Energy management system and method based on distributed braking and vehicle

Abstract

The invention discloses an energy management system and method based on distributed braking and a vehicle, and belongs to the technical field of electric vehicles. The sensor array unit is used for collecting the vehicle acceleration, the wheel rotating speed, the wheel vertical load and the road friction coefficient; a wheel vertical load and a road friction coefficient are obtained through a wheel control unit, and the real-time maximum braking force is calculated; the vehicle acceleration, the real-time maximum braking force and the wheel rotating speed are obtained through a central control unit, the vehicle required braking force is calculated according to the vehicle acceleration and the vehicle mass, and according to the real-time maximum braking force, the distribution coefficient is dynamically adjusted, and the vehicle required braking force is distributed to all wheels; according to the wheel rotating speed, the energy recovery efficiency and the regenerative braking torque are combined, and the energy recovery power is determined. Under emergency braking or complex road conditions, the stability of the vehicle can be better maintained, the braking distance can be better shortened, and the problem that an existing electric vehicle cannot deal with road emergency situations to conduct stable braking and energy recovery is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to an energy management system, method and vehicle based on distributed braking. Background Art

[0002] The statements in this section merely mention background art related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of electric vehicle technology, improving energy efficiency and reducing emissions have become important design directions, and the distributed braking management system of electric vehicles has emerged. The distributed braking energy management system of electric vehicles is an advanced technology that realizes efficient energy recovery and dynamic distribution of braking force through multi-node collaborative control. Its core goal is to maximize the recovery of braking energy while ensuring braking safety, while optimizing driving experience and battery life.

[0004] The existing distributed braking energy management system can dynamically adjust the braking force distribution ratio according to parameters such as brake pedal signal, vehicle speed, and battery status. However, electric vehicles usually face complex road conditions such as emergency braking or slippery roads during driving. The existing energy management is difficult to achieve dynamic coordination based on emergencies, resulting in reduced energy recovery efficiency; and it ignores the impact of the vehicle's own status, and its stability needs to be improved. Summary of the invention

[0005] In order to address the deficiencies of the prior art, the present invention provides an energy management system, method and vehicle based on distributed braking, which can adjust the braking force distribution in real time to adapt to changing driving conditions, help improve the braking response speed and accuracy, and further enhance driving safety, economy and efficiency.

[0006] In a first aspect, the present invention provides an energy management system based on distributed braking;

[0007] An energy management system based on distributed braking, comprising:

[0008] A sensor array unit for collecting vehicle acceleration and wheel speed, wheel vertical load and road friction coefficient of each wheel;

[0009] A wheel control unit, used to obtain the corresponding wheel vertical load and road friction coefficient and calculate the real-time maximum braking force;

[0010] A central control unit is configured to obtain the vehicle acceleration, the real-time maximum braking force of each wheel, and the wheel speed, calculate the vehicle required braking force according to the vehicle acceleration and the vehicle mass, dynamically adjust the distribution coefficient according to the real-time maximum braking force of each wheel, and distribute the vehicle required braking force to each wheel based on the distribution coefficient; determine the energy recovery power of each wheel according to the wheel speed, in combination with the energy recovery efficiency and the regenerative braking torque.

[0011] In some embodiments, the real-time maximum braking force of each wheel is expressed as:

[0012]

[0013] In the formula, represents the real-time maximum braking force of the i-th wheel, μ i represents the road friction coefficient of the i-th wheel, N i represents the vertical load of the i-th wheel.

[0014] In some embodiments, the step of dynamically adjusting the distribution coefficient according to the real-time maximum braking force of each wheel is specifically: normalizing the real-time maximum braking force of each wheel to generate the distribution coefficient.

[0015] In some embodiments, the step of distributing the vehicle required braking force to each wheel based on the distribution coefficient is specifically: calculating the braking force corresponding to each wheel respectively under the constraint of the real-time maximum braking force of each wheel according to the distribution coefficient of each wheel and the vehicle required braking force.

[0016] In some embodiments, the braking force corresponding to each wheel is expressed as:

[0017] F brake,i = k i ×F total ;

[0018] In the formula, F brake,i represents the braking force corresponding to the -th wheel, k i represents the distribution coefficient of the i-th wheel, F total represents the vehicle required braking force.

[0019] In some embodiments, the distribution coefficient is expressed as:

[0020]

[0021] In the formula, μ i represents the road friction coefficient of the i-th wheel, N i represents the vertical load of the i-th wheel, μ j represents the road friction coefficient of the j-th wheel, N jrepresents the vertical load on the jth wheel.

[0022] In some embodiments, the sum of the energy recovery power of each wheel is not greater than the maximum energy recovery power allowed under vehicle stability conditions, and the maximum energy recovery power is linearly related to the road friction coefficient.

