Low-voltage power supply management device and system of vehicle fuel cell system and control method

Abstract

The invention relates to a low-voltage power management apparatus for a fuel cell system of a vehicle. The low-voltage power management apparatus includes: a vehicle control unit for controlling the vehicle; a fuel cell control unit for controlling the fuel cell system; the low-voltage power supply unit is connected with the vehicle control unit and the fuel cell control unit to supply power to the vehicle control unit and the fuel cell control unit; the delay control switch (4) is arranged in a power supply path (2) through which the low-voltage power supply unit supplies power to the fuel cell control unit, the input end (42) of the delay control switch is connected to the vehicle control unit, and the output end (41) of the delay control switch is connected in series in the power supply path; the delay control switch is controlled by the vehicle control unit to be switched on when the vehicle is powered on and switched off after a preset delay time is delayed when the vehicle breaks down or is powered off. The invention also relates to a vehicle fuel cell system and a control method. The fuel cell system can be safely closed when the vehicle is powered off, and power-off protection is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly to a low-voltage power management device for a vehicle fuel cell system, and also relates to a control method and a vehicle fuel cell system executed by the low-voltage power management device. Background Art

[0002] With the development of new energy technologies, fuel cells are increasingly widely used in vehicles. The control unit of a fuel cell system generally needs to be powered by a low-voltage power supply.

[0003] In a low-voltage power supply circuit, a manual switch is usually provided to reduce the static current or to safely stop the vehicle in case of an emergency failure. However, if the manual switch is suddenly disconnected, the power supply voltage of the fuel cell control unit will slowly drop due to the capacitance discharge of the low-voltage circuit, for example, from 28V to 0V within more than 150 ms, which will make the driving ability unstable. The unstable driving voltage will cause the fuel cell system to lose its stable autonomous control ability or cause hardware failures. In addition, in a low-voltage power supply circuit without a manual switch, the above problems also exist when the vehicle fails.

[0004] Therefore, an improved low-voltage power management device for a vehicle fuel cell system is needed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a low-voltage power management device for a vehicle fuel cell system for power-off protection.

[0006] According to one aspect of the present invention, there is provided a low-voltage power management device for a vehicle fuel cell system, comprising:

[0007] A vehicle control unit for controlling the vehicle;

[0008] A fuel cell control unit for controlling the fuel cell system;

[0009] A low-voltage power supply unit connected to the vehicle control unit and the fuel cell control unit to supply power to them; and

[0010] A delay control switch provided in the power supply path of the low-voltage power supply unit for supplying power to the fuel cell control unit, an input end of the delay control switch is connected to the vehicle control unit, and an output end of the delay control switch is connected in series in the power supply path, wherein the delay control switch is controlled by the vehicle control unit to be turned on when the vehicle is powered on and to be turned off after a predetermined delay time when the vehicle fails or is powered off.

[0011] According to another aspect of the present invention, there is also provided a vehicle fuel cell system, which includes a fuel cell and the above-mentioned low-voltage power management device connected to the fuel cell to manage its power supply.

[0012] According to still another aspect of the present invention, there is also provided a control method executed by the low-voltage power management device, including the following steps:

[0013] S1: Power on the vehicle;

[0014] S2: Use the low-voltage power supply unit to supply power to the vehicle control unit;

[0015] S3: The vehicle control unit controls the delay control switch to turn on to close the power supply path of the fuel cell system;

[0016] S4: When a fault or power failure occurs in the vehicle, the vehicle control unit controls the delay control switch to turn off after delaying the predetermined delay time.

[0017] By setting a delay control switch in the power supply path of the fuel cell control unit, the present invention can stabilize the driving voltage of the fuel cell control unit when the vehicle is powered off, so that the vehicle fuel cell system can complete normal shutdown, avoid hardware damage, and achieve the function of power-off protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Specific details of various embodiments of the present invention are illustrated in the drawings and the following description. Based on these descriptions and illustrations, other features and advantages of the present invention will be apparent.

