A new energy vehicle and a method and device for controlling vehicle output torque

Abstract

The present invention belongs to the technical field of safety control of new energy vehicles, and specifically relates to a new energy vehicle and a method and device for controlling the output torque of the vehicle. The method uses a corresponding discrimination method to judge whether the vehicle is in an unexpected acceleration state / unexpected deceleration state in a driving mode / non-driving mode according to the operating mode of the vehicle and the acquired operating parameters of the vehicle, and when it is determined that the vehicle is in an unexpected acceleration state in a driving mode, an unexpected deceleration state in a driving mode, or an unexpected acceleration state in a non-driving mode, the output torque of the vehicle is controlled to be 0 to protect the vehicle, so that the vehicle can be processed in time in these cases to ensure the driving experience of the vehicle and prevent safety accidents.

Description

Technical Field

[0001] The present invention belongs to the technical field of safety control of new energy vehicles, and specifically relates to a new energy vehicle and a method and device for controlling the vehicle output torque. Background Art

[0002] At present, most new energy vehicles use open-loop control for the power system, which calculates the required torque of the vehicle based on the accelerator and brake pedal opening signals, motor speed, BMS current discharge capacity and other information. The open-loop power system control strategy is feasible when the motor components are fault-free, but when the motor fails, the actual output torque is not equal to the driver's required torque, and the vehicle controller VCU uses open-loop control for the torque output of the power system. Regardless of the driving mode or braking mode, there will be acceleration or deceleration conditions that are not expected by the driver.

[0003] Unexpected acceleration in driving mode means that the positive driving force output by the vehicle exceeds the positive driving force expected by the driver. For example, the vehicle accelerator is only pressed 10%, and the corresponding vehicle torque requirement is 50Nm. At this time, the vehicle can reach a uniform speed of 20km / h, but the actual torque output by the motor is 100Nm, which makes the vehicle travel at a speed of 50km / h, exceeding or even far exceeding the driver's expectations. Unexpected deceleration in driving mode means that the driver expects / expects a positive driving force, but from the actual performance of the vehicle, a deceleration occurs. At this time, the motor in the vehicle is in a feedback / braking state, that is, the motor is required to be in a driving state, but the motor is in a braking state.

[0004] Unexpected acceleration state in non-driving mode refers to a situation where the vehicle is required to brake but the vehicle actually outputs a positive driving force. For example, under normal circumstances, the vehicle should be in a deceleration process, the electric brake is output normally, and the reverse force output by the motor should cause the current to flow to the battery (after offsetting the power-off accessories), but the battery actually behaves in a discharge state, and the vehicle is not in a deceleration state but an acceleration state. Unexpected deceleration state in non-driving mode means that the actual braking power output by the motor is significantly greater than expected. For example, the required braking power is 30KW, but the actual battery charging power is displayed as 100KW, which means that the required deceleration of the whole vehicle is 1m / s 2 However, from the perspective of the vehicle performance, the deceleration actually reached 3m / s 2 .

[0005] At present, the existing technology cannot effectively identify these states, which may lead to a poor driver experience at best and traffic accidents (caused by unexpected acceleration in the driving mode) at worst. Summary of the invention

[0006] The present invention provides a new energy vehicle and a method and device for controlling the vehicle output torque, so as to solve the problem in the prior art that the driver experience is poor or a traffic accident occurs due to failure to identify unexpected acceleration / unexpected deceleration state.

[0007] In order to solve the above technical problems, the technical solution of the present invention includes:

[0008] The present invention provides a method for controlling the output torque of a new energy vehicle, comprising the following steps:

[0009] 1) Determine the operating mode of the vehicle, whether it is driving mode or non-driving mode;

[0010] 2) according to the operation mode of the vehicle and the obtained vehicle operation parameters, a corresponding determination method is used to determine whether the vehicle is in an unexpected acceleration state / unexpected deceleration state in a driving mode / non-driving mode; the vehicle operation parameters include at least three of the motor power, battery power, electric accessory power and vehicle required power;

[0011] 3) When it is determined that the vehicle is in an unexpected acceleration state in a driving mode, an unexpected deceleration state in a driving mode, or an unexpected acceleration state in a non-driving mode, the output torque of the vehicle is controlled to be 0.