[0023] In some embodiments, the energy recovery power of each wheel is expressed as:

[0024] P regen,i =η i ×ω i ×T i ;

[0025] Where P regen,i represents the energy recovery efficiency of the i-th wheel, η i represents the energy recovery efficiency of the i-th wheel, ω i represents the wheel speed of the i-th wheel, T i represents the regenerative braking torque of the i-th wheel.

[0026] In a second aspect, the present invention provides an energy management method based on distributed braking;

[0027] An energy management method based on distributed braking, comprising:

[0028] The sensor array unit collects the vehicle acceleration and the wheel speed of each wheel, the wheel vertical load and the road friction coefficient, and sends them to the wheel control unit and the central control unit;

[0029] The wheel control unit receives the corresponding wheel vertical load and road friction coefficient and calculates the real-time maximum braking force, which is sent to the central control unit;

[0030] The central control unit receives the vehicle acceleration and the real-time maximum braking force of each wheel, and the wheel speed, calculates the vehicle's required braking force based on the vehicle acceleration and vehicle mass, dynamically adjusts the distribution coefficient based on the real-time maximum braking force of each wheel, and distributes the vehicle's required braking force to each wheel based on the distribution coefficient; determines the energy recovery power of each wheel based on the wheel speed, combined with the energy recovery efficiency and regenerative braking torque.

[0031] In a third aspect, the present invention provides a vehicle;

[0032] A vehicle comprises the above-mentioned energy management system based on distributed braking.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The technical solution provided by the present invention can accurately distribute the braking force to each wheel according to the real-time dynamics of the vehicle and the operating requirements of the driver. By independently controlling the braking force on each wheel of the vehicle, efficient recovery of braking energy is achieved, thereby improving the handling stability and safety of the vehicle.

[0035] 2. The technical solution provided by the present invention can achieve the best energy recovery strategy under different road conditions and driving modes by accurately controlling the braking force of each wheel. It not only focuses on energy recovery, but also improves the vehicle's handling stability and safety by independently controlling the braking force of each wheel. In emergency braking or complex road conditions, it can better maintain the stability of the vehicle and reduce the braking distance.

[0036] 3. The technical solution provided by the present invention can optimize the distribution of braking force and energy recovery efficiency according to the state of the vehicle and the external environment, thereby ensuring efficient operation of the system.

[0037] 4. The technical solution provided by the present invention receives real-time data from each wheel control unit (ECU), including wheel speed, braking force, road friction coefficient, vehicle acceleration, etc. Based on these data, the CCU comprehensively analyzes the overall state of the vehicle and dynamically adjusts the braking force and energy recovery strategy of each wheel; this global optimization ensures the coordination of braking and energy recovery, and avoids vehicle instability or reduced energy recovery efficiency caused by local optimization.

[0038] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0039] Figure 1 A schematic diagram of an upper control flow of an energy management system based on distributed braking provided in an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the lower-level control flow of an energy management system based on distributed braking provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0042] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0043] Embodiment 1

[0044] The existing energy management system of electric vehicles is difficult to achieve dynamic coordination in complex scenarios during vehicle driving, and driving safety and efficiency need to be improved; therefore, the present invention provides an energy management system based on distributed braking, which can achieve the best energy recovery strategy under different road conditions.

[0045] Next, combine Figure 1-Figure 2 , a distributed braking-based energy management system disclosed in this embodiment is described in detail. The distributed braking-based energy management system includes a sensor array unit, a wheel control unit and a central control unit. The number of wheel control units is 4, which respectively manage the braking force and energy recovery of the wheels they are responsible for. The sensor array unit, the wheel control unit and the central control unit realize data transmission through a high-speed communication network (such as CAN bus, Ethernet); the sensor array unit is used to collect real-time data, including vehicle acceleration and wheel speed of each wheel, wheel vertical load and road friction coefficient; the wheel control unit is used to obtain the corresponding wheel vertical load and road friction coefficient and calculate the real-time maximum braking force; the central control unit is used to obtain the vehicle acceleration and the real-time maximum braking force and wheel speed of each wheel, calculate the vehicle demand braking force according to the vehicle acceleration and vehicle mass, dynamically adjust the distribution coefficient according to the real-time maximum braking force of each wheel, and distribute the vehicle demand braking force to each wheel based on the distribution coefficient; according to the wheel speed, combined with the energy recovery efficiency and the regenerative braking torque, determine the energy recovery power of each wheel.

[0046] Furthermore, the sensor array unit includes a wheel speed sensor, an acceleration sensor, a brake pressure sensor, etc., and the system obtains required signals through the sensors.

[0047] As an implementation mode, the wheel control unit corresponding to each wheel receives data from the sensor array unit, and uses the corresponding wheel vertical load and road friction coefficient to calculate the real-time maximum braking force corresponding to each wheel and transmit it to the central control unit, which is expressed as:

[0048]

[0049] In the formula, represents the real-time maximum braking force of the i-th wheel, μ i represents the road friction coefficient of the i-th wheel, N i represents the vertical load of the i-th wheel.

