An automatic discharge system for a hybrid vehicle and a control method

Abstract

The application provides an automatic discharge system and control method for a hybrid vehicle, and relates to the technical field of brake control of a hybrid vehicle. The automatic discharge system comprises a discharge controller, a discharge circuit, an actuator and a position sensor. The discharge circuit is connected in series with a power battery, a main contactor, a power module, a discharge resistor element and a grounding device. The grounding device can be connected to the ground to discharge electric energy. The discharge controller integrates data acquisition, grounding device control, power regulation and discharge termination units. The controller acquires signals of the whole vehicle and the battery, drives the grounding mechanism to extend or retract according to a determination rule, and regulates discharge power through PWM. The application can automatically dissipate excess feedback electric energy, continuously reserve battery charging capacity, prevent long downhill regenerative braking failure and improve driving safety.

Description

Technical Field

[0001] This invention relates to the field of braking control technology for hybrid vehicles, and specifically to an automatic discharge system and control method for hybrid vehicles. Background Technology

[0002] Hybrid vehicles (including hybrid heavy-duty trucks) are typically equipped with a power battery system, a drive motor, a vehicle control unit (VCU), and a battery management system (BMS). The basic principle of regenerative braking (also known as feedback braking) is as follows: when the driver presses the brake pedal or the vehicle is coasting, the drive motor switches from electric motor mode to generator mode, converting the vehicle's kinetic energy into electrical energy and storing it in the power battery. At this time, the reverse torque generated by the rotating motor rotor acts on the drive wheels, creating electric braking force, thereby decelerating the vehicle.

[0003] The braking control strategy of existing hybrid vehicles usually includes the following steps: (1) The vehicle controller receives the brake pedal opening signal, vehicle speed signal, battery SOC signal, etc.; (2) Calculate the target braking torque according to the braking demand; (3) When the battery SOC is lower than a certain upper limit threshold (such as 80%-90%), the motor torque is preferentially called for regenerative braking; (4) When the motor torque is insufficient, the mechanical friction braking system supplements the braking force. In terms of battery SOC management, the existing strategy generally adopts the "charge maintenance" principle, that is, the working range of the battery is limited by the logic threshold control strategy. When the SOC is higher than the upper limit, charging is restricted, and when it is lower than the lower limit, the engine is forced to start charging.

[0004] However, the aforementioned prior art has the following technical defects: Hybrid vehicles (especially heavy-duty hybrid trucks) typically have relatively small battery capacities (≤30kWh). During long downhill stretches or continuous braking, the regenerative braking energy quickly charges the battery. Once the battery's state of charge (SOC) reaches its upper limit, the battery management system (BMS) prevents further charging, the motor can no longer output regenerative braking torque, and electric braking is lost, requiring reliance on mechanical friction braking. However, prolonged use of mechanical braking carries a risk of overheating and failure, seriously impacting driving safety.

[0005] To compensate for insufficient braking force after the loss of electric braking, existing heavy commercial vehicles generally adopt the solution of adding hydraulic retarders or electric eddy current retarders. Hydraulic retarders convert the vehicle's kinetic energy into heat energy through hydraulic damping, which is then dissipated by the cooling system. They have high braking power and can work for a long time, but they have the following disadvantages: high cost (the purchase cost of a single set can reach tens of thousands of yuan), heavy weight (about 100-200 kg), require additional oil and cooling pipes, and have high requirements for the overall vehicle layout space.

[0006] In recent years, solutions have emerged that utilize braking resistors to dissipate excess electrical energy. For example, Chinese patent CN119749500A discloses a braking control method that arranges a resistor device inside the exhaust pipe of a hybrid vehicle's engine. When the power battery's state of charge (SOC) meets preset conditions, the power battery is controlled to supply power to the resistor device to dissipate electrical energy. Other literature reports a braking energy dissipation system composed of an internally flow-cooled braking resistor. However, these solutions have the following technical shortcomings: the resistor device is located inside the exhaust pipe, making it susceptible to the high temperature of the engine exhaust, thus placing extremely high demands on the resistor material and cooling system; the heat generated by the resistor is concentrated in the engine compartment area, potentially exacerbating the heat dissipation burden on the engine cooling system; and the resistor device is fixedly installed, making it impossible to flexibly control the switching timing and power consumption according to operating conditions.

[0007] Existing technical solutions all only respond passively based on the current SOC state, and cannot manage the battery capacity in advance according to the road conditions ahead (such as downhill length, slope, etc.). As a result, when the vehicle enters a long downhill, the battery has no charging capacity, and regenerative braking cannot play a full role.

