Dynamic power distribution method for electric vehicle

Abstract

The invention discloses a dynamic power distribution method for an electric vehicle, which has the main conception that in order to meet the differentiated requirements of different drivers, the upper limit value of the current available power is calculated based on the SOC value, the battery voltage and the maximum output power of the battery which change in real time; according to the selected driving mode, the driving power weight ratio corresponding to the current mode is dynamically corrected according to the SOC change rate; and dynamically distributing the vehicle running power and other accessory power in the current driving mode by combining the driving power weight proportion and the available power upper limit value. By identifying the driving scene and the power demand, the self-adaptive distribution of the energy of the whole vehicle is flexibly completed, the targeted power distribution can be executed in the SOC change scene, and the power competition problem of the driving system and the high-voltage accessory is effectively solved, so that the collaborative optimization of the user demand and the system energy efficiency is reliably realized.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and particularly to a method for dynamically allocating power of an electric vehicle. Background Art

[0002] Regarding the existing technology of power allocation for electric vehicles in the scenario of SOC change, the industry has a solution: obtain the electronic throttle signal, the maximum allowable discharge power of the high-voltage battery, the power demand of high-voltage accessories, the maximum output torque of the motor drive system, and the efficiency of the motor drive system of the electric vehicle. According to the obtained data, calculate the requested torque under the current working condition. After executing the requested torque in the motor drive system, calculate the actual power consumed by the current motor controller, and calculate the sum of the actual power consumed by the motor controller and the power consumed by the high-voltage accessories; finally, compare the sum result with the maximum allowable discharge power of the power battery, and re-allocate power according to the comparison result to achieve closed-loop power control of the electric vehicle.

[0003] In practice, the above existing technology has many drawbacks. For example, it can only compare and allocate according to the maximum allowable discharge power of the power battery and the power required by the whole vehicle, and cannot meet the personalized needs of different users; in addition, the vehicle power adopts a fixed threshold allocation strategy and does not consider the problem of dynamic adaptation of the user's driving mode. Summary of the Invention

[0004] In view of the above, the present invention aims to provide a method for dynamically allocating power of an electric vehicle to solve the power arbitration problem in the scenario of SOC change of the power battery.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention provides a method for dynamically allocating power of an electric vehicle, which includes:

[0007] Based on the SOC value, battery voltage, and maximum output power of the battery that change in real time, calculate the current available power upper limit value;

[0008] According to the currently selected driving mode, dynamically correct the driving power weight ratio corresponding to the current mode according to the SOC change rate;

[0009] Based on the driving power weight ratio and the available power upper limit value, dynamically allocate the vehicle driving power and other accessory powers in the current driving mode.

[0010] In at least one possible implementation manner, the calculation method of the available power upper limit value includes:

[0011]

[0012] Wherein, is the maximum available power of the whole vehicle; is the maximum output power nominal for the power battery; is the current output voltage of the power battery; is the maximum allowable discharge current of the power battery; is the SOC compensation coefficient that can be dynamically adjusted; is the SOC attenuation correction function negatively correlated with SOC.

[0013] In at least one possible implementation, the calculation method of the dynamic correction includes:

[0014]

[0015] where is the corrected weight coefficient; is the basic weight coefficient corresponding to the current driving mode; is the road condition correction factor; is the SOC change rate.

[0016] In at least one possible implementation, the road condition correction factor is calculated in real time based on in-vehicle navigation data.

[0017] In at least one possible implementation, the dynamic allocation of the vehicle driving power under the current driving mode further includes:

[0018] When in the endurance mode, determine whether the current SOC is less than the preset SOC lower threshold;

[0019] If so, reduce the power demand through a non-linear power limit function.

[0020] In at least one possible implementation, the power distribution method further includes: when the total vehicle demand power is greater than the available power upper limit value, perform conflict resolution according to the function priority.

[0021] Compared with the prior art, the main design concept of the present invention lies in that, in order to meet the different needs of different drivers for the performance, endurance, and comfort of electric vehicles, through the integrated processing of information such as driving requirements and driving scenarios, the endurance ability or power retention rate based on the SOC level under different driving modes is improved, and negative impacts such as hazards caused by sudden power-off of high-voltage safety components are avoided. Specifically, based on the real-time changing SOC value, battery voltage, and maximum battery output power, the current available power upper limit value is calculated; according to the selected driving mode, the driving power weight ratio corresponding to the current mode is dynamically corrected according to the SOC change rate; combining the driving power weight ratio and the available power upper limit value, the vehicle driving power and other accessory powers in the current driving mode are dynamically allocated. The present invention flexibly completes the adaptive allocation of the vehicle's overall energy by identifying the driving scenario and power demand, can perform targeted power allocation in the SOC change scenario, effectively solves the power competition problem between the drive system and high-voltage accessories, and thus reliably realizes the collaborative optimization of user needs and system energy efficiency.

