Method and device for switching power supply modes, vehicle and storage medium

Abstract

The invention provides a power supply mode switching method and device, a vehicle and a storage medium, and relates to the field of high-voltage power supply. And when the motor supplies power to the whole vehicle and the power supply for supplying power to the whole vehicle needs to be converted from the motor to the high-voltage battery, the motor is controlled to stop generating power. Therefore, when the motor and the high-voltage battery are a high-voltage power supply, the high-voltage battery is regarded as a load, and the battery relay of the high-voltage battery is closed, the battery relay is prevented from being damaged. After the motor stops generating power, the motor is in a driving mode, the motor cuts a stator winding due to residual magnetism and generates back electromotive force with residual inductance, and when the back electromotive force is large, the motor enters a three-phase parallel common-path active discharge mode, so that the current of the three-phase winding is multiplied. And when the current of the three-phase winding is multiplied, the back electromotive force is rapidly reduced, and the rapid discharge of the back electromotive force can be realized. After the motor enters the active discharge mode, the counter electromotive force is detected, so that the battery relay of the high-voltage battery is closed when the counter electromotive force is small, and the error switching risk when the active discharge mode does not reach the expectation is avoided.

Description

Technical Field

[0001] The present application relates to the field of high-voltage power supply, and more specifically, to a method, device, vehicle and storage medium for switching power supply modes in the field of high-voltage power supply. Background Art

[0002] With the continuous advancement of automotive technology and the improvement of people's living standards, the audience for vehicles is becoming increasingly broad. Hybrid vehicles are favored by more consumers due to their unique energy-saving and emission-reduction characteristics, flexibility, and economical features.

[0003] In a hybrid vehicle, the engine drives the electric motor, which then provides power to the vehicle in generator mode. Simultaneously, there's a need to switch the vehicle's power source from the motor to a high-voltage battery. This creates a need to switch from high-voltage power generated by the motor to high-voltage power provided by the high-voltage battery.

[0004] In the related art, the switching time is relatively long. Therefore, a method for accelerating the switching speed is urgently needed. Summary of the Invention

[0005] The present application provides a method, device, vehicle and storage medium for switching power supply modes, which can accelerate the switching speed from powering the entire vehicle from an electric motor to powering the entire vehicle from a high-voltage battery.

[0006] In a first aspect, a method for switching a power supply mode is provided, the method comprising: controlling the motor in a vehicle to stop generating power when the motor supplies power to the entire vehicle and the power supply for the entire vehicle needs to be switched from the motor to a high-voltage battery; after the motor stops generating power, upon detecting that the back electromotive force generated when the motor rotates is greater than a first preset back electromotive force, controlling the motor to enter a target discharge mode, the target discharge mode being an active discharge mode in which the three-phase windings of the motor are connected in parallel to form a common discharge; after the motor enters the target discharge mode, upon detecting that the back electromotive force is less than a second preset back electromotive force, controlling the battery relay of the high-voltage battery to close, the second preset back electromotive force being less than the first preset back electromotive force and being related to the normal operating voltage of the high-voltage battery.

[0007] In the above technical solution, when the motor supplies power to the vehicle and the vehicle's power supply needs to be switched from the motor to the high-voltage battery, the motor is controlled to stop generating power. This prevents damage to the battery relay when the high-voltage battery is considered a load and the high-voltage battery's battery relay is closed when the motor and the high-voltage battery share a high-voltage power source. After the motor stops generating power, it enters drive mode. The residual magnetism cuts through the stator windings and the residual electricity, inducing a back electromotive force. When the back electromotive force is large, it will hinder the motor from switching the power supply line. When the back electromotive force is large, this solution controls the motor to enter an active discharge mode (target discharge mode) with three phases connected in parallel. This doubles the current in the motor's three-phase windings. Based on the principle of voltage decay, a sharp increase in current accelerates voltage drop. Therefore, when the current in the three-phase winding doubles, the motor's back electromotive force drops rapidly, achieving rapid discharge of the back electromotive force, thereby accelerating the switching speed from motor powering the vehicle to the high-voltage battery powering the vehicle. After the motor enters the target discharge mode, the method continues to detect the back electromotive force, which can switch the power supply line (close the battery relay of the high-voltage battery) when ensuring that the back electromotive force is less than the first preset back electromotive force, and can avoid the risk of false switching when the active discharge strategy of the three-phase parallel common circuit does not meet expectations.

[0008] In combination with the first aspect, in some possible implementations, before controlling the motor to stop generating electricity, the method also includes: determining whether the high-voltage battery meets the preset power supply conditions; and controlling the motor to stop generating electricity, including: controlling the motor to stop generating electricity when the high-voltage battery meets the preset power supply conditions.

[0009] In the above technical solution, a verification step is added to determine whether the high-voltage battery meets the preset power supply conditions. This ensures that the subsequent operation of stopping power generation and switching to the high-voltage battery for high-voltage power supply is performed only when the high-voltage battery is reliably supplying power. This prevents blindly switching to the high-voltage battery for high-voltage power supply when the battery is in poor condition, thereby avoiding the risk of damage to the high-voltage battery. Furthermore, when the high-voltage battery meets the preset power supply conditions, the motor is controlled to stop generating power and switch, which can achieve a smoother power transition. When the high-voltage battery is ready to take over the power supply immediately, the duration of the power interruption can be reduced, ensuring the continuity of the power supply for the entire vehicle.

[0010] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the method for determining whether the high-voltage battery meets the preset power supply conditions includes: determining whether the current remaining power of the high-voltage battery is within the preset power range, and determining whether the current temperature of the high-voltage battery is within the preset temperature range; when the current remaining power is within the preset power range and the current temperature is within the preset temperature range, determining the theoretical operating voltage that the high-voltage battery should be at based on the current remaining power and the current temperature; determining the voltage deviation of the actual operating voltage of the high-voltage battery relative to the theoretical operating voltage; when the voltage deviation is less than the preset voltage deviation, determining that the high-voltage battery meets the preset power supply conditions.

[0011] In the above technical solution, the high-voltage battery's current remaining charge is required to be within a preset range. This prevents the high-voltage battery from being unable to provide continuous power when the remaining charge is too low or from being protected when the remaining charge is too high. Furthermore, the current temperature is required to be within a preset range to prevent internal short circuits in the high-voltage battery when the temperature is too low or thermal runaway chain reactions in the high-voltage battery when the temperature is too high, thus ensuring from the source that the high-voltage battery has the basic physical conditions for stable power supply. Furthermore, based on the real-time remaining charge and temperature, the current minimum recharging voltage (theoretical operating voltage) that the high-voltage battery should reach is determined. This takes into account the changes in battery characteristics over time and provides an adaptive reference point for voltage determination, rather than a fixed voltage threshold. By determining the voltage deviation between the actual operating voltage and the theoretical operating voltage, it is possible to determine, to a certain extent, whether the high-voltage battery is internally healthy (e.g., whether it has not significantly aged or whether its internal resistance has increased). This ensures that the high-voltage battery can not only provide power but also respond to load demands in the expected and optimal condition.

[0012] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the method for determining the first preset back electromotive force includes: obtaining the theoretical safety time and theoretical safety voltage when discharging the back electromotive force of the motor; based on the theoretical safety time, the theoretical safety voltage, the damping coefficient, the moment of inertia and the back electromotive force constant, determining the initial speed that the motor should meet, the damping coefficient is used to reflect the friction resistance of the motor when it rotates, the moment of inertia is used to reflect the ability of the motor to resist changes in speed, and the back electromotive force constant is used to indicate the back electromotive force generated by the motor per radian speed; based on the product between the initial speed and the back electromotive force constant, it is determined as the first preset back electromotive force.

