some embodiments are described with reference to method-type claims, while other embodiments are described with reference to device-type claims. However, those skilled in the art will understand from the above and below description that, unless otherwise stated, any combination of features related to different subject matter is also considered to be disclosed with this application, in addition to any combination of features belonging to one type of subject matter. However, all features can be combined to provide synergistic effects, rather than simply being a superposition of these features.

[0060] While this disclosure has been shown and described in detail in the accompanying drawings and specification, such showing and description is to be considered illustrative or exemplary and not restrictive. This disclosure is not limited to the disclosed embodiments. Other variations of the disclosed embodiments can be understood and implemented by those skilled in the art in practicing the claimed disclosure through a study of the drawings, the disclosure, and the dependent claims.

[0061] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple. A single processor or other unit can perform the function of several items re-referenced in the claims. The fact that certain measures are re-referenced in mutually different dependent claims does not indicate that a combination of these measures cannot function. Any reference marks in the claims should not be construed as limiting the scope.

Claims

1. An energy monitoring system (1) for a vehicle, comprising: -On-board battery charging system (20), - Traction inverter system (30), and -Control unit (21), The traction inverter system (30) is connected to the on-board battery charging system (20). The control unit (21) is configured to transfer energy stored in the traction inverter system (30) to the on-board battery charging system (20) when the energy level of the traction inverter system (30) exceeds a predetermined threshold.

2. The energy monitoring system (1) according to claim 1 further includes an energy storage system (40), wherein the traction inverter system (30) is arranged between the on-board battery charging system (20) and the energy storage system (40).

3. The energy monitoring system (1) according to claim 2, wherein the control unit (21) is configured to transfer energy from the traction inverter system (30) to the on-board battery charging system (20) only when the energy storage system (40) is disconnected from the traction inverter system (30).

4. The energy monitoring system (1) according to claim 1, wherein the traction inverter system (30) includes at least one traction capacitor (31).

5. The energy monitoring system (1) according to claim 4, wherein the control unit (21) is further configured to monitor the energy level of the traction capacitor (31).

6. The energy monitoring system (1) according to claim 1, wherein the on-board battery charging system (20) includes a bidirectional converter unit (23), through which energy stored in the traction inverter system (30) is transferred to the on-board battery charging system (20).

7. The energy monitoring system (1) according to claim 6, wherein the bidirectional converter unit (23) is a bidirectional DC / DC converter unit.

8. The energy monitoring system (1) according to claim 1, wherein the on-board battery charging system (20) further comprises at least one internal capacitor (24) configured to store energy transferred from the traction inverter system (30).

9. The energy monitoring system (1) according to claim 8, wherein the internal capacitor (24) is integrated in the power factor correction unit (22).

10. The energy monitoring system (1) according to claim 9, wherein the power factor correction unit (22) is configured to utilize the energy stored in the internal capacitor (24) before initiating AC charging.

11. The energy monitoring system (1) according to claim 1, wherein the on-board battery charging system (20) is always powered on.

12. A vehicle comprising an energy monitoring system (1) according to any one of claims 1 to 11, wherein the vehicle is a battery electric vehicle or a hybrid electric vehicle.

13. The vehicle according to claim 12, wherein the control unit (21) is configured to initiate energy transfer from the traction inverter system (30) to the on-board battery charging system (20) only when the vehicle is outside of driving mode and charging mode.

14. A method for manufacturing an energy monitoring system (1) for a vehicle, comprising: - Provides traction inverter system (30), - Provides an onboard battery charging system (20), and - Connect the on-board battery charging system (20) to the traction inverter system (30), and a control unit (21) is configured to transfer energy stored in the traction inverter system (30) to the on-board battery charging system (20) when the energy level of the traction inverter system (30) exceeds a predetermined threshold.

15. A method for operating an energy monitoring system (1) according to any one of claims 1 to 11 in a vehicle according to claim 12 or 13, comprising: - Receive (S2) information about the energy level of the traction inverter system (30), - Disconnect the traction inverter system (30) from the energy storage system (40) (S3), - Determine (S4) whether the energy level of the traction inverter system (30) exceeds a predetermined threshold, and - If the energy level of the traction inverter system (30) exceeds a predetermined threshold, the energy stored in the traction inverter system (30) is transferred (S5) to the on-board battery charging system (20).

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