Vehicle low-voltage power supply system and method

Abstract

The invention provides a vehicle low-voltage power supply system and method, and belongs to the technical field of vehicles. The system comprises a vehicle control unit, a battery management system, a direct-current converter, a power battery and low-voltage equipment. The vehicle control unit controls the power battery to provide high-voltage electricity for a high-voltage system of the vehicle through the battery management system after being awakened, and therefore high-voltage power-on is achieved. After high-voltage power-on, the direct-current converter can convert high-voltage electricity output by the power battery into low-voltage electricity according to a low-voltage enable signal sent by the battery management system, and then power is supplied to low-voltage equipment through the low-voltage electricity; and whether voltage conversion is carried out or not can be determined by detecting whether high voltage output by the power battery exists at the input end or not. According to the technical scheme, when the CAN interface of the direct-current converter breaks down and cannot receive the low-voltage enable signal, the direct-current converter can also conduct voltage conversion in time, so that power is supplied to low-voltage equipment, and the stability and reliability of the vehicle low-voltage power supply system are improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a vehicle low-voltage power supply system and method. Background Art

[0002] With the development of new energy technologies, the number of electric vehicles has gradually increased. In electric vehicles, the DC converter, as an important module in the vehicle's low-voltage system, can convert the high-voltage DC power output by the high-voltage battery into low-voltage DC power, thereby powering the vehicle's low-voltage equipment. Therefore, how to ensure that the DC converter can stably and correctly output low-voltage DC power to avoid voltage anomalies in low-voltage equipment is a technical problem that needs to be solved. Summary of the invention

[0003] The embodiment of the present application provides a vehicle low-voltage power supply system and method, which can improve the stability and reliability of the vehicle low-voltage power supply. The technical solution is as follows:

[0004] On the one hand, a vehicle low-voltage power supply system is provided, the system comprising a vehicle controller, a battery management system, a DC converter, a power battery and a low-voltage device;

[0005] The vehicle controller, the battery management system and the DC converter are connected via a CAN bus, the input end of the DC converter is connected to the power battery, and the output end of the DC converter is connected to the low-voltage device, and the low-voltage device includes a low-voltage battery and a low-voltage load;

[0006] The vehicle controller is used to send a high-voltage power-on request to the battery management system after waking up; and send a low-voltage enable signal to the DC converter;

[0007] The battery management system is used for controlling the relay of the power battery to close in response to the high-voltage power-on request, so as to provide the voltage output by the power battery to the DC converter;

[0008] The DC converter is used to respond to the low voltage enable signal, or when the voltage output by the power battery is detected at the input end, convert the voltage output by the power battery into the power supply voltage of the low voltage device, so as to supply power to the low voltage device through the power supply voltage.

[0009] In some embodiments, the low voltage enable signal includes a voltage signal and an enable signal, the voltage signal is used to represent the supply voltage of the low voltage device, and the enable signal is used to instruct the DC converter to convert the voltage output by the power battery into the supply voltage.

[0010] In some embodiments, the DC converter is also used to convert the voltage output by the power battery into the rated voltage when the power supply voltage indicated by the received voltage signal is greater than the rated voltage, so as to supply power to the low-voltage device through the rated voltage.

[0011] In some embodiments, a voltage sensor is connected to the input end of the DC converter, and the voltage sensor is used to detect the voltage of the input end.

[0012] In some embodiments, the DC converter is further used to determine that the input terminal has the voltage output by the power battery when the voltage at the input terminal is within a preset range.

[0013] In some embodiments, the battery management system is used to control the relay of the power battery to close in response to the high voltage power-on request, including:

[0014] The battery management system is used to control the main positive relay and the main negative relay of the power battery to close in response to the high-voltage power-on request, the main positive relay is connected to the positive electrode of the power battery, and the main negative relay is connected to the negative electrode of the power battery.