[0019] Figure 1 is a schematic configuration diagram of a low-voltage power management device for a vehicle fuel cell system according to the first embodiment of the present invention;

[0020] Figure 2 is Figure 1 the operation flowchart of the shown low-voltage power management device when powered on;

[0021] Figure 3 is Figure 1 the operation flowchart of the shown low-voltage power management device for manual operation when powered off;

[0022] Figure 4 is Figure 1 the operation flowchart of the shown low-voltage power management device for automatic operation when powered off;

[0023] Figure 5 is a schematic configuration diagram of a low-voltage power management device for a vehicle fuel cell system according to the second embodiment of the present invention;

[0024] Figure 6Yes Figure 5 The operation flowchart of the low-voltage power management device shown when powered on. Specific embodiments

[0025] Hereinafter, specific embodiments of the present invention and their variants will be described in detail with reference to the accompanying drawings. These specific embodiments and their variants are merely used to describe the exemplary technical solutions of the present invention by way of example, and are not intended to impose any limitation on the protection scope of the present invention.

[0026] The present invention relates to a low-voltage power management device for a vehicle fuel cell system. The low-voltage power management device is provided with a delay control switch on the power supply path of the fuel cell control unit, and the delay control switch is controlled to be turned on and off by the vehicle control unit. After the vehicle is powered on, the delay control switch is controlled to be turned on to supply power to the fuel cell control unit normally. When an emergency failure occurs in the vehicle or power is cut off (for example, a failure occurs in the vehicle's power battery), the vehicle control unit controls the delay control switch to delay turning off so as to continue to supply power to the fuel cell control unit within a predetermined delay time, thereby stabilizing the driving voltage of the fuel cell control unit to enable the vehicle fuel cell system to complete normal shutdown, avoiding hardware damage, and achieving the function of power-off protection.

[0027] (First Embodiment)

[0028] Figure 1 It is a schematic configuration diagram of a low-voltage power management device for a vehicle fuel cell system according to the first embodiment of the present invention.

[0029] As Figure 1 shown, the low-voltage power management device includes a vehicle control unit VCU, a fuel cell control unit FCCU, and a low-voltage power supply unit LVU connected to the vehicle control unit VCU and the fuel cell control unit FCCU to supply power to them. The vehicle control unit VCU is used to control the entire vehicle, and the fuel cell control unit FCCU is used to control the entire fuel cell system including the fuel cell stack. The low-voltage power supply unit LVU is used to supply power to the vehicle control unit VCU and the fuel cell control unit FCCU during vehicle startup and vehicle operation.

[0030] The low-voltage power supply unit LVU may include a vehicle startup battery LVB for supplying power to the key switch 1 (which is used to start the vehicle) and a DC buck module DCL for supplying power to the vehicle control unit VCU and the fuel cell control unit FCCU during vehicle operation. The DC buck module DCL is used to convert the high-voltage power of the vehicle power battery (not shown) into low-voltage power suitable for each control unit. The vehicle startup battery LVB and the DC buck module DCL may be arranged in parallel to be able to supply power jointly during vehicle operation.

[0031] The output terminal of the low-voltage power supply unit LVU is connected to the fuel cell control unit FCCU via the power supply path 2 (for example, connected to the fuel cell control unit FCCU through the power supply connector 3 of the fuel cell control unit FCCU) to supply power to the fuel cell control unit FCCU. A delay control switch 4 is provided on the power supply path 2. The output terminal 41 of the delay control switch 4 is connected in series in the power supply path 2, and the input terminal 42 is connected to the vehicle control unit VCU to control the on and off of the delay control switch 4 by the vehicle control unit VCU, thereby controlling the closing or opening of the power supply path 2.

[0032] The delay control switch 4 can be a relay such as an electromagnetic relay as shown in Figure 1 , or a transistor such as a MOS transistor, or designed as other appropriate switching circuits. To control the delayed disconnection of the delay control switch 4, the vehicle control unit VCU can be configured with delay control logic, for example, in the form of a timer. The delay control logic can set the delay time according to the time required for the fuel cell system to be completely shut down, such as shutdown or entering the sleep state. By implementing the delay control using software logic in the existing vehicle control unit VCU, no additional hardware needs to be added to the vehicle control unit VCU, thereby reducing the control cost. Alternatively, the delay control switch 4 itself can also use a delay relay, and the delay relay itself is provided with delay control, so that there is no need for the vehicle control unit VCU to set the delay time.

