阅读说明：本技术 一种用于新能源车辆的电池充放电功率限制方法及系统 (Battery charging and discharging power limiting method and system for new energy vehicle ) 是由 陈添 刘国瑞 张甲举 吕喜锋 张健康 张建磊 程伟 于 2020-04-09 设计创作，主要内容包括：本发明提供了一种用于新能源车辆的电池充放电功率限制方法及系统。电池充放电功率限制方法包括如下步骤：实时获取车辆的动力电池的实际功率P<Sub>Batt</Sub>、最大允许充放电功率P<Sub>y</Sub>、电机效率η以及电机转速N；对实际功率P<Sub>Batt</Sub>和最大允许充放电功率P<Sub>y</Sub>的差值进行积分获取功率积分值E,其中,E＞0；根据功率积分值E计算获得对最大允许充放电功率P<Sub>y</Sub>进行限制的限制比例K；根据最大允许充放电功率P<Sub>y</Sub>和限制比例K计算获得车辆的电机的允许驱动功率P<Sub>max</Sub>；根据允许驱动功率P<Sub>max</Sub>、车辆的电机效率以及电机转速获得电机的允许驱动扭矩T<Sub>max</Sub>,限制电机的输出扭矩小于或等于允许驱动扭矩T<Sub>max</Sub>。本发明方案可以避免动力电池在使用过程中出现长时间的过充过放现象。(The invention provides a battery charging and discharging power limiting method and system for a new energy vehicle. The battery charging and discharging power limiting method comprises the following steps: real-time acquisition of actual power P of power battery of vehicle Batt Maximum allowable charging and discharging power P y Motor efficiency η and motor speed N, for actual power P Batt And maximum allowable charging and discharging power P y The difference value of (a) is integrated to obtain a power integration value E, wherein E is more than 0; calculating and obtaining the maximum allowable charge-discharge power P according to the power integral value E y A limiting ratio K for limiting; according to the maximum allowable charge-discharge power P y Calculating and obtaining the allowable driving power P of the motor of the vehicle according to the limit proportion K max (ii) a According to the allowable driving power P max Obtaining allowable driving torque T of motor by motor efficiency and motor speed of vehicle max Limiting the output torque of the motor to be less than or equal toAllowable driving torque T max . The scheme of the invention can avoid the phenomenon of long-time overcharge and overdischarge of the power battery in the use process.)

1. A battery charging and discharging power limiting method for a new energy vehicle is characterized by comprising the following steps:

acquiring actual power P of power battery of vehicle in real time_BattMaximum allowable charging and discharging power P_yη and N;

for the actual power P_BattAnd said maximum allowable charging and discharging power P_yThe difference value of (a) is integrated to obtain a power integration value E, wherein E is more than 0;

calculating and obtaining maximum allowable charge-discharge power P according to the power integral value E_yA limiting ratio K for limiting;

according to the maximum allowable charge-discharge power P_yAnd calculating the limit ratio K to obtain the allowable driving power P of the motor of the vehicle_max；

According to the allowable driving power P_maxObtaining the allowable driving torque T of the motor by the motor efficiency and the motor speed of the vehicle_max，

Limiting the output torque of the motor to be less than or equal to the allowable driving torque T_max。

2. The battery charge-discharge power limiting method according to claim 1, wherein the actual power P is set to_BattAnd said maximum allowable charging and discharging power P_yIn the step of obtaining the power integration value E by integrating the difference value of (a), according to the formulaThe power integration value E is acquired.

3. The battery charge-discharge power limiting method according to claim 2, characterized in that according to the maximum allowable charge-discharge power P_yAnd calculating the limit ratio K to obtain the allowable driving power P of the motor of the vehicle_maxIn accordance with the formula P_max＝K×P_yObtaining allowable driving power P of a motor of the vehicle_max；

Optionally, according to the allowable driving power P_maxObtaining the allowable driving torque T of the motor by the motor efficiency and the motor speed of the vehicle_maxIn accordance with the formula T_max＝9550×P_max×η/N calculating to obtain allowable driving torque T of the motor_max。

4. The battery charge-discharge power limiting method according to claim 3, wherein the step of calculating a limit ratio K from the power integrated value E includes:

the power integral value E is compared with a preset threshold value E₁The comparison is carried out in such a way that,

when E < E₁When the K is equal to 1;

when E is more than or equal to E₁When the K is more than or equal to 0.5 and less than 1.