[0015] In some embodiments, the system further includes a body controller, which is configured to respectively wake up the vehicle controller, the battery management system, and the DC converter in response to a wake-up signal.

[0016] In some embodiments, the vehicle controller is further configured to send a high voltage power-off request to the battery management system in response to a sleep signal, and send a power-off enable signal to the DC converter;

[0017] The battery management system is further used to control the relay of the power battery to disconnect in response to the high voltage power-off request;

[0018] The DC converter is also used to enter a dormant state in response to the disconnection enable signal or when it is detected that the voltage output by the power battery is absent at the input terminal, so as to stop supplying power to the low-voltage device.

[0019] On the other hand, a vehicle low-voltage power supply method is provided, which is applied to a vehicle low-voltage power supply system, wherein the system includes a vehicle controller, a battery management system, a DC converter, a power battery, and a low-voltage device, wherein the vehicle controller, the battery management system, and the DC converter are connected via a CAN bus, an input end of the DC converter is connected to the power battery, and an output end of the DC converter is connected to the low-voltage device, and the method includes:

[0020] After waking up, the vehicle controller sends a high-voltage power-on request to the battery management system and sends a low-voltage enable signal to the DC converter;

[0021] The battery management system controls the relay of the power battery to close in response to the high-voltage power-on request, so as to provide the voltage output by the power battery to the DC converter;

[0022] The DC converter responds to the low voltage enable signal or, when detecting that the voltage output by the power battery exists at the input terminal, converts the voltage output by the power battery into the supply voltage of the low voltage device, so as to supply power to the low voltage device through the supply voltage.

[0023] In some embodiments, the method further comprises:

[0024] In response to the sleep signal, the vehicle controller sends a high voltage power-off request to the battery management system and sends a power-off enable signal to the DC converter;

[0025] The battery management system controls the relay of the power battery to be disconnected in response to the high voltage power-off request;

[0026] The DC converter enters a dormant state in response to the disconnection enable signal or when detecting that the voltage output by the power battery is absent at the input terminal, so as to stop supplying power to the low-voltage device.

[0027] The embodiment of the present application provides a low-voltage power supply system for a vehicle. After the high voltage of the vehicle is powered on, the battery management system sends a low-voltage enable signal to the DC converter through the CAN bus to instruct the DC converter to convert the high voltage electricity output by the power battery into low voltage electricity, and then use the low voltage electricity to power the low-voltage equipment. Furthermore, in the event of a CAN interface failure of the DC converter, the DC converter cannot receive the low-voltage enable signal through the CAN bus. At this time, the DC converter can determine whether to perform voltage conversion by detecting whether there is high voltage electricity output by the power battery at the input end. Using the above method, the DC converter can perform voltage conversion stably and timely, avoiding the failure of the vehicle's low-voltage equipment to be powered normally due to factors such as CAN interface failure, thereby improving the stability and reliability of the vehicle's low-voltage power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 is a structural schematic diagram of a vehicle low-voltage power supply system provided according to an embodiment of the present application;

[0030] Figure 2 is a structural schematic diagram of another vehicle low-voltage power supply system provided according to an embodiment of the present application;

[0031] Figure 3 It is a flow chart of a vehicle low-voltage power supply method provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0033] In this application, the terms "first", "second", etc. are used to distinguish identical or similar items with basically the same effects and functions. It should be understood that there is no logical or temporal dependency between "first", "second", and "nth", nor is there any limitation on quantity and execution order.

[0034] In the present application, the term "at least one" means one or more, and the term "plurality" means two or more.

[0035] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions.

[0036] Figure 1 is a structural diagram of a vehicle low-voltage power supply system provided according to an embodiment of the present application, see Figure 1 The system includes a vehicle controller 101, a battery management system 102, a DC converter 103, a power battery 104 and a low-voltage device 105.