[0022] It can be seen that, on the one hand, the present invention breaks through the traditional fixed threshold limit, realizes a multi-level dynamic weight mapping mechanism, and greatly improves the user experience; on the other hand, it can also combine the SOC change rate and road conditions to effectively avoid the sudden drop in endurance or power interruption caused by the previous static strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described below in conjunction with the drawings, where:

[0024] Figure 1 It is a schematic diagram of the electric vehicle dynamic power allocation method provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0026] The present invention proposes an embodiment of an electric vehicle dynamic power allocation method. Specifically, as Figure 1 shown, which includes:

[0027] Step S1: Based on the real-time changing SOC value, battery voltage, and maximum battery output power, calculate the current available power upper limit value.

[0028] In actual operation, the specific calculation method of the available power upper limit value can refer to but is not limited to the following:

[0029]

[0030] Among them, is the maximum available power of the whole vehicle, which can be dynamically adjusted according to the real-time working conditions (unit: kW); is the maximum output power nominal of the power battery, and this value is determined by the battery design (such as 150 kw); is the current output voltage of the power battery; is the maximum allowable discharge current of the power battery, which is limited by temperature and SOC; is the SOC compensation coefficient that can be dynamically adjusted (such as 0.8~1.2); is the SOC attenuation correction function, which is negatively correlated with SOC (for example, when SOC = 100%, 1.0 can be taken; while when SOC = 20%, 0.6 is taken).

[0031] Step S2, according to the currently selected driving mode, dynamically correct the driving power weight ratio corresponding to the current mode according to the SOC change rate;

[0032] Specifically, the driving mode can be preset with three basic modes: performance, endurance, and comfort, and each driving mode is preset with an initial basic weight ratio :

[0033] (1) Performance mode: ;

[0034] (2) Endurance mode: ;

[0035] (3) Comfort mode: .

[0036] Regarding the SOC change rate, it can be characterized as (%)), that is, the change amount of the battery charge state within a unit time (positive for charging and negative for discharging).

[0037] Specifically, a negative value indicates battery discharge (such as vehicle acceleration), and a positive value indicates charging (such as energy recovery). Examples are as follows:

[0038] During hard acceleration = -0.4% / s;

[0039] During energy recovery = +0.1% / s.

[0040] Thus, the calculation method of the dynamic correction can be referred to but not limited to the following (for example, a reinforcement learning algorithm can also be selected to replace fuzzy control, and a Q-learning model can be established to dynamically optimize the weight allocation):

[0041]

[0042] Among them, is the corrected weight coefficient, is the gain coefficient dynamically adjusted according to the predicted road conditions of the navigation, that is, the road condition correction factor, which can be calculated in real time through in-vehicle navigation data:

[0043]

[0044] Among them, K route is the preset road condition coefficient. For example, in a congested road condition (K route = 0.3): At this time, it can be used to reduce the proportion of driving power in the performance mode (power demand weight) in the algorithm and prioritize energy-saving requirements; in a highway road condition (K route = 0.8): It means that the proportion of driving power in the performance mode can be moderately increased; in a mountain road (K route = 1.2): Then the proportion of driving power in the performance mode can be significantly increased.

[0045] Step S3: Based on the driving power weight ratio and the available power upper limit value, dynamically allocate the vehicle driving power and other accessory powers in the current driving mode (for example, according to the dynamically updated weight, the two are allocated as 8:2). The other accessory powers mentioned here are relative to the driving power, that is, other components that require energy during vehicle operation except the power system.

[0046] It should also be supplemented here that in other embodiments of dynamically allocating available power, when in the endurance mode, it is also possible to preferably adopt a safety wall derating strategy of electrochemistry-vehicle speed (road conditions, weather and other data can also be added to improve the prediction accuracy) joint prediction, that is, when the SOC < the preset SOC lower threshold, the driving power demand is reduced through a non-linear power limit function.

