Vehicle and control method and control device thereof

Abstract

The invention discloses a vehicle and a control method and device thereof, and relates to the technical field of vehicles, the method comprises the steps that the current operation condition of the vehicle is obtained, and the operation condition comprises a starting condition and a braking condition; obtaining the maximum DC bus current allowed by the battery management system under the operation condition, and obtaining the target DC bus current corresponding to the driving device under the operation condition; generating a current adjusting signal according to a difference value between the maximum direct current bus current and the target direct current bus current; adjusting the magnetic flux and / or the torque of the driving device based on the current adjusting signal, so that the target direct current bus current does not exceed the maximum direct current bus current; according to the invention, the impact of large current on the battery can be effectively relieved in the starting and braking processes of the vehicle: on one hand, the peak current during starting is limited, and on the other hand, braking energy is recovered and kinetic energy is converted into electric energy; meanwhile, the charging current does not exceed the maximum limit value, so that the battery loss is reduced, and the energy efficiency of the whole vehicle is improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a vehicle and its control method and control device. Background Technology

[0002] Sales of new energy vehicles are increasing year by year. Batteries are a crucial component providing power to these vehicles, and multiple electronic control units rely on them for operation. Therefore, the health and performance of the battery significantly determine the lifespan of the entire vehicle. Reducing battery wear and extending its lifespan has become a significant technical challenge. Frequent acceleration, deceleration, starting, and braking operations generate large current charging and discharging shocks, leading to changes in the battery's internal electrode materials and voltage ripple, directly impacting battery wear and lifespan. The motor control unit, as the component using the largest proportion of battery energy, undoubtedly suffers the greatest wear and tear. Therefore, methods utilizing motor current control can be explored to reduce this wear. Summary of the Invention

[0003] The main objective of this invention is to propose a vehicle and its control method and device, which aims to effectively mitigate the impact of high current on the battery during vehicle start-up and braking: on the one hand, limiting the peak current during start-up, and on the other hand, recovering braking energy and converting kinetic energy into electrical energy; at the same time, ensuring that the charging current does not exceed the maximum limit, thereby reducing battery loss and improving the overall vehicle energy efficiency.

[0004] To achieve the above objectives, the present invention proposes a vehicle control method, wherein the vehicle includes a battery management system and a drive unit, and the vehicle control method includes:

[0005] Obtain the current operating conditions of the vehicle, including starting conditions and braking conditions; Obtain the maximum DC bus current allowed by the battery management system under the operating conditions, and obtain the target DC bus current corresponding to the drive device under the operating conditions; A current regulation signal is generated based on the difference between the maximum DC bus current and the target DC bus current. Based on the current regulation signal, the magnetic flux and / or torque of the drive device are adjusted so that the target DC bus current does not exceed the maximum DC bus current.

[0006] In one embodiment, the operating condition is the startup condition; adjusting the magnetic flux and / or torque of the drive device based on the current adjustment signal to ensure that the target DC bus current does not exceed the maximum DC bus current includes: Before the vehicle is started, a direct-axis current is input to the drive unit, which is used to establish the initial magnetic field of the drive unit. The quadrature axis given current of the drive device is obtained, and the quadrature axis given current is used to adjust the output torque of the drive device; Based on the current adjustment signal, the quadrature axis given current is corrected, and the direct axis given current is kept constant, so that the quadrature axis current output by the drive device tracks the corrected quadrature axis given current, and the target DC bus current does not exceed the maximum DC bus current.

[0007] In one embodiment, the corrected quadrature-axis given current is equal to the product of a preset proportional coefficient and the difference, plus the product of a preset integral coefficient and the time integral of the difference.

[0008] In one embodiment, the value of the direct-axis given current is negative, and the absolute value of the direct-axis given current is not less than 5 amperes and not greater than 15 amperes.

[0009] In one embodiment, the operating condition is the braking condition, and adjusting the magnetic flux and / or torque of the drive device based on the current adjustment signal to ensure that the target DC bus current does not exceed the maximum DC bus current includes: The direct-axis given current and quadrature-axis given current of the drive device are obtained. The direct-axis given current is used to adjust the magnetic field strength of the drive device, and the quadrature-axis given current is used to adjust the output torque of the drive device. Based on the current adjustment signal, the direct-axis given current and the quadrature-axis given current are corrected respectively, so that the direct-axis output current of the drive device tracks the corrected direct-axis given current and the quadrature-axis output current tracks the corrected quadrature-axis given current, so that the target DC bus current does not exceed the maximum DC bus current.

