A control method for a dual DCDC system of an autonomous driving vehicle

Abstract

A control method for a dual DCDC system in an autonomous vehicle relates to the field of vehicle technology and includes a power battery, a first DCDC converter, a second DCDC converter, a first battery, a second battery, a vehicle controller, an autonomous driving system, and a body controller. The power battery is electrically connected to the first and second DCDC converters; the first battery and the vehicle controller are electrically connected to the first DCDC converter; the second battery and the autonomous driving system are electrically connected to the second DCDC converter; and the body controller is electrically connected to the first and second batteries. The present invention utilizes a dual DCDC solution, configuring independently controllable DCDC converters and batteries for the autonomous driving system and the vehicle system, respectively. This ensures that the high power and safe operation requirements of the autonomous driving system are met while also improving the stability and safety of the vehicle system, effectively overcoming the problems associated with the single DCDC solution used in existing technologies.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a control method for a dual DCDC system of an autonomous driving vehicle. Background Art

[0002] As a key component of a pure electric vehicle's powertrain, the DC-DC converter converts the high-voltage DC power from the vehicle's power battery into a stable and reliable low-voltage DC power supply, which is used to power the vehicle's low-voltage electrical appliances and simultaneously charge the battery. Generally, a pure electric vehicle is designed and matched with a suitable DC-DC converter based on the vehicle's low-voltage electrical power balance, ensuring a balanced power consumption and battery charge and discharge.

[0003] With the rapid development of autonomous driving technology, vehicles are becoming increasingly intelligent, and the complexity of their intelligent equipment is increasing. As a result, the number of electronic control units (ECUs) on a self-driving vehicle is rapidly increasing, leading to a gradual increase in vehicle power consumption and dark current, and consequently, higher power requirements for DC-DC converters. Therefore, if a single DC-DC solution is still used, the DC-DC converter power requirement will be too high, making it difficult to find a suitable product.

[0004] In addition, autonomous driving systems have strict requirements for functional safety. To ensure the safe operation of autonomous driving systems, the requirements for power supply are even more stringent. Therefore, if a single DCDC solution is still used, and the autonomous driving system and the entire vehicle system share a power supply and DCDC converter, it will not be able to meet the safe operation requirements of the autonomous driving system, and will also affect the stability and safety of the entire vehicle's power supply. Summary of the Invention

[0005] The present invention provides a control method for a dual DCDC system of an autonomous driving vehicle, the main purpose of which is to solve the problems existing in the prior art.

[0006] The present invention adopts the following technical solutions:

[0007] A control method for a dual DCDC system of an autonomous driving vehicle, the dual DCDC system comprising a power battery, a first DCDC converter, a second DCDC converter, a first storage battery, a second storage battery, a vehicle controller, an autonomous driving system, and a body controller; the power battery is electrically connected to the first and second DCDC converters; the first storage battery and the vehicle controller are electrically connected to the first DCDC converter; the second storage battery and the autonomous driving system are electrically connected to the second DCDC converter; and the body controller is electrically connected to the first and second batteries;

[0008] The control method comprises the following steps:

[0009] S1. The vehicle controller determines whether the vehicle is in the off state, on state, or charging state. If the vehicle is in the off state, step S2 is executed; if the vehicle is in the on state, step S3 is executed; if the vehicle is in the charging state, step S4 is executed;

[0010] S2: In the ignition off state, if the voltage of any battery is lower than the set voltage, the intelligent charging signal is turned on, and the vehicle controller controls the corresponding DCDC converter to be in working state, thereby charging the battery;

[0011] S3, in the startup state, the vehicle controller controls the first DCDC converter and the second DCDC converter to be in the working state;

[0012] S4. In the charging state, the vehicle controller further determines the vehicle's charging mode. If it is the OFF gear charging mode, step S5 is executed; if it is the charging parallel ON gear mode, step S6 is executed; if it is the charging mode in the high voltage power-on state, step S7 is executed;

[0013] S5: The vehicle is in OFF charging mode, the vehicle controller controls the power battery to enter the charging state, and controls the first DCDC converter to be in the intermittent working state;

[0014] S6: The vehicle is in charging parallel ON mode. The vehicle controller controls the power battery to maintain a charging state, controls the first DCDC converter to maintain an operating state, and controls the second DCDC converter to enter an operating state.

[0015] S7, when the vehicle is in the high-voltage power-on state, the charging mode, the vehicle controller controls the driving power to zero, controls the power battery to enter the charging state, and controls the first DCDC converter and the second DCDC converter to remain in the working state.