[0008] The above-mentioned problems urgently need to be solved. Summary of the Invention

[0009] The purpose of this invention is to overcome at least one technical problem existing in the prior art and to provide an automatic discharge system and control method for hybrid vehicles.

[0010] On one hand, embodiments of the present invention provide an automatic discharge system for hybrid vehicles. The automatic discharge system includes: a discharge controller, a discharge circuit, an actuator, a position sensor, a battery management system, and a vehicle controller. The discharge circuit includes a power battery, a main contactor, a power module, a discharge resistor element, and a grounding discharge device connected in series. The grounding discharge device, in its extended state, forms a discharge path with the ground. The discharge controller integrates a data acquisition unit, a grounding device control unit, a discharge circuit conduction and power adjustment unit, and a discharge termination control unit. The data acquisition unit receives the grounding discharge device position signal transmitted by the position sensor, the real-time power battery SOC and battery charging status output by the battery management system, the real-time vehicle speed signal output by the vehicle controller, the brake pedal opening signal, and the vehicle's current gear signal. The grounding device control unit is used to receive the battery charging status, ... The real-time power battery SOC and real-time vehicle speed signal, combined with a preset discharge determination rule, generate a first control signal to drive the actuator to extend the grounding discharge device downwards to a preset target position. The discharge circuit conduction and power adjustment unit is used to send a first level signal to the main contactor after receiving the position signal of the grounding discharge device, thus conducting the discharge circuit. It also generates a PWM control signal based on the difference between the real-time power battery SOC and the target power battery SOC to adjust the discharge current through the power module. The discharge termination control unit is used to send a second level signal to the main contactor based on the real-time power battery SOC, brake pedal opening signal, and vehicle current gear signal, combined with a preset discharge termination determination rule, to disconnect the discharge circuit. The grounding device control unit generates a second control signal to drive the actuator to retract the grounding discharge device into the chassis.

[0011] Furthermore, an overcurrent fuse is connected in series between the power battery and the main contactor. When the circuit current of the discharge circuit exceeds the rated limit, the fuse blows, and the discharge circuit is cut off by hardware.

[0012] Furthermore, the grounding discharge device is a gap arc discharge end or a rolling grounding wheel; after the gap arc discharge end extends, it forms an air gap with the ground, and relies on the high-voltage arc to discharge electrical energy to the ground; the rolling grounding wheel is equipped with a rolling bearing, and after it extends, it rolls and conducts discharge while in contact with the ground; the actuator is an electrically controlled cylinder or an electrically controlled electromagnet, used to drive the grounding discharge device to complete the extension and retraction actions.

[0013] Furthermore, the discharge controller also integrates a prediction control unit; the data acquisition unit is communicatively connected to the navigation ADAS system and is used to receive the road condition prediction information ahead from the electronic map output by the navigation ADAS system; the prediction control unit is used to dynamically adjust the target power battery SOC based on the road condition prediction information and the real-time power battery SOC using a preset prediction control strategy.

[0014] Furthermore, the predictive control strategy includes: when the road condition ahead is predicted to be a long downhill section and the current power battery SOC is greater than a first threshold, dynamically adjusting the target power battery SOC to a preset first target power battery SOC; when the road condition ahead is predicted to be a gentle road section or a short downhill section and the current power battery SOC is greater than a second threshold, dynamically adjusting the target power battery SOC to a preset second target power battery SOC; wherein the first threshold is less than the second threshold, and the first target power battery SOC is less than the second target power battery SOC.

[0015] Furthermore, the preset discharge determination rules include: when the battery charging state, power battery SOC and real-time vehicle speed signal meet all discharge conditions, a first control signal is generated to drive the actuator to extend the grounding discharge device downward to a preset target position; the discharge conditions include: the power battery is in a charging state, the power battery SOC is greater than or equal to a third threshold and the real-time vehicle speed is greater than or equal to a preset vehicle speed threshold.

[0016] Furthermore, the automatic discharge system also includes an insulation monitoring unit; the insulation monitoring unit is used to detect the insulation resistance of the discharge circuit to ground in real time. When the insulation resistance is lower than the safety threshold, the insulation monitoring unit sends a fault signal to the discharge termination control unit, triggering the discharge termination control unit to perform an emergency shutdown operation.

[0017] Furthermore, the preset termination discharge determination rule includes: when the power battery SOC, brake pedal opening signal, and vehicle current gear signal meet at least one termination condition, a second level signal is sent to the main contactor to disconnect the discharge circuit, and the grounding device control unit generates a second control signal to drive the actuator to retract the grounding discharge device into the chassis; the termination conditions include: the power battery SOC drops to the fourth threshold, the regenerative braking charging condition ends, the brake pedal opening is returned to zero, the vehicle gear is switched to a non-D forward gear or the real-time vehicle speed is lower than the minimum discharge speed, and a fault signal is received from the insulation monitoring unit.