[0012] The beneficial effects of the above technical solution are as follows: the present invention combines at least three parameters of motor power, battery power, electrical accessory power and vehicle power demand to perform power closed-loop calibration on the whole vehicle, and verifies whether the output power of the motor is equal to the vehicle power demand, so as to identify unexpected acceleration, unexpected deceleration and other states, and when it is determined that the vehicle is in an unexpected acceleration state in driving mode, an unexpected deceleration state in driving mode, or an unexpected acceleration state in non-driving mode, the output torque of the whole vehicle is controlled to be 0, so as to protect the whole vehicle, so that the whole vehicle can be processed in time in these situations to ensure the driving experience of the whole vehicle, prevent safety accidents, increase vehicle driving safety, and avoid the inability to identify the whole vehicle when vehicle components are in abnormal states.

[0013] Furthermore, when it is determined that the vehicle is in an unexpected deceleration state in the non-driving mode, the output torque of the vehicle is not processed.

[0014] Furthermore, in order to accurately determine whether the vehicle is in an unexpected acceleration state in the driving mode, the method for determining whether the vehicle is in an unexpected acceleration state in the driving mode is that the vehicle operating parameters meet the following conditions and last for more than a set time:

[0015] η*P 电池 -k*P 需求 >P 电附件 ,I 电池 >0,I电机 >0, and a first condition, wherein the first condition is P 电机 -k*P 需求 >0 or η*P 电池 -k*P 电机 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of electrical accessories, P 需求 is the vehicle required power, η is the transmission efficiency, k is the safety factor, and the vehicle operation parameters also include the battery current I 电池 and motor current I 电机 .

[0016] Furthermore, in order to accurately determine whether the vehicle is in an unexpected deceleration state in the driving mode, the method for determining whether the vehicle is in an unexpected deceleration state in the driving mode is that the vehicle operating parameters meet the following conditions and last for more than a set time:

[0017] η*P 电池 -P 电附件 <P 需求 , and a second condition, wherein the second condition is P 电机 <0 or η*P 电机 -k*P 电池 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of electrical accessories, P 需求 is the required power of the whole vehicle, η is the transmission efficiency, and k is the safety factor.

[0018] Furthermore, in order to accurately determine whether the vehicle is in an unexpected acceleration state in a non-driving mode, the method for determining whether the vehicle is in an unexpected acceleration state in a non-driving mode is that the vehicle operating parameters meet the following conditions and last for more than a set time:

[0019] η*P 电池 -P 电附件 >0, and a third condition, wherein the third condition is P 电机 >0 or η*P 电池 -P 电机 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of the electrical accessories and η is the transmission efficiency.

[0020] Furthermore, in order to accurately determine whether the vehicle is in an unexpected deceleration state in a non-driving mode, the method for determining whether the vehicle is in an unexpected deceleration state in a non-driving mode is that the vehicle operating parameters meet the following conditions and last for more than a set time:

[0021] P 电附件 -η*P 电池 >k*P 需求 ,I 电池 <0, I 电机 <0, and a fourth condition, wherein the fourth condition is η*P 电机 -k*P 需求 >P 电附件 or η*P 电机 -k*P 电池 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of electrical accessories, P 需求 is the vehicle required power, η is the transmission efficiency, k is the safety factor, and the vehicle operation parameters also include the battery current I 电池 and motor current I 电机 .

[0022] Furthermore, in order to prevent the vehicle from experiencing rapid acceleration and deceleration and power outage, if the vehicle is in an unexpected acceleration state under the driving mode, the vehicle output torque is controlled to 0 only when the vehicle demand torque can make the vehicle produce the set acceleration.