[0016] Furthermore, in step S2, the body controller regularly monitors the voltage values ​​of the first battery and the second battery within a preset time interval T. If the body controller detects that the voltage value of any battery is lower than a preset threshold, the body controller will send an intelligent power replenishment start signal to wake up the vehicle controller and enter the intelligent power replenishment mode; if the voltage value of the first battery and / or the second battery is not lower than the set voltage value, the body controller will continue to maintain the monitoring state so as to respond in time.

[0017] Furthermore, in step S2, the vehicle controller determines whether the vehicle meets the charging conditions based on whether the current charge of the power battery is higher than the set threshold and whether the available discharge power of the power battery is higher than the set threshold. If the charging conditions are met, the intelligent charging mode is turned on; otherwise, the intelligent charging mode is not turned on.

[0018] Furthermore, in step S5, the vehicle controller monitors the voltage value of the first battery in real time. If the voltage value of the first battery is lower than a preset threshold, the first DCDC converter is controlled to start working to charge the first battery. If the voltage value of the first battery is not lower than the preset threshold, the first DCDC converter is controlled to stop working, thereby realizing intermittent operation of the first DCDC converter.

[0019] Furthermore, the dual DCDC system further includes a high-voltage distribution box, and the power battery is connected to the first DCDC converter and the second DCDC converter via the high-voltage distribution box.

[0020] Furthermore, the high-voltage distribution box is connected to the power battery through a main circuit, and is connected to the first DCDC converter and the second DCDC converter through a first branch and a second branch respectively, the first branch is provided with a first DCDC contactor and a first DCDC fuse, and the second branch is provided with a second DCDC contactor and a second DCDC fuse.

[0021] Furthermore, the power battery, the first DCDC converter, the second DCDC converter, the vehicle controller, the automatic driving system, the body controller and the high-voltage distribution box are all communicatively connected to each other via a CAN network.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention adopts a dual DCDC solution, configuring independently controllable DCDC converters and batteries for the autonomous driving system and the entire vehicle system, respectively. This ensures that the power management of the autonomous driving system and the entire vehicle system do not interfere with each other, thereby ensuring that the high power requirements and safe operation requirements of the autonomous driving system are met, while also improving the stability and safety of the entire vehicle system, effectively overcoming the problems existing in the existing technology using a single DCDC solution.

[0024] 2. The present invention achieves fine control of the dual DCDC system by finely dividing the vehicle state and charging state of the autonomous vehicle. This intelligently controls the operating mode of the DCDC converter and rationally adjusts the start and stop time of the DCDC converter, thereby improving the operating efficiency of the DCDC converter and the energy utilization rate of the entire vehicle, achieving better energy conservation and consumption reduction, increasing the vehicle's cruising range, and protecting the life of the DCDC converter.

[0025] 3. The present invention uses an intelligent control strategy to intelligently control the working mode of the dual DCDC system, realizes intelligent management of the low-voltage power supply of the autonomous driving vehicle, meets the special usage scenario requirements of the autonomous driving vehicle, and improves the power safety of the autonomous driving vehicle, with convenient operation, fast response speed and high control efficiency.

[0026] 4. The dual DCDC system of the present invention integrates a real-time battery voltage monitoring function, which can intelligently control the DCDC converter to charge the battery, preventing the battery from being depleted due to various factors such as the energy consumption of electrical components and the self-discharge rate. This optimizes the battery's operating environment, helps maintain the battery in good health, ensures the battery's service life, and reduces battery maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the overall block diagram of the dual DCDC system in the present invention.

[0028] Figure 2 Schematic diagram of the structure of the dual DCDC system in the present invention.

[0029] Figure 3 This is a circuit structure diagram of the high-voltage distribution box in the present invention.

[0030] Figure 4 Schematic diagram of the overall control method of the dual DCDC system in the present invention.

[0031] Figure 5 This is a control flow chart of the dual DCDC system in the intelligent power replenishment mode of the present invention.

[0032] Figure 6 This is a control flow chart of the dual DCDC system in the high voltage power-on mode of the present invention.

[0033] Figure 7 This is a control flow chart of the dual DCDC system in the OFF charging mode of the present invention.

[0034] Figure 8 This is a control flow chart of the dual DCDC system in the charging parallel ON mode of the present invention.

[0035] Figure 9 This is a control flow chart of the dual DCDC system in the high voltage power-on state charging mode of the present invention. DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention are described below with reference to the accompanying drawings. In order to fully understand the present invention, many details are described below, but for those skilled in the art, the present invention can be implemented without these details.