[0018] Secondly, embodiments of the present invention provide an automatic discharge control method for hybrid vehicles. The method is applied to the aforementioned automatic discharge system for hybrid vehicles. The method includes: Step S1, a data acquisition unit acquires the position signal of the grounding discharge device, real-time power battery SOC and battery charging status, real-time vehicle speed signal, brake pedal opening signal, and vehicle current gear signal; Step S2, the grounding device control unit, based on the battery charging status, real-time power battery SOC, and real-time vehicle speed signal, and in conjunction with preset discharge judgment rules, generates a first control signal to drive the actuator to extend the grounding discharge device downwards to a preset target position when the discharge conditions are met; Step S3, after the position sensor feeds back the extension signal, the discharge circuit is activated and the power regulation unit... Step S4: The discharge circuit connection and power adjustment unit generates a PWM control signal based on the difference between the real-time power battery SOC and the target power battery SOC, and adjusts the discharge current through the power module to reduce the power battery SOC to the target power battery SOC. Step S5: The discharge termination control unit, based on the real-time power battery SOC, brake pedal opening signal and vehicle current gear signal, and a preset discharge termination judgment rule, sends a second level signal to the main contactor to disconnect the discharge circuit when the discharge termination condition is met, and the grounding device control unit generates a second control signal to drive the actuator to retract the grounding discharge device into the chassis.

[0019] Furthermore, the method also includes a switching timing control process: when the discharge starts, the first level signal is sent to the main contactor to close the main contactor, and then the PWM control signal is output to drive the power module to perform high-frequency chopping; when the discharge ends, the PWM control signal is turned off to turn off the power module, and then the second level signal is sent to the main contactor to open the main contactor.

[0020] In another aspect, the present invention also provides a computer-readable storage medium storing one or more instructions for causing a computer to perform the above-described automatic discharge control method for hybrid vehicles.

[0021] In another aspect, the present invention provides an electronic device, comprising: a memory and a processor; the memory storing at least one program instruction; the processor loading and executing the at least one program instruction to implement the above-described automatic discharge control method for hybrid vehicles.

[0022] The beneficial effects of this invention are: 1. This invention automatically dissipates excess electrical energy through a grounding device when the battery is charging and has a high State of Charge (SOC), continuously freeing up battery capacity for regenerative braking. Under long downhill conditions, this invention can improve the contribution rate of motor braking, reduce the mechanical braking intervention time, avoid the risk of mechanical braking overheating and failure, and solve the safety problem of electric braking loss due to a fully charged battery in existing technologies.

[0023] 2. Compared to the solution of adding a hydraulic retarder (costing tens of thousands of yuan and weighing 100-200kg), the present invention mainly consists of an actuator, a grounding discharge device, a discharge resistor and a control module. It does not have complex hydraulic pipelines and a heat dissipation system. The manufacturing cost is less than 20% of the retarder solution, and the weight is only 20-30kg, which is beneficial to the lightweighting of the whole vehicle and cost control.

[0024] 3. The discharge resistor element of this invention has a self-protection characteristic that its resistance automatically increases with temperature; the insulation monitoring unit monitors the insulation resistance in real time and shuts down the machine in case of abnormality. The above design eliminates the safety hazards of resistor failure at high temperatures and high-voltage leakage in existing solutions.

[0025] 4. This invention introduces navigation ADAS road condition prediction information, which reduces the SOC to the target value in advance before long downhill sections to reserve capacity space for subsequent regenerative braking; and reduces the discharge priority on flat or urban sections to avoid unnecessary energy waste.

[0026] 5. The present invention adopts a topology of "main contactor → power module → discharge resistor → grounding device". When the power module is turned off, there is no high voltage downstream, and the high voltage energized area is greatly reduced. The timing control of "first disconnecting PWM, then disconnecting contactor" realizes zero current disconnection of the main contactor, eliminates arc damage, greatly extends the service life of the contactor, and ensures the safety and reliability of the system throughout its entire life cycle. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a structural diagram of an automatic discharge system for hybrid vehicles provided in Embodiment 1 of the present invention.

[0029] Figure 2 This is a structural diagram of another automatic discharge system for hybrid vehicles provided in Embodiment 1 of the present invention.

[0030] Figure 3 This is a flowchart of an automatic discharge control method for hybrid vehicles provided in Embodiment 2 of the present invention.