[0023] Furthermore, if the vehicle is in an unexpected acceleration state in a driving mode / non-driving mode / unexpected acceleration state, corresponding fault reporting processing is performed.

[0024] The present invention also provides a new energy vehicle output torque control device, including a memory and a processor, wherein the processor is used to execute instructions stored in the memory to implement the new energy vehicle output torque control method introduced above, and can achieve the same beneficial effects as the method.

[0025] The present invention also provides a new energy vehicle, including a vehicle body, and also includes the new energy vehicle output torque control device introduced above, and can achieve the same beneficial effects as the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of a method for controlling output torque of a new energy vehicle according to the present invention;

[0027] Figure 2 It is a system structure diagram for realizing the new energy vehicle output torque control method of the present invention;

[0028] Figure 3 It is a structural diagram of the output torque control device of a new energy vehicle of the present invention. DETAILED DESCRIPTION

[0029] The basic concept of the present invention is: the present invention determines that the vehicle required power P calculated by the vehicle controller VCU 需求 is a relatively accurate value, and the calculated motor power P 电机 If the power output is not accurate (for example, the calculated value is 30KW but the actual output of the motor is 50KW, resulting in an unexpected acceleration state in the driving mode, and other situations are similar), the present invention performs power closed-loop verification on the battery power, motor power, vehicle demand power, etc. to identify the unexpected acceleration state and unexpected deceleration state in the driving mode and non-driving mode, and performs corresponding fault alarms after identifying these states to implement corresponding protection strategies.

[0030] In the following, in conjunction with the accompanying drawings and embodiments, a new energy vehicle output torque control method, a new energy vehicle output torque control device and a new energy vehicle of the present invention are described in detail.

[0031] Method Example:

[0032] The vehicle in this embodiment is a new energy vehicle, and its power source includes a power battery (hereinafter referred to as a battery). Figure 2 The system shown is used to implement a new energy vehicle output torque control method of the present invention. The system includes a vehicle controller VCU, a motor controller MCU and a battery management system BMS. Data interaction can be performed between the vehicle controller VCU and the motor management system BMS. The battery management system BMS can send the acquired battery current and battery voltage to the vehicle controller VCU for the vehicle controller VCU to perform corresponding logical processing and calculations. Data interaction can also be performed between the vehicle controller VCU and the motor controller MCU. On the one hand, the motor controller MCU can send the acquired motor bus voltage, motor bus current and motor response torque to the vehicle controller VCU for the vehicle controller VCU to perform corresponding logical processing and calculations. On the other hand, the vehicle controller VCU can also send the vehicle required torque to the motor controller MCU, so that the motor controller MCU controls the motor to work according to the vehicle required torque. Among them, the vehicle controller VCU performs corresponding logical processing and calculations, and the methods that can be implemented include a new energy vehicle output torque control method of the present invention, and its process is as follows Figure 1 As shown, the following is a detailed introduction.

[0033] Step 1: During vehicle operation, if there is no fault in the communication between the vehicle controller VCU and the motor controller MCU, and there is no fault in the communication between the vehicle controller VCU and the battery management system BMS, the vehicle controller VCU determines the vehicle's operating mode, whether it is a driving mode or a non-driving mode:

[0034] When the vehicle is in driving mode, the vehicle's required torque is greater than 0 Nm, and step 2 is executed.

[0035] When the vehicle is in non-driving mode, it means that the vehicle is in braking or coasting condition, and the vehicle demand torque is less than or equal to 0Nm. At this time, execute step three.