[0037] like Figure 1As shown, the present invention provides a dual DCDC system for an autonomous driving vehicle, comprising a power battery, a first DCDC converter, a second DCDC converter, a first storage battery, a second storage battery, a vehicle controller, an autonomous driving system, and a body controller. The power battery is electrically connected to the first and second DCDC converters; the first storage battery and the vehicle controller are electrically connected to the first DCDC converter; the second storage battery and the autonomous driving system are electrically connected to the second DCDC converter; and the body controller is electrically connected to the first and second batteries. The present invention employs a dual DCDC solution, configuring independently controllable DCDC converters and batteries for the autonomous driving system and the vehicle system, respectively. This ensures that the power management of the autonomous driving system and the vehicle system do not interfere with each other, thereby ensuring that the high power requirements and safe operation requirements of the autonomous driving system are met while improving the stability and safety of the vehicle system. This effectively overcomes the problems of the single DCDC solution used in the prior art.

[0038] like Figures 1 to 3 As shown, the dual DC-DC system also includes a high-voltage power distribution unit (PDU), which connects the power battery to the first and second DC-DC converters via the PDU. Specifically, the PDU is connected to the power battery via a main circuit and to the first and second DC-DC converters via a first branch circuit and a second branch circuit, respectively. The first branch circuit is equipped with a first DC-DC contactor and a first DC-DC fuse, while the second branch circuit is equipped with a second DC-DC contactor and a second DC-DC fuse. The PDU enables centralized management of high-voltage power distribution to the power battery, enabling precise control of each voltage output. Due to the presence of two DC-DC converters and batteries, this embodiment integrates the PDU into the power battery compartment to conserve interior space.

[0039] like Figure 1 and Figure 2 As shown, the power battery, first and second DC-DC converters, vehicle controller, autonomous driving system, body controller, and high-voltage power distribution box are all interconnected via a CAN network. During operation, these components exchange information via the CAN network, enabling intelligent control of the dual-DC-DC system.

[0040] like Figure 2As shown, as a preferred solution: the autonomous driving vehicle in this embodiment is a special vehicle working in the autonomous driving park. Based on the driving environment of the autonomous driving park and the working requirements of the vehicle, the autonomous driving system includes a decision-making and planning system, a vehicle positioning and motion perception system, a human-computer interaction system and an environmental perception system, which are respectively connected to the second DCDC converter. Specifically, the decision-making and planning system is connected to a computing unit, a switch, a router and a security module; the vehicle positioning and motion perception system is connected to an inertial navigation host, a GPS antenna and a 4G module. The human-computer exchange system is connected to an information display screen and a voice box. The environmental perception system is connected to a laser radar, a millimeter-wave radar, an ultrasonic radar and a visual camera. Of course, in actual applications, the various modules of the autonomous driving system can also be reasonably set according to the driving environment and functional requirements of the autonomous driving vehicle.

[0041] like Figure 4 To more clearly illustrate the working principle of the dual DCDC system, the overall control method of the dual DCDC system is described in detail below. The control method includes the following steps:

[0042] S1. The vehicle controller determines whether the vehicle status is off, on, or charging. If the vehicle status is off, execute step S2; if the vehicle status is on, execute step S3; if the vehicle status is charging, execute step S4.

[0043] S2. In the ignition-off state, if the voltage of any battery falls below a set value, an intelligent charging signal is activated, and the vehicle controller controls the corresponding DC-DC converter to operate, thereby charging the battery. Specifically, the body controller monitors the voltage of the first and second batteries in real time. If the body controller detects that the voltage of either battery falls below a set value, it sends an intelligent charging activation signal, waking the vehicle controller and entering intelligent charging mode. The vehicle controller then controls the power battery output and sends an operating enable signal via the CAN network, thereby controlling the corresponding DC-DC converter to operate and charge the battery. If the voltage of the first and / or second battery does not fall below the set value, the body controller continues monitoring to facilitate timely response. In this step, the vehicle controller determines whether the vehicle meets the charging conditions based on whether the current charge of the power battery is above a set threshold and whether the available discharge power of the power battery is above a set threshold. If the conditions are met, the intelligent charging mode is activated; otherwise, the intelligent charging mode is not activated.

[0044] In S3, in the startup state, the vehicle controller controls both the first and second DCDC converters to be in the operating state. Specifically, when the vehicle controller recognizes that the vehicle ignition signal is in the startup state, that is, in the high-voltage power-up mode, it controls the power battery to output high voltage by sending a control instruction to the CAN network and sends an operation enable signal to control both the first and second DCDC converters to be in the operating state.

