A vehicle low-voltage power supply system and a low-voltage power supply method

Abstract

The application discloses a kind of vehicle low-voltage power supply system and low-voltage power supply method, the system includes: battery;Current conversion DCDC module, it includes multiple DCDC, multiple DCDC is mutually parallel with the battery, for being connected with whole vehicle electrical load;Power domain controller PDCU, for enabling single DCDC to supply power for the whole vehicle electrical load according to the power consumption of the whole vehicle electrical load, or enabling multiple DCDC to be balanced output and the battery together to supply power for the whole vehicle electrical load.Multiple DCDC is mutually parallel with battery, when single DCDC fails, other DCDC can normally work to supply power for low-voltage load, improve the stability of DCDC power supply and low-voltage power supply system power supply, and according to the power consumption of the whole vehicle electrical load, multiple DCDC or single DCDC is selected to supply power for the whole vehicle electrical load, can reduce vehicle energy consumption while guaranteeing power supply.

Description

Technical Field

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

[0002] With the development of electric vehicles, the load on the vehicle is increasing, which requires the DC-DC converter to output more and more power. A single DC-DC converter can no longer meet the normal operation of the vehicle's electrical load.

[0003] In related technologies, the problem of insufficient power supply is solved by setting up dual or multiple DC-DC converters in the low-voltage power supply system of a vehicle, and by connecting these dual or multiple DC-DC converters in series to jointly supply power to the electrical load. In a dual-DC-DC low-voltage power supply system, a constant-voltage DC-DC converter and a constant-current DC-DC converter are connected in series to supply power to the electrical load. Because the two DC-DC converters are connected in series, if the constant-voltage DC-DC converter fails, the entire vehicle's low-voltage power supply system will collapse, the voltage will become uncontrollable, and the output power to the electrical load will be unstable. Furthermore, the series-connected dual DC-DC converters can only be used simultaneously, increasing power consumption. When the power demand of the electrical load is low, the simultaneous operation of both DC-DC converters increases the vehicle's energy consumption and wastes energy.

[0004] Therefore, how to improve the stability of DC-DC power supply and low-voltage power supply system and reduce energy consumption while ensuring that DC-DC supplies sufficient power to the electrical load is a technical problem that needs to be solved. Summary of the Invention

[0005] The main objective of this application is to provide a low-voltage power supply system and method for vehicles, aiming to solve the aforementioned technical problems.

[0006] In a first aspect, this application provides a low-voltage power supply system for a vehicle, the system comprising:

[0007] Storage battery;

[0008] A current conversion DC-DC module, comprising multiple DC-DC converters connected in parallel with the battery for connection to the vehicle's electrical load;

[0009] The Power Domain Controller (PDCU) is used to enable a single DC-DC converter to supply power to the vehicle's electrical load based on the power consumption of the vehicle's electrical load, or to enable multiple DC-DC converters to output in a balanced manner and supply power to the vehicle's electrical load together with the battery.

[0010] In some embodiments, the DC-DC module includes a main DC-DC and at least one auxiliary DC-DC, the output power of the main DC-DC is greater than or equal to that of the auxiliary DC-DC, and the PDCU is further used for:

[0011] Determine whether the power consumption of the vehicle's electrical load is less than the output power of the main DC-DC converter;

[0012] If so, then enable the main DC-DC converter to supply power to the vehicle's electrical loads independently;

[0013] Otherwise, when the battery is fault-free and the main output relay of the battery is closed, the main DC-DC converter and the auxiliary DC-DC converter are enabled to output in a balanced manner to supply power to the vehicle's electrical load together with the battery.

[0014] In some embodiments, the PDCU is also used for:

[0015] When the main DC-DC converter and the auxiliary DC-DC converter are enabled to supply power to the vehicle's electrical load together with the battery, the output voltage of the main DC-DC converter is adjusted according to the voltage demand of the vehicle's electrical load.

[0016] The output voltage of the secondary DC-DC converter is adjusted according to the output voltage of the primary DC-DC converter, so that the difference between the output voltages of the primary DC-DC converter and the secondary DC-DC converter is less than a preset voltage difference threshold, and the difference between the output currents is less than a preset current difference threshold.