[0013] In the above technical solution, the theoretical safety time, theoretical safety voltage, damping coefficient (friction resistance), moment of inertia (inertia resistance), and back-electromotive force constant during discharge are introduced to construct a speed attenuation model of the motor, solve the initial speed that the motor should meet, and determine the first preset back-electromotive force based on the initial speed. This allows the trigger point (first preset back-electromotive force) of the target discharge mode to dynamically adapt to different motors and working conditions, avoiding insufficient discharge (arcing risk) of the fixed back-electromotive force threshold in high-inertia rotors or low-friction scenarios, or premature discharge in low-inertia scenarios. In other words, the solution upgrades the empirical threshold to an adaptive back-electromotive force threshold based on energy equations and kinematics, eliminating excessive discharge or ineffective discharge from the root, while optimizing the discharge time, that is, the switching time.

[0014] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the method for determining the second preset back electromotive force includes: determining the voltage detection deviation based on the inherent measurement deviation of the voltage sensor when measuring the operating voltage of the high-voltage battery, the temperature drift deviation caused by temperature change, and the random fluctuation deviation caused by noise; determining the theoretical transient voltage drop when the battery relay of the high-voltage battery is closed based on the first impact voltage when the target power switch tube is turned off and the second impact voltage when the battery relay of the high-voltage battery is closed, and the target power switch tube is used to exit the target discharge mode; determining the sum of the voltage detection deviation and the theoretical transient voltage drop as the total voltage deviation, and determining the difference between the minimum normal operating voltage of the high-voltage battery and the total voltage deviation as the second preset back electromotive force.

[0015] In the above technical solution, the inherent measurement deviation, temperature drift deviation and random fluctuation deviation of the integrated voltage sensor are used to quantify the total voltage detection deviation, which can eliminate the misjudgment caused by measuring the back electromotive force. Furthermore, the above-mentioned first impulse voltage and second impulse voltage are introduced to determine the total transient voltage drop to ensure that when the power supply branch is switched, the back electromotive force threshold (the second preset back electromotive force) can reserve an impact margin. Furthermore, combined with the minimum normal operating voltage, the second back electromotive force of the motor can be forced to be absolutely lower than the electrochemical safety boundary during switching, which can avoid the arc discharge phenomenon caused by premature switching and cause the contact adhesion of the battery relay.

[0016] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the method also includes: when it is detected that the back electromotive force generated when the motor rotates is greater than or equal to the second preset back electromotive force and less than or equal to the first preset back electromotive force, determining whether the preset gear switching condition is met when the vehicle is driving, and the preset gear switching condition is the condition for switching from the current gear to a higher gear; when the preset gear switching condition is met when the vehicle is driving, switching the current gear to the first gear, which is higher than the current gear; after the current gear is switched to the first gear, when it is detected that the back electromotive force is less than the second preset back electromotive force, controlling the battery relay of the high-voltage battery to close.

[0017] In the above technical solution, when the back electromotive force is between the second preset back electromotive force and the first preset back electromotive force, if the preset gear switching conditions are met while the vehicle is driving, the solution actively accelerates the discharge speed of the back electromotive force of the motor indirectly through the upshift strategy. The above solution can avoid the problem of long switching time caused by the natural attenuation of the back electromotive force when the back electromotive force is between the second preset back electromotive force and the first preset back electromotive force. After upshifting, the back electromotive force is continuously monitored, and the battery relay is controlled to close only when the back electromotive force is less than the second preset back electromotive force. This can avoid the risk of false switching when the upshift strategy does not meet expectations. In addition, by actively controlling the gear change, the originally passive discharge waiting process can be transformed into a controllable active adjustment, which can significantly shorten the waiting time for switching the task of supplying high voltage power.

[0018] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the method for determining whether the preset gear switching condition is satisfied when the vehicle is traveling includes: when the current gear is not the highest gear of the vehicle, determining multiple gears that the vehicle can switch to based on the current gear and the highest gear; determining the maximum theoretical speed that the vehicle can travel based on the multiple gears and the maximum speed limit on the current driving road; determining whether the vehicle can travel at the maximum theoretical speed based on the driving conditions on the driving road, the driving conditions being road conditions, traffic conditions and environmental conditions; when the vehicle can travel at the maximum theoretical speed, determining that the preset gear switching condition is satisfied when the vehicle is traveling.

[0019] In the above technical solution, the upshift strategy only occurs in scenarios other than the highest gear. This avoids logical conflicts when the vehicle is in the highest gear and has no gear to shift to, ensuring that the upshift operation is physically feasible. Based on the current gear and the highest gear, the vehicle's multiple shiftable gears are determined. Furthermore, based on the multiple gears and the maximum speed limit, the maximum theoretical speed for the upshiftable gear is determined, ensuring that the vehicle speed never exceeds the speed limit after the upshift, thus ensuring driving safety. Road conditions (such as wetness, slope, and congestion), traffic conditions (congestion level), and environmental conditions (such as fog and visibility) are introduced to verify whether the vehicle can actually travel at the maximum theoretical speed. This prevents the motor speed from rebounding and the back EMF rebounding due to forced deceleration after the upshift due to road conditions. In other words, the above solution only executes the upshift operation when it is both physically feasible and fully adapted to the current driving environment. This ensures that the motor speed steadily decreases without the risk of a sudden increase, allowing the motor's back EMF to quickly decay to less than the second preset back EMF.

[0020] In a second aspect, a device for switching power supply branches is provided, which includes: a control module, used to: control the motor in the vehicle to stop generating electricity when the motor supplies power to the entire vehicle and the power supply for the entire vehicle needs to be converted from the motor to a high-voltage battery; after the motor stops generating power, when it is detected that the back electromotive force generated when the motor rotates is greater than a first preset back electromotive force, control the motor to enter a target discharge mode, wherein the target discharge mode is an active discharge mode in which the three-phase windings of the motor are connected in parallel to form a common discharge; a switching module, used to control the battery relay of the high-voltage battery to close after the motor enters the target discharge mode, when it is detected that the back electromotive force is less than a second preset back electromotive force, wherein the second preset back electromotive force is less than the first preset back electromotive force and is related to the normal operating voltage of the high-voltage battery.

[0021] In combination with the second aspect, in some possible implementations, before controlling the motor to stop generating electricity, the device also includes: a determination module for determining whether the high-voltage battery meets the preset power supply conditions; and a control module for specifically controlling the motor to stop generating electricity when the high-voltage battery meets the preset power supply conditions.

[0022] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is specifically used to: determine whether the current remaining power of the high-voltage battery is within a preset power range, and determine whether the current temperature of the high-voltage battery is within a preset temperature range; when the current remaining power is within the preset power range and the current temperature is within the preset temperature range, determine the theoretical operating voltage that the high-voltage battery should be at based on the current remaining power and the current temperature; determine the voltage deviation of the actual operating voltage of the high-voltage battery relative to the theoretical operating voltage; when the voltage deviation is less than the preset voltage deviation, determine that the high-voltage battery meets the preset power supply condition.

[0023] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the device also includes: an acquisition module, used to obtain the theoretical safety time and theoretical safety voltage when discharging the back electromotive force of the motor; the determination module is specifically used to: determine the initial speed that the motor should meet based on the theoretical safety time, the theoretical safety voltage, the damping coefficient, the moment of inertia and the back electromotive force constant, the damping coefficient is used to reflect the friction resistance of the motor when it rotates, the moment of inertia is used to reflect the ability of the motor to resist speed changes, and the back electromotive force constant is used to indicate the back electromotive force generated by the motor per radian speed; based on the product between the initial speed and the back electromotive force constant, it is determined to be the first preset back electromotive force.

[0024] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: determine the voltage detection deviation based on the inherent measurement deviation of the voltage sensor when measuring the operating voltage of the high-voltage battery, the temperature drift deviation caused by temperature changes, and the random fluctuation deviation caused by noise; determine the theoretical transient voltage drop when the battery relay of the high-voltage battery is closed based on the first impact voltage when the target power switch tube is turned off and the second impact voltage when the battery relay of the high-voltage battery is closed, and the target power switch tube is used to exit the target discharge mode; determine the sum of the voltage detection deviation and the theoretical transient voltage drop as the total voltage deviation, and determine the difference between the minimum normal operating voltage of the high-voltage battery and the total voltage deviation as the second preset back electromotive force.