5. The battery charge-discharge power limiting method according to claim 4, wherein when E.gtoreq.E₁The limiting proportion K is inversely proportional to the power integration value E such that the limiting proportion K decreases with an increase in the power integration value E and increases with a decrease in the power integration value E.

6. The battery charge-discharge power limiting method according to any one of claims 1 to 5, wherein the real-time acquisition of the actual power P of the power battery of the vehicle_BattThe method comprises the following steps:

acquiring voltage U and current I of a power battery of the vehicle in real time;

according to formula P_BattObtaining the actual power P of the power battery_Batt；

Optionally, the maximum allowed charge-discharge power is a maximum allowed discharge power or a maximum allowed charge power.

7. A battery charge-discharge power limiting system for a new energy vehicle, characterized by comprising:

a battery power acquisition unit for acquiring the actual power P of the power battery of the vehicle in real time_BattMaximum allowable charging and discharging power P_yη and N;

a power integral value acquisition unit for acquiring the actual power P_BattAnd said maximum allowable charging and discharging power P_yThe difference value of (a) is integrated to obtain a power integration value E, wherein E is more than 0;

a limit ratio obtaining unit for calculating and obtaining a limit ratio K according to the power integral value E;

an allowable drive power obtaining unit for obtaining the maximum allowable charge/discharge power P_yAnd calculating the limit ratio K to obtain the allowable driving power P of the motor of the vehicle_max；

A permissible driving torque obtaining unit for obtaining the permissible driving power P_maxObtaining the allowable driving torque T of the motor by the motor efficiency and the motor speed of the vehicle_max；

A limiting unit for limiting the output torque of the motor to be less than or equal to the allowable driving torque T_max。

8. The battery charge-discharge power limiting system according to claim 7, wherein the power integration value acquisition unit is configured to follow a formulaAcquiring the power integral value E;

optionallyThe allowable driving power obtaining unit is used for obtaining the formula P_max＝K×P_yObtaining allowable driving power P of a motor of the vehicle_max；

Optionally, the allowable driving torque obtaining unit is used for obtaining the formula T_max＝9550×P_max×η/N calculating to obtain allowable driving torque T of the motor_max；

Optionally, the limit ratio obtaining unit includes:

a comparison subunit for comparing the power integration value E with a preset threshold value E₁Comparing;

a value subunit for E < E₁Taking K as 1 when E is more than or equal to E₁K is more than or equal to 0.5 and less than 1.

9. The battery charge-discharge power limiting system of claim 8 wherein the value sub-unit is configured to determine the value of the battery charge-discharge power when E is greater than or equal to E₁And taking a value of the limiting proportion K according to the power integral value E, wherein the limiting proportion K is inversely proportional to the power integral value E.

10. The battery charge-discharge power limiting system according to any one of claims 7 to 9, wherein the battery power acquiring unit includes:

the voltage and current acquisition subunit is used for acquiring the voltage U and the current I of a power battery of the vehicle in real time;

an actual power obtaining subunit for obtaining the actual power according to the formula P_BattObtaining the actual power P of the power battery_Batt。

Technical Field

The invention relates to the technical field of new energy vehicles, in particular to a battery charging and discharging power limiting method and system for a new energy vehicle.

Background

With the development of new energy technology, more and more new energy automobiles are equipped with large-capacity power battery packs. If the power battery is frequently overcharged or overdischarged in the using process, the probability of thermal runaway and failure of the power battery is increased, and the service life of the power battery is also shortened, so that the method is not safe and economical. Therefore, the phenomena of long-time over-discharge and over-charge of the power battery must be avoided in the energy management strategy of the new energy automobile.

In order to solve the above technical problems, the prior art is as follows: and when the difference value obtained by subtracting the actual discharge power of the battery from the available discharge power of the battery is smaller than a preset threshold value, limiting the actual discharge power of the battery. However, this scheme can only determine the condition for performing power limiting, and performs power limiting after this condition is satisfied, and is not intelligent. In addition, the process of adjusting the driving power and the output torque of the motor is not stable, and the driving feeling is poor.

Disclosure of Invention

One purpose of the invention is to avoid the phenomenon of long-time overcharge or overdischarge of the power battery in the using process.

Another purpose of the present invention is to solve the technical problems of the prior art that the power limiting scheme is not intelligent and the process of adjusting the driving power and the output torque of the motor is not stable.