[0017] In some embodiments, the system further includes a battery management module, the communication module of which is directly connected to the PDCU for communication;

[0018] The battery management module is used for:

[0019] During battery charging, the charging request voltage of the battery is adjusted according to the charging state of the battery, and the output voltage of the DC-DC module is adjusted through the PDCU to enable the battery to perform constant current charging in each charging stage.

[0020] In some embodiments, the battery management module is further configured to:

[0021] The charging request voltage of the battery is determined by looking up a table based on the battery's SOC and temperature.

[0022] The charging request voltage is sent to the PDCU so that the PDCU enables multiple DC-DC converters in the DC-DC module to output equalized values ​​based on the charging request voltage to charge the battery.

[0023] Monitor the charging current of the battery, and when the charging current is greater than or equal to a preset current, reduce the charging request voltage of the battery until the charging current is within the preset current range.

[0024] In some embodiments, the DC-DC module is configured to connect to a high-voltage battery to receive power from the high-voltage battery, and the battery management module is further configured to:

[0025] Based on the SOC status of the battery, the SOC status of the high-voltage battery, and the vehicle status, the PDCU is requested to enable the DC-DC module to recharge the battery.

[0026] In some embodiments, the battery management module is further configured to:

[0027] When the vehicle is in the OFF position, the SOC of the battery is less than a preset first SOC threshold, the SOC of the high-voltage battery is greater than a preset second SOC threshold, the vehicle doors and hood locks are both closed, and the vehicle has no high-voltage fault, the PDCU is requested to enable the DC-DC module to enter the high-voltage state to recharge the battery.

[0028] When the SOC of the storage battery is greater than the preset third SOC threshold or the SOC of the high-voltage battery is less than the preset fourth SOC threshold, the high-voltage power supply system and the low-voltage power supply system of the vehicle are powered down to stop charging the storage battery.

[0029] When the duration of the DC-DC module charging the battery is greater than or equal to a preset time, when the vehicle door is open, when the vehicle is not in the OFF position, or when the vehicle enters a high-voltage charging state, the PDCU is requested to control the DC-DC module to stop charging the battery.

[0030] In some embodiments, the system further includes a status display module, which is used for:

[0031] The system displays the battery charge, the output power of the DC-DC module, and fault information of the low-voltage power supply system.

[0032] In some embodiments, the battery is a lithium battery.

[0033] Secondly, this application also provides a method for supplying low-voltage power to a vehicle, the method comprising the following steps:

[0034] Multiple DC-DC converters in the DC-DC module are connected in parallel with the battery, and the DC-DC module is connected to the vehicle's electrical load.

[0035] The PDCU enables a single DC-DC converter to supply power to the vehicle's electrical load based on the power consumption of the vehicle's electrical load, or enables multiple DC-DC converters to output in a balanced manner to supply power to the vehicle's electrical load together with the battery.

[0036] This application discloses a low-voltage power supply system and method for vehicles. The system includes: a battery; a current conversion DC-DC module comprising multiple DC-DC converters connected in parallel with the battery for connection to the vehicle's electrical load; and a power domain controller (PDCU) for enabling a single DC-DC converter to supply power to the vehicle's electrical load, or enabling multiple DC-DC converters to output power in a balanced manner along with the battery to supply power to the vehicle's electrical load, based on the power consumption of the vehicle's electrical load. The parallel connection of multiple DC-DC converters with the battery ensures that if a single DC-DC converter fails, the others can continue to supply power to the low-voltage load, improving the stability of the DC-DC power supply and the low-voltage power supply system. Furthermore, by selecting between multiple or a single DC-DC converter to supply power to the vehicle's electrical load based on its power consumption, the system can reduce vehicle energy consumption while ensuring power supply. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A schematic block diagram of a vehicle low-voltage power supply system provided in this application embodiment;

[0039] Figure 2 A schematic diagram of the battery charging process;

[0040] Figure 3 A voltage meter representing the charging request at each stage of battery charging.

[0041] Figure 4 This is a schematic flowchart of a low-voltage power supply method for a vehicle provided in an embodiment of this application.

