A method for calculating torque of wheel hub motor vehicle

Abstract

The present invention provides a method for calculating the torque of a hub motor vehicle. By limiting the torque output by the hub motor according to the charging and discharging capacity of the power battery and considering the change in the power output capacity of the power battery caused by high-voltage accessories, the problem of overcharging or over-discharging of the power battery of the hub motor vehicle is solved. The present invention is not only applicable to the working conditions where all wheels of the hub motor are driven to consume electric energy at the same time and all wheels are braked to generate electric energy, but also applicable to the working conditions where different wheels of the hub motor vehicle are in different states: for example, some wheels are in a state of braking to generate electric energy, and some wheels are in a driving state to consume electric energy, so as to maximize the torque output of the whole vehicle, while protecting the power battery, avoiding the failure of overcharging and over-discharging of the power battery, and improving the reliability and safety of the whole vehicle.

Description

Technical Field

[0001] The invention belongs to the technical field of electric vehicle transmission, and in particular relates to a method for calculating the torque of a hub motor vehicle. Background Art

[0002] As environmental standards and regulations become increasingly stringent, the development trend of electric vehicles is becoming more and more obvious. Among them, the wheel hub motor car can improve the stability of the vehicle because the torque of each wheel is independently controllable. However, since the wheel hub motor has multiple motors, the difficulty of the vehicle control algorithm increases. The working state of each wheel is complex and changeable. There are working modes in which all the wheel hub motors are driven at the same time, all the wheel hub motors are braked at the same time, and some of the wheel hub motors are driven and other motors are braked. Therefore, compared with the traditional single-motor battery protection control method, it is not directly applicable to wheel hub motor cars with multiple motors. In order to protect the power battery in various working modes of the wheel hub motor, a reasonable control algorithm must be designed to avoid the overcharging or over-discharging of the power battery caused by excessive output drive or braking torque of the wheel hub motor. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for calculating the torque of a hub motor vehicle, so as to solve the problem of overcharging or overdischarging of a power battery of the hub motor vehicle.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a method for calculating the torque of a hub motor vehicle, comprising the following steps:

[0005] Calculate the total power consumed by high-voltage components other than the hub motor of the hub motor vehicle model based on the actual current of the power battery, the actual current of the hub motor and the total voltage of the power battery;

[0006] The power battery charging capacity difference and the power battery discharging capacity difference are calculated according to the method of calculating the total power consumed by the high-voltage components except the wheel hub motors, based on the maximum allowable charging power and the maximum allowable discharging power of the power battery;

[0007] According to the difference in the charging capacity and the discharging capacity of the power battery, the wheel hub motor braking power is compared with the maximum allowable charging power of the power battery, and the wheel hub motor driving power is compared with the maximum allowable discharging power of the power battery, and the change value of the wheel hub motor braking wheel torque and the change value of the driving wheel torque caused by the power exceeding the charging capacity and discharging capacity of the power battery are calculated accordingly;

[0008] According to the basic torque of the hub motor at a certain moment and the sign state of the basic torque, the positive and negative states of the basic torque of each hub motor are obtained;

[0009] Calculate the first target torque of each hub motor according to the positive and negative states of the hub motor basic torque, and the change value of the hub motor brake wheel torque and the change value of the drive wheel torque;

[0010] According to the state of the wheel hub motor at the current moment, one of the basic torque of the wheel hub motor and the first target torque is selected as the execution target torque output of the wheel hub motor;

[0011] After the output of the hub motor executes the target torque, the change value of the basic driving anti-skid or yaw stability requirement calculation of the whole vehicle is obtained, and the basic torque of the hub motor is updated according to the change value.

[0012] According to the above scheme, the specific steps of calculating the total power consumed by the high-voltage components of the hub motor vehicle except the hub motor are as follows:

[0013] Let I bms is the actual current of the power battery, if I bms If it is negative, the power battery is in charging state. bms If the power battery is in a discharge state, bms If it is 0, the power battery is neither charged nor discharged; i is the actual current of the i-th wheel hub motor, i∈[1,n], n is the total number of wheel hub motors configured on the vehicle, if I i If the i-th wheel hub motor consumes high voltage electricity and is in driving state, i If I is negative, the i-th wheel hub motor is in the state of braking energy recovery to charge the power battery. i If it is zero, the i-th wheel hub motor is in a non-driving and non-braking state; U is the total voltage of the power battery; then the total power consumed by the high-voltage components of the wheel hub motor model except the wheel hub motor is P f for:

[0014] P f =(I bms -∑I i )*U.