Particularly, the invention provides a battery charging and discharging power limiting method for a new energy vehicle, which comprises the following steps:

acquiring actual power P of power battery of vehicle in real time_BattMaximum allowable charging and discharging power P_yMotor efficiency and motor speed;

for the actual power P_BattAnd said maximum allowable charging and discharging power P_yThe difference value of (a) is integrated to obtain a power integration value E, wherein E is more than 0;

calculating and obtaining maximum allowable charge-discharge power P according to the power integral value E_yA limiting ratio K for limiting;

according to the maximum allowable charge-discharge power P_yAnd calculating the limit ratio K to obtain the allowable driving power P of the motor of the vehicle_max；

According to the allowable driving power P_maxObtaining the allowable driving torque T of the motor by the motor efficiency and the motor speed of the vehicle_max，

Limiting the output torque of the motor to be less than or equal to the allowable driving torque T_max。

Optionally, for the actual power P_BattAnd said maximum allowable charging and discharging power P_yIs carried out by the difference of

In the step of obtaining the power integral value E by integration, according to the formulaThe power integration value E is acquired.

Optionally, according to the maximum allowable charge-discharge power P_yAnd calculating the limit ratio K to obtain the allowable driving power P of the motor of the vehicle_maxIn accordance with the formula P_max＝K×P_yObtaining allowable driving power P of a motor of the vehicle_max；

Optionally, according to the allowable driving power P_maxObtaining the allowable driving torque T of the motor by the motor efficiency and the motor speed of the vehicle_maxIn accordance with the formula T_max＝9550×P_max×η/N calculating to obtain allowable driving torque T of the motor_maxWhere η is the motor efficiency and N is the motor speed.

Optionally, the step of calculating the obtained limit ratio K from the power integration value E includes:

the power integral value E is compared with a preset threshold value E₁The comparison is carried out in such a way that,

when E < E₁When the K is equal to 1;

when E is more than or equal to E₁When the K is more than or equal to 0.5 and less than 1.

Optionally, when E ≧ E₁The limiting proportion K is inversely proportional to the power integration value E such that the limiting proportion K decreases with an increase in the power integration value E and increases with a decrease in the power integration value E.

Optionally, the real-time acquisition of the actual power P of the power battery of the vehicle_BattThe method comprises the following steps:

acquiring voltage U and current I of a power battery of the vehicle in real time;

according to formula P_BattObtaining the actual power P of the power battery_Batt。

Optionally, the maximum allowed charge-discharge power is a maximum allowed discharge power or a maximum allowed charge power.

Particularly, the present invention also provides a battery charge-discharge power limiting system for a new energy vehicle, including:

a battery power acquisition unit for acquiring the actual power P of the power battery of the vehicle in real time_BattMaximum allowable charging and discharging power P_yMotor efficiency and motor speed;

a power integral value acquisition unit for acquiring the actual power P_BattAnd said maximum allowable charging and discharging power P_yThe difference value of (a) is integrated to obtain a power integration value E, wherein E is more than 0;

a limit ratio obtaining unit for calculating and obtaining a limit ratio K according to the power integral value E;

an allowable drive power obtaining unit for obtaining the maximum allowable charge/discharge power P_yAnd calculating the limit ratio K to obtain the allowable driving power P of the motor of the vehicle_max；

A permissible driving torque obtaining unit for obtaining the permissible driving power P_maxObtaining the allowable driving torque T of the motor by the motor efficiency and the motor speed of the vehicle_max；

A limiting unit for limiting the output torque of the motor to be less than or equal to the allowable driving torque T_max。

Optionally, the power integration value obtaining unit is configured to follow a formulaAcquiring the power integral value E;

optionally, the allowable driving power obtaining unit is used for obtaining the formula P_max＝K×P_yObtaining allowable driving power P of a motor of the vehicle_max；

Optionally, the allowable driving torque obtaining unit is used for obtaining the formula T_max＝9550×P_max×η/N calculating to obtain allowable driving torque T of the motor_maxWherein η is the motor efficiency, and N is the motor speed;

optionally, the limit ratio obtaining unit includes:

a comparison subunit for comparing the power integration value E with a preset threshold value E₁Comparing;

a value subunit for E < E₁Taking K as 1 when E is more than or equal to E₁K is more than or equal to 0.5 and less than 1.