[0031] Figure 4 This is a partial block diagram of the electronic device provided in Embodiment 4 of the present invention. Detailed Implementation

[0032] Before discussing the exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the figures. The process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0033] It should be understood that although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are used merely to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] The present invention will now be described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0035] Example 1 The specific implementation method is as follows: like Figure 1 The diagram shown is a structural diagram of an automatic discharge system for hybrid vehicles provided by the present invention.

[0036] As an example, the automatic discharge system includes: a discharge controller 1, a discharge circuit 2, an actuator 3, a position sensor 4, a battery management system 5, and a vehicle controller 6; the discharge circuit 2 includes a power battery 21, a main contactor 22, a power module 23, a discharge resistor element 24, and a grounding discharge device 25 connected in series, the grounding discharge device 25 forming a discharge path with the ground in the extended state; the discharge controller 1 integrates a data acquisition unit 11, a grounding device control unit 12, a discharge circuit conduction and power adjustment unit 13, and a discharge termination control unit 14; the data acquisition unit 11 is used to receive the grounding discharge device position signal transmitted by the position sensor 4, the real-time power battery SOC and battery charging status output by the battery management system 5, the real-time vehicle speed signal, brake pedal opening signal, and vehicle current gear signal output by the vehicle controller 6; the grounding device control unit 12 is used to receive the battery charging status and real-time power... The battery SOC and real-time vehicle speed signal are combined with a preset discharge determination rule to generate a first control signal, which drives the actuator 3 to extend the grounding discharge device 25 downward to a preset target position. The discharge circuit conduction and power adjustment unit 13 is used to send a first level signal to the main contactor 22 after receiving the position signal of the grounding discharge device, so as to conduct the discharge circuit. It also generates a PWM control signal based on the difference between the real-time power battery SOC and the target power battery SOC to adjust the discharge current through the power module 23. The discharge termination control unit 14 is used to send a second level signal to the main contactor 22 based on the real-time power battery SOC, brake pedal opening signal and vehicle current gear signal combined with a preset discharge termination determination rule to disconnect the discharge circuit, and cause the grounding device control unit 12 to generate a second control signal to drive the actuator 3 to retract the grounding discharge device 25 into the chassis.

[0037] In some feasible implementations, the grounding discharge device 25 is a gap arc discharge end or a rolling grounding wheel; after the gap arc discharge end extends, it forms an air gap with the ground, and relies on the high-voltage arc to discharge electrical energy to the ground; the rolling grounding wheel is equipped with a rolling bearing, and after it extends, it rolls and conducts discharge in contact with the ground; the actuator 3 is an electrically controlled cylinder or an electrically controlled electromagnet, used to drive the grounding discharge device 25 to complete the extension and retraction actions.

[0038] Specifically, the grounding discharge device 25 can take the form of a grounding strip or a grounding wheel, installed under the vehicle chassis, and has a telescopic function (such as being driven by an electronically controlled cylinder or electromagnet). In the non-operating state, it retracts into the chassis; in the operating state, it extends downwards to contact or nearly contact the ground, forming a ground discharge path. The contact material of the grounding discharge device 25 is made of copper-based powder metallurgy friction pads, which are both wear-resistant and conductive. The device has a floating following function: after the contact contacts the ground, an internal compression spring can compress it, ensuring that the contact maintains a stable contact pressure with the ground. In the retracted state, a mechanical locking hook secures the device to prevent accidental drop during high-speed driving.

[0039] In some feasible implementations, an overcurrent fuse is connected in series between the power battery 21 and the main contactor 22. When the circuit current of the discharge circuit exceeds the rated limit, the fuse blows, and the discharge circuit is cut off by hardware.

[0040] In some feasible implementations, the power module 23 is disposed between the main contactor 22 and the discharge resistor element 24, and is an IGBT (insulated gate bipolar transistor) or a SiC MOSFET (silicon carbide field-effect transistor).

[0041] In some feasible implementations, the discharge resistor element 24 is a PTC (Positive Temperature Coefficient) thermistor, whose resistance automatically increases as the temperature rises to limit the increase of the discharge current.

[0042] In some feasible implementations, the position sensor 4 is disposed at the grounding discharge device 25 to detect the extended and retracted states of the grounding discharge device.

[0043] In some feasible implementations, combined with Figure 2 As shown, the automatic discharge system also includes an insulation monitoring unit 7; the insulation monitoring unit 7 is used to detect the insulation resistance of the discharge circuit to ground in real time. When the insulation resistance is lower than the safety threshold, the insulation monitoring unit 7 sends a fault signal to the discharge termination control unit 14, triggering the discharge termination control unit 14 to perform an emergency shutdown operation.