[0010] In one embodiment, the corrected direct-axis given current is equal to the current direct-axis given current, plus the product of a preset proportional coefficient and the difference, plus the product of a preset integral coefficient and the time integral of the difference; The corrected quadrature-axis given current is equal to the current quadrature-axis given current, plus the product of the preset proportional coefficient and the difference, plus the product of the preset integral coefficient and the time integral of the difference.

[0011] In one embodiment, the vehicle control method further includes: When the difference between the target DC bus current and the maximum DC bus current reaches a preset range, it is determined that the vehicle has entered a smooth braking state. In the smooth braking state, the electrical energy recovered during the vehicle braking process is distributed.

[0012] In one embodiment, obtaining the maximum DC bus current allowed by the battery management system under the operating conditions includes: Obtain the maximum discharge power and battery voltage of the battery management system; The maximum DC bus current is calculated based on the maximum discharge power and battery voltage. And / or, obtaining the target DC bus current corresponding to the drive device under the operating condition includes: Obtain the direct-axis voltage, quadrature-axis voltage, direct-axis given current, and quadrature-axis given current of the drive device; Calculate the electric power of the drive device in the rotating coordinate system based on the direct-axis voltage, quadrature-axis voltage, direct-axis current, and quadrature-axis current of the drive device. The target DC bus current is calculated based on the electrical power and the efficiency of the drive device under the current operating conditions.

[0013] The present invention also proposes a vehicle control device, including a processor and a memory, wherein the memory stores a vehicle control program, and when the vehicle control program is executed by the processor, the vehicle control method described above is implemented.

[0014] The present invention also proposes a vehicle comprising: The vehicle body; The battery is electrically connected to the vehicle body and is used to supply power to the vehicle body; A battery management system, electrically connected to the battery, is used to manage the charging and discharging of the battery; A drive unit, mechanically connected to the vehicle body, is used to drive the vehicle body to move; The control device described above is electrically connected to the vehicle body, the battery, the battery management system, and the drive device, respectively.

[0015] The technical solution of this invention acquires the current operating conditions of the vehicle, including starting and braking conditions, and simultaneously acquires the maximum DC bus current allowed by the battery management system under these operating conditions, as well as the target DC bus current of the drive unit under the same conditions. A current regulation signal is generated based on the difference between the maximum DC bus current and the target DC bus current, and the magnetic flux and / or torque of the drive unit are adjusted based on this signal to ensure that the target DC bus current does not exceed the maximum DC bus current allowed by the battery management system. This method limits the peak current generated by the drive unit during vehicle startup, preventing damage to the internal electrode materials and voltage ripple caused by high-rate discharge of the battery. During vehicle braking, it controls the feedback current to not exceed the maximum allowable charging current of the battery, effectively recovering braking kinetic energy and converting it into electrical energy for storage, preventing battery overcharging and the resulting losses. By actively adjusting the current demand of the drive unit directly, the battery always operates within its safe current boundary, reducing the large current impact caused by frequent acceleration, deceleration, starting, and braking, minimizing battery losses, and improving the overall energy utilization efficiency of the vehicle. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of an embodiment of the vehicle control method provided by the present invention; Figure 2 A schematic diagram of another embodiment of the vehicle control method provided by the present invention; Figure 3 A schematic diagram of another embodiment of the vehicle control method provided by the present invention; Figure 4 A schematic diagram of another embodiment of the vehicle control method provided by the present invention; Figure 5 A schematic diagram of the circuit functional modules of an embodiment of the vehicle control device provided by the present invention; Figure 6 A schematic diagram of the circuit functional modules of a vehicle according to an embodiment of the present invention.

[0018] Explanation of icon numbers: 100. Vehicle; 10. Control device; 11. Processor; 12. Memory; 20. Vehicle body; 30. Battery; 40. Battery management system; 50. Drive unit.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Sales of new energy vehicles are increasing year by year. Batteries are a crucial component providing power to these vehicles, and multiple electronic control units rely on them for operation. Therefore, the health and performance of the battery significantly determine the lifespan of the entire vehicle. Reducing battery wear and extending its lifespan has become a significant technical challenge. Frequent acceleration, deceleration, starting, and braking operations generate large current charging and discharging shocks, leading to changes in the battery's internal electrode materials and voltage ripple, directly impacting battery wear and lifespan. The motor control unit, as the component using the largest proportion of battery energy, undoubtedly suffers the greatest wear and tear. Therefore, methods utilizing motor current control can be explored to reduce this wear.