[0045] S4. When the vehicle controller determines that the vehicle state is charging according to the charging connection signal, it further determines the vehicle charging mode according to the identification of the vehicle ignition signal. If it is the OFF gear charging mode, execute step S5; if it is the charging parallel ON gear mode, execute S6; if it is the charging mode in the high-voltage power-on state, execute S7.

[0046] S5. The vehicle is in the OFF charging mode. The vehicle controller controls the power battery to enter the charging state and controls the first DCDC converter to enter the intermittent operation state. Specifically, the vehicle controller controls the power battery to enter the charging state by sending control instructions to the CAN network. While the power battery is charging, the vehicle controller monitors the voltage of the first battery in real time. If the voltage of the first battery is lower than a preset threshold, the vehicle controller controls the first DCDC converter to start charging the first battery. If the voltage of the first battery is higher than the preset threshold, the vehicle controller controls the first DCDC converter to stop operating, thereby achieving intermittent operation of the first DCDC converter.

[0047] S6: The vehicle is in charging parallel ON mode. The vehicle controller controls the power battery to maintain a charging state, controls the first DCDC converter to maintain an operating state, and controls the second DCDC converter to enter an operating state. Specifically, the vehicle controller controls the power battery to maintain a charging state by sending control instructions to the CAN network, controls the first DCDC converter to maintain a high-voltage input at its input terminal and to enable operation, thereby maintaining the first DCDC converter in an operating state. Simultaneously, the vehicle controller controls the second DCDC converter to receive power at its high-voltage input terminal and to send an operation enable signal, thereby maintaining the second DCDC converter in an operating state.

[0048] S7: When the vehicle is in the high-voltage power-on state, the vehicle controller controls the driving power to zero, controls the power battery to enter the charging state, and controls the first and second DCDC converters to remain in the operating state. Specifically, the vehicle controller sends control instructions to the CAN network to control the power battery to enter the charging state by closing the charging circuit, controlling the disconnection of the main drive high-voltage circuit, and controlling the first and second DCDC converters to maintain the high-voltage input at their input terminals and enable operation, thereby keeping the first and second DCDC converters in the operating state.

[0049] The reason why the present invention further subdivides the vehicle's charging mode into three states: OFF gear charging mode, charging parallel ON gear mode, and charging mode in high-voltage power-on state is that: if the user has ample charging time or has high requirements for charging efficiency, he can choose to charge in OFF gear, that is, to turn off the automatic driving system, thereby reducing energy consumption and speeding up the charging speed. However, since the automatic driving system is equipped with a large number of intelligent equipment, the time to start networking is also relatively long. Therefore, if the user wants to reduce the startup waiting time of the automatic driving system, he can choose to enter the charging parallel ON gear mode when the OFF gear charging is about to end, and power on the automatic driving system in advance to ensure that the vehicle can be used immediately after charging is completed. If the vehicle is in the high-voltage power-on state before charging, you can also choose the charging mode in the high-voltage power-on state, that is, the vehicle does not reduce the high voltage and charges directly in the ON gear, thereby ensuring that the automatic driving system is always in a real-time online state. The specific differences and advantages of these three charging modes are:

[0050] (1) In the OFF charging mode, all components that are not required to work during the charging process are turned off, and there is no need to turn on the second DCDC converter to power the autonomous driving system. Only the first DCDC converter is needed to power the components of the vehicle system that must work during the charging process. Therefore, the vehicle has lower energy consumption and faster charging speed.

[0051] (2) In the ON charging mode, the second DCDC converter starts working only when there is an ON signal, which can reduce some energy consumption, appropriately optimize the charging speed, and shorten the startup waiting time of the intelligent driving system.

[0052] (3) In the charging mode when the high voltage is on, the second DCDC converter is always in the on-working state. The autonomous driving system is online in real time and can work at any time without waiting for restart, thereby improving operational efficiency.

[0053] The following is based on Figure 3 and Figure 5 The dual DCDC system control method in the intelligent charging mode of step S2 is described in detail:

[0054] S2-1. When the vehicle is in an ignition-off state, the vehicle body controller regularly monitors the voltages of the first battery and the second battery within a preset time interval T.

[0055] S2-2. The vehicle body controller determines whether the voltage value of any battery is lower than the preset threshold value U1. If so, step S2-3 is executed; otherwise, the battery voltage value continues to be monitored.