[0042] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0045] This application provides a vehicle low-voltage power supply system and a low-voltage power supply method.

[0046] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0047] Please refer to Figure 1 , Figure 1 A schematic block diagram of a vehicle low-voltage power supply system provided for embodiments of this application.

[0048] The vehicle's low-voltage power supply system includes: a battery, a DC-DC converter module, and a power domain controller (PDCU).

[0049] It is worth noting that the battery in question is a low-voltage battery, specifically a lithium battery. Lithium batteries are characterized by a high depth of discharge; for the same effective discharge energy, lithium batteries are lighter than other batteries. Installing lithium batteries as low-voltage batteries in a vehicle can reduce the overall vehicle weight and increase its range.

[0050] The DC-DC converter module includes multiple DC-DC converters, which are connected in parallel with the battery for connection to the vehicle's electrical load.

[0051] The Power Domain Controller (PDCU) is used to enable a single DC-DC converter to supply power to the vehicle's electrical load based on the power consumption of the vehicle's electrical load, or to enable multiple DC-DC converters to output in a balanced manner and work together with the battery to supply power to the vehicle's electrical load.

[0052] Specifically, the DC-DC module includes a main DC-DC and at least one auxiliary DC-DC. The output power of the main DC-DC is greater than or equal to that of the auxiliary DC-DC. The PDCU is also used to: determine whether the power consumption of the vehicle's electrical load is less than the output power of the main DC-DC; if so, enable the main DC-DC to supply power to the vehicle's electrical load independently; otherwise, when the battery is fault-free and the battery's main output relay is closed, enable the main DC-DC and the auxiliary DC-DC to output in a balanced manner and supply power to the vehicle's electrical load together with the battery.

[0053] Furthermore, the PDCU is also used to: when enabling the main DC-DC and the auxiliary DC-DC to output in a balanced manner together with the battery to supply power to the vehicle's electrical load, adjust the output voltage of the main DC-DC according to the voltage demand of the vehicle's electrical load; adjust the output voltage of the auxiliary DC-DC according to the output voltage of the main DC-DC, so that the difference between the output voltages of the main DC-DC and the auxiliary DC-DC is less than a preset voltage difference threshold, and the difference in output current is less than a preset current difference threshold.

[0054] As an example, this embodiment uses a DC-DC module including DC-DC1 and DC-DC2, where DC-DC1 is the main DC-DC with an output power of 3 kW, and DC-DC2 is the auxiliary DC-DC with an output power of 2.8 kW. The two DC-DCs are connected in parallel with the battery. Under the vehicle's electrical load, when the vehicle's electrical load is low (i.e., the power consumption of the vehicle's electrical load is less than the output power of DC-DC1), only DC-DC1 can be enabled, while DC-DC2 remains disabled and does not participate in providing low-voltage power to the vehicle. When the power supply of a single DC-DC1 cannot meet the vehicle's electrical load, the battery assists in discharging, and the PDCU simultaneously enables both DC-DCs. Furthermore, when the PDCU receives a request voltage from the vehicle's electrical load when the battery is fault-free and the battery's main relay is closed, it receives the requested voltage from the main DC-DC1 and uses this voltage as the target value. Based on the voltage of DC-DC1, it adjusts the voltage value of DC-DC2 to ensure that the load current difference between the two DC-DCs does not exceed 20A and the voltage values ​​of the two DC-DCs do not exceed the target value ±0.3V.

[0055] In this embodiment, a single DC-DC converter or multiple DC-DC converters combined with a battery are selected to supply power to the vehicle's electrical load based on the power consumption of the vehicle's electrical load. This solves the problem of insufficient output from a single DC-DC converter and provides a coordinated control scheme for multiple DC-DC converters, which improves the stability of DC-DC power supply and low-voltage power supply system, while reducing vehicle energy consumption.

[0056] Furthermore, the vehicle low-voltage power supply system also includes a battery management module, whose communication module is directly connected to the PDCU for communication; the battery management module is used to: adjust the charging request voltage of the battery according to the charging state of the battery when the battery is charging, and adjust the output voltage of the DC-DC module through the PDCU so that the battery can be charged with constant current at each charging stage.