[0022] In practical engineering applications, there are two main approaches to addressing battery wear during the starting and braking processes of new energy vehicles: The first type is the battery management system (BMS), which controls energy recovery, monitors the vehicle's operating status, implements current limiting algorithms, and provides thermal management protection. Its core principle is to allow high power release during startup, recover and store the electrical energy generated by the motor during braking, and combine this with a state-of-charge (SOC) algorithm to reduce losses caused by overcharging or over-discharging. This method can monitor and manage the battery charging and discharging process in real time, reducing battery losses to some extent, and is widely used. However, it mainly focuses on battery management itself and lacks coordinated control with other power-consuming components in the vehicle. The second method is applicable to hybrid vehicles, reducing reliance on batteries through engine control technology. Its core lies in using bench testing and vehicle calibration to ensure the engine continuously operates within its optimal efficiency range according to its universal characteristic curve, thereby reducing the frequency of battery charging and discharging. This method requires extensive calibration work, is time-consuming and complex, and is not suitable for pure electric vehicles. It places high demands on engine performance and typically requires repeated debugging and verification in a laboratory environment.

[0023] To this end, the present invention proposes a control method for a vehicle 100. This control method can effectively mitigate the impact of high current on the battery 30 during the starting and braking processes of the vehicle 100: on the one hand, it limits the peak current during starting, and on the other hand, it recovers braking energy and converts kinetic energy into electrical energy; at the same time, it ensures that the charging current does not exceed the maximum limit, thereby reducing battery 30 losses and improving the overall vehicle energy efficiency.

[0024] Please see Figure 1 and Figure 6 In one embodiment of the present invention, the vehicle 100 includes a vehicle body 20, a battery 30, a battery management system 40, and a drive unit 50. The vehicle body 20 includes a shell, a chassis disposed on the shell, a body structure, wheels, an accelerator pedal, a brake pedal, and multiple electronic control units. The accelerator pedal is used to receive the driver's acceleration intention and output a corresponding opening signal, and the brake pedal is used to receive the driver's deceleration or stopping intention and output a corresponding travel signal. Together, they constitute the basis for the input of the vehicle 100's operating state. The battery 30 is used to supply power to electrical devices, which may include, but are not limited to, vehicle air conditioning, lighting systems, infotainment systems, brake assist devices, and the drive unit 50, and is the main source of the vehicle's electrical energy. The battery management system 40 is electrically connected to the battery 30 and is used to monitor the voltage, current, temperature, and state of charge of the battery 30 in real time, and to set charge and discharge boundaries according to the health status of the battery 30 to prevent overcharging, over-discharging, or thermal runaway, ensuring the safe operation of the battery 30. The drive unit 50 includes a motor controller and a motor. The motor controller is electrically connected to the battery 30 via a DC bus. It receives torque or speed commands from the control device 10 of the vehicle 100, controls the motor to operate, and converts electrical energy into mechanical energy to drive the vehicle 100. Its current demand is directly applied to the battery 30.

[0025] Based on the above hardware structure, such as Figure 1 and Figure 6 As shown, the control method of the vehicle 100 includes: S100: Obtain the current operating conditions of the vehicle, including starting conditions and braking conditions; S200: Obtain the maximum DC bus current allowed by the battery management system under operating conditions, and obtain the target DC bus current corresponding to the drive device under operating conditions. S300: Generate a current regulation signal based on the difference between the maximum DC bus current and the target DC bus current; S400: Based on the current regulation signal, adjust the magnetic flux and / or torque of the drive device so that the target DC bus current does not exceed the maximum DC bus current.

[0026] In this embodiment, in the actual application of vehicle 100, the current operating condition of vehicle 100 can be obtained, including starting condition and braking condition. Starting condition refers to the process of vehicle 100 accelerating from a standstill or low speed to the target speed. At this time, the drive unit 50 needs to draw a large current from battery 30 to output sufficient torque. Braking condition refers to the process of vehicle 100 decelerating or stopping, in which drive unit 50, as a generator, converts the kinetic energy of vehicle 100 into electrical energy and feeds it back to battery 30. The current starting condition or braking condition can be determined by the accelerator pedal opening, brake pedal travel, vehicle speed change rate, and motor speed direction. This is because an increase in accelerator pedal opening and vehicle speed usually corresponds to the starting state, while a brake pedal being depressed or vehicle speed decreasing accompanied by reverse motor power generation reflects the braking state. The accelerator pedal signal, brake pedal signal, vehicle speed signal, and motor speed signal are collected by sensors in vehicle body 20 and transmitted to control device 10, which has the feasibility of discrimination.