[0025] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is also used to determine whether the preset gear switching condition is met when the vehicle is driving when it is detected that the back electromotive force generated when the motor rotates is greater than or equal to the second preset back electromotive force and less than or equal to the first preset back electromotive force. The preset gear switching condition is the condition for switching from the current gear to a higher gear; the switching module is also used to: when the preset gear switching condition is met when the vehicle is driving, switch the current gear to the first gear, which is higher than the current gear; after the current gear is switched to the first gear, when it is detected that the back electromotive force is less than the second preset back electromotive force, control the battery relay of the high-voltage battery to close.

[0026] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: determine, based on the current gear and the highest gear, a plurality of gears that the vehicle can switch to, when the current gear is not the highest gear of the vehicle; determine, based on the plurality of gears and the maximum speed limit on the current driving road, the maximum theoretical speed at which the vehicle can travel; determine, based on the driving conditions on the driving road, whether the vehicle can travel at the maximum theoretical speed, the driving conditions being road conditions, traffic conditions and environmental conditions; and, when the vehicle can travel at the maximum theoretical speed, determine that the preset gear switching conditions are met when the vehicle is driving.

[0027] In a third aspect, a vehicle is provided, comprising a memory and a processor. The memory is configured to store executable program code, and the processor is configured to retrieve and execute the executable program code from the memory, so that the vehicle executes the method of the first aspect or any possible implementation of the first aspect.

[0028] In a fourth aspect, a computer-readable storage medium is provided, which stores an executable program code. When the executable program code runs on a computer, the computer executes the method in the above-mentioned first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of a scenario of using a vehicle provided in an embodiment of the present application;

[0030] Figure 2 is a schematic flow chart of a method for switching a power supply mode provided in an embodiment of the present application;

[0031] Figure 3 This is a schematic diagram of a circuit for discharging the back electromotive force of a motor provided in an embodiment of the present application;

[0032] Figure 4 This is a schematic diagram of controlling the switching of the power supply circuit of a motor provided in an embodiment of the present application;

[0033] Figure 5 1 is a schematic structural diagram of a device for switching power supply branches provided in an embodiment of the present application;

[0034] Figure 6 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will clearly and thoroughly describe the technical solutions in this application in conjunction with the accompanying drawings. In the description of the embodiments of this application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more than two.

[0036] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0037] Figure 1 This is a schematic diagram of a hybrid vehicle power supply scenario provided in an embodiment of the present application.

[0038] For example, Figure 1 In the hybrid vehicle shown, such as vehicle A, the engine in vehicle A drives the electric motor, which, in generator mode, generates electricity to power the vehicle. However, there's a need to switch the vehicle's power source from the electric motor to a high-voltage battery. For example, if a high-voltage component (such as the air-conditioning compressor) requests charging from the high-voltage battery, there's a need to switch from high-voltage power generation by the electric motor to high-voltage power supplied by the battery.

[0039] In the related art, the switching time is relatively long. The related art starts the switching by waiting for the back electromotive force of the motor to decay naturally until it drops to a preset back electromotive force. The whole process usually takes 60 seconds.

[0040] During these 60 seconds, i.e., the switching period, the entire vehicle's power supply is simply supplied by a 12V battery without high-voltage power input. This is determined by the safety mechanism and electrical characteristics of the high-voltage system. Specifically, 1) the high-voltage battery cannot function during the switching period: the high-voltage battery relay is physically disconnected during the switching period; the high-voltage battery needs to close the relay when it is connected to the bus, but the bus voltage is maintained by the motor in the early stage of the switching. The voltage difference between the bus voltage and the high-voltage battery voltage is large, and forcing it to close can cause danger; furthermore, the DC-DC converter cannot operate when the voltage is unstable and cannot convert the input voltage. 2) As an independent power source that is not affected by the high-voltage switching, the 12V battery can maintain the operation of safety systems such as steering and braking within a certain time window.

[0041] However, the aforementioned time is very short, typically less than 10 seconds. However, the aforementioned related technology requires 60 seconds. This means that every additional second of switching time, and therefore every additional second of 12V battery power supply time, poses an increasing risk to the vehicle. For example, if the power supply lasts for 15 seconds and the voltage is 11 volts, the electronic power steering system will experience a response delay; if the power supply lasts for 32 seconds and the voltage is 10 volts, the steering wheel's power steering function will fail and the vehicle's instrument panel will remain black.

[0042] In order to solve the above problems, the present application proposes a method for switching power supply modes to accelerate the switching speed and shorten the switching time.

[0043] Figure 2 This is a schematic flowchart of a method for switching power supply modes provided in an embodiment of the present application.

[0044] It should be understood that the method for switching power supply modes provided in the embodiment of the present application can be applied to Figure 1 A hybrid vehicle (eg, vehicle A) is shown.

[0045] For example, Figure 2 As shown, the method 200 includes the following steps 201 to 203.

[0046] Step 201 : When a motor in a vehicle supplies power to the entire vehicle and the power source for the entire vehicle needs to be switched from the motor to a high-voltage battery, the motor is controlled to stop generating power.

[0047] It should be understood that the vehicle in step 201 is a hybrid vehicle, specifically a gasoline-electric hybrid vehicle. The motor in step 201 can be considered a P2 motor, which can generate electricity with the help of the engine. The motor is located between the engine and the transmission, and the motor's operating modes include drive mode and power generation mode. When the motor is in power generation mode and is driven by the engine, the motor can convert mechanical energy into electrical energy, which can be used for high-voltage electrical components or stored in a high-voltage battery. When the motor is in drive mode and is driven by the engine, the motor superimposes the mechanical energy output by the engine with its own mechanical energy, and then transmits the superimposed mechanical energy to the transmission to drive the wheels.

[0048] Optionally, the above-mentioned motor is a permanent magnet synchronous motor.

[0049] It should also be understood that when the motor supplies power to the entire vehicle and the power supply for the entire vehicle needs to be converted from the motor to a high-voltage battery, the vehicle needs to switch from high-voltage power generated by the original motor to high-voltage power supplied by the high-voltage battery.

[0050] It should be noted here that in the process of the motor supplying power to the entire vehicle, the hallmark feature of power supply is that the battery relay of the high-voltage battery (including the main positive relay and the main negative relay) is disconnected.

[0051] In some embodiments, the motor is a permanent magnet synchronous motor, and controlling the motor to stop generating electricity in step 201 includes: gradually reducing the excitation current of the motor until it reaches zero.

[0052] It should be understood that the condition for a motor to generate electricity requires the presence of an excitation current. This excitation current creates a rotor magnetic field within the rotor windings. When driven, this rotor magnetic field cuts through the stator windings, generating an induced electromotive force (EMF) in the stator windings. When the excitation current is zero, no rotor magnetic field is generated, and no magnetic lines of force cut through the stator windings, resulting in no induced EMF, which stops the motor from generating electricity. When the motor is in generating mode, it converts mechanical energy into electrical energy. When the motor is actively outputting electrical energy, its electromotive force is called an induced EMF.

[0053] In one possible implementation, before controlling the motor to stop generating electricity in step 201, the method 200 also includes: determining whether the high-voltage battery meets the preset power supply conditions; and controlling the motor to stop generating electricity in step 201 includes: controlling the motor to stop generating electricity when the high-voltage battery meets the preset power supply conditions.