[0037] Among them, the vehicle controller 101, the battery management system 102 and the DC converter 103 are connected through a CAN (Controller Area Network) bus. The input end of the DC converter 103 is connected to the power battery 104, and the output end of the DC converter 103 is connected to the low-voltage device 106. The low-voltage device 106 includes a low-voltage battery and a low-voltage load. Among them, the low-voltage load refers to the load equipment in the vehicle that is powered by the low-voltage system, including but not limited to the lighting system, air conditioning system, instrument system, etc.

[0038] The vehicle controller 101 is used to send a high-voltage power-on request to the battery management system 102 after waking up. Specifically, the vehicle controller 101 performs a self-test after waking up, and then sends a high-voltage power-on request to the battery management system 102 through the CAN bus after the self-test is completed. By performing a self-test, the vehicle controller 101 can avoid potential problems in the hardware system, software system, etc. of the vehicle controller 101, thereby ensuring the reliability of the vehicle control system throughout the entire driving cycle.

[0039] The battery management system 102 is used to control the relay of the power battery 104 to close in response to the high-voltage power-on request, so as to provide the voltage output by the power battery 104 to the DC converter 103. The power battery 104 refers to a storage battery that provides a power source for the vehicle. The process of controlling the relay of the power battery 104 to close so that the power battery 104 can supply power to high-voltage load devices such as the motor controller and the drive motor in the high-voltage system of the vehicle is called high-voltage power-on.

[0040] In some embodiments, the relay of the power battery 104 includes a main positive relay and a main negative relay. The main positive relay is connected to the positive electrode of the power battery 104, and the main negative relay is connected to the negative electrode of the power battery 104. Accordingly, the battery management system 102 is used to control the main positive relay and the main negative relay of the power battery 104 to close in response to the high-voltage power-on request, so as to realize high-voltage power-on of the whole vehicle. After the above two relays are closed, the output voltage of the power battery 104 can be transmitted to multiple high-voltage load devices of the vehicle high-voltage system through a medium such as a high-voltage line, so as to realize high voltage on the whole vehicle.

[0041] In order to ensure that the power battery 104 can supply power to the low-voltage device 105 of the vehicle, the vehicle controller 101 is also used to send a low-voltage enable signal to the DC converter 103 after the high voltage is powered on. The DC converter 103 is used to respond to the low-voltage enable signal and convert the voltage output by the power battery 104 into the power supply voltage of the low-voltage device 105, so as to supply power to the low-voltage device through the power supply voltage. Optionally, the power battery 104 outputs high-voltage direct current, which can be converted into low-voltage direct current through the DC converter 103. Low-voltage direct current is used to power the low-voltage equipment of the vehicle. Among them, the voltage of the low-voltage direct current is usually 12V (volts) or 24V. In addition, the DC converter 103 is also used to return status information to the vehicle controller 101 after voltage conversion. Among them, the status information includes a status flag, and the status flag can indicate that the DC converter 103 enters the working state, that is, the DC converter 103 starts to perform voltage conversion.

[0042] In some embodiments, the low voltage enable signal includes a voltage signal and an enable signal. Among them, the voltage signal is used to indicate the power supply voltage of the low voltage device. The voltage signal may also be referred to as a low voltage output voltage signal, and the low voltage output voltage signal carries a low voltage value, that is, the value of the power supply voltage output by the DC converter. The enable signal is used to instruct the DC converter to convert the voltage output by the power battery into the power supply voltage. The enable signal may also be referred to as a low voltage output enable signal. Accordingly, the vehicle controller 101 is also used to send a voltage signal and an enable signal to the DC converter 103 after the high voltage is powered on, so as to instruct the DC converter 103 to convert the voltage output by the power battery 104 into the power supply voltage indicated by the voltage signal.

[0043] In some embodiments, the low voltage enable signal may also be an enable signal carrying a low voltage value. Accordingly, the vehicle controller 101 sends a low voltage enable signal to the DC converter 103, which can control the DC converter 103 to perform voltage conversion, avoiding the signal timing synchronization problem that needs to be considered when sending multiple signals, and can also reduce the probability of signal errors during transmission, thereby improving the voltage conversion efficiency and accuracy.