[0044] In some feasible implementations, combined with Figure 2 As shown, the discharge controller 1 also integrates a prediction control unit 15; the data acquisition unit 11 is communicatively connected to the navigation ADAS system 8 and is used to receive the road condition prediction information ahead from the electronic map output by the navigation ADAS system 8; the prediction control unit 15 is used to dynamically adjust the target power battery SOC based on the road condition prediction information and the real-time power battery SOC using a preset prediction control strategy.

[0045] Preferably, the predictive control strategy includes: when the road condition ahead is predicted to be a long downhill section and the current power battery SOC is greater than a first threshold, dynamically adjusting the target power battery SOC to a preset first target power battery SOC; when the road condition ahead is predicted to be a gentle road section or a short downhill section and the current power battery SOC is greater than a second threshold, dynamically adjusting the target power battery SOC to a preset second target power battery SOC; wherein the first threshold is less than the second threshold, and the first target power battery SOC is less than the second target power battery SOC.

[0046] Specifically, the first threshold reference value is 70%, the preset first target power battery SOC reference value is 40%, the second threshold reference value is 85%, and the preset second target power battery SOC reference value is 55%. By default, the target power battery SOC is set to 70%.

[0047] In some feasible implementations, the preset discharge determination rules include: when the battery charging state, power battery SOC and real-time vehicle speed signal meet all discharge conditions, a first control signal is generated to drive the actuator to extend the grounding discharge device downward to a preset target position; the discharge conditions include: the power battery is in a charging state, the power battery SOC is greater than or equal to a third threshold and the real-time vehicle speed is greater than or equal to a preset vehicle speed threshold.

[0048] Specifically, the power battery is in a charging state, meaning regenerative braking is in progress; the third threshold reference value is 85%; the preset vehicle speed threshold reference value is 5km / h, ensuring that the vehicle is in motion rather than stationary, and preventing accidental discharge.

[0049] In some feasible implementations, the preset termination discharge determination rule includes: when the power battery SOC, brake pedal opening signal, and vehicle current gear signal meet at least one termination condition, a second level signal is sent to the main contactor to disconnect the discharge circuit, and the grounding device control unit generates a second control signal to drive the actuator to retract the grounding discharge device into the chassis; the termination conditions include: the power battery SOC drops to the fourth threshold, the regenerative braking charging condition ends, the brake pedal opening is returned to zero, the vehicle gear is switched to a non-D forward gear or the real-time vehicle speed is lower than the minimum discharge speed, and a fault signal is received from the insulation monitoring unit.

[0050] Specifically, the fourth threshold reference value is 70%; regenerative braking charging ends, that is, the driver releases the brake pedal or the vehicle stops; the vehicle gear is switched to a non-D forward gear, that is, the gear is switched from D (forward) to P (park), N (neutral), or R (reverse); the real-time vehicle speed is lower than the minimum discharge speed, that is, the vehicle decelerates to a speed lower than the system's preset minimum speed threshold (e.g., 5 km / h); and an insulation fault is reported by the insulation monitoring module.

[0051] In some feasible implementations, to facilitate understanding of the above embodiments, the specific workflow of the above system is described here: After the vehicle is powered on, the discharge controller 1 continuously receives the power battery SOC and battery charging status output by the battery management system (BMS) via the CAN bus in real time; it also receives the real-time vehicle speed, brake pedal opening, and vehicle gear signal output by the vehicle controller (VCU); the data acquisition unit 11 synchronously acquires the grounding discharge device retraction / extension signal fed back by the position sensor; if equipped with a navigation ADAS system, it synchronously receives the road condition prediction information ahead; and the insulation monitoring unit 7 collects the insulation resistance of the discharge branch to ground in real time and continuously uploads the status to the discharge controller.