[0057] Specifically, such as Figure 2 As shown, the battery management module is further configured to: determine the charging request voltage of the battery by looking up a table based on the battery's SOC and temperature; send the charging request voltage to the PDCU so that the PDCU enables multiple DC-DC converters in the DC-DC module to output in a balanced manner with the charging request voltage as the target, to charge the battery; monitor the charging current of the battery, and when the charging current is greater than or equal to a preset current, reduce the charging request voltage of the battery until the charging current is within the preset current range.

[0058] As an example, the battery management module collects state parameters such as SOC, voltage, current, and temperature, and requests the DC-DC converter to output different voltages to charge the battery based on these parameters. For example... Figure 3 As shown, the battery, based on its own state, aims for constant current charging. During the charging process, a stable voltage difference is maintained between the DC-DC output and the battery's internal voltage. Battery charging is divided into four stages: depletion and replenishment stage, full charge stage, power preservation stage, and overvoltage prevention stage. In the depletion and full charge stages, the battery's charging request voltage is approximately 0.5V greater than or equal to the DC-DC module's output voltage. This voltage difference is maintained to ensure a current value of approximately 100A, achieving fast charging. If the detected current value deviates significantly from this target current value of 100A, for example, a deviation greater than or equal to 10A, the battery's charging request voltage is reduced to keep the current near the target value. Voltage regulation is stepless to ensure the constant current charging effect. In the power preservation stage, the battery is fully charged. Due to the vehicle's electrical balance, a battery buffer discharge occurs, and both the battery voltage and the DC-DC module's output voltage are stable. The charging current is reduced at this time to prevent excessive current from damaging the battery's lifespan. During the overvoltage protection phase, the battery charging request voltage remains constant, and the DC-DC module also maintains a constant voltage level. At this time, the charging current is essentially zero, preventing current surges that could cause battery overvoltage. Furthermore, if a fault exists in the low-voltage power supply system, leading to excessively high voltage, the battery will request a lower voltage to allow the PDCU to reduce the DC-DC module's output, and the battery will enter an auxiliary discharge state, preventing voltage runaway in the low-voltage power supply system.

[0059] Furthermore, the DC-DC module is used to connect to the high-voltage battery to receive power from the high-voltage battery. The battery management module is also used to request the PDCU to enable the DC-DC module to recharge the battery based on the SOC state of the battery, the SOC state of the high-voltage battery, and the vehicle state.

[0060] Specifically, the battery management module is also used to: request the PDCU to enable the DC-DC module to enter high-voltage state to charge the battery when the vehicle is in the OFF position, the SOC of the battery is less than a preset first SOC threshold, the SOC of the high-voltage battery is greater than a preset second SOC threshold, the vehicle doors and hood locks are both closed, and the vehicle has no high-voltage fault; when the SOC of the battery is greater than a preset third SOC threshold or the SOC of the high-voltage battery is less than a preset fourth SOC threshold, control the high-voltage power supply system and low-voltage power supply system of the vehicle to shut down and stop charging the battery; when the duration of the DC-DC module charging the battery is greater than or equal to a preset time, the vehicle doors are open, the vehicle is not in the OFF position, or the vehicle enters high-voltage charging state, request the PDCU to control the DC-DC module to stop charging the battery.

[0061] As an example, the battery management module communicates directly with the power domain controller (PDCU), avoiding multiple information transmissions. The low-voltage power supply system of this application enables intelligent wake-up and recharging, solving the problem of the vehicle failing to start due to a dead battery during long-term storage or abnormal vehicle power consumption. Specifically, when the vehicle is in the OFF position, the recharging function is activated. When the battery SOC < X1%, the power battery SOC ≥ Y1%, and the vehicle's five doors and hood locks are closed, and there is no high-voltage fault in the vehicle, the battery management module requests the PDCU to enable the DC-DC module to actively charge the battery with high voltage.