[0027] To ensure that the battery 30 does not age rapidly due to current exceeding safety limits under different operating conditions, it is necessary to obtain the maximum DC bus current allowed by the battery management system 40 under the current operating conditions. This maximum DC bus current refers to the maximum charge and discharge current limit that the battery 30 can safely accept or provide under the current state. Its value reflects the current carrying capacity of the battery 30 without causing risks such as overheating, overvoltage, and material degradation. It can be determined by the current temperature, state of charge, and health status of the battery 30. This is because the internal resistance, chemical reaction rate, and thermal diffusion capacity of the battery 30 change with temperature, and the usable capacity fluctuates with the state of charge. Furthermore, the capacity decay and internal resistance increase caused by long-term use directly affect its ability to withstand large currents. At the same time, it is necessary to obtain the target DC bus current that the drive unit 50 originally planned to execute under the same operating conditions. The target DC bus current refers to the current value that the drive unit 50 is expected to draw from or feed back from the DC bus based on the current driving needs. It can be derived from the driver's intention and the power demand of the vehicle 100. This is because the accelerator pedal opening, vehicle speed command and driving resistance jointly determine the torque or speed that the motor needs to output, and thus map it to the corresponding current demand.

[0028] Understandably, if the target DC bus current exceeds the maximum DC bus current allowed by the battery management system 40, the battery 30 will be forced to operate beyond its safety limits. This will result in a large current surge, causing stress changes and voltage fluctuations in the internal electrode materials of the battery 30, increasing the risk of battery 30 damage. By comparing the difference between the maximum DC bus current and the target DC bus current and generating a current adjustment signal, it can be determined whether the current of the current drive device 50 exceeds the safe supply or absorption capacity of the battery 30. Since the magnetic flux and torque of the drive device 50 directly determine the current during motor operation, this difference can be used as a basis to adjust the magnetic flux and / or torque of the drive device 50 to ensure that the target DC bus current does not exceed the maximum DC bus current.

[0029] For example, when the difference between the maximum DC bus current and the target DC bus current is less than zero, the magnetic flux of the drive device 50 can be weakened to reduce the back electromotive force, thereby reducing the current flowing through the DC bus until the target DC bus current is adjusted to the range of the maximum DC bus current; or, the torque of the drive device 50 can be reduced proportionally to reduce the power output of the motor accordingly, thereby reducing the current flowing through the DC bus until the target DC bus current is adjusted to the range of the maximum DC bus current; or, the magnetic flux and torque of the drive device 50 can be adjusted simultaneously, that is, while moderately weakening the magnetic flux, the torque can be adjusted so that the excitation component of the motor and the torque component work together to more smoothly reduce the current amplitude flowing through the DC bus, avoiding torque sudden changes or efficiency reduction caused by single adjustment, thereby effectively controlling the target DC bus current within the range of the maximum DC bus current allowed by the battery 30 while meeting the driving performance requirements.

[0030] If the difference between the maximum DC bus current and the target DC bus current is greater than zero, it indicates that the current required by the drive unit 50 has not reached the upper limit that the battery 30 can withstand, and the battery 30 has sufficient current margin. At this time, the original magnetic flux and torque of the drive unit 50 can be maintained without applying restrictive adjustments. Alternatively, depending on the operating requirements of the vehicle 100, the magnetic flux or torque can be appropriately increased without exceeding the maximum DC bus current to improve acceleration performance or enhance the braking energy recovery effect.

[0031] The current flowing through the DC bus here refers to the current drawn from or fed back to the battery 30 by the drive unit 50. This current is controlled by the motor controller in the drive unit 50 and transmitted between the battery 30 and the motor through the DC bus. During startup, this current is a discharge current, flowing from the battery 30 to the drive unit 50; during braking, this current is a charging current, flowing from the drive unit 50 to the battery 30.

[0032] The above adjustment method can limit the current actually flowing through the DC bus of the drive unit 50 to within the safe range of the battery 30, while meeting basic driving needs, thereby reducing battery 30 wear and extending battery 30 service life.

[0033] like Figure 2 and Figure 6 As shown, in one embodiment, the operating condition is the startup condition; Based on the above hardware structure, such as Figure 1 and Figure 6 As shown, step S400 includes: S411. Before starting the vehicle, input a direct-axis given current to the drive unit. The direct-axis given current is used to establish the initial magnetic field of the drive unit. S412. Obtain the quadrature axis reference current of the drive unit. The quadrature axis reference current is used to adjust the output torque of the drive unit. S413. Based on the current adjustment signal, correct the quadrature axis given current and keep the direct axis given current constant, so that the quadrature axis current output by the drive device tracks the corrected quadrature axis given current, so that the target DC bus current does not exceed the maximum DC bus current.