[0033] To monitor whether the delay control switch 4 is working properly, the output terminal 41 of the delay control switch 4 can also be feedback-connected to the vehicle control unit VCU. After the vehicle control unit VCU has controlled the delay control switch 4 to be turned on or off, the vehicle control unit VCU obtains the on and off information of the delay control switch 4 through this feedback connection F to determine whether the delay control switch 4 is working properly. When it is determined that the delay control switch 4 is not working properly, the vehicle control unit VCU can control the delay control switch 4 to be turned on or off again, and / or send an alarm signal outward.

[0034] In addition, a manual switch 5 can also be provided in parallel with the delay control switch 4 between the power supply path 2 of the fuel cell control unit FCCU and the vehicle control unit VCU. One end of the manual switch 5 is connected to the power supply path 2 between the output terminal 41 of the delay control switch 4 and the low-voltage power supply unit LVU, and the other end is connected to the vehicle control unit VCU.

[0035] When the manual switch 5 is closed, the vehicle control unit VCU receives the hardware enable signal sent by the manual switch 5 or automatically detects that the manual switch 5 is closed, and then controls the delay control switch 4 to turn on, so as to close the power supply path 2 of the fuel cell control unit FCCU to supply power to the fuel cell control unit FCCU. When the manual switch 5 is opened, for example, intentionally opened due to an emergency failure of the vehicle power battery or unintentionally opened due to misoperation, the vehicle control unit VCU receives the hardware disable signal sent by the manual switch 5 or automatically detects that the manual switch 5 is opened, and controls the delay control switch 4 to turn off after a predetermined delay time from when the vehicle is powered off or when it learns that the manual switch 5 is opened or other trigger signals, so as to disconnect the power supply path 2 and stop supplying power to the fuel cell control unit FCCU, realizing an emergency stop protection, for example, it can protect the power battery and / or the fuel cell system.

[0036] In order for the fuel cell control unit FCCU to obtain the switch state of the manual switch 5, one end of the manual switch 5 can also be connected to the fuel cell control unit FCCU (for example, connected to the fuel cell control unit FCCU through the control connector 6 of the fuel cell control unit FCCU), so as to transmit the disconnection information to the fuel cell control unit FCCU when the manual switch 5 is opened (whether intentionally or unintentionally). After receiving the disconnection information of the manual switch 5, the fuel cell control unit FCCU can autonomously shut down, so that even if the vehicle control unit VCU fails and does not send a shutdown signal to the fuel cell control unit FCCU, the fuel cell control unit FCCU can still shut down.

[0037] The vehicle control unit VCU is connected to the vehicle starting battery LVB via the key switch 1 to wake up the vehicle control unit VCU when the key switch 1 is closed. In addition, the vehicle control unit VCU can be connected to the fuel cell control unit FCCU through the CAN bus to communicate with it. For example, the vehicle control unit VCU woken up when the key switch 1 is closed wakes up the fuel cell control unit FCCU.

[0038] In the case where the low-voltage power management device does not have the manual switch 5, the vehicle control unit VCU can be configured to directly turn on the delay control switch 4 when the vehicle is powered on, and delay a predetermined delay time to turn off the delay control switch 4 when the vehicle is powered off (for example, when the vehicle control unit VCU learns that the vehicle is powered off or receives other trigger signals). The predetermined delay time is set according to the shutdown time required for the fuel cell system to completely shut down (for example, shut down and enter the sleep state) after the vehicle is powered off, so that the delay control switch 4 is turned off after the fuel cell system is completely shut down, to ensure that the fuel cell system can be normally and completely shut down after the vehicle is powered off.