[0044] In some embodiments, the DC converter 103 is also used for voltage verification. When the power supply voltage indicated by the received voltage signal is greater than the rated voltage, the DC converter 103 converts the voltage output by the power battery into the rated voltage to supply power to the low-voltage device 105 through the rated voltage, which can prevent the actual power supply voltage of the low-voltage device 105 from being greater than the rated voltage, thereby preventing the low-voltage device 105 from being damaged. The rated voltage can be set according to the actual operating conditions of the low-voltage device 105, and the embodiment of the present application does not limit the value of the rated voltage.

[0045] It should be noted that the vehicle controller 101 and the DC converter 103 communicate data via the CAN network, that is, the vehicle controller 101 sends a low-voltage enable signal to the DC converter 103 via the CAN network. A CAN network usually includes multiple CAN nodes, and a CAN node refers to an independent electronic device or control unit connected to the CAN bus, that is, an endpoint that can send and receive data in the CAN network. For example, the vehicle controller 101 and the DC converter 103 in the embodiment of the present application can be considered as CAN nodes.

[0046] For the DC converter 103, the CAN node of the DC converter 103 can be an interface for receiving signals transmitted on the CAN bus. In some cases, the CAN node of the DC converter 103 may be lost due to hardware connection problems, software problems, and other factors, and the DC converter 103 cannot receive signals through the CAN network. For example, the CAN interface line of the DC converter 103 is loose, broken or short-circuited, or the communication protocol configuration of the DC converter 103 is incorrect, which may cause the CAN node of the DC converter 103 to be lost. If the CAN node of the DC converter 103 is lost, the DC converter 103 cannot receive signals through the CAN network, and the DC converter 103 cannot receive the low-voltage enable signal sent by the vehicle controller 101 through the CAN network, and it is impossible to perform voltage conversion according to the normal working mode, thereby causing the low-voltage device 105 of the vehicle to be unable to be powered, thereby affecting the normal driving of the vehicle.

[0047] In order to ensure that the low-voltage device 105 of the vehicle can be powered in time even when the CAN node is lost, the DC converter 103 can not only perform voltage conversion after receiving the low-voltage enable signal, but also perform voltage conversion when the voltage output by the power battery 104 is detected at the input end, so as to power the low-voltage device 105 of the vehicle in time. Among them, since the input end of the DC converter 103 is connected to the power battery 104, when the voltage output by the power battery 104 is present at the input end of the DC converter 103, it indicates that the main positive relay and the main negative relay of the power battery 104 are closed, and the vehicle has completed high-voltage power-up, and the low-voltage device of the vehicle can be powered at this time. Correspondingly, when the voltage output by the power battery 104 is detected at the input end, the DC converter 103 can convert the voltage output by the power battery 104 into a preset supply voltage or a rated voltage.

[0048] In some embodiments, a voltage sensor is connected to the input end of the DC converter 103. The voltage sensor is used to detect the voltage of the input end. Through the voltage sensor connected to the input end, the voltage of the input end can be quickly and accurately detected, and then it can be quickly determined whether the vehicle has completed high-voltage power-up. After the DC converter 103 wakes up, the voltage detected by the voltage sensor can be obtained in real time, or the voltage detected by the voltage sensor can be obtained periodically, which is not limited in the embodiments of the present application.

[0049] Optionally, the DC converter 103 is further used to determine that there is a voltage output by the power battery at the input terminal when the voltage at the input terminal is within a preset range. The preset range can be set according to the voltage value output by the power battery 105, and the specific value of the preset range is not limited in the embodiment of the present disclosure.