[0062] Furthermore, battery charging will cease under the following circumstances: When the battery SOC > X2%, battery charging will stop, and the vehicle's high and low voltages will be cut off; or, when the power battery SOC < Y2%, or when the power battery malfunctions, the PDCU will report that the DC-DC converter cannot charge the battery, and the vehicle's high and low voltages will be cut off; or, if the charging time exceeds 30 minutes, the battery management module will send a stop charging request to the PDCU; or, when a door is opened, unlocked, or the hood lock is opened, the battery management module will send a stop charging request to the PDCU; or, when the vehicle's power supply level changes, and the vehicle's power supply level is no longer OFF, the charging request will stop; or, when the vehicle enters the high-voltage charging process, battery charging will cease, and the DC-DC converter will output normally.

[0063] In one embodiment, the system further includes a status display module for displaying the battery charge, the output power of the DC-DC module, and fault information of the low-voltage power supply system.

[0064] As an example, the vehicle low-voltage power supply system also includes a communication module composed of a body domain controller (VIU), an audio-visual domain controller (IVI), and a PDCU, as well as a combination of an instrument cluster and a central control screen. The battery, high-voltage battery, and DC-DC module transmit their status information to the PDCU via CAN / LIN communication. The PDCU forwards this information to the IVI, displaying the low-voltage power supply system information and enabling interaction with the driver. It displays real-time information such as DC-DC output power, battery and high-voltage battery charge levels and battery health, and provides pop-up and graphic alerts in case of low-voltage power supply system failure.

[0065] The beneficial effects of the vehicle low-voltage power supply system provided in this application embodiment are as follows: the low-voltage power supply system composed of lithium batteries can reduce the power consumption of the low-voltage power supply system, and the advantage of low weight can also increase the vehicle's range. Furthermore, the low-voltage power supply system and control scheme composed of dual or multiple DC-DC converters and batteries solve the problems of insufficient output of a single DC-DC converter and the collaborative construction of a low-voltage power supply system by multiple DC-DC converters. The battery charging and discharging control achieves target constant current and dynamic stepless adjustment, realizing closed-loop control of the low-voltage power supply system during the charging process, avoiding large current surges and instability of the low-voltage power supply system during charging, and extending the battery's service life. The intelligent charging scheme prevents the problem of the vehicle failing to start due to battery depletion after long-term storage. The addition of a low-voltage power supply system status display allows for information interaction with the user, enabling real-time understanding of the vehicle's information.

[0066] like Figure 4 As shown, this application also provides a low-voltage power supply method for a vehicle, characterized by comprising:

[0067] Multiple DC-DC converters in the DC-DC module are connected in parallel with the battery, and the DC-DC module is connected to the vehicle's electrical load.

[0068] The PDCU enables a single DC-DC converter to supply power to the vehicle's electrical load based on the power consumption of the vehicle's electrical load, or enables multiple DC-DC converters to output in a balanced manner to supply power to the vehicle's electrical load together with the battery.

[0069] The battery in question is a lithium battery.

[0070] The DC-DC module includes a main DC-DC and at least one auxiliary DC-DC. The output power of the main DC-DC is greater than or equal to that of the auxiliary DC-DC. The step of enabling a single DC-DC to supply power to the vehicle's electrical load, or enabling multiple DC-DCs to output in a balanced manner to supply power to the vehicle's electrical load together with the battery, via the PDCU based on the power consumption of the vehicle's electrical load, includes:

[0071] The PDCU determines whether the power consumption of the vehicle's electrical load is less than the output power of the main DC-DC converter.

[0072] If so, then enable the main DC-DC converter to supply power to the vehicle's electrical loads independently;

[0073] Otherwise, when the battery is fault-free and the main output relay of the battery is closed, the PDCU enables the main DC-DC converter and the auxiliary DC-DC converter to output power in a balanced manner together with the battery to supply power to the vehicle's electrical load.

[0074] The system further includes enabling the main DC-DC converter and the auxiliary DC-DC converter to balance their outputs and supply power to the vehicle's electrical loads together with the battery via the PDCU.

[0075] The PDCU adjusts the output voltage of the main DC-DC converter according to the voltage requirements of the vehicle's electrical load.

[0076] The PDCU adjusts the output voltage of the secondary DC-DC based on the output voltage of the primary DC-DC, so that the difference between the output voltages of the primary DC-DC and the secondary DC-DC is less than a preset voltage difference threshold, and the difference between the output currents is less than a preset current difference threshold.