[0039] When a manual switch 5 is provided in the low-voltage power management device, the vehicle control unit VCU is configured to turn on the delay control switch 4 when the manual switch 5 is closed, and is configured to delay for a predetermined delay time to turn off the delay control switch 4 when the manual switch 5 is opened (for example, when the vehicle control unit VCU receives the information that the manual switch 5 is opened or other trigger signals). Or, even if the manual switch 5 is not opened, but when the vehicle is powered off (for example, when the vehicle control unit VCU detects or receives the power-off information), the delay control switch 4 is turned off after delaying for a predetermined delay time. Similarly, the predetermined delay time is set according to the shutdown time required for the fuel cell system to be completely shut down (for example, shut down and enter the sleep state) after the vehicle is powered off, so that the delay control switch 4 is turned off after the fuel cell system is completely shut down, to ensure that the fuel cell system can be normally and completely shut down after the vehicle is powered off.

[0040] By opening the manual switch 5 when an emergency failure occurs in the vehicle or other situations where power-off or accidents are required, the power battery can be disconnected from the fuel cell system which is a low-voltage component of the vehicle to protect the power battery and / or the fuel cell system. In addition, by setting the manual switch 5 to implement the emergency stop function, the whole vehicle system can quickly complete the emergency stop and cut off the high voltage, for example, within 5 s. This can be used to manually control the emergency stop of the system, for example, when a minor collision or other undetected failures occur. Moreover, the present invention controls whether the low-voltage power is connected to the fuel cell system only by operating one component, the manual switch, which greatly simplifies the system design and reduces the failure rate of the system design.

[0041] The present invention also relates to a control method executed by the above-mentioned low-voltage power management device, including the following steps:

[0042] S1: Power on the vehicle;

[0043] S2: Use the low-voltage power supply unit LVU to supply power to the vehicle control unit VCU;

[0044] S3: The vehicle control unit VCU controls the delay control switch 4 to turn on to close the power supply path 2 of the fuel cell system;

[0045] S4: When a failure or power-off occurs in the vehicle, the vehicle control unit VCU controls the delay control switch 4 to turn off after delaying for a predetermined delay time

[0046] Next, refer to Figures 2 to 4 Describe Figure 1 The exemplary control operations of the shown low-voltage power management device when the vehicle is powered on and off.

[0047] As Figure 2 shown, when the vehicle is powered on, the low-voltage power management device performs the following operations:

[0048] S101: Close the key switch 1 to power on the vehicle;

[0049] S102: Wake up the vehicle control unit VCU;

[0050] S103: The vehicle control unit VCU determines whether the manual switch 5 is turned on. If so, proceed to step S104; if not, repeat step S103;

[0051] S104: The vehicle control unit VCU controls the delay control switch 4 to turn on;

[0052] S105: The vehicle control unit VCU wakes up the fuel cell system and the vehicle starts.

[0053] Through the above operations, after the vehicle is powered on, the delay control switch 4 is turned on after the manual switch 5 is closed, so that the fuel cell control unit FCCU is in a fault or power-off protection state during the vehicle operation.

[0054] When a fault or anomaly occurs during vehicle operation, the manual switch 5 can be manually disconnected, or when the manual switch 5 is accidentally disconnected, the low-voltage power management device such as Figure 3 performs the following operations as shown:

[0055] S201: Disconnect the manual switch 5:

[0056] S202: The vehicle control unit VCU receives the information that the manual switch 5 is disconnected;

[0057] S203: The vehicle control unit VCU sends an emergency shutdown request to the fuel cell control unit FCCU;

[0058] S204: The fuel cell control unit FCCU performs an emergency shutdown and sends a shutdown completion flag to the vehicle control unit VCU after the emergency shutdown;

[0059] S205: The vehicle control unit VCU controls the fuel cell control unit FCCU to enter the sleep state (pull down the wake-up signal);

[0060] S206: After delaying a predetermined delay time, the vehicle control unit VCU disconnects the delay control switch 4 and the fuel cell system is safely powered off.