[0050] The above embodiment mainly introduces that after the vehicle high voltage is powered on, the DC converter 103 converts the voltage output by the power battery 104 into the power supply voltage of the low voltage device 105. The following embodiment is used to illustrate the wake-up process of multiple modules in the vehicle low voltage power supply system. In some embodiments, Figure 2 is a schematic diagram of the structure of another vehicle low-voltage power supply system provided according to an embodiment of the present application. Figure 2 The system also includes a body controller 106, which is connected to the vehicle controller 101, the battery management system 102 and the DC converter 103 through hard wires.

[0051] The body controller 106 is used to respond to the wake-up signal and wake up the vehicle controller 101, the battery management system 102 and the DC converter 103 respectively. Among them, the wake-up signal is usually a hardware signal, such as a key wake-up signal. When the driver turns the key from the OFF position to the ON position in the vehicle's ignition switch, the contacts inside the ignition switch will change the connection state, and a corresponding key wake-up signal will be generated and sent to the body controller 106. In response to the key wake-up signal, the body controller 106 will perform a power-on self-test, and after the self-test is completed, it will send a low-voltage hard-line signal to the vehicle controller 101, the battery management system 102 and the DC converter 103 to wake up the above modules. Among them, the low-voltage hard-line signal can be an IGN2 low-voltage wake-up signal transmitted by hard wire. When the driver turns the key to the ON position in the ignition switch, the body controller 106 will close the IG2 relay through the internal control circuit and relay drive circuit, thereby generating an IGN2 low-voltage wake-up signal. Accordingly, the vehicle controller 101, the battery management system 102 and the DC converter 103 can all perform power-on self-test in response to the IGN2 low-voltage wake-up signal. After the vehicle controller 101 completes the self-test, it sends a high-voltage power-on request to the battery management system 102 to request the vehicle to power on the high voltage. After the high voltage is powered on, the vehicle controller 101 sends a low-voltage enable signal to the DC converter 103 to instruct the DC converter 103 to convert the voltage output by the power battery 104 into the power supply voltage of the low-voltage device 105, thereby providing power to the low-voltage device 105.

[0052] The above embodiment mainly introduces that after the vehicle is awakened, the vehicle low-voltage power supply system supplies power to the low-voltage devices. The following describes that when the vehicle enters a dormant state, the vehicle low-voltage power supply system stops supplying power to the low-voltage devices.

[0053] In some embodiments, the vehicle controller 101 is also used to respond to the sleep signal, send a high-voltage power-off request to the battery management system 102, and send a disconnection enable signal to the DC converter 103. Among them, the high-voltage power-off request is used to request high-voltage power-off. The battery management system 102 is also used to control the relay of the power battery to disconnect in response to the high-voltage power-off request, so as to achieve high-voltage power-off of the whole vehicle. The disconnection enable signal is used to instruct the DC converter 103 to stop voltage conversion. Accordingly, the DC converter 103 is also used to respond to the disconnection enable signal, or when it is detected that there is no voltage output by the power battery 104 at the input end, enter a sleep state to stop supplying power to the low-voltage device 105. The body controller 106 is also used to respond to the key sleep signal, and send an IGN2 low-voltage sleep signal to the vehicle controller 101, the battery management system 102 and the DC converter 103 respectively to instruct the above modules to enter a sleep state, so as to achieve vehicle sleep. Similar to the key wake-up signal, when the driver turns the key to the OFF position in the vehicle's ignition switch, or pulls out the key, the contacts inside the ignition switch will change the connection state, generating a corresponding key sleep signal and sending it to the body controller 106 .

[0054] The embodiment of the present application provides a low-voltage power supply system for a vehicle, which includes a vehicle controller, a battery management system, a DC converter, a power battery and a low-voltage device. The vehicle controller can control the closure of the relay of the power battery through the battery management system to realize the high-voltage power-on of the vehicle. After the high-voltage power-on of the vehicle, the battery management system sends a low-voltage enable signal to the DC converter through the CAN bus to instruct the DC converter to convert the high-voltage electricity output by the power battery into low-voltage electricity, and then power the low-voltage equipment through the low-voltage electricity. Furthermore, in the case of a CAN interface failure of the DC converter, the DC converter cannot receive the low-voltage enable signal through the CAN bus. At this time, the DC converter can determine whether to perform voltage conversion by detecting whether there is high-voltage electricity output by the power battery at the input end. Using the above method, the DC converter can stably and accurately perform voltage conversion, avoiding the failure of the low-voltage equipment of the vehicle to be powered normally due to factors such as CAN interface failure, and improving the stability and reliability of the low-voltage power supply of the vehicle.