[0052] First mode: Complete workflow of conventional long downhill braking and discharge (without prior prediction): Condition Judgment Phase: When the vehicle is traveling on a long downhill section, the driver depresses the brake pedal, the motor enters regenerative braking mode, and the BMS reports that the battery is in regenerative charging state; the data acquisition unit identifies that the current power battery SOC is greater than or equal to the third threshold, the real-time vehicle speed is greater than or equal to the preset minimum vehicle speed threshold, and the vehicle is in drive (D) gear. All discharge conditions are met simultaneously, and the grounding device control unit generates a first control signal and sends it to the actuator; the actuator drives the grounding discharge device to extend downward to the preset target position, and the position sensor provides real-time feedback of the position signal; only when the discharge controller receives the signal that the grounding discharge device is fully extended to the position is the high-voltage discharge circuit allowed to be connected; the discharge circuit connection and power regulation unit send a first level signal (such as a high level) to the main contactor, the main contactor engages, and the high-voltage discharge circuit is fully connected; the discharge circuit connection and power regulation unit generate a PWM control signal with a corresponding duty cycle based on the difference between the real-time SOC and the target SOC, driving the power module to adjust the discharge current by high-frequency chopping; electrical energy passes sequentially through the power module, discharge resistor element, and grounding device. The ground discharge device discharges to ground, continuously consuming the power battery's charge and gradually reducing the State of Charge (SOC). The discharge termination control unit continuously polls all termination conditions: the power battery SOC drops to the fourth threshold of the corresponding operating condition; the driver releases the brake pedal, the regenerative braking charging condition ends, and the brake pedal opening returns to zero; the vehicle switches to N / R / P (non-D gear) or the vehicle speed is lower than the minimum discharge speed; the insulation monitoring unit reports an insulation fault; after any one of the termination conditions is met, a standardized power-off sequence is executed: Step 1: The discharge circuit is turned on and the power regulation unit shuts off all PWM control signals, the power module is turned off, and the discharge current returns to zero; Step 2: The discharge termination control unit sends a second-level signal (such as a low level) to the main contactor, the main contactor disconnects, cutting off the high-voltage circuit and preventing the high-voltage arc from being interrupted; Step 3: The discharge termination control unit generates a second control signal to drive the actuator, retracting the ground discharge device upwards into the chassis; Step 4: The position sensor feeds back the retraction signal, the system returns to standby monitoring state, and waits for the next discharge trigger condition.

[0053] The second mode: Navigation ADAS predictive pre-discharge process (pre-discharge on long downhill slopes): The navigation ADAS transmits a "long downhill slope ahead" prediction signal to the discharge controller; the prediction control unit determines that the current SOC is >70% (first threshold); the prediction control unit lowers the target SOC to 40% (first target SOC); after recognizing the long downhill road condition, the prediction control unit unlocks the pre-discharge permission in advance, triggering the discharge judgment without waiting for the regenerative braking charging signal; the power battery SOC is greater than or equal to the third threshold, and the real-time vehicle speed is greater than or equal to the preset vehicle speed threshold, all conditions for discharge are met; the grounding device control unit generates the first control signal, driving the actuator to extend the grounding discharge device; the position sensor provides feedback on the extension position signal; the discharge circuit is connected and the power regulation unit closes the main contactor; a PWM control signal is output to start discharging to the ground; the SOC continues to decrease to 40% (preset first target SOC); the discharge terminates, and the grounding device is retracted. When the vehicle officially enters the downhill section, the driver presses the brake pedal, and the motor immediately performs regenerative feedback. The battery has a large amount of remaining charging space and will not be quickly fully charged, thus preventing the loss of regenerative braking force.

[0054] After the vehicle has passed the long downhill section, the navigation ADAS transmits a "long downhill end" signal to the discharge controller. The prediction control unit performs a reverse switching operation: switching the "navigation ADAS long downhill prediction signal" in the discharge trigger condition back to "battery charging state". The system then returns to normal mode.

[0055] In summary, this invention achieves intelligent management of battery SOC during regenerative braking in hybrid vehicles through a closed-loop control process involving state monitoring, condition determination, grounding device extension, discharge circuit activation, PWM power adjustment, discharge termination, and device retraction. In normal mode, discharge is initiated when the SOC reaches the 85% trigger threshold during regenerative braking. Electrical energy is dissipated as heat through the PTC resistor, reducing the SOC to 70%. The battery maintains a charging capacity range of 70% to 85% (approximately 15% SOC), ensuring continuous output of regenerative braking torque from the motor. In predictive mode, the navigation ADAS transmits a predictive signal before the vehicle reaches the top of a long downhill slope. The system switches the discharge trigger source from "battery charging status" to "navigation ADAS long downhill predictive signal". The SOC trigger threshold is lowered from 85% to 70%, and the target SOC is lowered from 70% to 40%. Discharge is started in advance when the driver does not apply the brakes and the motor has not entered regenerative charging, so that the SOC is pre-reduced from 75% to 40%, which makes up sufficient charging capacity space for subsequent continuous downhill braking. The electric braking torque can be maintained throughout the process.

[0056] It is worth mentioning that all modules involved in this embodiment are logical units. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0057] Example 2 Please see Figure 3 The above is a flowchart of an automatic discharge control method for a hybrid vehicle provided in an embodiment of the present invention.