[0061] The above describes the operations performed by the low-voltage power management device when the manual switch 5 is manually disconnected. If the vehicle can detect the power-off by itself when the vehicle is powered off, even if the manual switch 5 is still turned on, the low-voltage power management device also performs the following operations as shown in Figure 4 :

[0062] S301: The fuel cell control unit FCCU automatically shuts down or the vehicle control unit VCU controls the fuel cell control unit FCCU to shut down:

[0063] S302: After the fuel cell control unit FCCU completes shutdown, it sends a shutdown completion flag to the vehicle control unit VCU:

[0064] S303: The vehicle control unit VCU controls the fuel cell control unit FCCU to enter the sleep state (pull down the wake-up signal);

[0065] S304: After delaying for a predetermined delay time, the vehicle control unit VCU disconnects the delay control switch 4, and the fuel cell system is safely powered off.

[0066] As described above, even if the manual switch 5 is still in the on state, after the fuel cell system is completely shut down, the vehicle control unit VCU can still control the power-off of the fuel cell system, thereby avoiding a high static current and reducing the static power consumption.

[0067] In this embodiment, whether the manual switch 5 is accidentally disconnected during normal vehicle operation, or the power is cut off through the manual switch 5 when the vehicle has an abnormality, or the vehicle automatically detects an abnormality and cuts off the power, the vehicle control unit VCU can control the delay control switch 4 to delay disconnection, that is, after waiting for a predetermined delay time for the fuel cell system to safely shut down or enter the sleep state, the delay control switch 4 is disconnected, so that the fuel cell system can be safely powered off, avoiding control loss and hardware damage caused by the slow drop of the drive voltage of the fuel cell control unit FCCU, and being able to reduce the static current of the fuel cell system, reduce the static power consumption, and also protect the power battery when the power battery fails.

[0068] (Second Embodiment)

[0069] Figure 5 It is a schematic configuration diagram of a low-voltage power management device for a vehicle fuel cell system according to the second embodiment of the present invention. The difference between this second embodiment and the first embodiment is only that the manual switch 5 is omitted, and other configurations are the same as or similar to those of the first embodiment. Therefore, only the differences between the second embodiment and the first embodiment are described below.

[0070] As Figure 5 shown, since the manual switch 5 is omitted, the control of the low-voltage power management device in this embodiment is no longer subject to human intervention and is completely automatic.

[0071] When the vehicle is powered on, as Figure 6 shown, the low-voltage power management device performs the following operations:

[0072] S1001: Close the key switch 1, and the vehicle is powered on;

[0073] S1002: Wake up the vehicle control unit VCU;

[0074] S1003: The vehicle control unit VCU controls the delay control switch 4 to turn on;

[0075] S1004: The vehicle control unit VCU wakes up the fuel cell system and the vehicle starts.

[0076] Through the above operations, after the vehicle is powered on, the delay control switch 4 is directly controlled to close, so that the fuel cell control unit FCCU is in a fault or power-off protection state during the vehicle operation.

[0077] When a power-off anomaly occurs, the vehicle itself detects the power-off anomaly and performs the same operations as Figure 4 shown:

[0078] S301: The fuel cell control unit FCCU automatically shuts down or the vehicle control unit VCU controls the fuel cell control unit FCCU to shut down:

[0079] S302: After the fuel cell control unit FCCU completes shutdown, it sends a shutdown completion flag to the vehicle control unit VCU:

[0080] S303: The vehicle control unit VCU controls the fuel cell control unit FCCU to enter the sleep state (pull down the wake-up signal);

[0081] S304: After delaying a predetermined delay time, the vehicle control unit VCU disconnects the delay control switch 4 and the fuel cell system is safely powered off.

[0082] Except for no human intervention, the second embodiment can achieve the same technical effects as the first embodiment, that is, by controlling the delay control switch 4 to delay disconnection during a power-off anomaly, waiting for a predetermined time for the fuel cell unit to completely shut down or enter the sleep state and then disconnecting the delay control switch 4, the fuel cell control unit FCCU can be safely powered off, avoiding unstable driving of the fuel cell control unit FCCU, and can avoid damage to the hardware, reduce the static power consumption, and can also protect the power battery when the power battery fails.