[0015] According to the above scheme, the specific steps of calculating the difference between the power battery charging capacity and the power battery discharging capacity are as follows:

[0016] Let P maxcharge is the maximum allowable charging power of the power battery, P maxcharge <0;P maxdischarge is the maximum allowable discharge power of the power battery, P maxdischarge >0; α1 and α2 are the adjustment coefficients of the power battery soc value; β is the corresponding coefficient of the power battery fault level; then the power battery charging capacity difference ΔP1 and the power battery discharging capacity difference ΔP2 are respectively:

[0017]

[0018] Furthermore, in the step of calculating the difference between the power battery charging capacity and the power battery discharging capacity,

[0019] If ΔP1≤0, then ΔP2>0; if ΔP2≤0, then ΔP1>0; or ΔP2>0 and ΔP1>0;

[0020] If the power battery SOC value is greater than or equal to the power battery full charge threshold soc max When α1=0; if the power battery SOC value is less than the power battery full charge threshold soc max When α1=1, the power battery is protected to avoid overcharging. If the power battery is low, the battery SOC value is less than the threshold soc min When α2=0, otherwise α2=1; the power battery is protected to avoid over-discharge of the power battery;

[0021] When the power battery has no fault, β=1; when the power battery has a general fault, β=0.5; when the power battery has a serious fault, β=0.

[0022] According to the above scheme, the specific steps of changing the torque of the hub motor brake wheel and the torque of the driving wheel are as follows:

[0023] When the power battery charging capacity difference is less than 0, it means that the absolute value of the hub motor braking power is greater than the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1<0, then the hub motor torque in the braking state approaches the value of 0; when the power battery charging capacity difference is not less than 0, it means that the absolute value of the hub motor braking power is less than or equal to the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1≥0, then the hub motor torque in the braking state remains unchanged; let ΔT1 be the change in the hub motor torque in the braking state approaching the value of 0, and ΔT1 is always a non-negative number; K 11 is the proportional adjustment coefficient, K 12 is the integral adjustment coefficient; t1 is the duration of ΔP1 being less than 0. Each time ΔP1 is greater than or equal to 0, the timing starts again from 0; T max is the maximum torque of the hub motor and is the mechanical characteristic parameter of the hub motor; then the change value ΔT1 of the brake wheel torque is:

[0024]

[0025] When the difference in the power battery discharge capacity is less than 0, it means that the hub motor driving power is greater than the maximum allowable discharge power of the power battery, that is, ΔP2<0, then the torque of the hub motor in the driving state approaches the value of 0; when the difference in the power battery discharge capacity is not less than 0, it means that the hub motor driving power is less than or equal to the maximum allowable discharge power of the power battery, that is, ΔP2≥0, then the torque of the hub motor in the driving state remains unchanged; let ΔT2 be the change in the torque of the hub motor in the driving state approaching the value of 0, and ΔT2 is always a non-negative number; K 21 is the proportional adjustment coefficient, K 22 is the integral adjustment coefficient; t2 is the duration of ΔP2 being less than 0. Each time ΔP2 is greater than or equal to 0, t2 starts again from 0. Then the change value of the driving wheel torque ΔT2 is:

[0026]

[0027] According to the above scheme, the specific steps of obtaining the positive and negative states of the basic torque of each hub motor are as follows:

[0028] Let T(k-1) i is the basic torque of the i-th wheel hub motor at time k-1, T(k-1) i >0 means the i-th wheel hub motor is in driving state, T(k-1) i <0 means the i-th wheel hub motor is in braking state, T(k-1) i =0 means that the i-th wheel hub motor is in a non-operating state without driving or braking; S i is the sign state of the basic torque of the i-th wheel hub motor, S i =1 means the i-th wheel hub motor is in non-braking state, S i =-1 means that the i-th wheel hub motor is in braking state; then the positive and negative states of the basic torque of each wheel hub motor are:

[0029]

[0030] According to the above scheme, the specific steps of calculating the first target torque of each wheel hub motor are:

[0031] Assume T i1 is the first target torque of the i-th wheel hub motor, T i1The existing states include when the i-th wheel hub motor is in a non-braking state and the difference in the power battery discharge capacity is less than 0, that is, the wheel hub motor driving power is greater than the maximum allowable discharge power of the power battery; when the i-th wheel hub motor is in a braking state and the difference in the power battery discharge capacity is less than 0, that is, the wheel hub motor driving power is greater than the maximum allowable discharge power of the power battery; when the i-th wheel hub motor is in a non-braking state and the difference in the power battery charging capacity is less than 0, that is, the absolute value of the wheel hub motor braking power is greater than the absolute value of the maximum allowable charging power of the power battery; when the i-th wheel hub motor is in a braking state and the difference in the power battery charging capacity is less than 0, that is, the absolute value of the wheel hub motor braking power is greater than the absolute value of the maximum allowable charging power of the power battery; then T i1 for:

[0032]

[0033] Furthermore, in the step of calculating the first target torque of each wheel hub motor,

[0034] If the i-th wheel hub motor is in the non-braking state, that is, T(k-1) i ≥0, and the difference in the power battery discharge capacity is less than 0, that is, when the wheel hub motor driving power is greater than the maximum allowable discharge power of the power battery, that is, when ΔP2 is less than 0, then S i =1, ΔT1=0, ΔT2≠0; at the same time, the wheel hub motor in the non-braking state is subjected to torque reduction processing, and the first target torque of the i-th wheel hub motor is converted into:

[0035] T i1 =|T(k-1) i |-ΔT2;

[0036] If the i-th wheel hub motor is in braking state, that is, T(k-1) i <0, and the difference in the power battery discharge capacity is less than 0, that is, when the wheel hub motor driving power is greater than the maximum allowable discharge power of the power battery, that is, when ΔP2<0, then S i =-1, ΔT1=0, ΔT2≠0; meanwhile, the torque of the hub motor in the braking state is not processed, and the first target torque of the i-th hub motor is converted into:

[0037] T i1 =|T(k-1) i |;

[0038] If the i-th wheel hub motor is in the non-braking state, that is, T(k-1) i ≥0, and the difference in the power battery charging capacity is less than 0, that is, the absolute value of the hub motor braking power is greater than the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1<0, then S i=1, ΔT1≠0, ΔT2=0; meanwhile, the torque of the hub motor in the non-braking state is not processed, and the first target torque of the i-th hub motor is converted into:

[0039] T i1 =|T(k-1) i |;

[0040] If the i-th wheel hub motor is in braking state, that is, T(k-1) i <0, and the difference in power battery charging capacity is less than 0, that is, the absolute value of the hub motor braking power is greater than the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1<0, then S i =-1, ΔT1≠0, ΔT2=0; at the same time, the wheel hub motor in the braking state is subjected to torque reduction processing, and the first target torque of the i-th wheel hub motor is converted into:

[0041] T i1 =|T(k-1) i |-ΔT1.

[0042] According to the above scheme, the specific steps of calculating the execution target torque of the hub motor are:

[0043] Assume T i2 is the target torque of the i-th wheel hub motor; T(k) i is the basic torque of the i-th wheel hub motor at time k;

[0044] If the power consumed or generated by the current wheel hub motor does not exceed the battery capacity, that is, ΔP2>0 and ΔP1>0, the execution target torque T of the wheel hub motor i2 for:

[0045] T i2 =T(k) i ;

[0046] If the total power consumed by the current hub motor exceeds the battery capacity, that is, ΔP2≤0 and ΔP1>0, the execution target torque of the hub motor in the non-braking state is equal to the smaller of the first target torque and the basic torque, and the execution target torque of the hub motor in the braking state is equal to the basic torque, that is:

[0047]

[0048] If the total power generated by the current hub motor exceeds the battery capacity, that is, ΔP2>0 and ΔP1≤0, the execution target torque of the hub motor in the braking state is equal to the larger of the first target torque and the basic torque, and the execution target torque of the hub motor in the non-braking state is equal to the basic torque, that is:

[0049]

[0050] According to the above scheme, the specific steps of updating the basic torque of the hub motor are:

[0051] Let γ be the percentage of the accelerator pedal or brake pedal opening, γ∈[0,1]; T(w) i is the external characteristic torque corresponding to the actual speed w of the i-th wheel hub motor; according to the wheel slip rate and yaw angle state of the vehicle, the change value ΔTa of the basic driving anti-skid or yaw stability demand calculation of the vehicle is obtained i , let ΔTa i is 0, negative or positive; take the basic torque T(k) of the i-th hub motor at time k i is the driving intention torque calculated based on the accelerator pedal and brake pedal; ΔTa of each wheel i Different causes T(k-1) i If there are positive and negative differences between them, the basic torque of the hub motor is updated as:

[0052] T(k-1) i =T(k) i ;

[0053] T(k) i =γ*T(w) i -ΔTa i .

[0054] The beneficial effects of the present invention are:

[0055] 1. A method for calculating the torque of a hub motor vehicle of the present invention limits the torque output by the hub motor according to the charging and discharging capacity of the power battery and the change in the power output capacity of the power battery caused by high-voltage accessories, thereby solving the problem of overcharging or over-discharging of the power battery of the hub motor vehicle.

[0056] 2. The present invention is not only applicable to the working conditions where all wheels of the hub motor are driven simultaneously to consume electric energy and all wheels are braked to generate electric energy, but also applicable to the working conditions where different wheels of the hub motor vehicle are in different states: for example, some wheels are in a braking state to generate electric energy, and some wheels are in a driving state to consume electric energy. This maximizes the torque output of the whole vehicle, while protecting the power battery, avoiding overcharge and over-discharge failures of the power battery, and improving the reliability and safety of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0059] See also Figure 1 A method for calculating the torque of a hub motor vehicle according to an embodiment of the present invention comprises the following steps:

[0060] Step 1: In addition to the high-voltage electricity consumed by the hub motor, the hub motor model also has other high-voltage components such as DCDC, high-voltage air conditioning, etc., which consume high-voltage electricity. Therefore, it is necessary to calculate the power consumed by the high-voltage components other than the hub motor:

[0061] P f =(I bms -ΣI i )*U

[0062] Where: P f ——The sum of high-voltage electrical power consumed by all other high-voltage components except the wheel hub motor; I bms ——Actual current of power battery, I bms If it is a negative number, it means that the power battery is in a charging state. bms To describe the normal state of the power battery discharge, I bms If it is 0, it means that the power battery is neither charging nor discharging; i ——The actual current of the i-th wheel hub motor, i∈[1,n], n is the total number of wheel hub motors configured on the vehicle, I i If it is positive, it means that the i-th wheel hub motor consumes high voltage electricity and is in driving state. i If it is negative, it means that the i-th wheel hub motor is in the state of braking energy recovery to charge the power battery. i If it is zero, it means that the i-th wheel hub motor is in a non-driving and non-braking state; U is the total voltage of the power battery.

[0063] Step 2: Calculate the range in which the actual power consumed by the hub motor exceeds the maximum charge and discharge capacity of the power battery:

[0064]

[0065] Where: P maxcharge ——Maximum allowable charging power of the power battery, P maxcharge <0;P maxdischarge ——Maximum allowable discharge power of power battery, P maxdischarge >0; α1, α2——power battery SOC value adjustment coefficient; β——power battery fault level corresponding coefficient; ΔP1——power battery charging capacity difference; ΔP2——power battery discharging capacity difference.

[0066] It can be further known that: if ΔP1≤0, then ΔP2>0, and if ΔP2≤0, then ΔP1>0. ΔP2>0 and ΔP1>0 can exist at the same time.

[0067] Furthermore, the power battery SOC value is greater than or equal to the power battery full charge threshold soc max , α1=0; otherwise α1=1; protect the power battery to avoid overcharging; the power battery SOC value power battery power loss threshold soc min , α2=0; otherwise α2=1; the power battery is protected to avoid over-discharge.

[0068] Furthermore, when the power battery has no fault, β=1; when the power battery has a general fault, β=0.5; when the power battery has a serious fault, β=0.

[0069] Step 3: Calculate the reduction in wheel hub motor torque caused by power exceeding the charging and discharging capabilities of the power battery.