[0058] As an example, the method is applied to the automatic discharge system for a hybrid vehicle described in Embodiment 1, the method comprising: Step S1: The data acquisition unit acquires the position signal of the grounding discharge device, the real-time power battery SOC and battery charging status, the real-time vehicle speed signal, the brake pedal opening signal, and the vehicle's current gear signal; Step S2: Based on the battery charging status, real-time power battery SOC and real-time vehicle speed signal, combined with the preset discharge judgment rules, the grounding device control unit generates a first control signal to drive the actuator to extend the grounding discharge device downward to the preset target position when the discharge conditions are met. Step S3: After the position sensor sends a signal indicating that the device has extended to the position, the discharge circuit is turned on and the power regulation unit sends a first-level signal to the main contactor to close the main contactor and turn on the discharge circuit. Step S4: The discharge circuit conduction and power regulation unit generates a PWM control signal based on the difference between the real-time power battery SOC and the target power battery SOC, and adjusts the discharge current through the power module to reduce the power battery SOC to the target power battery SOC. Step S5: The discharge termination control unit, based on the real-time power battery SOC, brake pedal opening signal, and vehicle current gear signal, combined with the preset discharge termination judgment rule, sends a second level signal to the main contactor to disconnect the discharge circuit when the discharge termination condition is met, and causes the grounding device control unit to generate a second control signal to drive the actuator to retract the grounding discharge device into the chassis.

[0059] In some feasible implementations, the method further includes an on / off timing control process: when the discharge starts, the first level signal is sent to the main contactor to close the main contactor, and then the PWM control signal is output to drive the power module to perform high-frequency chopping; when the discharge ends, the PWM control signal is turned off to turn off the power module, and then the second level signal is sent to the main contactor to open the main contactor.

[0060] It is not difficult to see that this embodiment is a method embodiment corresponding to the first embodiment, and this embodiment can be implemented in conjunction with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the first embodiment.

[0061] Example 3 This invention also proposes a storage medium storing an automatic discharge control method for a hybrid vehicle. When the program for automatic discharge control of a hybrid vehicle is executed by a processor, it implements the steps of the automatic discharge control method for a hybrid vehicle as described above. Since this storage medium employs all the technical solutions of the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here.

[0062] Example 4 Please see Figure 4 The present invention also provides an electronic device, including: a memory and a processor; the memory stores at least one program instruction; the processor loads and executes the at least one program instruction to implement the automatic discharge control method for hybrid vehicles provided in Embodiment 2.

[0063] The memory 702 and processor 701 are connected via a bus, which may include any number of interconnecting buses and bridges, connecting various circuits of one or more processors 701 and memory 702 together. The bus may also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. A bus interface provides an interface between the bus and the transceiver. The transceiver may be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by processor 701 is transmitted over a wireless medium via an antenna, which further receives data and transmits it to processor 701.

[0064] Processor 701 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory 702 can be used to store data used by processor 701 during operation.

[0065] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An automatic discharge system for hybrid vehicles, characterized in that, The automatic discharge system includes: a discharge controller, a discharge circuit, an actuator, a position sensor, a battery management system, and a vehicle controller; The discharge circuit includes a power battery, a main contactor, a power module, a discharge resistor element, and a grounding discharge device connected in series. The grounding discharge device forms a discharge path with the ground when it is extended. The discharge controller integrates a data acquisition unit, a grounding device control unit, a discharge circuit conduction and power regulation unit, and a discharge termination control unit. The data acquisition unit is used to receive the grounding discharge device position signal transmitted by the position sensor, the real-time power battery SOC and battery charging status output by the battery management system, the real-time vehicle speed signal output by the vehicle controller, the brake pedal opening signal and the vehicle's current gear signal. The grounding device control unit is used to generate a first control signal based on the battery charging state, real-time power battery SOC and real-time vehicle speed signal combined with a preset discharge determination rule, and drive the actuator to extend the grounding discharge device downward to a preset target position; The discharge circuit activation and power regulation unit is used to send a first level signal to the main contactor after receiving the position signal of the grounding discharge device being in place, thereby activating the discharge circuit; and to generate a PWM control signal based on the difference between the real-time power battery SOC and the target power battery SOC to adjust the discharge current through the power module. The discharge termination control unit is used to send a second level signal to the main contactor based on the real-time power battery SOC, brake pedal opening signal and vehicle current gear signal combined with a preset discharge termination judgment rule to disconnect the discharge circuit, and to cause the grounding device control unit to generate a second control signal to drive the actuator to retract the grounding discharge device into the chassis.

2. The automatic discharge system for hybrid vehicles according to claim 1, characterized in that, An overcurrent fuse is connected in series between the power battery and the main contactor. When the circuit current of the discharge circuit exceeds the rated limit, the fuse blows, and the discharge circuit is cut off by hardware.

3. The automatic discharge system for hybrid vehicles according to claim 1, characterized in that, The grounding discharge device is a gap arc discharge end or a rolling grounding wheel; the gap arc discharge end extends out and forms an air gap with the ground, relying on the high-voltage arc to release electrical energy to the ground; the rolling grounding wheel is equipped with a rolling bearing, and after extending out, it rolls and conducts discharge in contact with the ground. The actuator is an electrically controlled cylinder or an electrically controlled electromagnet, used to drive the grounding discharge device to complete the extension and retraction actions.