[0056] S2-3. When the vehicle body controller detects that the voltage of any battery is lower than the preset threshold U1, it sends an "intelligent recharge request" message of the corresponding battery to the CAN network and outputs a 12V high level to wake up the vehicle controller.

[0057] S2-4, the vehicle controller is automatically awakened by the 12V high level input through the hard line, and controls the output of 12V high level to wake up the BMS according to the "intelligent power replenishment request" message in the CAN network.

[0058] S2-5, BMS wakes up and performs self-test through the 12V high level input by hard line, and sends basic battery information including the current charge of the power battery and the current available discharge power of the power battery to the CAN network.

[0059] S2-7. The vehicle controller determines whether the vehicle meets the charging conditions based on whether the current charge of the power battery is higher than the set threshold and whether the available discharge power of the power battery is higher than the set threshold; if the charging conditions are not met, execute step S2-8; if the charging conditions are met, execute step S2-9.

[0060] S2-8. The vehicle controller sends a "smart charging function prohibition request" message to the body controller, and at the same time pushes the battery low power information to the cloud server, and charges the power battery in time. The body controller sets the sent smart charging request signal, disconnects the 12V high-level wake-up output, and restarts the timing to re-execute step S2-1.

[0061] S2-9, the vehicle controller turns on the intelligent charging mode and sends a control instruction to the BMS, so that the BMS controls the main negative contactor, the first DCDC contactor and / or the second DCDC contactor in the high-voltage control box to close in sequence.

[0062] S2-10. The vehicle controller sends a "work enable request" message to the first DCDC converter and / or the second DCDC converter through the CAN network.

[0063] S2-11. The first DCDC converter and / or the second DCDC converter are awakened and work, converting the high voltage output by the power battery into a low voltage power supply to replenish the first battery and / or the second battery, and at the same time feeding back the message containing the DCDC working status to the CAN network. The first stage of the DCDC converter's operation is the constant current output stage, replenishing the battery with a constant current. When the replenishment voltage reaches the set threshold U2, it enters the constant voltage output stage, replenishing the battery with a constant voltage. The closer the battery is to a fully charged state, the smaller the output current.

[0064] S2-12: Determine whether the battery is fully charged based on whether the output current of the DCDC converter is less than the set value I.

[0065] S2-13. After the battery is fully charged, the intelligent charging mode is exited, and the vehicle controller sets the work enable request sent to the first DCDC converter and / or the second DCDC converter, and sends a control instruction to the BMS, so that the BMS controls the first DCDC contactor and / or the second DCDC contactor and the main negative contactor in the high-voltage control box to be disconnected in sequence.

[0066] S2-14: The vehicle controller, the BMS, the first DCDC converter and / or the second DCDC converter stop working and enter a dormant state.

[0067] The following is based on Figure 3 and Figure 6 The dual DCDC system control method in the high voltage power-on mode of step S3 is described in detail:

[0068] S3-1. The vehicle ignition signal is in the start state.

[0069] S3-2: The vehicle controller wakes up autonomously via a hard-wired 12V high-level input, follows the high-voltage power-on process, and controls the low-voltage power supply required by the controllers of the output high-voltage components (such as the BMS or motor controller).

[0070] S3-3, BMS wakes up autonomously through the 12V high level input by the hard line and self-checks whether there is a fault. If the self-check finds a fault, it reports the fault and records it, and stops applying high voltage.

[0071] S3-4. If the BMS self-test shows no faults, it will perform contactor adhesion diagnosis and send each contactor readiness status message to the CAN network.

[0072] S3-5. The vehicle controller determines whether the high-voltage conditions are met. If the high-voltage conditions are not met, a fault is reported and recorded, and the high-voltage application is terminated.

[0073] S3-6. If the vehicle controller determines that the high-voltage conditions are met, it sends a "main negative contactor close" command to the BMS, causing the BMS to control the main negative contactor in the high-voltage control box to close and feedback the main negative contactor closing status.

[0074] S3-7. The vehicle controller sends a "pre-charge contactor close" command to the BMS, causing the BMS to control the pre-charge contactor in the high-voltage control box to close and feedback the pre-charge contactor closing status.

[0075] S3-8. The vehicle controller determines whether the pre-charging of the main drive circuit is completed. If the pre-charging fails, the fault is reported and recorded, and the high voltage is terminated.