[0070] Furthermore, when the absolute value of the power generated by the wheel hub motor braking is greater than the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1 < 0, the braking wheel hub motor torque should approach the value of 0; when the absolute value of the power generated by the wheel hub motor braking is not greater than the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1 ≥ 0, the braking wheel hub motor torque does not change. The calculation formula for the change in the braking wheel torque ΔT1 is:

[0071]

[0072] Where: ΔT1——the change of the wheel hub motor torque approaching 0 in the braking state, and ΔT1 is always a non-negative number; K 11 ——Proportional adjustment coefficient, K 12 ——Integral adjustment coefficient; t1——The duration of ΔP1 less than 0. Each time ΔP1 is greater than or equal to 0, the timing starts from 0 again; T max ——The maximum torque of the hub motor, which is a mechanical characteristic parameter of the hub motor;

[0073] Furthermore, when the power consumed by the hub motor is greater than the maximum allowable discharge power of the power battery, that is, ΔP2 < 0, the torque of the hub motor in the driving state should approach the value of 0; when the power consumed by the hub motor is not greater than the maximum allowable discharge power of the power battery, that is, ΔP2 ≥ 0, the torque of the hub motor in the driving state can remain unchanged.

[0074]

[0075] Where: ΔT2——The change in the wheel hub motor torque approaching 0 in the driving state, and ΔT2 is always a non-negative number. K 21 ——Proportional adjustment coefficient, K 22 ——Integral adjustment coefficient; t2——The duration of ΔP2 less than 0. Every time ΔP2 is greater than or equal to 0, the timing starts from 0 again.

[0076] Step 4: Obtain the positive and negative status of the basic torque of each hub motor.

[0077]

[0078] Where: T(k-1) i ——The basic torque of the i-th wheel hub motor at time k-1, T(k-1) i >0 means the i-th wheel hub motor is in driving state; T(k-1) i <0 means that the i-th wheel hub motor is in braking state; T(k-1) i =0 means that the i-th wheel hub motor is in a non-operating state without driving or braking. i ——The sign state of the basic torque of the i-th wheel hub motor, S i =1 means the i-th wheel hub motor is in non-braking state; S i =-1 means the i-th wheel hub motor is in braking state;

[0079] Step 5: Calculate the first target torque of each wheel motor

[0080]

[0081] Where: T i1 ——The first target torque of the i-th wheel hub motor;

[0082] Furthermore, T i1 There are four states, including:

[0083] The first one is that if the i-th wheel hub motor is in a non-braking state, that is, T(k-1) i ≥0, and when the power consumed by the hub motor is greater than the maximum allowable discharge power of the power battery, that is, ΔP2<0, then S i =1, ΔT1=0, ΔT2≠0; at the same time, the torque reduction process is performed on the non-braking wheel hub motor, that is, the first target torque of the i-th wheel hub motor can be converted into:

[0084] T i1 =|T(k-1) i |-ΔT2

[0085] The second type is if the i-th wheel hub motor is in the braking state, that is, T(k-1) i <0, and when the power consumed by the hub motor is greater than the maximum allowable discharge power of the power battery, that is, ΔP2<0, then S i =-1, ΔT1=0, ΔT2≠0; at the same time, the torque of the braking hub motor is not processed, that is, the first target torque of the i-th hub motor can be converted into:

[0086] T i1 =|T(k-1) i |

[0087] The third type is if the i-th wheel hub motor is in a non-braking state, that is, T(k-1) i ≥0, and when the absolute value of the power generated by the hub motor braking is greater than the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1<0, then S i =1, ΔT1≠0, ΔT2=0; at the same time, the torque of the non-braking hub motor is not processed, that is, the first target torque of the i-th hub motor can be converted into:

[0088] T i1 =|T(k-1) i |

[0089] The fourth type is that if the i-th wheel hub motor is in the braking state, that is, T(k-1) i <0, and when the absolute value of the power generated by the hub motor braking is greater than the absolute value of the maximum allowable charging power of the power battery, that is, ΔP1<0, then S i =-1, ΔT1≠0, ΔT2=0; at the same time, the torque reduction of the braking wheel hub motor, that is, the first target torque of the i-th wheel hub motor can be converted into:

[0090] T i1 =|T(k-1) i |-ΔT1

[0091] Step 6: Calculate the execution target torque of each wheel hub motor by comparing the relative magnitude relationship between the basic torque calculated based on the brake pedal and the brake pedal according to the current state and the first target torque.