[0054] It should be understood that the preset power supply conditions in the above scheme refer to the safety margins that the high-voltage battery must meet before taking over the task of supplying high-voltage power. This safety margin can be defined by the remaining power, temperature, and voltage. This is because when the remaining power is ignored, switching to the high-voltage battery for high-voltage power supply may result in deep power supply when the remaining power is low, causing the negative electrode graphite layer structure in the high-voltage battery to collapse, or the high-voltage battery's capacity to permanently decay. When the temperature is ignored, switching to the high-voltage battery for high-voltage power supply may cause the high-voltage battery's internal circuit to short-circuit in low-temperature scenarios, or the electrolyte in the high-voltage battery reacts with the negative electrode in high-temperature scenarios, leading to a thermal runaway chain reaction and extremely high temperatures in the high-voltage battery. When the voltage is ignored, switching to the high-voltage battery for high-voltage power supply may cause the negative electrode potential of the high-voltage battery to be less than zero when the voltage is very low. If the high-voltage battery is a lithium-ion high-voltage power battery, the high-voltage battery may undergo lithium deposition, which will cause the high-voltage battery's capacity to decay.

[0055] Among them, the above-mentioned lithium deposition reaction refers to the lithium ions of the positive electrode being reduced to lithium metal on the surface of the negative electrode and deposited on the surface of the negative electrode. Most of this deposited lithium metal cannot be embedded in the negative accumulation layer, nor can it be embedded back into the positive electrode. The number of lithium ions participating in the charge and discharge reaction is reduced, thus causing the capacity of the high-voltage battery to decay.

[0056] In the above technical solution, a verification step is added to determine whether the high-voltage battery meets the preset power supply conditions. This ensures that the subsequent operation of stopping power generation and switching to the high-voltage battery for high-voltage power supply is performed only when the high-voltage battery is reliably supplying power, thereby preventing blindly switching to the high-voltage battery for high-voltage power supply when the battery is in poor condition, thereby avoiding the risk of damage to the high-voltage battery. Furthermore, when the high-voltage battery meets the preset power supply conditions, the motor is controlled to stop power generation and switch, which can achieve a smoother power transition. When the high-voltage battery is ready to take over power supply immediately, the duration of power interruption can be reduced, ensuring the continuity of power supply for the entire vehicle.

[0057] In one possible implementation, the method for determining whether the high-voltage battery meets the preset power supply condition includes: determining whether the current remaining power of the high-voltage battery is within the preset power range, and determining whether the current temperature of the high-voltage battery is within the preset temperature range; when the current remaining power is within the preset power range and the current temperature is within the preset temperature range, determining the theoretical operating voltage of the high-voltage battery based on the current remaining power and the current temperature; determining the voltage deviation of the actual operating voltage of the high-voltage battery relative to the theoretical operating voltage; when the voltage deviation is less than the preset voltage deviation, determining that the high-voltage battery meets the preset power supply condition.

[0058] It should be understood that the high-voltage battery in the above solution provides high-voltage power to the vehicle, and the current remaining charge of the high-voltage battery must be relatively sufficient. Optionally, the preset charge range is greater than 30%. In addition, the current temperature of the high-voltage battery should be between 15°C and 55°C.

[0059] It should also be understood that the theoretical operating voltage in the above scheme can be regarded as the minimum charging voltage corresponding to the remaining power and temperature. The minimum charging voltage refers to the absolute lower limit of the high-voltage battery's safe discharge.

[0060] In the above technical solution, the high-voltage battery's current remaining charge is required to be within a preset range. This prevents the high-voltage battery from being unable to provide continuous power when the remaining charge is too low or from being protected when the remaining charge is too high. Furthermore, the current temperature is required to be within a preset range to prevent internal short circuits in the high-voltage battery when the temperature is too low or thermal runaway (a chain reaction) in the high-voltage battery when the temperature is too high, thus ensuring the high-voltage battery has the basic physical conditions for stable power supply from the source. Furthermore, the current minimum recharging voltage (theoretical operating voltage) required by the high-voltage battery is determined based on the real-time remaining charge and temperature. This takes into account the changing battery characteristics over time and provides an adaptive reference point for voltage determination, rather than a fixed voltage threshold. By determining the voltage deviation between the actual operating voltage and the theoretical operating voltage, it is possible to determine, to a certain extent, whether the high-voltage battery is internally healthy (e.g., whether it has not significantly aged or whether its internal resistance has increased). This ensures that the high-voltage battery can not only provide power but also respond to load demands in the expected and healthy state. In other words, by implementing these three-dimensional judgments, the switching operation is only performed when the battery has sufficient charge, a suitable temperature, and good internal health. This greatly reduces the risk of vehicle high-voltage system collapse, power-consuming equipment downtime, or damage to the high-voltage battery itself due to insufficient high-voltage battery capacity at the moment of switching. It can ensure an extremely high success rate for high-voltage power supply network switching while optimizing the service life of the high-voltage battery.

[0061] Step 202 , after the motor stops generating electricity, when it is detected that the back electromotive force generated when the motor rotates is greater than a first preset back electromotive force, the motor is controlled to enter a target discharge mode, where the target discharge mode is an active discharge mode in which the three-phase windings of the motor are connected in parallel to form a common discharge.

[0062] It should be understood that in step 202, the three-phase windings of the motor include a U-phase winding, a V-phase winding, and a W-phase winding, indicating different groups of coils or windings in the motor. Essentially, these are three windings that are spatially symmetrically distributed and electrically fed with currents 120 degrees out of phase with each other. The target discharge mode is an active discharge (back EMF) mode that connects the three-phase windings of the motor in parallel to form a common discharge path, converting back EMF energy (electrical energy) into heat energy.

[0063] It should also be understood that in the above step 202, after the motor stops generating electricity, the motor is still in a rotating state, and at this time, the motor is in a driving mode. After the motor stops generating electricity, there is still residual magnetism in the rotor winding, and the residual magnetism cuts the stator winding, thereby generating an electromotive force in the stator winding. In addition, after the motor stops generating electricity, the electric energy originally generated by the motor has not been fully output, and the motor has residual electricity. In this application, when the motor is in the driving mode, the electromotive force generated by the residual magnetism cutting the stator winding and the electromotive force obtained by releasing the residual electricity are referred to as the back electromotive force of the motor. That is, the difference between the electromotive force and the back electromotive force lies in the different modes in which the motor is located.

[0064] It should also be understood that the back EMF in step 202 is the sum of the back EMFs generated by residual magnetism cutting the stator windings and residual electricity release when the motor is in the drive mode after it stops generating electricity. The first preset back EMF is the back EMF threshold for the motor to enter the target discharge mode.

[0065] It's also important to note that to switch from high-voltage power generated by the original motor to high-voltage power supplied by the high-voltage battery, the motor's back EMF needs to be less than the high-voltage battery's operating voltage. However, just after the motor stops generating power, the sum of the back EMF generated by residual magnetism cutting the stator windings and the back EMF generated by the residual charge released is still relatively large. When the back EMF exceeds a first preset back EMF, the motor's back EMF needs to be quickly discharged. This solution employs the motor entering a target discharge mode.

[0066] In some embodiments, controlling the motor to enter a target discharge mode includes: controlling each phase winding of the three-phase winding of the motor to be connected to a switching device corresponding to each phase winding, controlling the switching device corresponding to each phase winding to be connected to a discharge resistor, and controlling the discharge resistor to be grounded.

[0067] It should be understood that the switching device corresponding to each phase winding may be an insulated gate bipolar transistor (IGBT).

[0068] In the above scheme, the motor's three-phase windings generate back EMF. After the current in each phase passes through its corresponding switching device, it converges in front of a discharge resistor and ultimately drains to ground through a unified discharge resistor. The above parallel discharge path superimposes the currents of the three-phase windings, doubling the discharge current. According to the voltage decay formula, an increase in current accelerates voltage drop. Therefore, when the discharge current doubles, the motor's back EMF drops rapidly, achieving rapid discharge of the back EMF.

[0069] Figure 3 This is a circuit diagram of a motor back electromotive force discharge circuit provided by the embodiment of the present application. Figure 3 , giving the specific process of the motor entering the target discharge mode.