[0034] In this embodiment, at the instant the motor starts, the rotor is stationary and the back electromotive force is zero. If voltage is applied directly, the current flowing through the DC bus will rise sharply, potentially reaching five to seven times the current during normal motor operation. This instantaneous high current may not only impact the battery 30 but also trigger the overcurrent protection of the battery management system 40, and may even cause the vehicle 10's control device 10 to stop the drive device 50 from operating. To achieve a safe and stable starting condition, the vehicle 100's control device 10 employs a control method that first establishes a stable magnetic field, then adjusts the torque, and limits the target DC bus current.

[0035] At the initial moment when the vehicle 100 enters the starting condition, the control device 10 sets a fixed direct-axis current to the motor controller in the drive device 50. This direct-axis current does not generate output torque, but is used to establish an initial excitation magnetic field inside the motor, providing a basis for subsequent torque control. This direct-axis current remains constant during the starting condition, and its value is determined through actual vehicle calibration.

[0036] In one embodiment, the direct-axis given current is negative, and its absolute value is not less than 5 amperes and not greater than 15 amperes, for example, a value of -10 amperes. Within this range, the sufficiency of magnetic field establishment and the rationality of excitation loss can be balanced, avoiding both torque response lag due to an insufficiently weak magnetic field and unnecessary current burden due to excessively strong excitation.

[0037] At the same time, the battery management system 40 calculates the maximum allowable discharge power of the battery 30 in real time based on the current voltage, temperature and state of charge of the battery 30. The maximum discharge power It is a variable that changes with operating conditions. This is combined with the current battery voltage of 30V. The maximum allowable DC bus current of battery 30 under this starting condition can be calculated. ,Right now: ; On the other hand, the motor controller provides the current based on the current direct-axis current of the motor. With cross-axis given current Combined with the motor's fixed parameters, including stator resistance Direct-axis inductor quadrature axis inductance Permanent magnet flux and current electric angular velocity Calculate the direct-axis voltage using the voltage equation With cross-axis voltage : ; ; Based on this, calculate the electrical power that the motor obtains from the DC bus. : ; Combined with the driving efficiency of the motor and control device 10 By deducing the target DC bus current corresponding to the current motor demand, we can deduce the actual current required by the motor. : ; Subsequently, the control device 10 sets the maximum DC bus current allowed by the battery management system 40. The target DC bus current derived from the drive unit 50 Compare and obtain the difference. This difference is fed into a proportional-integral controller to correct the quadrature-axis setpoint current. Due to the cross-axis given current. This directly determines the motor's output torque and also dictates the magnitude of the current drawn from or fed back from battery 30. Therefore, adjusting the quadrature shaft current is crucial. This can effectively regulate the target DC bus current. .

[0038] In one embodiment, the modified quadrature-axis given current Equal to the preset ratio coefficient and difference The product of the products, plus the preset integral coefficient. and difference The product of time integrals, i.e.: ; When the target DC bus current Greater than the maximum DC bus current In the case that, This indicates that the motor's current power demand exceeds the battery's safe discharge or charging capacity. At this point, the proportional-integral controller outputs a negative adjustment to reduce the quadrature-axis setpoint current. The corrected quadrature-axis current can be obtained. This reduces the motor output torque and energy consumption or feedback intensity, thereby reducing the target DC bus current. Falling back to maximum DC bus current Within the range; when the target DC bus current Less than the maximum DC bus current In the case that, This indicates that battery 30 still has a usable power margin, and the proportional-integral controller outputs a positive adjustment, increasing the quadrature-axis setpoint current. The corrected quadrature-axis current can be obtained. This closed-loop regulation is implemented to improve output torque or energy recovery efficiency, fully utilizing the available capacity of battery 30. The regulation continues until the target DC bus current approaches the maximum DC bus current, matching the motor's actual current requirements with the safe output or input capacity of battery 30.

[0039] Throughout the startup process, the direct-axis current remains constant, while the quadrature-axis current is dynamically generated by the proportional-integral controller. This ensures the necessary starting torque while preventing the target DC bus current from exceeding its limit, thus preventing battery overload, suppressing electromagnetic oscillations, and achieving a smooth, safe, and controlled startup. As the motor speed gradually increases and the back electromotive force is gradually established, the vehicle exits the startup condition and enters normal operation.