[0077] The methods also include:

[0078] The communication module of the battery management module is connected directly to the PDCU for communication;

[0079] During battery charging, the battery management module adjusts the battery charging request voltage according to the battery's charging status, and adjusts the output voltage of the DC-DC module through the PDCU, so that the battery can be charged with constant current at each charging stage.

[0080] The method also includes:

[0081] The battery management module determines the charging request voltage of the battery by looking up a table based on the battery's SOC and temperature.

[0082] The battery management module sends the charging request voltage to the PDCU, so that the PDCU enables multiple DC-DC converters in the DC-DC module to output in a balanced manner with the charging request voltage as the target, so as to charge the battery.

[0083] The battery management module monitors the charging current of the battery, and when the charging current is greater than or equal to a preset current, it reduces the charging request voltage of the battery until the charging current is within the preset current range.

[0084] The method also includes:

[0085] The DC-DC module is used to connect to a high-voltage battery to receive power from the high-voltage battery;

[0086] The battery management module requests the PDCU to enable the DC-DC module to recharge the battery based on the SOC status of the storage battery, the SOC status of the high-voltage battery, and the vehicle status.

[0087] The method also includes:

[0088] When the vehicle is in the OFF position, the SOC of the battery is less than a preset first SOC threshold, the SOC of the high-voltage battery is greater than a preset second SOC threshold, the vehicle doors and hood locks are both closed, and the vehicle has no high-voltage fault, the battery management module requests the PDCU to enable the DC-DC module to enter the high-voltage state to recharge the battery.

[0089] When the SOC of the battery is greater than a preset third SOC threshold or the SOC of the high-voltage battery is less than a preset fourth SOC threshold, the battery management module controls the high-voltage power supply system and the low-voltage power supply system of the vehicle to shut down and stop charging the battery.

[0090] When the duration of the DC-DC module charging the battery is greater than or equal to a preset time, when the vehicle door is open, when the vehicle is not in the OFF position, or when the vehicle enters a high-voltage charging state, the battery management module requests the PDCU to control the DC-DC module to stop charging the battery.

[0091] The method also includes:

[0092] The status display module displays the battery charge, the output power of the DC-DC module, and fault information of the low-voltage power supply system.

[0093] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0094] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0095] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A low-voltage power supply system for a vehicle, characterized in that, include: Storage battery; A current conversion DC-DC module, comprising multiple DC-DC converters connected in parallel with the battery for connection to the vehicle's electrical load; The Power Domain Controller (PDCU) is used to enable a single DC-DC converter to supply power to the vehicle's electrical load based on the power consumption of the vehicle's electrical load, or to enable multiple DC-DC converters to output in a balanced manner and supply power to the vehicle's electrical load together with the battery. The DC-DC module includes a main DC-DC converter and at least one auxiliary DC-DC converter. The output power of the main DC-DC converter is greater than or equal to that of the auxiliary DC-DC converter. The PDCU is also used for: Determine whether the power consumption of the vehicle's electrical load is less than the output power of the main DC-DC converter; If so, then enable the main DC-DC converter to supply power to the vehicle's electrical loads independently; Otherwise, when the battery is fault-free and the main output relay of the battery is closed, the main DC-DC converter and the auxiliary DC-DC converter are enabled to output in a balanced manner to supply power to the vehicle's electrical load together with the battery; The PDCU is also used for: When the main DC-DC converter and the auxiliary DC-DC converter are enabled to supply power to the vehicle's electrical load together with the battery, the output voltage of the main DC-DC converter is adjusted according to the voltage demand of the vehicle's electrical load. The output voltage of the secondary DC-DC converter is adjusted according to the output voltage of the primary DC-DC converter, so that the difference between the output voltages of the primary DC-DC converter and the secondary DC-DC converter is less than a preset voltage difference threshold, and the difference between the output currents is less than a preset current difference threshold.