[0070] For example, Figure 3 As shown, the motor includes a U-phase winding, a V-phase winding and a W-phase winding. The U-phase winding is connected to the U-phase switching device, the V-phase winding is connected to the V-phase switching device, and the W-phase winding is connected to the W-phase switching device. The U-phase switching device, the V-phase switching device and the W-phase switching device are all connected to a discharge resistor, which is grounded.

[0071] In one possible implementation, the method for determining the first preset back electromotive force in step 202 includes: obtaining a theoretical safe time and a theoretical safe voltage when discharging the back electromotive force of the motor; determining an initial speed that the motor should meet based on the theoretical safe time, the theoretical safe voltage, the damping coefficient, the moment of inertia and the back electromotive force constant, wherein the damping coefficient is used to reflect the friction resistance of the motor during rotation, the moment of inertia is used to reflect the ability of the motor to resist speed changes, and the back electromotive force constant is used to indicate the back electromotive force generated by the motor per radian speed; and determining the first preset back electromotive force based on the product between the initial speed and the back electromotive force constant.

[0072] It should be understood that the theoretical safety time in the above solution may be 5 seconds, the theoretical safety voltage may be 60 volts, and the back electromotive force constant may be 0.08 volts·seconds / radian.

[0073] It should be noted here that when determining the first preset back electromotive force, the theoretical safety time, the theoretical safety voltage, the damping coefficient, the moment of inertia and the back electromotive force constant are introduced. The principle is to use the theoretical safety time and the theoretical safety voltage as constraints, combined with the damping coefficient, the moment of inertia and the back electromotive force constant, to inversely solve the allowable higher initial speed of the motor. The higher initial speed represents the discharge process, which can ensure that the back electromotive force of the motor is relatively small at the end of the target discharge mode and the total heat generated is less than the heat capacity of the discharge resistor; finally, the higher initial speed is multiplied by the back electromotive force constant to determine the first preset back electromotive force, which can make the triggering back electromotive force (first preset back electromotive force) of the target discharge mode dynamically adapt to different working conditions (such as increasing the first preset back electromotive force to delay discharge when friction is high, and reducing the first preset back electromotive force to discharge earlier when inertia is high), thereby optimizing the discharge efficiency.

[0074] In the above technical solution, the theoretical safety time, theoretical safety voltage, damping coefficient (friction resistance), moment of inertia (inertia resistance), and back-electromotive force constant during discharge are introduced to construct a speed attenuation model of the motor, solve the initial speed that the motor should meet, and determine the first preset back-electromotive force based on the initial speed. This allows the trigger point (first preset back-electromotive force) of the target discharge mode to dynamically adapt to different motors and working conditions, avoiding insufficient discharge (arcing risk) of the fixed back-electromotive force threshold in high-inertia rotors or low-friction scenarios, or premature discharge in low-inertia scenarios. In other words, the solution upgrades the empirical threshold to an adaptive back-electromotive force threshold based on energy equations and kinematics, eliminating excessive discharge or ineffective discharge from the root, while optimizing the discharge time, that is, the switching time.

[0075] In some embodiments, based on the theoretical safety time, the theoretical safety voltage, the damping coefficient, the moment of inertia, and the back electromotive force constant, determining the initial speed that the motor should meet includes: determining a speed range based on the following formula (1); determining the maximum speed in the speed range as the initial speed;

[0076]

[0077] Among them, t safe is the theoretical safety time, the speed range is as follows (2), B is the damping coefficient, J is the moment of inertia, V safe is the theoretical safety voltage, k e is the back electromotive force constant;

[0078]

[0079] Among them, the initial speed r0 is the maximum speed in formula (2), that is,

[0080] In some embodiments, determining the first preset back electromotive force based on the product of the initial rotational speed and the back electromotive force constant includes: determining the first preset back electromotive force based on the following formula (3);

[0081] E1=k e *r0 (3)

[0082] Wherein, E1 is the first preset back electromotive force. Wherein, the unit of r0 is radian / second.

[0083] Step 203, after the motor enters the target discharge mode, when it is detected that the back electromotive force is less than a second preset back electromotive force, controlling the battery relay of the high-voltage battery to close, the second preset back electromotive force is less than the first preset back electromotive force and is related to the normal operating voltage of the high-voltage battery.

[0084] The normal operating voltage in step 203 is typically a voltage range. Optionally, the voltage range is [200, 750) volts.

[0085] In one possible implementation, the method for determining the second preset back electromotive force in step 203 includes: determining the voltage detection deviation based on the inherent measurement deviation of the voltage sensor when measuring the operating voltage of the high-voltage battery, the temperature drift deviation caused by temperature change, and the random fluctuation deviation caused by noise; determining the theoretical transient voltage drop when the battery relay of the high-voltage battery is closed based on the first impact voltage when the target power switch tube is turned off and the second impact voltage when the battery relay of the high-voltage battery is closed, and the target power switch tube is used to exit the target discharge mode; determining the sum of the voltage detection deviation and the theoretical transient voltage drop as the total voltage deviation, and determining the difference between the minimum normal operating voltage of the high-voltage battery and the total voltage deviation as the second preset back electromotive force.

[0086] It should be understood that the inherent measurement deviation in the above solution refers to the absolute measurement deviation of the voltage sensor within the calibrated voltage range (eg, 0V to 600V), and is only related to the measurement accuracy of the voltage sensor.

[0087] It should also be understood that turning off the target power switch is a necessary operation after the back electromotive force of the motor is discharged. Closing the battery relay is a prerequisite step for the high-voltage battery to resume supplying high voltage power.

[0088] It should be noted that when determining the second preset back EMF during the process of switching from motor-powered vehicle power to high-voltage battery power, inherent measurement deviation, temperature drift deviation, and random fluctuation deviation, as well as the first and second surge voltages, are introduced. This is because: inherent measurement deviation, temperature drift deviation, and random fluctuation deviation refer to measurement errors introduced during voltage measurement; the first and second surge voltages refer to transient surge voltages introduced during the actual switching process; and the minimum normal operating voltage refers to the electrochemical safety margin of the high-voltage battery. The motor's back EMF is measured using a voltage sensor. To prevent the motor's back EMF from being affected by measurement errors and transient surges during power branch switching, this solution compensates for these errors and transient surges, ensuring that switching is initiated when the motor's back EMF is less than the minimum normal operating voltage.

[0089] In the above technical solution, the inherent measurement deviation, temperature drift deviation and random fluctuation deviation of the integrated voltage sensor are used to quantify the total voltage detection deviation, which can eliminate the misjudgment caused by measuring the back electromotive force. Furthermore, the above-mentioned first impulse voltage and second impulse voltage are introduced to determine the total transient voltage drop to ensure that when the power supply branch is switched, the back electromotive force threshold (the second preset back electromotive force) can reserve an impact margin. Furthermore, combined with the minimum normal operating voltage, the second back electromotive force of the motor can be forced to be absolutely lower than the electrochemical safety boundary during switching, which can avoid the arc discharge phenomenon caused by premature switching and cause the contact adhesion of the battery relay.

[0090] In some embodiments, determining a voltage detection deviation based on an inherent measurement deviation of a voltage sensor when measuring the operating voltage of the high-voltage battery, a temperature drift deviation caused by temperature change, and a random fluctuation deviation caused by noise includes: determining the voltage detection deviation based on the following formula (4);

[0091]

[0092] Among them, Dd v is the voltage detection deviation, D im is the inherent measurement deviation, D td is the temperature drift deviation, D n The units of the above three deviations are all volts.

[0093] In some embodiments, based on a first impulse voltage when the target power switch tube is turned off and a second impulse voltage when the battery relay of the high-voltage battery is closed, a theoretical transient voltage drop when the battery relay of the high-voltage battery is closed is determined, including: determining the sum of the first impulse voltage and the second impulse voltage as the theoretical transient voltage drop.