[0076] S3-9. If the vehicle controller determines that pre-charging is completed, the vehicle controller sends a "main positive contactor, first DCDC contactor, second DCDC contactor closed" command to the BMS, so that the BMS controls the main positive contactor, first DCDC contactor, and second DCDC contactor in the high-voltage control box to close, and feedback the closing status of each contactor.

[0077] S3-10. The vehicle controller sends a "pre-charge contactor disconnect" command to the BMS, causing the BMS to control the pre-charge contactor in the high-voltage control box to disconnect and feedback the pre-charge contactor disconnection status.

[0078] S3-11. The vehicle controller sends a "work enable request" message to the first DCDC converter and the second DCDC converter through the CAN network.

[0079] S3-12. The first DCDC converter is awakened and starts working, converting the high voltage output by the power battery into a low voltage power supply, supplying power to the conventional low-voltage electrical appliances of the vehicle and charging the first battery, and at the same time feeding back the "first DCDC converter working status" message to the CAN network; the second DCDC is awakened and starts working, converting the high voltage output by the power battery into a low voltage power supply, independently supplying power to the autonomous driving system and charging the second battery, and at the same time feeding back the "second DCDC converter working status" message to the CAN network.

[0080] S3-13, vehicle high voltage power-up is completed.

[0081] The following is based on Figure 3 and Figure 7 The dual DCDC system control method in the OFF charging mode of step S5 is described in detail:

[0082] S5-1. With the vehicle in OFF gear and the engine off, plug in the charger to charge.

[0083] S5-2. The BMS determines whether there is a charging connection signal (CC2, CC, CP, etc.). If yes, it executes step S5-3; otherwise, it continues to wait.

[0084] S5-3. BMS determines whether the charging mode is AC or DC.

[0085] S5-4. The vehicle controller determines whether the charging conditions are met: the vehicle is in a stagnant state, the parking brake is pulled, and a charging permission request is received from the BMS. If so, step S5-5 is executed, otherwise continue to wait.

[0086] S5-5. The vehicle enters charging mode.

[0087] S5-6, the vehicle controller controls the main negative contactor and charging contactor to close, and sends the "main negative contactor, charging contactor close" command to the BMS, so that the BMS controls the main negative contactor and charging contactor in the high-voltage control box to close, and feedbacks the closing status of the main negative contactor and charging contactor.

[0088] S5-7. BMS communicates with the charger and enters the normal charging state.

[0089] S5-8. The vehicle controller sends a "first DCDC contactor close" command to the BMS, causing the BMS to control the first DCDC contactor in the high-voltage control box to close and feedback the closing status of the first DCDC contactor.

[0090] S5-9, the vehicle controller determines whether the voltage of the first battery is lower than a preset threshold value U1;

[0091] S5-10. If the voltage value of the first battery is lower than the preset threshold value U1, the vehicle controller controls the first DCDC converter to start intermittently, and sends a "work enable request" message to the first DCDC converter through the CAN network. The first DCDC converter is awakened and works, converting the high voltage output of the power battery into a low voltage power supply to replenish the first battery, thereby supplying power to low-voltage electrical equipment. At the same time, the first DCDC converter feeds back the "DCDC working status" message to the CAN network; otherwise, the first DCDC converter does not start working and is in standby state.

[0092] S5-11. Count the working time of the first DCDC converter and determine whether it reaches the preset time T1.

[0093] S5-12. If the working time of the first DCDC converter reaches the preset time T1, the vehicle controller will set the working enable request sent to the first DCDC converter, and the first DCDC converter will stop working; otherwise, the first DCDC converter remains in the working state and is in the constant voltage output working mode.

[0094] S5-13, the vehicle controller and BMS detect in real time whether there is a fault that does not allow charging or charging is completed. If so, execute step S5-14, otherwise execute step S5-7 again.

[0095] S5-14. If the vehicle controller and BMS detect a fault that does not allow charging or charging is completed, charging stops and the charging end process is followed. The vehicle controller sets the work enable request sent to the first DCDC converter and sends a "charging contactor, first DCDC contactor, main negative contactor disconnect" command to the BMS, causing the BMS to control the charging contactor, first DCDC contactor, and main negative contactor in the high-voltage control box to disconnect in sequence; otherwise, the charging mode continues and normal charging is maintained;

[0096] S5-15, the vehicle controller, BMS and the first DCDC converter stop working and enter the sleep state.

[0097] The following is based on Figure 3 and Figure 8 The dual DCDC system control method in the charging parallel ON mode in step S6 is described in detail:

[0098] S6-1. The vehicle is in charging state and the ignition signal is turned on.