4. The automatic discharge system for hybrid vehicles according to claim 1, characterized in that, The discharge controller also integrates a prediction control unit; the data acquisition unit is communicatively connected to the navigation ADAS system and is used to receive the electronic map road condition prediction information output by the navigation ADAS system. The prediction control unit is used to dynamically adjust the target power battery SOC based on the road condition prediction information and the real-time power battery SOC using a preset prediction control strategy.

5. The automatic discharge system for hybrid vehicles according to claim 4, characterized in that, The predictive control strategy includes: When the road conditions ahead are predicted to be a long downhill section and the current power battery SOC is greater than the first threshold, the target power battery SOC is dynamically adjusted to the preset first target power battery SOC. When the road conditions ahead are predicted to be a flat section or a short downhill section and the current power battery SOC is greater than the second threshold, the target power battery SOC is dynamically adjusted to the preset second target power battery SOC. The first threshold is less than the second threshold, and the first target power battery SOC is less than the second target power battery SOC.

6. The automatic discharge system for hybrid vehicles according to claim 1, characterized in that, The preset discharge determination rules include: when the battery charging state, power battery SOC and real-time vehicle speed signal meet all discharge conditions, a first control signal is generated to drive the actuator to extend the grounding discharge device downward to the preset target position; The discharge conditions include: the power battery is in a charging state, the power battery SOC is greater than or equal to a third threshold, and the real-time vehicle speed is greater than or equal to a preset vehicle speed threshold.

7. The automatic discharge system for hybrid vehicles according to claim 1, characterized in that, The automatic discharge system also includes an insulation monitoring unit; the insulation monitoring unit is used to detect the insulation resistance of the discharge circuit to ground in real time. When the insulation resistance is lower than the safety threshold, the insulation monitoring unit sends a fault signal to the discharge termination control unit, triggering the discharge termination control unit to perform an emergency shutdown operation.

8. The automatic discharge system for hybrid vehicles according to claim 7, characterized in that, The preset termination discharge determination rule includes: when the power battery SOC, brake pedal opening signal and vehicle current gear signal meet at least one termination condition, a second level signal is sent to the main contactor to disconnect the discharge circuit, and the grounding device control unit generates a second control signal to drive the actuator to retract the grounding discharge device into the chassis. The termination conditions include: the SOC of the power battery drops to the fourth threshold, the regenerative braking charging condition ends, the brake pedal opening is reduced to zero, the vehicle gear is switched to a non-D forward gear or the real-time vehicle speed is lower than the minimum discharge speed, and a fault signal is received from the insulation monitoring unit.

9. An automatic discharge control method for hybrid vehicles, characterized in that, The method is applied to the automatic discharge system for hybrid vehicles according to any one of claims 1-8, and the method includes: Step S1: The data acquisition unit acquires the position signal of the grounding discharge device, the real-time power battery SOC and battery charging status, the real-time vehicle speed signal, the brake pedal opening signal, and the vehicle's current gear signal; Step S2: Based on the battery charging status, real-time power battery SOC and real-time vehicle speed signal, combined with the preset discharge judgment rules, the grounding device control unit generates a first control signal to drive the actuator to extend the grounding discharge device downward to the preset target position when the discharge conditions are met. Step S3: After the position sensor sends a signal indicating that the device has extended to the position, the discharge circuit is turned on and the power regulation unit sends a first-level signal to the main contactor to close the main contactor and turn on the discharge circuit. Step S4: The discharge circuit conduction and power regulation unit generates a PWM control signal based on the difference between the real-time power battery SOC and the target power battery SOC, and adjusts the discharge current through the power module to reduce the power battery SOC to the target power battery SOC. Step S5: The discharge termination control unit, based on the real-time power battery SOC, brake pedal opening signal, and vehicle current gear signal, combined with the preset discharge termination judgment rule, sends a second level signal to the main contactor to disconnect the discharge circuit when the discharge termination condition is met, and causes the grounding device control unit to generate a second control signal to drive the actuator to retract the grounding discharge device into the chassis.

10. The automatic discharge control method for hybrid vehicles according to claim 9, characterized in that, The method further includes an on / off timing control process: when the discharge starts, the first level signal is first sent to the main contactor to close the main contactor, and then the PWM control signal is output to drive the power module to perform high-frequency chopping; When the discharge is terminated, the PWM control signal is first turned off to shut down the power module, and then the second level signal is sent to the main contactor to disconnect the main contactor.

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