[0040] like Figure 3 and Figure 6 As shown, in one embodiment, the operating condition is the braking condition; Based on the above hardware structure, such as Figure 1 and Figure 6 As shown, step S400 includes: S421. Obtain the direct-axis given current and quadrature-axis given current of the drive device. The direct-axis given current is used to adjust the magnetic field strength of the drive device, and the quadrature-axis given current is used to adjust the output torque of the drive device. S422. Based on the current regulation signal, the direct-axis given current and the quadrature-axis given current are corrected respectively, so that the direct-axis output current of the drive device tracks the corrected direct-axis given current and the quadrature-axis output current tracks the corrected quadrature-axis given current, so that the target DC bus current does not exceed the maximum DC bus current.

[0041] In this embodiment, when the vehicle 100 is braking, the drive unit 50 switches from driving mode to power generation mode, converting the kinetic energy of the vehicle 100 into electrical energy, and feeding it back to the battery 30 via the motor controller. If the braking intensity is high or the deceleration process is rapid, the motor braking torque increases significantly, which may generate a large power generation current in a short period of time. If this current is not limited, especially when the battery 30 has a high state of charge, low temperature, or limited usable capacity, it can easily lead to overcharging of the battery 30, increased temperature rise, accelerated lifespan degradation, or even triggering the protection mechanism of the battery management system 40 to interrupt energy recovery.

[0042] To avoid the aforementioned risks, the battery management system 40 calculates the maximum allowable charging power of the battery 30 in real time based on the current voltage, temperature, and state of charge of the battery 30. Combined with the current battery voltage of 30V The maximum allowable DC bus current of battery 30 under this braking condition can be calculated. (This is the charging current), that is: ; At the same time, the motor controller provides the current based on the current direct-axis current of the motor. With cross-axis given current Combined with the motor's fixed parameters, including stator resistance Direct-axis inductor quadrature axis inductance Permanent magnet flux and current electric angular velocity Calculate the direct-axis voltage using the voltage equation With cross-axis voltage : ; ; Based on this, calculate the current electrical power output of the motor. : ; Combined with the power generation efficiency of the motor and control device 10 By deducing the target DC bus current corresponding to the current motor demand, we can deduce the actual current required by the motor. : ; Subsequently, the control device 10 sets the maximum DC bus current allowed by the battery management system 40. The target DC bus current derived from the drive unit 50 Compare and obtain the difference. This difference is fed into a proportional-integral controller to simultaneously correct the direct-axis given current. With cross-axis given current Due to the cross-axis given current. The magnitude of the generating torque and power is determined by the main axis, and its correction plays a major role in current regulation; while the direct-axis given current... Fine-tuning can be used to optimize the distribution of the magnetic field inside the motor, reduce copper or iron losses, and improve the overall efficiency of the vehicle.

[0043] In one embodiment, the corrected direct-axis current is equal to the current direct-axis current, plus the product of a preset proportional coefficient and the difference, plus the product of a preset integral coefficient and the time integral of the difference, i.e.: ; The corrected quadrature-axis current is equal to the current quadrature-axis current, plus the product of the preset proportional coefficient and the difference, plus the product of the preset integral coefficient and the time integral of the difference, that is: ; in , The corrected quadrature-axis and direct-axis reference currents are given. , These are the current quadrature-axis and direct-axis given currents, respectively. , These are the preset proportional coefficient and preset integral coefficient for the cross-axis channel, respectively. , These are the preset proportional coefficient and preset integral coefficient for the linear channel, respectively. , , , The value is relatively small and is only used for auxiliary adjustment.

[0044] When the target DC bus current Greater than the maximum DC bus current In the case that, This indicates that the current power generation of the motor exceeds the absorption capacity of the battery 30, and the proportional-integral controller outputs a negative adjustment to reduce the quadrature-axis given current. The corrected quadrature-axis current can be obtained. Fine-tune the direct-axis set current if necessary. The corrected quadrature-axis current can be obtained. This reduces the overall generating torque and feedback power, causing the target DC bus current to fall back to a safe range; when the target DC bus current... Less than the maximum DC bus current In the case that, This indicates that battery 30 still has a charging margin, and the proportional-integral controller appropriately increases the quadrature-axis setpoint current. The corrected quadrature-axis current can be obtained. This is to improve energy recovery efficiency and fully utilize the available charging capacity of battery 30. This closed-loop regulation continues until the target DC bus current is reached. Approaching maximum DC bus current This achieves a match between power generation and the battery's receiving capacity.