[0036] Step 2: When the vehicle is in driving mode (theoretically, P 电池 =P 电机 +P 电附件 , efficiency is not considered here), the vehicle controller VCU compares and judges the acquired data to determine whether the vehicle is in an unexpected acceleration state under the driving mode or an unexpected deceleration state under the driving mode, and performs corresponding processing. Specifically:

[0037] 1) The vehicle controller VCU obtains the motor bus current I from the motor controller MCU 电机 and motor bus voltage U 电机 , and according to the motor bus current I 电机 and motor bus voltage U 电机 Calculate the motor power P 电机 The vehicle controller VCU also obtains the battery current I from the battery management system BMS 电池 and battery voltage U 电池 , and according to the battery current I 电池 and battery voltage U 电池 Calculate the battery power P 电池 Moreover, the vehicle controller VCU also calculates the power P of the electrical accessories according to the current and voltage of each electrical accessory. 电附件 Depending on the model, the electric accessories include but are not limited to air conditioners, water pumps, electric steering, air compressors, electric defrosters, electric heaters, lamps, etc. The power of the electric accessories P 电附件 It is the sum of the power of all electrical accessories.

[0038] 2) Make the following comparison and judgment on the acquired and calculated data:

[0039] If η*P is satisfied 电池 -k*P 需求 >P 电附件 ,I 电池 >0,(P 电机 -k*P 需求 >0 or η*P电池 -k*P 电机 >P 电附件 ), and I 电机 >0, and this condition is met for 3 seconds, the vehicle is considered to be in an unexpected acceleration state in the driving mode. At this time, the vehicle controller VCU outputs a command that the vehicle's required torque is 0 to the motor controller MCU, and reports the corresponding fault code. The fault can only be reset after the vehicle is disconnected from the B-level power. Moreover, the vehicle's required torque can make the vehicle generate +0.075m / s 2 This function is activated only when the acceleration is reached, otherwise it is not activated. Among them, η is the transfer efficiency, which is the power loss when the motor charges the battery or the power loss when the battery discharges the motor. These two power losses are actually similar, so in this embodiment, the transfer efficiency corresponding to these two power losses is expressed by η; k is the safety factor, which is equivalent to designing a fault-tolerant space.

[0040] If η*P is satisfied 电池 -P 电附件 <P 需求 , and (P 电机 <0 or η*P 电机 -k*P 电池 >P 电附件 ), and this condition continues to be met for 3 seconds, it is considered that the vehicle is in an unexpected deceleration state in the driving mode. At this time, the vehicle controller VCU outputs a command that the vehicle's required torque is 0 to the motor controller MCU, and reports the corresponding fault code. The fault can only be reset after the vehicle is disconnected from the B-level power.

[0041] If neither of the above two conditions is met, the vehicle controller VCU can normally output the required vehicle torque to the motor controller MCU.

[0042] Step 3: When the vehicle is in non-driving mode (theoretically, P 电机 =P 电池 +P 电附件 , efficiency is not considered here), the vehicle controller VCU compares and judges the acquired data to determine whether the vehicle is in an unexpected acceleration state in a non-driving mode or an unexpected deceleration state in a non-driving mode, and performs corresponding processing. Specifically:

[0043] 1) The vehicle controller VCU obtains the motor bus current I from the motor controller MCU 电机 and motor bus voltage U 电机 , and according to the motor bus current I 电机 and motor bus voltage U 电机 Calculate the motor power P 电机 The vehicle controller VCU also obtains the battery current I from the battery management system BMS 电池and battery voltage U 电池 , and according to the battery current I 电池 and battery voltage U 电池 Calculate the battery power P 电池 Moreover, the vehicle controller VCU also calculates the power P of the electrical accessories according to the current and voltage of each electrical accessory. 电附件 Depending on the model, the electric accessories include but are not limited to air conditioners, water pumps, electric steering, air compressors, electric defrosters, electric heaters, lamps, etc. The power of the electric accessories P 电附件 It is the sum of the power of all electrical accessories.

[0044] 2) Make the following comparison and judgment on the acquired and calculated data:

[0045] If η*P is satisfied 电池 -P 电附件 >0, and (P 电机 >0 or η*P 电池 -P 电机 >P 电附件 ), and this condition continues to be met for 3 seconds, it is considered that the vehicle is in an unexpected acceleration state in non-driving mode. At this time, the vehicle controller VCU outputs a command that the vehicle's required torque is 0 to the motor controller MCU, and reports the corresponding fault code. The fault can only be reset after the vehicle is disconnected from the B-level power.