[0094] In one possible implementation, the method 200 also includes: when it is detected that the back electromotive force generated when the motor rotates is greater than or equal to the second preset back electromotive force and less than or equal to the first preset back electromotive force, determining whether the preset gear switching condition is met when the vehicle is driving, and the preset gear switching condition is the condition for switching from the current gear to a higher gear; when the preset gear switching condition is met when the vehicle is driving, switching the current gear to the first gear, which is higher than the current gear; after the current gear is switched to the first gear, when it is detected that the back electromotive force is less than the second preset back electromotive force, controlling the battery relay of the high-voltage battery to close.

[0095] It should be understood that in the above solution, when the back EMF is between the second preset back EMF and the first preset back EMF, the back EMF of the motor is discharged by switching the vehicle's current gear to a higher gear. This is because the motor speed decreases after switching the current gear to a higher gear. There is a proportional relationship between the motor speed and the back EMF, so the back EMF decreases as the speed decreases.

[0096] In the above technical solution, when the back electromotive force is between the second preset back electromotive force and the first preset back electromotive force, if the preset gear switching conditions are met while the vehicle is driving, the solution actively accelerates the discharge speed of the back electromotive force of the motor indirectly through the upshift strategy. The above solution can avoid the problem of long switching time caused by the natural attenuation of the back electromotive force when the back electromotive force is between the second preset back electromotive force and the first preset back electromotive force. After upshifting, the back electromotive force is continuously monitored, and the battery relay is controlled to close only when the back electromotive force is less than the second preset back electromotive force. This can avoid the risk of false switching when the upshift strategy does not meet expectations. In addition, by actively controlling the gear change, the originally passive discharge waiting process can be transformed into a controllable active adjustment, which can significantly shorten the waiting time for switching the task of supplying high voltage power.

[0097] In one possible implementation, a method for determining whether the preset gear switching condition is satisfied when the vehicle is traveling includes: determining, based on the current gear and the highest gear, a plurality of gears to which the vehicle can switch, when the current gear is not the highest gear of the vehicle; determining, based on the plurality of gears and the maximum speed limit on the current driving road, a maximum theoretical speed at which the vehicle can travel; determining, based on driving conditions on the driving road, whether the vehicle can travel at the maximum theoretical speed, wherein the driving conditions are road conditions, traffic conditions, and environmental conditions; and determining that the preset gear switching condition is satisfied when the vehicle is traveling, when the vehicle can travel at the maximum theoretical speed.

[0098] It should be understood that the highest gear, current gear, and multiple gears in the above scheme are all forward gears. In addition, the maximum theoretical speed in the above scheme refers to the vehicle speed limited by the speed range corresponding to each gear in the multiple gears and the maximum speed limit.

[0099] It should also be understood that the road conditions in the above scheme may include road adhesion conditions, turning conditions, and conditions that can reflect whether the vehicle can pass smoothly through the bumpiness level; traffic conditions can be reflected through the congestion index; and environmental conditions can be reflected through the weather on the road.

[0100] In the above technical solution, the upshift strategy only occurs in scenarios other than the highest gear. This avoids logical conflicts when the vehicle is in the highest gear and has no gear to shift to, ensuring that the upshift operation is physically feasible. Based on the current gear and the highest gear, the vehicle's multiple shiftable gears are determined. Furthermore, based on the multiple gears and the maximum speed limit, the maximum theoretical speed for the upshiftable gear is determined, ensuring that the vehicle speed never exceeds the speed limit after the upshift, thus ensuring driving safety. Road conditions (such as wetness, slope, and congestion), traffic conditions (congestion level), and environmental conditions (such as fog and visibility) are introduced to verify whether the vehicle can actually travel at the maximum theoretical speed. This prevents the motor speed from rebounding and the back EMF rebounding due to forced deceleration after the upshift due to road conditions. In other words, the above solution only executes the upshift operation when it is both physically feasible and fully adapted to the current driving environment. This ensures that the motor speed steadily decreases without the risk of a sudden increase, allowing the motor's back EMF to quickly decay to less than the second preset back EMF.

[0101] In some embodiments, based on the current gear and the highest gear, the multiple gears that the vehicle can switch to are determined, including: on the basis of the gear of the current gear, upshifting according to a preset gear step until the upshift is to the highest gear, and determining at least one gear after upshifting as the multiple gears, and the multiple gears include the highest gear.

[0102] Optionally, the preset gear step is 1.

[0103] For example, the current gear is 2nd gear, the highest gear is 5th gear, and the preset gear step is 1. Based on the gear of the current gear, the gear is shifted up according to the preset gear step until the highest gear is shifted up. At least one gear after shifting up can be obtained, including 3rd gear, 4th gear and 5th gear.

[0104] In some embodiments, based on the multiple gears and the maximum speed limit on the current driving road, the maximum theoretical speed at which the vehicle can travel is determined, including: obtaining the mechanical maximum speed of the highest gear among the multiple gears of the vehicle; comparing the mechanical maximum speed with the maximum speed limit, and if the mechanical maximum speed is less than the maximum speed limit, determining the mechanical maximum speed as the maximum theoretical speed; if the mechanical maximum speed is greater than or equal to the maximum speed limit, determining the maximum speed limit as the maximum theoretical speed.

[0105] It should be understood that the mechanical maximum speed mentioned above refers to the maximum vehicle speed limited by the maximum speed of the vehicle's generator. When the mechanical maximum speed is less than the maximum speed limit, it indicates that the highest gear is unable to operate at the maximum speed limit, that is, the maximum speed limit cannot be reached. In this case, the mechanical maximum speed is determined as the maximum theoretical speed.

[0106] In the above technical solution, when the mechanical maximum speed is less than the maximum speed limit, the mechanical maximum speed is used as the maximum theoretical speed. This prevents overloading of the vehicle's powertrain. Furthermore, the maximum theoretical speed is also less than the maximum speed limit, ensuring strict compliance with speed limit regulations. When the mechanical maximum speed is greater than or equal to the maximum speed limit, the maximum speed limit is used as the maximum theoretical speed, thus preventing speeding. In other words, the above solution provides dual safety measures at both the regulatory and mechanical levels of the powertrain to determine a practical maximum theoretical speed.

[0107] In some embodiments, based on the driving conditions on the driving road, determining whether the vehicle can travel at the maximum theoretical speed includes: obtaining the road adhesion coefficient of the driving road based on the road surface type of the driving road; determining a first maximum safe vehicle speed based on the road adhesion coefficient and the curve radius of the driving road; obtaining the bumpiness level of the driving road when the maximum theoretical speed is less than or equal to the first maximum safe vehicle speed; determining the congestion index on the driving road when the bumpiness level is less than a preset level; determining whether the current weather is the first preset weather when the congestion index is less than the preset index; and determining whether the current weather is the first preset weather when the current weather is the first preset weather. The vehicle can travel at the maximum theoretical speed, and the first preset weather includes cloudy weather and sunny weather; when the current weather is not the first preset weather and the current weather is the second preset weather, it is determined whether the vehicle can travel at the maximum theoretical speed in the second preset weather, and the second preset weather includes windy weather and rainy weather; when the maximum theoretical speed is greater than the first maximum safe speed, or, when the bumpiness level is greater than or equal to the preset level, or, when the congestion index is greater than or equal to the preset index, or, when the current weather is not the first preset weather and the current weather is not the second preset weather, it is determined that the vehicle cannot travel at the maximum theoretical speed.

[0108] It should be understood that the curve radius of the road in the above solution is used to indicate the degree of curvature of the road. A straight road has no curves, and its curve radius is theoretically infinite. The smaller the curve radius, the sharper the turn; the larger the curve radius, the gentler the turn.

[0109] Optionally, the preset index is 0.4.

[0110] In some embodiments, determining a first maximum safe vehicle speed based on the road adhesion coefficient and the curve radius of the driving road includes: determining the first maximum safe vehicle speed based on the following formula (5);

[0111]

[0112] Among them, v safe-1 is the first maximum safe vehicle speed, μ is the road adhesion coefficient, g is the acceleration of gravity, and R is the curve radius.