[0045] Throughout the braking process, the control device 10 senses the current charging capacity of the battery 30, estimates the current demand of the drive device 50 in the power generation state, calculates the deviation between the target DC bus current and the maximum DC bus current, and uses proportional-integral control to correct the direct-axis given current and quadrature-axis given current based on the deviation, thereby adjusting the magnetic field strength and power generation torque of the motor so that the feedback current is always within the safe range of the battery 30.

[0046] like Figure 4 and Figure 6 As shown, in one embodiment, the control method for vehicle 100 further includes: S500: When the difference between the target DC bus current and the maximum DC bus current reaches a preset range, the vehicle is determined to enter a smooth braking state. S600: Under stable braking conditions, it distributes the electrical energy recovered during vehicle braking.

[0047] In this embodiment, if, under extreme braking conditions, even if the quadrature axis current is reduced to zero, the drive unit 50 still generates excess kinetic energy due to high vehicle speed or strong deceleration, causing the target DC bus current to approach or exceed the maximum DC bus current, and the battery 30 can no longer absorb more electrical energy, then the vehicle 100's control device 10 activates the energy redistribution mechanism. This mechanism guides the electrical energy that cannot be received by the battery 30 to other electrical loads in the vehicle for consumption, such as the vehicle's air conditioning compressor, cabin heater, battery 30 heating unit, or low-voltage system power supply module. By activating other electrical loads in the vehicle 100 through the vehicle 100's control device 10, redundant electrical energy can be effectively consumed, preventing abnormal increases in DC bus voltage, inverter shutdown due to overvoltage, or energy waste, while maintaining the smoothness and controllability of the braking process.

[0048] The present invention also proposes a control device 10 for a vehicle 100, such as Figure 5As shown, the control device 10 of the vehicle 100 includes a processor 11 and a memory 12. The memory 12 stores the control program of the vehicle 100. When the control program of the vehicle 100 is executed by the processor 11, the control method of the vehicle 100 as described above is implemented. The specific structure of the control method of the vehicle 100 refers to the above embodiments. Since the control device 10 of the vehicle 100 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0049] The present invention also proposes a vehicle 100, such as Figure 6 As shown, the vehicle 100 includes a vehicle body 20, a battery 30, a battery management system 40, a drive device 50, and a control device 10. The specific structure of the control device 10 is as described in the above embodiments. Since the vehicle 100 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0050] The battery 30 is electrically connected to the vehicle body 20 to supply power to the electrical equipment in the vehicle body 20; the battery management system 40 is electrically connected to the battery 30 to monitor the voltage, current, temperature and state of charge of the battery 30 in real time, and to set charge and discharge boundaries according to the health status of the battery 30 to prevent overcharging, over-discharging or thermal runaway; the drive unit 50 is connected to the vehicle body 20 to convert electrical energy into mechanical energy to drive the vehicle body 20; the control unit 10 is electrically connected to the vehicle body 20, the battery 30, the battery management system 40 and the drive unit 50 respectively, and is used to obtain the operating conditions of the vehicle 100, coordinate the work of each component and execute current regulation strategies.

[0051] During startup, the control device 10 can acquire the maximum DC bus current allowed by the battery management system 40 and the target DC bus current of the drive device 50. Based on this, the control device 10 maintains a constant direct-axis given current and corrects the quadrature-axis given current to ensure that the target DC bus current output by the drive device 50 tracks the maximum DC bus current. This avoids excessive inrush current due to zero back EMF at startup and ensures the safety and stability of the battery 30 during high-power output.

[0052] Under braking conditions, the control device 10 also determines whether the current generation current exceeds the charging capacity of the battery 30 based on the comparison between the maximum DC bus current and the target DC bus current. It also corrects the direct-axis given current and the quadrature-axis given current through proportional-integral regulation to ensure that the target DC bus current does not exceed the maximum DC bus current, thereby achieving precise control of the feedback energy.

[0053] In addition, when there is excess energy recovery and the battery 30 cannot fully absorb the feedback energy, the control device 10 can also dispatch electrical loads such as the vehicle air conditioner, heater or low-voltage power supply unit to guide the excess energy to the load for consumption, so as to avoid abnormal rise in DC bus voltage or inverter shutdown due to overvoltage.

[0054] Through the above control, the vehicle 100 can effectively limit the impact of the current flowing through the DC bus on the battery 30 under different operating conditions, reduce the internal material stress and voltage fluctuation of the battery 30, extend the service life of the battery 30, and at the same time take into account driving performance and energy utilization efficiency.