[0092] Furthermore, if the power consumed or generated by the current wheel hub motor does not exceed the battery capacity, that is, ΔP2>0 and ΔP1>0, the wheel hub motor directly outputs the basic torque, that is:

[0093] T i2 =T(k) i

[0094] Where: T i2 ——The execution target torque of the i-th wheel hub motor.

[0095] Furthermore, if the total power consumed by the current hub motor exceeds the battery capacity, that is, ΔP2≤0 and ΔP1>0, the hub motor output torque in the non-braking state is the smaller of the first target torque and the basic torque (that is, the power consumed by the driving wheel will not increase, but the power consumption is allowed to decrease), and the hub motor in the braking state outputs the basic torque, that is:

[0096]

[0097] Furthermore, if the total power generated by the current wheel hub exceeds the battery capacity, that is, ΔP2>0 and ΔP1≤0, the wheel hub motor in the braking state outputs the larger of the first target torque and the basic torque (that is, the power generated by the braking wheel will not increase, but the power generated is allowed to decrease), and the wheel hub motor in the non-braking state outputs the basic torque, that is:

[0098]

[0099] Where: T i2 ——The target torque of the i-th wheel hub motor; T(k) i ——The basic torque of the i-th wheel hub motor at time k

[0100] Step 7: Update the base torque of each wheel motor.

[0101] T(k-1) i =T(k) i

[0102] Furthermore, T(k) i is the driving intention torque calculated based on the accelerator pedal and the brake pedal. One calculation method is:

[0103] T(k) i =γ*T(w) i -ΔTa i

[0104] Where: γ——the percentage of the accelerator pedal or brake pedal opening, γ∈[0,1]; T(w) i ——External characteristic torque corresponding to the actual speed w of the i-th wheel hub motor; ΔTa i ——The change value of the basic driving anti-skid or yaw stability requirement calculation of the whole vehicle can be 0, a negative number, or a positive number, and is obtained according to the wheel slip rate and yaw angle status of the whole vehicle.

[0105] Furthermore, the ΔTa of each round i Different, it leads to T(k-1) i There are positive and negative situations between each other.

[0106] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A method for calculating the torque of a hub motor vehicle, characterized in that: The following steps are involved: Calculate the total power consumed by high-voltage components other than the hub motor of the hub motor vehicle model based on the actual current of the power battery, the actual current of the hub motor and the total voltage of the power battery; The power battery charging capacity difference and the power battery discharging capacity difference are calculated according to the method of calculating the total power consumed by the high-voltage components except the wheel hub motors, based on the maximum allowable charging power and the maximum allowable discharging power of the power battery; The specific steps of calculating the difference between the charging capacity of the power battery and the discharging capacity of the power battery are as follows: Let I i is the actual current of the i-th wheel hub motor, i∈[1,n], n is the total number of wheel hub motors configured on the vehicle, if I i If the i-th wheel hub motor consumes high voltage electricity and is in driving state, i If I is negative, the i-th wheel hub motor is in the state of braking energy recovery to charge the power battery. i If it is zero, the i-th wheel hub motor is in a non-driving and non-braking state; U is the total voltage of the power battery; P f It is the sum of the power consumed by the high-voltage components of the hub motor model except the hub motor; Let P maxcharge is the maximum allowable charging power of the power battery, P maxcharge <0;P maxdischarge is the maximum allowable discharge power of the power battery, P maxdischarge >0; α1 and α2 are the adjustment coefficients of the power battery soc value; β is the corresponding coefficient of the power battery fault level; then the power battery charging capacity difference ΔP1 and the power battery discharging capacity difference ΔP2 are respectively: According to the difference in the charging capacity and the discharging capacity of the power battery, the wheel hub motor braking power is compared with the maximum allowable charging power of the power battery, and the wheel hub motor driving power is compared with the maximum allowable discharging power of the power battery, and the change value of the wheel hub motor braking wheel torque and the change value of the driving wheel torque caused by the power exceeding the charging capacity and discharging capacity of the power battery are calculated accordingly; According to the basic torque of the hub motor at a certain moment and the sign state of the basic torque, the positive and negative states of the basic torque of each hub motor are obtained; Calculate the first target torque of each hub motor according to the positive and negative states of the hub motor basic torque, and the change value of the hub motor brake wheel torque and the change value of the drive wheel torque; According to the state of the wheel hub motor at the current moment, one of the basic torque of the wheel hub motor and the first target torque is selected as the execution target torque output of the wheel hub motor; After the output of the hub motor executes the target torque, the change value of the basic driving anti-skid or yaw stability requirement calculation of the whole vehicle is obtained, and the basic torque of the hub motor is updated according to the change value.