[0113] In some embodiments, determining the congestion index on the driving road includes: obtaining a following distance between the vehicle and a preceding vehicle, an average speed of a plurality of networked vehicles within a preset distance from the vehicle, and a historical congestion index on the driving road; and determining the congestion index based on the following formula (6);

[0114]

[0115] Among them, i con is the congestion index, a1 is the first weight, v max is the maximum speed limit, v curr is the current speed of the vehicle, a2 is the second weight, d gap is the following distance, a3 is the third weight, v region is the average speed, a4 is the fourth weight, i hist In addition, the historical congestion index in the above scheme is the same as the congestion index, which quantifies the congestion level of the road in the same sub-section, the same week and the same time period.

[0116] It should be understood that The larger the value, the farther the current vehicle speed (actual speed) deviates from the maximum speed limit (ideal speed), and the greater the contribution to the congestion index. The first weight is used to indicate The contribution of the item to the congestion index. It refers to the ratio between the safe following distance and the following distance (actual following distance). The larger the ratio is, the lower the utilization rate of road resources. The second weight is used to indicate The contribution of the item to the congestion index. The ratio between the ideal vehicle speed and the average speed (free flow speed) is used to predict the future driving resistance of the road. The third weight is used to indicate The fourth weight is used to indicate the contribution of i to the congestion index. hist The contribution of the item to the congestion index.

[0117] Optionally, the first weight is 0.3, the second weight is 0.4, the third weight is 0.2, and the fourth weight is 0.1.

[0118] In some embodiments, when the current weather is not the first preset weather and the current weather is the second preset weather, determining whether the vehicle can travel at the maximum theoretical speed in the second preset weather includes: when the current weather is not the first preset weather and the current weather is the second preset weather, if the second preset weather is windy weather, obtaining the wind level; when the wind level is less than or equal to the preset level, determining that the vehicle can travel at the maximum theoretical speed in the second preset weather; when the wind level is greater than the preset level, determining that the vehicle cannot travel at the maximum theoretical speed in the second preset weather; if the second preset weather is rainy weather, determining the second maximum safe speed based on the road adhesion coefficient and the rainfall thickness; when the maximum theoretical speed is less than or equal to the second maximum safe speed, determining that the vehicle can travel at the maximum theoretical speed; when the maximum theoretical speed is greater than the second maximum safe speed, determining that the vehicle cannot travel at the maximum theoretical speed.

[0119] In some embodiments, determining the second maximum safe vehicle speed based on the road adhesion coefficient and the rainfall thickness includes: determining the second maximum safe vehicle speed based on the following formula (7);

[0120]

[0121] Among them, v safe-2 is the second maximum safe speed, and P is the rainfall thickness.

[0122] Figure 4 This is a schematic diagram of controlling the switching of the power supply circuit of a motor provided in an embodiment of the present application.

[0123] For example, when the motor is supplying power to the entire vehicle and the vehicle's power source needs to be switched from the motor to a high-voltage battery, the motor is controlled to stop generating power. After the motor stops generating power, the back EMF generated by the motor's rotation is detected in real time. If the back EMF is detected to be greater than a first preset back EMF, the motor is controlled to enter a target discharge mode. After the motor enters the target discharge mode, the back EMF generated by the motor's rotation is detected in real time. If the back EMF is detected to be less than a second preset back EMF, the battery relay of the high-voltage battery is controlled to close. If the back EMF is greater than or equal to the second preset back EMF and less than or equal to the first preset back EMF, a determination is made as to whether a preset gear shift condition is satisfied while the vehicle is in motion. If the preset gear shift condition is satisfied while the vehicle is in motion, the current gear is switched to the first gear. After the current gear is switched to the first gear, the back EMF generated by the motor's rotation is detected in real time. If the back EMF is detected to be less than the second preset back EMF, the battery relay of the high-voltage battery is controlled to close. If the back EMF is initially less than the second preset back EMF, the battery relay of the high-voltage battery is controlled to close.

[0124] Figure 5 It is a structural diagram of a device for switching power supply branches provided in an embodiment of the present application.

[0125] For example, Figure 5 As shown, the device 500 includes:

[0126] The control module 501 is configured to:

[0127] When a motor in a vehicle supplies power to the entire vehicle and the power supply for the entire vehicle needs to be switched from the motor to a high-voltage battery, controlling the motor to stop generating power;

[0128] After the motor stops generating electricity, if it is detected that the back electromotive force generated by the motor during rotation is greater than a first preset back electromotive force, the motor is controlled to enter a target discharge mode, wherein the target discharge mode is an active discharge mode in which the three-phase windings of the motor are connected in parallel to form a common discharge;

[0129] The switching module 502 is configured to control the battery relay of the high-voltage battery to close after the motor enters the target discharge mode and when it is detected that the back electromotive force is less than a second preset back electromotive force, wherein the second preset back electromotive force is less than the first preset back electromotive force and is related to the normal operating voltage of the high-voltage battery.

[0130] Optionally, before controlling the motor to stop generating electricity, the device 500 also includes: a determination module for determining whether the high-voltage battery meets the preset power supply conditions; and the control module 501, specifically for controlling the motor to stop generating electricity when the high-voltage battery meets the preset power supply conditions.

[0131] Optionally, the determination module is specifically used to: determine whether the current remaining power of the high-voltage battery is within a preset power range, and determine whether the current temperature of the high-voltage battery is within a preset temperature range; when the current remaining power is within the preset power range and the current temperature is within the preset temperature range, determine the theoretical operating voltage of the high-voltage battery based on the current remaining power and the current temperature; determine the voltage deviation of the actual operating voltage of the high-voltage battery relative to the theoretical operating voltage; when the voltage deviation is less than the preset voltage deviation, determine that the high-voltage battery meets the preset power supply condition.

[0132] Optionally, the device 500 also includes: an acquisition module, used to obtain the theoretical safe time and theoretical safe voltage when discharging the back electromotive force of the motor; the determination module is specifically used to: determine the initial speed that the motor should meet based on the theoretical safe time, the theoretical safe voltage, the damping coefficient, the moment of inertia and the back electromotive force constant, the damping coefficient is used to reflect the friction resistance of the motor when it rotates, the moment of inertia is used to reflect the ability of the motor to resist speed changes, and the back electromotive force constant is used to indicate the back electromotive force generated by the motor per radian speed; based on the product between the initial speed and the back electromotive force constant, it is determined to be the first preset back electromotive force.

[0133] Optionally, the determination module is further specifically used to: determine the voltage detection deviation based on the inherent measurement deviation of the voltage sensor when measuring the operating voltage of the high-voltage battery, the temperature drift deviation caused by temperature change, and the random fluctuation deviation caused by noise; determine the theoretical transient voltage drop when the battery relay of the high-voltage battery is closed based on the first impact voltage when the target power switch tube is turned off and the second impact voltage when the battery relay of the high-voltage battery is closed, and the target power switch tube is used to exit the target discharge mode; determine the sum of the voltage detection deviation and the theoretical transient voltage drop as the total voltage deviation, and determine the difference between the minimum normal operating voltage of the high-voltage battery and the total voltage deviation as the second preset back electromotive force.

[0134] Optionally, the determination module is also used to determine whether the preset gear switching condition is met when the vehicle is driving, when it is detected that the back electromotive force generated when the motor rotates is greater than or equal to the second preset back electromotive force and less than or equal to the first preset back electromotive force. The preset gear switching condition is the condition for switching from the current gear to a higher gear; the switching module is also used to: when the preset gear switching condition is met when the vehicle is driving, switch the current gear to the first gear, which is higher than the current gear; after the current gear is switched to the first gear, when it is detected that the back electromotive force is less than the second preset back electromotive force, control the battery relay of the high-voltage battery to close.