[0046] If P is satisfied 电附件 -η*P 电池 >k*P 需求 ,I 电池 <0, (η*P 电机 -k*P 需求 >P 电附件 or η*P 电机 -k*P 电池 >P 电附件 ), and I 电机 <0, and this condition is met for 3 seconds, the vehicle is considered to be in an unexpected deceleration state in the non-driving mode. At this time, the vehicle controller VCU does not process the power of the vehicle and reports the corresponding fault code. The fault can only be reset after the vehicle is disconnected from the B-level power. In addition, the vehicle requires torque that can make the vehicle generate -0.075m / s 2 This function is activated only when the vehicle is accelerating, otherwise it is not activated.

[0047] If neither of the above two conditions is met, the vehicle controller VCU can normally output the required vehicle torque to the motor controller MCU.

[0048] At this point, the output torque control method for a new energy vehicle of the present invention is completed.

[0049] The implementation of the entire method needs to be performed under the condition that there is no fault in the communication between the vehicle controller VCU and the motor controller MCU, and there is no fault in the communication between the vehicle controller VCU and the battery management system BMS. Otherwise, the method of the present invention cannot be implemented and the entire function cannot be triggered.

[0050] Unexpected acceleration in driving mode and unexpected deceleration in non-driving mode can generate ±0.075m / s in the vehicle's required torque. 2 This function is activated only during acceleration, otherwise it is not activated. The main reason is that there is a certain difference between the required torque and the motor output torque under small torque, and it will not cause the vehicle to accelerate or decelerate quickly, and prevent this function from being triggered by mistake, causing the vehicle to lose power.

[0051] Moreover, in this embodiment, the safety factor is 1.3, that is, the motor output torque is not greater than 30% of the vehicle's required torque, and the transmission efficiency is 0.92. The two coefficients are obtained from experiments. After multiple real vehicle experiments, the energy output from the battery to the components is 92% efficient. When the motor output torque exceeds the vehicle's required torque by 30%, the driver will have an obvious sense of unexpected acceleration.

[0052] Device Example:

[0053] An embodiment of a new energy vehicle output torque control device of the present invention is as follows: Figure 3 As shown, it includes a memory, a processor and an internal bus, and the processor and the memory communicate and exchange data with each other through the internal bus. The memory includes at least one software function module stored in the memory for storing programs; the processor executes various functional applications and data processing by running the software programs and modules stored in the memory to implement a new energy vehicle output torque control method introduced in the method embodiment of the present invention. The method has been described in detail in the method embodiment, and its process is as follows Figure 1 shown.

[0054] Among them, the processor can be a processing device such as a microprocessor MCU, a programmable logic device FPGA, etc., or it can be the vehicle controller VCU mentioned in the method embodiment.

[0055] The memory may be various types of memories that use electrical energy to store information (such as RAM, ROM, etc.), various types of memories that use magnetic energy to store information (such as hard disk, floppy disk, magnetic tape, magnetic core memory, bubble memory, USB flash drive, etc.), and various types of memories that use optical methods to store information (such as CD, DVD, etc.). Of course, it can also be other types of memories (such as quantum memory, graphene memory, etc.).

[0056] Vehicle Example:

[0057] A vehicle embodiment of the present invention includes a vehicle body (including a vehicle shell, etc.), and also includes a new energy vehicle output torque control device, the device includes a memory and a processor, and the processor is used to execute instructions stored in the memory to implement a new energy vehicle output torque control method of the present invention. The device has been described in detail in the device embodiment, and the method has been described in detail in the method embodiment, and will not be repeated here.