[0055] Figure 3It is a flow chart of a vehicle low-voltage power supply method provided according to an embodiment of the present application. The method is executed by a vehicle low-voltage power supply system configured in a vehicle, the system including a body controller, a vehicle controller, a battery management system, a DC converter, a power battery and a low-voltage device; the body controller communicates data with the vehicle controller, the battery management system and the DC converter through a hard line; the vehicle controller, the battery management system and the DC converter are connected through a CAN bus; the input end of the DC converter is connected to the power battery, and the output end of the DC converter is connected to the low-voltage device, the low-voltage device including a low-voltage battery and a low-voltage load, such as Figure 3 As shown, the vehicle low-voltage power supply method includes the following steps:

[0056] 301. The body controller performs a power-on self-test in response to a key wake-up signal, and wakes up the vehicle controller, the battery management system, and the DC converter respectively through a low-voltage wake-up signal after the self-test is completed.

[0057] Among them, the body controller (BCM) is an electronic control unit inside the vehicle, which is responsible for driving and monitoring other electronic control units related to body functions, such as the vehicle control unit (VCU), battery management system (BMS) and DC-to-DC converter (DCDC). The key wake-up signal is a hardware signal. When the driver turns the key from the OFF position to the ON position in the vehicle's ignition switch, the contacts inside the ignition switch will change the connection state, generate a corresponding key wake-up signal and send it to the body controller. The low-voltage wake-up signal can be an IGN2 low-voltage wake-up signal transmitted via hard wire.

[0058] 302. The vehicle controller sends a high voltage power-on request to the battery management system.

[0059] The high voltage power-on request is used to instruct the main positive relay and the main negative relay of the power battery to close. By controlling the main positive relay and the main negative relay to close, the output voltage of the power battery can be transmitted to various parts of the vehicle's high voltage system through media such as high voltage wires, thereby achieving high voltage on the entire vehicle.

[0060] 303. In response to the high-voltage power-on request, the battery management system controls the main positive relay and the main negative relay of the power battery to close, so as to provide the voltage output by the power battery to the DC converter.

[0061] The DC converter is used to convert the input DC power into DC power output with different voltage values ​​according to specific requirements. For example, in the embodiment of the present application, the DC converter can convert the high-voltage DC power output by the power battery into a stable low-voltage DC power for powering the low-voltage system of the vehicle. The voltage value of the high-voltage DC power is usually higher, such as 300-400V, and the voltage value of the low-voltage DC power is lower, such as 12V or 24V.

[0062] 304. The vehicle controller sends a low voltage enable signal to the DC converter.

[0063] Among them, the vehicle controller can send a low-voltage enable signal to the DC converter through the CAN network. Optionally, the low-voltage enable signal may include a voltage signal and an enable signal. Among them, the voltage signal is used to indicate the power supply voltage of the low-voltage device. The voltage signal can also be called a low-voltage output voltage signal, and the low-voltage output voltage signal carries a low-voltage voltage value, that is, the value of the power supply voltage output by the DC converter. The enable signal is used to instruct the DC converter to convert the voltage output by the power battery into the power supply voltage.

[0064] 305. In response to the low voltage enable signal or when the input terminal detects the presence of the voltage output by the power battery, the DC converter converts the voltage output by the power battery into the power supply voltage of the low voltage device, so as to supply power to the low voltage device through the power supply voltage.