[0135] Optionally, the determination module is further specifically used to: determine multiple gears that the vehicle can switch to based on the current gear and the highest gear when the current gear is not the highest gear of the vehicle; determine the maximum theoretical speed that the vehicle can travel at based on the multiple gears and the maximum speed limit on the current driving road; determine whether the vehicle can travel at the maximum theoretical speed based on driving conditions on the driving road, the driving conditions being road conditions, traffic conditions and environmental conditions; and determine that the preset gear switching conditions are met when the vehicle is traveling, when the vehicle can travel at the maximum theoretical speed.

[0136] Figure 6 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0137] For example, Figure 6 As shown, the vehicle 600 includes: a memory 601 and a processor 602, wherein the memory 601 stores an executable program code 603, and the processor 602 is used to call and execute the executable program code 603 to perform a method for switching the power supply mode.

[0138] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores executable program code, and the processor is used to call and execute the executable program code to perform a method for switching power supply modes provided in an embodiment of the present application.

[0139] In this embodiment, the device can be divided into functional modules based on the above-described method examples. For example, each functional module can be mapped to a specific functional module, or two or more functions can be integrated into a single processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and represents only a logical functional division. In actual implementation, other division methods may be used.

[0140] In the case of dividing each functional module into corresponding functional modules, the device may further include a control module, a determination module, an acquisition module, a switching module, etc. It should be noted that all relevant contents involved in the above method embodiment can be referred to the functional description of the corresponding functional modules and will not be repeated here.

[0141] It should be understood that the device provided in this embodiment is used to execute the above-mentioned method of switching the power supply mode, and thus can achieve the same effect as the above-mentioned implementation method.

[0142] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is used in a vehicle, the processing module may be used to control and manage the vehicle's movements. The storage module may be used to support the vehicle's execution of relevant executable program code, etc.

[0143] The processing module may be a processor or controller that implements or executes the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processing system (DSP) and a microprocessor, and the storage module may be a memory.

[0144] In addition, the device provided in the embodiments of the present application can specifically be a chip, component or module, and the chip may include a connected processor and memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a method for switching power supply modes provided in the above embodiments.

[0145] This embodiment also provides a computer-readable storage medium, which stores executable program code. When the executable program code runs on a computer, the computer executes the above-mentioned related method steps to implement a method for switching power supply modes provided in the above embodiment.

[0146] This embodiment further provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement a method for switching power supply modes provided in the above embodiment.

[0147] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0148] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0149] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0150] The above content is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for switching a power supply mode, characterized in that: The method comprises: When a motor in a vehicle supplies power to the entire vehicle and the power supply for the entire vehicle needs to be switched from the motor to a high-voltage battery, controlling the motor to stop generating power; After the motor stops generating electricity, when it is detected that the back electromotive force generated when the motor rotates is greater than a first preset back electromotive force, controlling the motor to enter a target discharge mode, wherein the target discharge mode is an active discharge mode in which the three-phase windings of the motor are connected in parallel to form a common discharge; After the motor enters the target discharge mode, when it is detected that the back electromotive force is less than a second preset back electromotive force, the battery relay of the high-voltage battery is controlled to close, and the second preset back electromotive force is less than the first preset back electromotive force and is related to the normal operating voltage of the high-voltage battery.

2. The method according to claim 1, characterized in that Before controlling the motor to stop generating electricity, the method further includes: determining whether the high-voltage battery meets a preset power supply condition; Furthermore, controlling the motor to stop generating electricity comprises: When the high-voltage battery meets the preset power supply condition, the motor is controlled to stop generating electricity.

3. The method according to claim 2, characterized in that The method for determining whether the high-voltage battery meets the preset power supply condition includes: determining whether a current remaining power of the high-voltage battery is within a preset power range, and determining whether a current temperature of the high-voltage battery is within a preset temperature range; When the current remaining power is within the preset power range and the current temperature is within the preset temperature range, determining a theoretical operating voltage of the high-voltage battery based on the current remaining power and the current temperature; determining a voltage deviation of an actual operating voltage of the high-voltage battery relative to the theoretical operating voltage; When the voltage deviation is less than the preset voltage deviation, it is determined that the high-voltage battery meets the preset power supply condition.

4. The method according to claim 1, wherein The method for determining the first preset back electromotive force includes: Obtaining a theoretical safe duration and a theoretical safe voltage when discharging the back electromotive force of the motor; Determining an initial speed that the motor should meet based on the theoretical safety time, the theoretical safety voltage, the damping coefficient, the moment of inertia, and the back electromotive force constant, wherein the damping coefficient is used to reflect the frictional resistance of the motor during rotation, the moment of inertia is used to reflect the ability of the motor to resist speed changes, and the back electromotive force constant is used to indicate the back electromotive force generated per radian speed of the motor; The first preset back electromotive force is determined based on the product of the initial rotation speed and the back electromotive force constant.

5. The method according to claim 1, wherein The method for determining the second preset back electromotive force includes: determining a voltage detection deviation based on an inherent measurement deviation of a voltage sensor when measuring the operating voltage of the high-voltage battery, a temperature drift deviation caused by temperature change, and a random fluctuation deviation caused by noise; determining a theoretical transient voltage drop when the battery relay of the high-voltage battery is closed based on a first impulse voltage when the target power switch tube is turned off and a second impulse voltage when the battery relay of the high-voltage battery is closed, wherein the target power switch tube is used to exit the target discharge mode; The sum of the voltage detection deviation and the transient voltage drop is determined as a total voltage deviation, and the difference between the minimum normal operating voltage of the high-voltage battery and the total voltage deviation is determined as the second preset back electromotive force.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: determining whether a preset gear shift condition is satisfied when the vehicle is traveling, when detecting that the back electromotive force generated when the motor rotates is greater than or equal to the second preset back electromotive force and less than or equal to the first preset back electromotive force, the preset gear shift condition being a condition for switching from a current gear to a higher gear; When the preset gear shifting condition is satisfied while the vehicle is traveling, switching the current gear to a first gear, the first gear being higher than the current gear; After the current gear is switched to the first gear, when it is detected that the back electromotive force is less than the second preset back electromotive force, the battery relay of the high-voltage battery is controlled to be closed.

7. The method according to claim 6, characterized in that The method for determining whether the preset gear shift condition is satisfied when the vehicle is traveling includes: If the current gear is not the highest gear of the vehicle, determining a plurality of shiftable gears of the vehicle based on the current gear and the highest gear; determining a maximum theoretical speed at which the vehicle can travel based on the plurality of gears and a maximum speed limit on a current driving road; determining whether the vehicle can travel at the maximum theoretical speed based on driving conditions on the driving road, the driving conditions being road conditions, traffic conditions, and environmental conditions; In a case where the vehicle can travel at the maximum theoretical speed, it is determined that the preset gear shift condition is satisfied when the vehicle is traveling.

8. A device for switching power supply branches, characterized in that: The device comprises: Control module for: When a motor in a vehicle supplies power to the entire vehicle and the power supply for the entire vehicle needs to be switched from the motor to a high-voltage battery, controlling the motor to stop generating power; After the motor stops generating electricity, when it is detected that the back electromotive force generated when the motor rotates is greater than a first preset back electromotive force, controlling the motor to enter a target discharge mode, wherein the target discharge mode is an active discharge mode in which the three-phase windings of the motor are connected in parallel to form a common discharge; a switching module configured to control the battery relay of the high-voltage battery to close after the motor enters the target discharge mode and when detecting that the back electromotive force is less than a second preset back electromotive force, wherein the second preset back electromotive force is less than the first preset back electromotive force and is related to the normal operating voltage of the high-voltage battery.

9. A vehicle, characterized in that: The vehicle comprises: a memory for storing executable program code; A processor is configured to call and run the executable program code from the memory, so that the vehicle executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores an executable program code, and when the executable program code is executed, the method according to any one of claims 1 to 7 is implemented.

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