Claims

1. A method for controlling output torque of a new energy vehicle, characterized in that: The steps include: 1) Determine the operating mode of the vehicle, whether it is driving mode or non-driving mode; 2) Based on the operation mode of the vehicle and the obtained vehicle operation parameters, a corresponding discrimination method is used to determine whether the vehicle is in an unexpected acceleration state / unexpected deceleration state in a driving mode / non-driving mode; The vehicle operation parameters include motor power, battery power, electric accessory power and vehicle required power; the method for determining that the vehicle is in an unexpected acceleration state in the driving mode is that the vehicle operation parameters meet the following conditions and last for more than a set time: η*P 电池 -k*P 需求 >P 电附件 ,I 电池 >0,I 电机 >0, and a first condition, wherein the first condition is P 电机 -k*P 需求 >0 or η*P 电池 -k*P 电机 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of electrical accessories, P 需求 is the vehicle required power, η is the transmission efficiency, k is the safety factor, and the vehicle operation parameters also include the battery current I 电池 and motor current I 电机 ; 3) When it is determined that the vehicle is in an unexpected acceleration state in a driving mode, an unexpected deceleration state in a driving mode, or an unexpected acceleration state in a non-driving mode, the output torque of the vehicle is controlled to be 0.

2. The method for controlling the output torque of a new energy vehicle according to claim 1, characterized in that: When it is determined that the vehicle is in an unexpected deceleration state in a non-driving mode, the output torque of the vehicle is not processed.

3. The method for controlling the output torque of a new energy vehicle according to claim 1, characterized in that: The method for determining that the vehicle is in an unexpected deceleration state in the driving mode is that the vehicle operating parameters meet the following conditions and last for more than a set time: η*P 电池 -P 电附件 <P 需求 , and a second condition, wherein the second condition is P 电机 <0 or η*P 电机 -k*P 电池 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of electrical accessories, P 需求 is the required power of the whole vehicle, η is the transmission efficiency, and k is the safety factor.

4. The method for controlling the output torque of a new energy vehicle according to claim 1, characterized in that: The method for determining the unexpected acceleration state of the vehicle in the non-driving mode is that the vehicle operating parameters meet the following conditions and last for more than a set time: η*P 电池 -P 电附件 >0, and a third condition, wherein the third condition is P 电机 >0 or η*P 电池 -P 电机 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of the electrical accessories and η is the transmission efficiency.

5. The new energy vehicle output torque control method according to claim 1 or 2, characterized in that: The method for determining that the vehicle is in an unexpected deceleration state in the non-driving mode is that the vehicle operating parameters meet the following conditions and last for more than a set time: P 电附件 -η*P 电池 >k*P 需求 ,I 电池 <0, I 电机 <0, and a fourth condition, wherein the fourth condition is η*P 电机 -k*P 需求 >P 电附件 or η*P 电机 -k*P 电池 >P 电附件 ; Among them, P 电池 is the battery power, P 电机 is the motor power, P 电附件 is the power of electrical accessories, P 需求 is the vehicle required power, η is the transmission efficiency, k is the safety factor, and the vehicle operation parameters also include the battery current I 电池 and motor current I 电机 .

6. The method for controlling the output torque of a new energy vehicle according to claim 1, characterized in that: If the vehicle is in an unexpected acceleration state in the driving mode, the vehicle output torque is controlled to 0 only when the vehicle demand torque can make the vehicle produce the set acceleration.

7. The method for controlling the output torque of a new energy vehicle according to claim 1, characterized in that: If the vehicle is in driving mode / unexpected acceleration / unexpected acceleration state in non-driving mode, perform corresponding fault reporting and processing.

8. A new energy vehicle output torque control device, characterized in that: It includes a memory and a processor, and the processor is used to execute instructions stored in the memory to implement the new energy vehicle output torque control method as described in any one of claims 1 to 7.

9. A new energy vehicle, comprising a vehicle body, characterized in that: It also includes the new energy vehicle output torque control device as described in claim 8.

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