[0065] Among them, the DC converter can also perform voltage verification in response to the low-voltage enable signal. When the power supply voltage indicated by the received low-voltage enable signal is greater than the rated voltage, the DC converter converts the voltage output by the power battery into the rated voltage to supply power to the low-voltage equipment through the rated voltage, which can avoid the actual power supply voltage of the low-voltage equipment being greater than the rated voltage, thereby avoiding damage to the low-voltage equipment. The DC converter is also used to return status information to the vehicle controller after voltage conversion. Among them, the status information includes a status flag, which can indicate that the DC converter enters the working state, that is, the DC converter starts voltage conversion.

[0066] It should also be noted that, when the input terminal detects the presence of a voltage output by the power battery, the DC converter can perform voltage conversion according to a preset supply voltage or rated voltage to achieve conversion of the voltage output by the power battery into a preset voltage.

[0067] 306. In response to the key sleep signal, the body controller sends a low-voltage sleep signal to the vehicle controller, the battery management system and the DC converter respectively.

[0068] When the driver turns the key to the OFF position in the ignition switch of the vehicle or pulls out the key, the contacts inside the ignition switch change the connection state, generate a corresponding key sleep signal and send it to the body controller. The low-voltage sleep signal can be an IGN2 low-voltage sleep signal transmitted through hard wire.

[0069] 307. In response to the low-voltage sleep signal, the vehicle controller sends a high-voltage power-off request to the battery management system and sends a power-off enable signal to the DC converter.

[0070] The high voltage power-off request is used to instruct the vehicle to power off the high voltage. The power-off enable signal is used to instruct the DC converter to stop voltage conversion.

[0071] 308. In response to the high voltage power-off request, the battery management system controls the main positive relay and the main negative relay of the power battery to be disconnected.

[0072] Among them, after the main positive relay and the main negative relay of the power battery are disconnected, the path between the power battery and the vehicle's high-voltage system is disconnected, and the power battery can no longer continue to supply power to the vehicle's high-voltage system, thereby achieving high-voltage power-off of the entire vehicle.

[0073] 309. The DC converter enters a sleep state in response to the disconnection enable signal or when it is detected that there is no voltage output by the power battery at the input terminal, so as to stop supplying power to the low-voltage device.

[0074] After the DC converter enters the sleep state, it can be awakened the next time it receives a low-voltage wake-up signal from the vehicle controller, and after awakening, it responds to the low-voltage enable signal or detects the presence of high-voltage DC at the input end to perform voltage conversion, so as to power the low-voltage device with the converted low-voltage DC. In addition, the DC converter is also used to return status information to the vehicle controller after entering the sleep state. The status information includes a status flag, which can indicate that the DC converter has entered the sleep state.

[0075] The embodiment of the present application provides a method for low-voltage power supply for a vehicle, which can enable the battery management system to send a low-voltage enable signal to the DC converter through the CAN bus after the vehicle is awakened and powered on at high voltage, so as to instruct the DC converter to convert the high-voltage electricity output by the power battery into low-voltage electricity, and then use the low-voltage electricity to power the low-voltage equipment. Furthermore, in the case of a CAN interface failure of the DC converter, the DC converter cannot receive the low-voltage enable signal through the CAN bus. At this time, the DC converter can determine whether to perform voltage conversion by detecting whether there is high-voltage electricity output by the power battery at the input end. Using the above method, the DC converter can stably and accurately perform voltage conversion, avoid the low-voltage equipment of the vehicle from being unable to be powered normally due to factors such as CAN interface failure, and improve the stability and reliability of the low-voltage power supply of the vehicle.

[0076] It should be noted that the vehicle low-voltage power supply method provided in the embodiment of the present application belongs to the same concept as the embodiment of the vehicle low-voltage power supply system provided above. Its implementation process can be found in the embodiment of the vehicle low-voltage power supply system above, and will not be repeated here.