2. The vehicle low-voltage power supply system according to claim 1, characterized in that, The system also includes a battery management module, whose communication module is directly connected to the PDCU for communication. The battery management module is used for: During battery charging, the charging request voltage of the battery is adjusted according to the charging state of the battery, and the output voltage of the DC-DC module is adjusted through the PDCU to enable the battery to perform constant current charging in each charging stage.

3. The vehicle low-voltage power supply system according to claim 2, characterized in that, The battery management module is also used for: The charging request voltage of the battery is determined by looking up a table based on the battery's SOC and temperature. The charging request voltage is sent to the PDCU, so that the PDCU enables multiple DC-DC converters in the DC-DC module to output equalized values ​​based on the charging request voltage to charge the battery. Monitor the charging current of the battery, and when the charging current is greater than or equal to a preset current, reduce the charging request voltage of the battery until the charging current is within the preset current range.

4. The vehicle low-voltage power supply system according to claim 2, characterized in that, The DC-DC module is used to connect to the high-voltage battery to receive power from the high-voltage battery. The battery management module is also used for: Based on the SOC status of the battery, the SOC status of the high-voltage battery, and the vehicle status, the PDCU is requested to enable the DC-DC module to recharge the battery.

5. The vehicle low-voltage power supply system according to claim 4, characterized in that, The battery management module is also used for: When the vehicle is in the OFF position, the SOC of the battery is less than a preset first SOC threshold, the SOC of the high-voltage battery is greater than a preset second SOC threshold, the vehicle doors and hood locks are both closed, and the vehicle has no high-voltage fault, the PDCU is requested to enable the DC-DC module to enter the high-voltage state to recharge the battery. When the SOC of the storage battery is greater than the preset third SOC threshold or the SOC of the high-voltage battery is less than the preset fourth SOC threshold, the high-voltage power supply system and the low-voltage power supply system of the vehicle are powered down to stop charging the storage battery. When the duration of the DC-DC module charging the battery is greater than or equal to a preset time, when the vehicle door is open, when the vehicle is not in the OFF position, or when the vehicle enters a high-voltage charging state, the PDCU is requested to control the DC-DC module to stop charging the battery.

6. The vehicle low-voltage power supply system according to claim 1, characterized in that, The system also includes a status display module, which is used for: The system displays the battery charge, the output power of the DC-DC module, and fault information of the low-voltage power supply system.

7. The vehicle low-voltage power supply system according to claim 1, characterized in that, The battery is a lithium battery.

8. A method for supplying low-voltage power to a vehicle, characterized in that, include: Multiple DC-DC converters in the DC-DC module are connected in parallel with the battery, and the DC-DC module is connected to the vehicle's electrical load. The PDCU enables a single DC-DC converter to supply power to the vehicle's electrical load based on the power consumption of the vehicle's electrical load, or enables multiple DC-DC converters to output in a balanced manner and supply power to the vehicle's electrical load together with the battery. The DC-DC module includes a main DC-DC and at least one auxiliary DC-DC. The output power of the main DC-DC is greater than or equal to that of the auxiliary DC-DC. The step of enabling a single DC-DC to supply power to the vehicle's electrical load, or enabling multiple DC-DCs to output in a balanced manner to supply power to the vehicle's electrical load together with the battery, via the PDCU based on the power consumption of the vehicle's electrical load, includes: The PDCU determines whether the power consumption of the vehicle's electrical load is less than the output power of the main DC-DC converter. If so, then enable the main DC-DC converter to supply power to the vehicle's electrical loads independently; Otherwise, when the battery is fault-free and the main output relay of the battery is closed, the PDCU enables the main DC-DC converter and the auxiliary DC-DC converter to output in a balanced manner to supply power to the vehicle's electrical load together with the battery; The system further includes enabling the main DC-DC converter and the auxiliary DC-DC converter to balance their outputs and supply power to the vehicle's electrical loads together with the battery via the PDCU. The PDCU adjusts the output voltage of the main DC-DC converter according to the voltage requirements of the vehicle's electrical load. The PDCU adjusts the output voltage of the secondary DC-DC based on the output voltage of the primary DC-DC, so that the difference between the output voltages of the primary DC-DC and the secondary DC-DC is less than a preset voltage difference threshold, and the difference between the output currents is less than a preset current difference threshold.

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