[0083] The present invention also relates to a vehicle fuel cell system, which includes a fuel cell and the above-mentioned low-voltage power management device connected to the fuel cell to manage its power supply.

[0084] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above specific configurations or method steps, but covers various deformations and equivalent features. Those skilled in the art can make various changes without departing from the protection scope of the present invention.

Claims

1. A low-voltage power management device for a vehicle fuel cell system, comprising: A vehicle control unit for controlling the vehicle; A fuel cell control unit for controlling the fuel cell system; A low-voltage power supply unit connected to the vehicle control unit and the fuel cell control unit to supply power to them; And A delay control switch (4) provided in the power supply path (2) for the low-voltage power supply unit to supply power to the fuel cell control unit. The input terminal (42) of the delay control switch (4) is connected to the vehicle control unit, and the output terminal (41) of the delay control switch (4) is connected in series in the power supply path (2). The delay control switch (4) is controlled by the vehicle control unit to turn on when the vehicle is powered on and turn off after a predetermined delay time when the vehicle fails or loses power.

2. The low-voltage power management device according to claim 1, wherein, The delay control switch (4) is a relay or transistor whose delay time is set by the vehicle control unit.

3. The low-voltage power management device according to claim 1, wherein, The delay control switch (4) is a delay relay.

4. The low-voltage power management device according to claim 1, wherein, The output terminal (41) of the delay control switch (4) is feedback-connected to the vehicle control unit to provide the switching state of the delay control switch (4).

5. The low-voltage power management device according to any one of claims 1-4, wherein, After the fuel cell system completes shutdown and the vehicle control unit receives the shutdown completion flag sent by the fuel cell system, the fuel cell system enters a sleep state, and the delay control switch (4) turns off after the fuel cell system enters the sleep state.

6. The low-voltage power management device according to any one of claims 1-5, further comprising a manual switch (5) connected in parallel with the delay control switch (4). One end of the manual switch (5) is connected to the power supply path (2) between the output terminal (41) of the delay control switch (4) and the low-voltage power supply unit, and the other end of the manual switch (5) is connected to the vehicle control unit. Among them, The vehicle control unit controls the delay control switch (4) to turn on when the manual switch (5) is turned on, and controls the delay control switch (4) to turn off after a predetermined delay time when the manual switch (5) is turned off or the fuel cell system shuts down.

7. The low-voltage power management device according to claim 6, wherein, When the manual switch (5) is turned off, the vehicle control unit sends an emergency shutdown request to the fuel cell system, and after receiving the shutdown completion flag sent by the fuel cell system, makes the fuel cell system enter a sleep state, and the delay control switch (4) turns off after the fuel cell system enters the sleep state.

8. The low-voltage power management device according to claim 6 or 7, wherein, One end of the manual switch (5) is connected to the fuel cell control unit to provide the disconnection information of the manual switch (5) to the fuel cell control unit.

9. The low-voltage power management device according to any one of claims 1-8, wherein, The low-voltage power supply unit includes a vehicle starting battery and a DC buck module connected in parallel with each other. The vehicle starting battery is connected to the vehicle control unit via a key switch (1). The vehicle control unit is awakened when the key switch (1) is turned on and awakens the fuel cell control unit after being awakened. The DC buck module supplies power to the vehicle control unit after the vehicle control unit is awakened and supplies power to the fuel cell control unit after the delay control switch (4) is closed.

10. A vehicle fuel cell system, comprising a fuel cell and a low-voltage power management device according to any one of claims 1-9, which is connected to the fuel cell to manage its power supply.

11. A control method executed by the low-voltage power management device according to any one of claims 1-9, comprising the following steps: S1: Power on the vehicle; S2: Use the low-voltage power supply unit to supply power to the vehicle control unit; S3: The vehicle control unit controls the delay control switch (4) to turn on to close the power supply path (2) of the fuel cell system; S4: When a fault or power failure occurs in the vehicle, the vehicle control unit controls the delay control switch (4) to open after delaying the predetermined delay time.

Images