[0047] For example, when the SOC < 20%, activate the safety wall mechanism, according to:

[0048]

[0049] Calculate the derated vehicle driving power to ensure more reliable guarantee for the endurance mode on the basis of the above dynamically updated driving weights. Among them, P drive is the vehicle driving power to be allocated, and P drive_base is the preset basic driving power to maintain vehicle driving.

[0050] Finally, it can also be supplemented that for some special working conditions, such as when the total vehicle demand power is greater than the upper limit value of the available power, conflict resolution can be performed according to the functional priority, that is, the energy requirements of the drive system and safety-related accessories (such as braking, lighting, etc.) that maintain vehicle driving can be preferentially ensured, while the energy requirements of other accessories such as comfort-related accessories (air conditioning, entertainment, etc.) are forced to be reduced.

[0051] In summary, the main design concept of the present invention is to meet the different drivers' differentiated requirements for the performance, endurance, and comfort of electric vehicles. Through the fusion processing of information such as driving requirements and driving scenarios, the endurance ability or power retention rate based on the SOC level in different driving modes is improved, and negative impacts such as sudden power failure of high-voltage safety components are avoided. Specifically, based on the real-time changing SOC value, battery voltage, and maximum battery output power, the current upper limit value of the available power is calculated; according to the selected driving mode, the weight ratio of the driving power corresponding to the current mode is dynamically corrected according to the SOC change rate; combined with the weight ratio of the driving power and the upper limit value of the available power, the vehicle driving power and the power of other accessories in the current driving mode are dynamically allocated. The present invention can flexibly complete the adaptive allocation of the vehicle's overall energy by identifying the driving scenario and power demand, can perform targeted power allocation in the SOC change scenario, effectively solve the power competition problem between the drive system and high-voltage accessories, and thus reliably achieve the coordinated optimization of user requirements and system energy efficiency.

[0052] In the embodiments of the present invention, if there are any expressions of directions, they are based on the relative concepts of the embodiments. In addition, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects and indicates that there can be three relationships. For example, A and / or B can represent the situation where A exists alone, A and B exist simultaneously, or B exists alone. Where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one of the following" and its similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0053] The structure, features, and effects of the present invention have been described in detail based on the embodiments shown in the diagrams above. However, the above are only the preferred embodiments of the present invention. It should be noted that for the technical features involved in the above embodiments and their preferred modes, those skilled in the art can reasonably combine and match them into a variety of equivalent solutions without departing from or changing the design concept and technical effects of the present invention. Therefore, the scope of implementation of the present invention is not limited by the diagrams shown. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to equivalent changes, that still do not exceed the spirit covered by the description and the diagrams shall fall within the protection scope of the present invention.

Claims

1. A dynamic power distribution method for an electric vehicle, characterized in that, Including: Calculating the current available power upper limit value based on the SOC value, battery voltage, and battery maximum output power that change in real time; According to the currently selected driving mode, dynamically correcting the driving power weight ratio corresponding to the current mode according to the SOC change rate; Based on the driving power weight ratio and the available power upper limit value, dynamically allocating the vehicle driving power and other accessory powers in the current driving mode.

2. The electric vehicle dynamic power distribution method according to claim 1, wherein The calculation method of the available power upper limit value includes: Among them, is the maximum available power of the whole vehicle; is the maximum output power nominal of the power battery; is the current output voltage of the power battery; is the maximum allowable discharge current of the power battery; is the SOC compensation coefficient that can be dynamically adjusted; is the SOC attenuation correction function negatively correlated with SOC.

3. The method for dynamically allocating power of an electric vehicle according to claim 1, characterized in that, The calculation method of the dynamic correction includes: Among them, is the corrected weight coefficient; is the basic weight coefficient corresponding to the current driving mode; is the road condition correction factor; is the SOC change rate.

4. The method for dynamically distributing power of an electric vehicle according to claim 3, wherein The road condition correction factor is calculated in real time based on in-vehicle navigation data.

5. The electric vehicle dynamic power distribution method according to claim 1, wherein The dynamically allocating the vehicle driving power in the current driving mode further includes: When in the endurance mode, determining whether the current SOC is less than a preset SOC lower threshold; If so, reducing the power demand of the driving force through a non-linear power limit function.

6. The method for dynamically allocating power of an electric vehicle according to any one of claims 1 to 5, characterized in that, The power distribution method further includes: when the total vehicle demand power is greater than the available power upper limit value, performing conflict resolution according to the function priority.

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