2. A method for calculating the torque of a hub motor vehicle according to claim 1, characterized in that: The specific steps of calculating the total power consumed by the high-voltage components other than the hub motor of the hub motor vehicle are as follows: Assume I bms is the actual current of the power battery, if I bms If it is negative, the power battery is in charging state. bms If the power battery is in a discharge state, bms If it is 0, the power battery is neither charged nor discharged; then the total power consumed by the high-voltage components of the hub motor model except the hub motor is P f for: P f =(I bms -∑I i )*IN.

3. The method for calculating the torque of a hub motor vehicle according to claim 1, characterized in that: In the step of calculating the difference between the power battery charging capacity and the power battery discharging capacity, If ΔP1≤0, then ΔP2>0; if ΔP2≤0, then ΔP1>0; or ΔP2>0 and ΔP1>0; If the power battery SOC value is greater than or equal to the power battery full charge threshold soc max When α1=0; if the power battery SOC value is less than the power battery full charge threshold soc max When α1=1, the power battery is protected to avoid overcharging. If the power battery is low, the battery SOC value is less than the threshold soc min When α2=0, otherwise α2=1; the power battery is protected to avoid over-discharge of the power battery; When the power battery has no fault, β=1; when the power battery has a general fault, β=0.5; when the power battery has a serious fault, β=0.

4. A method for calculating the torque of a hub motor vehicle according to claim 3, characterized in that: The specific steps of calculating the change value of the hub motor brake wheel torque and the change value of the drive wheel torque are as follows: When the difference in the power battery charging capacity is less than 0, that is, ΔP1 < 0, the wheel hub motor torque in the braking state approaches 0; when the difference in the power battery charging capacity is not less than 0, that is, ΔP1 ≥ 0, the wheel hub motor torque in the braking state remains unchanged; let ΔT1 be the change in the wheel hub motor torque in the braking state approaching 0, and ΔT1 is always a non-negative number; K 11 is the proportional adjustment coefficient, K 12 is the integral adjustment coefficient; t1 is the duration of ΔP1 being less than 0. Each time ΔP1 is greater than or equal to 0, the timing starts again from 0; T max is the maximum torque of the hub motor and is the mechanical characteristic parameter of the hub motor; then the change value ΔT1 of the brake wheel torque is: When the difference in the power battery discharge capacity is less than 0, that is, ΔP2 < 0, the torque of the hub motor in the driving state approaches 0; when the difference in the power battery discharge capacity is not less than 0, that is, ΔP2 ≥ 0, the torque of the hub motor in the driving state remains unchanged; let ΔT2 be the change in the torque of the hub motor in the driving state approaching 0, and ΔT2 is always a non-negative number; K 21 is the proportional adjustment coefficient, K 22 is the integral adjustment coefficient; t2 is the duration of ΔP2 being less than 0. Each time ΔP2 is greater than or equal to 0, t2 starts again from 0. Then the change value of the driving wheel torque ΔT2 is:

5. A method for calculating the torque of a hub motor vehicle according to claim 4, characterized in that: The specific steps of obtaining the positive and negative states of the basic torque of each hub motor are as follows: Let T(k-1) i is the basic torque of the i-th wheel hub motor at time k-1, T(k-1) i >0 means the i-th wheel hub motor is in driving state, T(k-1) i <0 means the i-th wheel hub motor is in braking state, T(k-1) i =0 means that the i-th wheel hub motor is in a non-operating state without driving or braking; S i is the sign state of the basic torque of the i-th wheel hub motor, S i =1 means the i-th wheel hub motor is in non-braking state, S i =-1 means that the i-th wheel hub motor is in braking state; then the positive and negative states of the basic torque of each wheel hub motor are:

6. A method for calculating the torque of a hub motor vehicle according to claim 5, characterized in that: The specific steps of calculating the first target torque of each wheel hub motor are: Assume T i1 is the first target torque of the i-th wheel hub motor, T i1 The existing states include the i-th wheel hub motor being in a non-braking state and the power battery discharge capacity difference being less than 0, the i-th wheel hub motor being in a braking state and the power battery discharge capacity difference being less than 0, the i-th wheel hub motor being in a non-braking state and the power battery charge capacity difference being less than 0, and the i-th wheel hub motor being in a braking state and the power battery charge capacity difference being less than 0; then T i1 for:

7. A method for calculating the torque of a hub motor vehicle according to claim 6, characterized in that: In the step of calculating the first target torque of each wheel hub motor, If the i-th wheel hub motor is in the non-braking state, that is, T(k-1) i ≥0, and the difference in the power battery discharge capacity is less than 0, that is, ΔP2<0, then S i =1, ΔT1=0, ΔT2≠0; at the same time, the wheel hub motor in the non-braking state is subjected to torque reduction processing, and the first target torque of the i-th wheel hub motor is converted into: T i1 =|T(k-1) i |-ΔT2; If the i-th wheel hub motor is in braking state, that is, T(k-1) i <0, and the difference in the power battery discharge capacity is less than 0, that is, ΔP2<0, then S i =-1, ΔT1=0, ΔT2≠0; meanwhile, the torque of the hub motor in the braking state is not processed, and the first target torque of the i-th hub motor is converted into: T i1 =|T(k-1) i |; If the i-th wheel hub motor is in the non-braking state, that is, T(k-1) i ≥0, and the difference in power battery charging capacity is less than 0, that is, ΔP1<0, then S i =1, ΔT1≠0, ΔT2=0; meanwhile, the torque of the hub motor in the non-braking state is not processed, and the first target torque of the i-th hub motor is converted into: T i1 =|T(k-1) i |; If the i-th wheel hub motor is in braking state, that is, T(k-1) i <0, and the difference in power battery charging capacity is less than 0, that is, ΔP1<0, then S i =-1, ΔT1≠0, ΔT2=0; at the same time, the wheel hub motor in the braking state is subjected to torque reduction processing, and the first target torque of the i-th wheel hub motor is converted into: T i1 =|T(k-1) i |-ΔT1。 8. A method for calculating the torque of a hub motor vehicle according to claim 7, characterized in that: The specific steps of calculating the execution target torque of the hub motor are: Assume T i2 is the target torque of the i-th wheel hub motor; T(k) i is the basic torque of the i-th wheel hub motor at time k; If the power consumed or generated by the current wheel hub motor does not exceed the battery capacity, that is, ΔP2>0 and ΔP1>0, the execution target torque T of the wheel hub motor i2 for: T i2 =T(k) i ; If the total power consumed by the current hub motor exceeds the battery capacity, that is, ΔP2≤0 and ΔP1>0, the execution target torque of the hub motor in the non-braking state is equal to the smaller of the first target torque and the basic torque, and the execution target torque of the hub motor in the braking state is equal to the basic torque, that is: If the total power generated by the current hub motor exceeds the battery capacity, that is, ΔP2>0 and ΔP1≤0, the execution target torque of the hub motor in the braking state is equal to the larger of the first target torque and the basic torque, and the execution target torque of the hub motor in the non-braking state is equal to the basic torque, that is:

9. A method for calculating the torque of a hub motor vehicle according to claim 8, characterized in that: The specific steps of updating the basic torque of the hub motor are as follows: Let γ be the percentage of the accelerator pedal or brake pedal opening, γ∈[0,1]; T(w) i is the external characteristic torque corresponding to the actual speed w of the i-th wheel hub motor; according to the wheel slip rate and yaw angle state of the vehicle, the change value ΔTa of the basic driving anti-skid or yaw stability demand calculation of the vehicle is obtained i , let ΔTa i is 0, negative or positive; take the basic torque T(k) of the i-th hub motor at time k i is the driving intention torque calculated based on the accelerator pedal and brake pedal; ΔTa of each wheel i Different causes T(k-1) i If there are positive and negative differences between them, the basic torque of the hub motor is updated as: T(k-1) i =T(k) i ; T(k) i =γ*T(w) i -ΔTa i 。

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