[0077] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A vehicle low-voltage power supply system, characterized in that: The system includes a vehicle controller, a battery management system, a DC converter, a power battery and low-voltage equipment; The vehicle controller, the battery management system and the DC converter are connected via a CAN bus, the input end of the DC converter is connected to the power battery, and the output end of the DC converter is connected to the low-voltage device, and the low-voltage device includes a low-voltage battery and a low-voltage load; The vehicle controller is used to send a high-voltage power-on request to the battery management system after waking up; and send a low-voltage enable signal to the DC converter; The battery management system is used for controlling the relay of the power battery to close in response to the high-voltage power-on request, so as to provide the voltage output by the power battery to the DC converter; The DC converter is used to respond to the low voltage enable signal, or when the voltage output by the power battery is detected at the input end, convert the voltage output by the power battery into the power supply voltage of the low voltage device, so as to supply power to the low voltage device through the power supply voltage.

2. The system according to claim 1, characterized in that The low voltage enable signal includes a voltage signal and an enable signal, the voltage signal is used to indicate the power supply voltage of the low voltage device, and the enable signal is used to instruct the DC converter to convert the voltage output by the power battery into the power supply voltage.

3. The system according to claim 2, characterized in that The DC converter is also used to convert the voltage output by the power battery into the rated voltage when the power supply voltage indicated by the received voltage signal is greater than the rated voltage, so as to supply power to the low-voltage device through the rated voltage.

4. The system according to claim 1, characterized in that The input end of the DC converter is connected to a voltage sensor, and the voltage sensor is used to detect the voltage of the input end.

5. The system according to claim 1, characterized in that The DC converter is further used to determine that the voltage output by the power battery exists at the input terminal when the voltage at the input terminal is within a preset range.

6. The system according to claim 1, characterized in that The battery management system is used to control the relay of the power battery to close in response to the high voltage power-on request, including: The battery management system is used to control the main positive relay and the main negative relay of the power battery to close in response to the high-voltage power-on request, the main positive relay is connected to the positive electrode of the power battery, and the main negative relay is connected to the negative electrode of the power battery.

7. The system according to claim 1, characterized in that The system further includes a body controller, which is used to respectively wake up the vehicle controller, the battery management system and the DC converter in response to a wake-up signal.

8. The system according to claim 1, characterized in that The vehicle controller is also used to send a high voltage power-off request to the battery management system in response to the sleep signal, and send a power-off enable signal to the DC converter; The battery management system is further used to control the relay of the power battery to disconnect in response to the high voltage power-off request; The DC converter is also used to enter a dormant state in response to the disconnection enable signal or when it is detected that the voltage output by the power battery is absent at the input terminal, so as to stop supplying power to the low-voltage device.

9. A vehicle low-voltage power supply method, characterized in that: Applied to a vehicle low-voltage power supply system, the system includes a vehicle controller, a battery management system, a DC converter, a power battery and a low-voltage device, the vehicle controller, the battery management system and the DC converter are connected via a CAN bus, the input end of the DC converter is connected to the power battery, and the output end of the DC converter is connected to the low-voltage device, the method includes: After waking up, the vehicle controller sends a high-voltage power-on request to the battery management system and sends a low-voltage enable signal to the DC converter; The battery management system controls the relay of the power battery to close in response to the high-voltage power-on request, so as to provide the voltage output by the power battery to the DC converter; The DC converter responds to the low voltage enable signal or, when detecting that the voltage output by the power battery exists at the input terminal, converts the voltage output by the power battery into the supply voltage of the low voltage device, so as to supply power to the low voltage device through the supply voltage.

10. The method according to claim 9, characterized in that The method further comprises: In response to the sleep signal, the vehicle controller sends a high voltage power-off request to the battery management system and sends a power-off enable signal to the DC converter; The battery management system controls the relay of the power battery to be disconnected in response to the high voltage power-off request; The DC converter enters a dormant state in response to the disconnection enable signal or when detecting that the voltage output by the power battery is absent at the input terminal, so as to stop supplying power to the low-voltage device.

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