[0050] In summary, the maximum braking force of the wheel is proportional to the road friction coefficient and the vertical load on the wheel. The maximum allowable value under the current road conditions is calculated based on the above formula, which provides a basis for subsequent dynamic distribution and ensures that the braking force does not exceed the maximum allowable value under the current road conditions.

[0051] As an implementation mode, the central control unit receives data collected by the sensor array unit and the real-time maximum braking force of each wheel, calculates the vehicle's required braking force according to the vehicle acceleration and the vehicle mass, calculates the distribution coefficient of each wheel according to the real-time maximum braking force of each wheel in combination with the wheel speed, and distributes the vehicle's required braking force to each wheel based on the distribution coefficient.

[0052] Specifically, the vehicle required braking force is expressed as:

[0053]

[0054] Where m is the mass of the vehicle and a is the acceleration of the vehicle (deceleration during braking).

[0055] In order to ensure the stability of the vehicle, the braking force needs to be distributed according to the grip and load of each wheel. The wheel status includes the vertical load of the wheel, the wheel speed and the grip of the wheel. The vertical load of each wheel is different (for example, when turning or accelerating, the load will be redistributed). The larger the vertical load, the stronger the grip of the wheel, and more braking force can be distributed; if the speed of a wheel is abnormal (for example, slipping), the braking force distribution of the wheel will be reduced to avoid further slipping; the road condition is mainly determined by the road friction coefficient μ i To reflect, on roads with high friction coefficients (such as dry roads), the wheels have strong grip and can be allocated more braking force. On roads with low friction coefficients (such as wet or icy roads), the wheels have weak grip and the system will reduce the braking force distribution of the wheel to avoid slipping.

[0056] Therefore, in this embodiment, the distribution coefficient is dynamically adjusted according to the real-time maximum braking force of each wheel; specifically, the real-time maximum braking force of each wheel is normalized to generate the distribution coefficient, and the distribution coefficient is expressed as:

[0057]

[0058] In the formula, μ i represents the road friction coefficient of the i-th wheel, N i represents the vertical load of the i-th wheel, μ j represents the road friction coefficient of the jth wheel, N j represents the vertical load on the jth wheel.

[0059] Based on this, the allocation coefficient k is dynamically updated according to the real-time monitoring of the wheel status and road conditions. i , ensuring optimal braking force distribution.

[0060] Next, according to the distribution coefficient of each wheel and the required braking force of the vehicle, under the real-time maximum braking force constraint of each wheel, the braking force corresponding to each wheel is calculated and transmitted to the corresponding wheel control unit to control the braking force of the wheel; the braking force corresponding to each wheel is expressed as:

[0061]

[0062] In the formula, F brake,i represents the braking force corresponding to the i-th wheel, k i represents the allocation coefficient of the i-th wheel, F total Indicates the vehicle's required braking force.

[0063] Energy recovery is achieved through regenerative braking, that is, kinetic energy is converted into electrical energy and stored in the battery. As an implementation method, the energy recovery power of each wheel is expressed as:

[0064] P regen,i =η i ×ω i ×T i ;

[0065] Where P regen,i represents the energy recovery power of the i-th wheel, η i represents the energy recovery efficiency of the i-th wheel, ω i represents the wheel speed of the i-th wheel, T i represents the regenerative braking torque of the i-th wheel.

[0066] Here, the energy recovery efficiency can be obtained by measuring the electric energy recovered during braking and the total mechanical energy consumed by the vehicle during braking and calculating the ratio of the two. For example, a sensor is used to record the change in the vehicle's kinetic energy before and after braking, while monitoring the electric energy generated by the energy recovery device, and calculating the efficiency value. The regenerative braking torque refers to the braking force of each wheel in the above calculation process.

[0067] The central control unit adjusts the working state of the motor according to the energy recovery power of each wheel, putting it in power generation mode. The motor converts the vehicle's kinetic energy into electrical energy, which is processed by the power conversion device and stored in the on-board energy storage device, such as a battery pack, to complete the energy recovery process.

[0068] Embodiment 2

[0069] Based on the energy management system based on distributed braking described in the first embodiment, this embodiment discloses an energy management method based on distributed braking, including:

[0070] The sensor array unit collects vehicle acceleration as well as the wheel speed of each wheel, the wheel vertical load and the road friction coefficient, and sends them to the wheel control unit and the central control unit.

[0071] The wheel control unit receives the corresponding wheel vertical load and road friction coefficient and calculates the real-time maximum braking force, which is then sent to the central control unit.