[0099] S6-2: The vehicle controller determines whether an ON gear signal is recognized. If so, step S6-3 is executed; otherwise, the vehicle controller continues to wait.

[0100] S6-3. The vehicle controller remains in the charging state and enters the high-voltage power-on state in parallel, locks the driving function, and prohibits entering the driving mode.

[0101] S6-4, the vehicle controller controls the second DCDC contactor to close, sends a "second DCDC contactor close" command to the BMS, so that the BMS controls the second DCDC contactor in the high-voltage control box to close, and feeds back the closing status of the second DCDC contactor.

[0102] S6-5. The vehicle controller turns off the intermittent working control mode of the first DCDC converter, and continuously sends "working enable request" messages to the first DCDC converter and the second DCDC converter through the CAN network.

[0103] S6-6. The first DCDC converter continues to work, converting the high voltage output by the power battery into a low-voltage power supply, supplying power to the conventional low-voltage electrical appliances of the vehicle and charging the first battery, and at the same time feeding back the "first DCDC converter working status" message to the CAN network; the second DCDC converter is awakened and continues to work, converting the high voltage output by the power battery into a low-voltage power supply, independently supplying power to the autonomous driving system and charging the second battery, and at the same time feeding back the "second DCDC converter working status" message to the CAN network.

[0104] S6-7. The high voltage power-up of the auxiliary components is completed and the vehicle remains in the charging state.

[0105] based on Figure 3 and Figure 9 The dual DCDC system control method in the ON high-voltage charging mode in step S7 is described in detail:

[0106] S7-1. When the vehicle is powered on with high voltage, plug in the charging cable to charge it.

[0107] S7-2. The BMS determines whether there is a charging connection signal (CC2, CC, CP, etc.). If yes, it executes step S7-3; otherwise, it continues to wait.

[0108] S7-3, BMS determines AC and DC charging modes.

[0109] S7-4. The vehicle controller determines whether the charging conditions are met: the vehicle is in a stagnant state, the parking brake is pulled, and a charging permission request is received from the BMS. If so, step S7-5 is executed; otherwise, continue waiting.

[0110] S7-5, limit driving power to zero and enter charging mode.

[0111] S7-6, the vehicle controller controls the main drive high-voltage circuit to be disconnected, sends a "main positive contactor disconnect" command to the BMS, causes the BMS to control the main positive contactor in the high-voltage control box to be disconnected, and feeds back the main positive contactor disconnection status.

[0112] S7-7. The vehicle controller sends a "charging contactor closed" command to the BMS, causing the BMS to control the charging contactor in the high-voltage control box to close and feedback the charging contactor closing status.

[0113] S7-8 and BMS communicate and interact with the charger and enter the normal charging state.

[0114] S7-9. The vehicle controller controls the first DCDC converter and the second DCDC converter to maintain the high voltage input and operation enable at the input end, so that the first DCDC converter and the second DCDC converter remain in the working state.

[0115] S7-10. The vehicle controller detects in real time whether there is a fault that does not allow charging or whether there is a fault in which the first DCDC converter does not enter the working state in the charging mode. If so, the vehicle controller sends a "charging is not allowed" instruction to the BMS and executes step S7-12. Otherwise, execute step S7-11.

[0116] S7-11. The BMS detects whether there is a charging prohibition fault or a charging completion signal. If so, step S7-12 is executed; otherwise, the charging state is maintained.

[0117] S7-12, charging stops, and BMS goes through the charging end process.

[0118] S7-13. Exit charging mode and enter driving mode.

[0119] In summary, the control method of the dual DCDC system has the following advantages over the control method of the single DCDC solution in the prior art:

[0120] 1. The dual DCDC system of the present invention integrates a real-time battery voltage monitoring function and can intelligently control the DCDC converter to charge the battery, preventing the battery from being depleted due to various factors such as the energy consumption of electrical components and the self-discharge rate. This optimizes the battery's operating environment, helps maintain the battery in good health, ensures the battery's service life, and reduces battery maintenance costs.

[0121] 2. The present invention achieves fine control of the dual DCDC system by finely dividing the vehicle state and charging state of the autonomous vehicle. This intelligently controls the operating mode of the DCDC converter and rationally adjusts the start and stop time of the DCDC converter, thereby improving the operating efficiency of the DCDC converter and the energy utilization rate of the entire vehicle, achieving better energy conservation and consumption reduction, increasing the vehicle's cruising range, and protecting the life of the DCDC converter.