Optionally, the value subunit is used for determining whether E is greater than or equal to E₁And taking a value of the limiting proportion K according to the power integral value E, wherein the limiting proportion K is inversely proportional to the power integral value E.

Optionally, the battery power obtaining unit includes:

the voltage and current acquisition subunit is used for acquiring the voltage U and the current I of a power battery of the vehicle in real time;

an actual power obtaining subunit for obtaining the actual power according to the formula P_BattObtaining the actual power P of the power battery_Batt。

Optionally, the maximum allowed charge-discharge power is a maximum allowed discharge power or a maximum allowed charge power.

According to the scheme of the invention, the phenomenon of long-time overcharge and overdischarge of the power battery in the use process can be avoided. When the battery has unexpected overpower phenomenon, the strategy can limit the driving or feedback power of the motor to reduce the actual charging and discharging power of the battery, thereby ensuring that the battery does not have long-time overpower phenomenon.

In addition, when unexpected overpower occurs in the battery, the invention can judge the severity of the overpower from the magnitude of the power integral value, and carry out power limitation of different degrees. This kind of power restriction scheme is more intelligent than prior art scheme, and the process of adjusting drive power is also more steady, and is also more smooth-going when adjusting motor output torque, promotes the driving and feels. When the battery is recovered to the normal use state from the super-power state, the power integral value is gradually smaller to zero, the power limit proportion is also gradually transited to 1, and the recovery process is smoother compared with the prior art scheme.

The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

fig. 1 shows a schematic flowchart of a battery charge-discharge power limiting method for a new energy vehicle according to an embodiment of the invention;

fig. 2 is a schematic configuration diagram showing a battery charge-discharge power limiting system for a new energy vehicle according to an embodiment of the present invention.

Detailed Description

Fig. 1 shows a schematic flowchart of a battery charge-discharge power limiting method for a new energy vehicle according to an embodiment of the present invention. As shown in fig. 1, the battery charge and discharge power limiting method includes:

step S100, real-time obtaining actual power P of power battery of vehicle_BattMaximum allowable charging and discharging power P_yη and N;

step S200, for actual power P_BattAnd maximum allowable charging and discharging power P_yThe difference value of (a) is integrated to obtain a power integration value E, wherein E is more than 0;

step S300, calculating and obtaining the maximum allowable charge-discharge power P according to the power integral value E_yA limiting ratio K for limiting;

step S400, according to the maximum allowable charge-discharge power P_yCalculating and obtaining the allowable driving power P of the motor of the vehicle according to the limit proportion K_max；

Step S500, according to the allowable driving power P_maxObtaining allowable driving torque T of motor by motor efficiency and motor speed of vehicle_max，

Step S600, limiting the output torque of the motor to be less than or equal to the allowable driving torque T_max。

In a specific embodiment, in step S100, the maximum allowable charging/discharging power P_yIs the maximum allowable discharge power or the maximum allowable charge power. At the maximum allowable charging and discharging power P_yWhen the maximum allowable discharge power is obtained, the step S100 is preceded by determining whether the vehicle is in a drivable state, i.e., whether the vehicle is driving or the engine is started, and if so, executing the step S100.

At the maximum allowable charging and discharging power P_yFor maximum allowable charging powerBefore step S100, it is determined whether the vehicle is in an undriven state, that is, whether the engine is not started or whether the vehicle is in an external charging state, and if so, step S100 is executed.

The step S100 includes: acquiring voltage U and current I of a power battery of a vehicle in real time; according to formula P_BattObtaining the actual power P of the power battery_Batt。

In step S200, according to the formulaA power integration value E is acquired. When the power integral value E is less than zero, the phenomenon that the battery is overdischarged or overcharged does not exist at the moment, namely the battery is in a normal state, or the battery is recovered to the normal state from the overdischarged state, or the battery is recovered to the normal state from the overcharged state.

The step S300 includes: the power integral value E is compared with a predetermined threshold value E₁Making a comparison when E < E₁When the K is equal to 1; when E is more than or equal to E₁When the K is more than or equal to 0.5 and less than 1. When E < E₁When the battery is in the normal state, the battery is in the over-discharge state, or the battery is in the normal state, or the battery is in the over-charge state. When E is more than or equal to E₁When the battery is in the over-discharge or over-charge state, the current battery is explained. The limiting ratio K is inversely proportional to the power integration value E, i.e., the limiting ratio K decreases as the power integration value E increases and increases as the power integration value E decreases.