[0072] The central control unit receives the vehicle acceleration and the real-time maximum braking force of each wheel, and the wheel speed, calculates the vehicle's required braking force based on the vehicle acceleration and vehicle mass, dynamically adjusts the distribution coefficient based on the real-time maximum braking force of each wheel, and distributes the vehicle's required braking force to each wheel based on the distribution coefficient; determines the energy recovery power of each wheel based on the wheel speed, combined with the energy recovery efficiency and regenerative braking torque.

[0073] The specific details of the above steps have been introduced in detail in the first embodiment and will not be repeated here.

[0074] Embodiment 3

[0075] Based on the energy management system based on distributed braking described in the above embodiment, this embodiment also provides a vehicle, which is provided with the energy management system based on distributed braking described in the above embodiment. Since the above energy management system based on distributed braking has the above technical effects, please refer to the above embodiment for the technical effects of the vehicle adopting the energy management system based on distributed braking.

[0076] The description of each embodiment in the above embodiments has different emphases. For parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Energy management system based on distributed braking, characterized in that: include: A sensor array unit for collecting vehicle acceleration and wheel speed, wheel vertical load and road friction coefficient of each wheel; A wheel control unit, used to obtain the corresponding wheel vertical load and road friction coefficient and calculate the real-time maximum braking force; A central control unit, for obtaining the vehicle acceleration and the real-time maximum braking force of each wheel and the wheel speed, calculating the vehicle required braking force according to the vehicle acceleration and the vehicle mass, dynamically adjusting the distribution coefficient according to the real-time maximum braking force of each wheel, and distributing the vehicle required braking force to each wheel based on the distribution coefficient; The energy recovery power of each wheel is determined based on the wheel speed, combined with the energy recovery efficiency and the regenerative braking torque.

2. The energy management system based on distributed braking according to claim 1, characterized in that: The real-time maximum braking force of each wheel is expressed as: In the formula, represents the real-time maximum braking force of the i-th wheel, μ i represents the road friction coefficient of the i-th wheel, N i represents the vertical load of the i-th wheel.

3. The energy management system based on distributed braking according to claim 1, characterized in that: The dynamically adjusting the distribution coefficient according to the real-time maximum braking force of each wheel specifically includes: normalizing the real-time maximum braking force of each wheel to generate the distribution coefficient.

4. The energy management system based on distributed braking according to claim 1, characterized in that: The method of distributing the required braking force of the vehicle to each wheel based on the distribution coefficient is as follows: according to the distribution coefficient of each wheel and the required braking force of the vehicle, under the constraint of the real-time maximum braking force of each wheel, the braking force corresponding to each wheel is calculated respectively.

5. The energy management system based on distributed braking as claimed in claim 4, characterized in that: The braking force corresponding to each wheel is expressed as: F brake,i =k i ×F total ; In the formula, F brake,i represents the braking force corresponding to the th wheel, k i represents the allocation coefficient of the i-th wheel, F total Indicates the vehicle's required braking force.

6. The energy management system based on distributed braking according to claim 1, characterized in that: The partition coefficient is expressed as: In the formula, μ i represents the road friction coefficient of the i-th wheel, N i represents the vertical load of the i-th wheel, μ j represents the road friction coefficient of the jth wheel, N j represents the vertical load on the jth wheel.

7. The energy management system based on distributed braking according to claim 1, characterized in that: The sum of the energy recovery power of each wheel is not greater than the maximum energy recovery power allowed under vehicle stability conditions, and the maximum energy recovery power is linearly related to the road friction coefficient.

8. The energy management system based on distributed braking according to claim 1, characterized in that: The energy recovery power of each wheel is expressed as: P regen,i =the i ×ω i ×T i ; Where P regen,i represents the energy recovery power of the i-th wheel, η i represents the energy recovery efficiency of the i-th wheel, ω i represents the wheel speed of the i-th wheel, T i represents the regenerative braking torque of the i-th wheel.

9. An energy management method based on distributed braking, characterized in that: include: The sensor array unit collects the vehicle acceleration and the wheel speed of each wheel, the wheel vertical load and the road friction coefficient, and sends them to the wheel control unit and the central control unit; The wheel control unit receives the corresponding wheel vertical load and road friction coefficient and calculates the real-time maximum braking force, which is sent to the central control unit; The central control unit receives the vehicle acceleration, the real-time maximum braking force of each wheel, and the wheel speed, calculates the vehicle required braking force according to the vehicle acceleration and the vehicle mass, dynamically adjusts the distribution coefficient according to the real-time maximum braking force of each wheel, and distributes the vehicle required braking force to each wheel based on the distribution coefficient; The energy recovery power of each wheel is determined based on the wheel speed, combined with the energy recovery efficiency and the regenerative braking torque.

10. A vehicle, characterized in that: An energy management system based on distributed braking comprising any one of claims 1-8.

Images