[0122] 3. The present invention uses an intelligent control strategy to intelligently control the working mode of the dual DCDC system, realizes intelligent management of the low-voltage power supply of the autonomous driving vehicle, meets the special usage scenario requirements of the autonomous driving vehicle and improves the power safety of the autonomous driving vehicle. It is easy to operate, has a fast response speed and high control efficiency.

[0123] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A control method for a dual DCDC system of an autonomous driving vehicle, characterized by: The dual DCDC system includes a power battery, a first DCDC converter, a second DCDC converter, a first battery, a second battery, a vehicle controller, an automatic driving system, and a body controller; the power battery is electrically connected to the first DCDC converter and the second DCDC converter; the first battery and the vehicle controller are electrically connected to the first DCDC converter; the second battery and the automatic driving system are electrically connected to the second DCDC converter; and the body controller is electrically connected to the first battery and the second battery; The control method comprises the following steps: S1. The vehicle controller determines whether the vehicle is in the off state, on state, or charging state. If the vehicle is in the off state, step S2 is executed; if the vehicle is in the on state, step S3 is executed; if the vehicle is in the charging state, step S4 is executed; S2: In the ignition off state, if the voltage of any battery is lower than the set voltage, the intelligent charging signal is turned on, and the vehicle controller controls the corresponding DCDC converter to be in working state, thereby charging the battery; S3, in the startup state, the vehicle controller controls the first DCDC converter and the second DCDC converter to be in the working state; S4. In the charging state, the vehicle controller further determines the vehicle's charging mode. If it is the OFF gear charging mode, step S5 is executed; if it is the charging parallel ON gear mode, step S6 is executed; if it is the charging mode in the high voltage power-on state, step S7 is executed; S5: The vehicle is in OFF charging mode, the vehicle controller controls the power battery to enter the charging state, and controls the first DCDC converter to be in the intermittent working state; S6: The vehicle is in charging parallel ON mode. The vehicle controller controls the power battery to maintain a charging state, controls the first DCDC converter to maintain an operating state, and controls the second DCDC converter to enter an operating state. S7, when the vehicle is in the high-voltage power-on state, the charging mode, the vehicle controller controls the driving power to zero, controls the power battery to enter the charging state, and controls the first DCDC converter and the second DCDC converter to remain in the working state.

2. The control method of the dual DCDC system of an autonomous driving vehicle according to claim 1, characterized in that: In step S2, the body controller regularly monitors the voltage values ​​of the first battery and the second battery within a preset time interval T. If the body controller detects that the voltage value of any battery is lower than the preset threshold, the body controller will send an intelligent power replenishment start signal to wake up the vehicle controller and enter the intelligent power replenishment mode; if the voltage value of the first battery and / or the second battery is not lower than the set voltage value, the body controller will continue to maintain the monitoring state so as to respond in time.

3. The control method of the dual DCDC system of an autonomous driving vehicle according to claim 1, characterized in that: In step S2, the vehicle controller determines whether the vehicle meets the charging conditions based on whether the current charge of the power battery is higher than the set threshold and whether the available discharge power of the power battery is higher than the set threshold. If the charging conditions are met, the intelligent charging mode is turned on; otherwise, the intelligent charging mode is not turned on.

4. The control method of a dual DCDC system for an autonomous driving vehicle according to claim 1, wherein: In step S5, the vehicle controller monitors the voltage of the first battery in real time. If the voltage of the first battery is lower than a preset threshold, the first DCDC converter is controlled to start working to charge the first battery. If the voltage of the first battery is not lower than the preset threshold, the first DCDC converter is controlled to stop working, thereby realizing intermittent operation of the first DCDC converter.

5. The control method of the dual DCDC system of an autonomous driving vehicle according to claim 1, characterized in that: The dual DCDC system further includes a high-voltage distribution box, and the power battery is connected to the first DCDC converter and the second DCDC converter via the high-voltage distribution box.

6. The control method of the dual DCDC system of an autonomous driving vehicle according to claim 5, characterized in that: The high-voltage distribution box is connected to the power battery through a main circuit, and is connected to the first DCDC converter and the second DCDC converter through a first branch and a second branch respectively. The first branch is provided with a first DCDC contactor and a first DCDC fuse, and the second branch is provided with a second DCDC contactor and a second DCDC fuse.

7. The control method of the dual DCDC system of an autonomous driving vehicle according to claim 6, characterized in that: The power battery, the first DCDC converter, the second DCDC converter, the vehicle controller, the automatic driving system, the body controller and the high-voltage distribution box are all interconnected through a CAN network.

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