[0055] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for controlling a vehicle, characterized in that, The vehicle includes a battery management system and a drive unit, and the vehicle control method includes: Obtain the current operating conditions of the vehicle, including starting conditions and braking conditions; Obtain the maximum DC bus current allowed by the battery management system under the operating conditions, and obtain the target DC bus current corresponding to the drive device under the operating conditions; A current regulation signal is generated based on the difference between the maximum DC bus current and the target DC bus current. Based on the current regulation signal, the magnetic flux and / or torque of the drive device are adjusted so that the target DC bus current does not exceed the maximum DC bus current.

2. The vehicle control method as described in claim 1, characterized in that, The operating condition is the startup condition; adjusting the magnetic flux and / or torque of the drive device based on the current adjustment signal to ensure that the target DC bus current does not exceed the maximum DC bus current includes: Before the vehicle is started, a direct-axis current is input to the drive unit, which is used to establish the initial magnetic field of the drive unit. The quadrature axis given current of the drive device is obtained, and the quadrature axis given current is used to adjust the output torque of the drive device; Based on the current adjustment signal, the quadrature axis given current is corrected, and the direct axis given current is kept constant, so that the quadrature axis current output by the drive device tracks the corrected quadrature axis given current, and the target DC bus current does not exceed the maximum DC bus current.

3. The vehicle control method as described in claim 2, characterized in that, The corrected quadrature-axis given current is equal to the product of the preset proportional coefficient and the difference, plus the product of the preset integral coefficient and the time integral of the difference.

4. The vehicle control method as described in claim 2, characterized in that, The value of the direct-axis given current is negative, and the absolute value of the direct-axis given current is not less than 5 amperes and not greater than 15 amperes.

5. The vehicle control method as described in claim 1, characterized in that, The operating condition is the braking condition, and the adjustment of the magnetic flux and / or torque of the drive device based on the current adjustment signal to ensure that the target DC bus current does not exceed the maximum DC bus current includes: The direct-axis given current and quadrature-axis given current of the drive device are obtained. The direct-axis given current is used to adjust the magnetic field strength of the drive device, and the quadrature-axis given current is used to adjust the output torque of the drive device. Based on the current adjustment signal, the direct-axis given current and the quadrature-axis given current are corrected respectively, so that the direct-axis output current of the drive device tracks the corrected direct-axis given current and the quadrature-axis output current tracks the corrected quadrature-axis given current, so that the target DC bus current does not exceed the maximum DC bus current.

6. The vehicle control method as described in claim 5, characterized in that, The corrected direct-axis given current is equal to the current direct-axis given current, plus the product of the preset proportional coefficient and the difference, plus the product of the preset integral coefficient and the time integral of the difference. The corrected quadrature-axis given current is equal to the current quadrature-axis given current, plus the product of the preset proportional coefficient and the difference, plus the product of the preset integral coefficient and the time integral of the difference.

7. The vehicle control method as described in claim 5, characterized in that, The vehicle control method also includes: When the difference between the target DC bus current and the maximum DC bus current reaches a preset range, it is determined that the vehicle has entered a smooth braking state. In the smooth braking state, the electrical energy recovered during the vehicle braking process is distributed.

8. The vehicle control method as described in claim 1, characterized in that, The step of obtaining the maximum DC bus current allowed by the battery management system under the operating conditions includes: Obtain the maximum discharge power and battery voltage of the battery management system; The maximum DC bus current is calculated based on the maximum discharge power and battery voltage. And / or, obtaining the target DC bus current corresponding to the drive device under the operating condition includes: Obtain the direct-axis voltage, quadrature-axis voltage, direct-axis given current, and quadrature-axis given current of the drive device; Calculate the electric power of the drive device in the rotating coordinate system based on the direct-axis voltage, quadrature-axis voltage, direct-axis current, and quadrature-axis current of the drive device. The target DC bus current is calculated based on the electrical power and the efficiency of the drive device under the current operating conditions.

9. A vehicle control device, characterized in that, It includes a processor and a memory, wherein the memory stores a vehicle control program, and when the vehicle control program is executed by the processor, it implements the vehicle control method as described in any one of claims 1 to 8.

10. A vehicle, characterized in that, include: The vehicle body; The battery is electrically connected to the vehicle body and is used to supply power to the vehicle body; A battery management system, electrically connected to the battery, is used to manage the charging and discharging of the battery; A drive unit, connected to the vehicle body, is used to drive the vehicle body to move; The control device as described in claim 9 is electrically connected to the vehicle body, the battery, the battery management system, and the drive device, respectively.

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