In step S400, according to the formula P_max＝K×P_yObtaining allowable drive power P of motor of vehicle_max. In step S500, according to the formula T_max＝9550×P_max×η/N calculation to obtain allowable driving torque T of motor_max。

In the embodiment of the invention, the power limit proportion can be dynamically adjusted according to the severity of the overpower of the battery. Firstly, the difference value of the actual discharge power of the battery minus the available discharge power of the battery is integrated, and then the available discharge power of the battery is limited according to the size of the integral value, wherein the larger the integral value is, the smaller the power limitation proportion is, and the larger the limitation amplitude is. And, the available discharge power of the battery is not limited when the battery is not overpowered. When the available discharge power of the battery is larger than the actual discharge power of the battery, the power integral value is reduced, and when the power integral value is smaller than a preset threshold value, the available discharge power of the battery is not limited any more.

According to the scheme of the embodiment of the invention, when unexpected overpower of the battery occurs, the severity of the overpower can be judged from the magnitude of the power integral value, and power limitation can be carried out in different degrees. This kind of power restriction scheme is more intelligent than prior art scheme, and the process of adjusting drive power is also more steady, and is also more smooth-going when adjusting motor output torque, promotes the driving and feels. When the battery is recovered to the normal use state from the super-power state, the power integral value is gradually smaller to zero, the power limit proportion is also gradually transited to 1, and the recovery process is smoother compared with the prior art scheme.

The method can avoid the phenomenon of long-time overcharge and overdischarge of the power battery in the using process. When the battery has unexpected overpower phenomenon, the strategy can limit the driving or feedback power of the motor to reduce the actual charging and discharging power of the battery, thereby ensuring that the battery does not have long-time overpower phenomenon.

Fig. 2 is a schematic configuration diagram showing a battery charge-discharge power limiting system for a new energy vehicle according to an embodiment of the present invention. As shown in fig. 2, the battery charge/discharge power limiting system includes: battery power acquisition unit 1, power integral value acquisition unit 2, limit ratio acquisition unit 3, allowable drive power acquisition unit 4, allowable drive torque acquisition unit 5, and limit unit 6.

The battery power obtaining unit 1 is used for obtaining the actual power P of the power battery of the vehicle in real time_BattAnd maximum allowable charge and discharge power P_y. A power integral value obtaining unit 2 for obtaining the actual power P_BattAnd said maximum allowable charging and discharging power P_yAccording to the formulaAnd integrating to obtain a power integration value E, wherein E is greater than 0. The limit ratio obtaining unit 3 is used for obtaining the limit ratio K according to the power integral value E. Allowing the drive power deriving unit 4 to be used according to the formula P_max＝K×P_yObtaining allowable driving power P of a motor of the vehicle_max. Allowing the drive torque obtaining unit 5 to be used according to the formula T_max＝9550×P_max×η/N calculating to obtain allowable driving torque T of the motor_maxWherein η is the motor efficiency, N is the motor speed, the limiting unit 6 is used for limiting the output torque of the motor to be less than or equal to the allowable driving torque T_max。

The limit ratio obtaining unit 3 includes a comparison subunit and a value-taking subunit. The comparison subunit is used for comparing the power integration value E with a preset threshold value E₁A comparison is made. Value subunit for E < E₁Taking K as 1 when E is more than or equal to E₁K is more than or equal to 0.5 and less than 1. The value subunit is used for determining that E is more than or equal to E₁And taking a value of the limiting proportion K according to the power integral value E, wherein the limiting proportion K is inversely proportional to the power integral value E.

The battery power acquisition unit 1 includes a voltage current acquisition subunit and an actual power acquisition subunit. And the voltage and current acquisition subunit is used for acquiring the voltage U and the current I of the power battery of the vehicle in real time. The actual power obtaining subunit is used for obtaining the actual power according to the formula P_BattObtaining the actual power P of the power battery_Batt。

The battery charging and discharging power limiting system corresponds to the characteristics of the battery charging and discharging power limiting method one by one, and the details are not repeated here.

The system can avoid the phenomenon of long-time overcharge and overdischarge of the power battery in the using process. When the battery has unexpected overpower phenomenon, the strategy can limit the driving or feedback power of the motor to reduce the actual charging and discharging power of the battery, thereby ensuring that the battery does not have long-time overpower phenomenon.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.