Fuel cell bus braking energy management control method and system

Abstract

The application discloses a fuel cell bus braking energy management control method and system, which comprises the following steps: obtaining the SOC value of a battery, the brake pedal opening degree and the motor speed; judging whether the vehicle is in a braking state according to the brake pedal opening degree and the motor speed; when it is judged that the vehicle is in the braking state, if the SOC value of the battery is greater than or equal to a first set value, the required request power of the fuel cell system is determined to be 0; if the SOC value of the battery is less than the first set value, the expected braking recovery power of the vehicle is determined according to the motor speed, and the difference between the maximum continuous chargeable power of the battery and the expected braking recovery power of the vehicle is calculated to determine the required request power of the fuel cell system. The braking system recovery energy is involved in the determination process of the required request power of the fuel cell system, the balanced management of the fuel cell system and the braking system energy recovery is realized, and the fuel consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of fuel cell control technology, and in particular to a method and system for brake energy management and control of fuel cell buses. Background Technology

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

[0003] With the rapid development of hydrogen energy technology, the fuel cell bus market is experiencing rapid growth. However, "range anxiety" has become a significant factor hindering the widespread adoption of fuel cell buses. How to rationally manage and allocate energy between the fuel cell system and the braking system to improve vehicle range has become a key technology in current fuel cell bus research. Most currently available braking energy management and control methods for fuel cell buses simply determine the output power of the fuel cell system based on the current state of charge (SOC) of the battery when the system is operating, and then output this power to the power battery to charge it. This process does not consider the braking energy recovered by the new energy vehicle, failing to achieve comprehensive and balanced management of the fuel cell and braking energy recovery, leading to resource waste. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a braking energy management and control method and system for fuel cell buses. When determining the required power of the fuel cell system, the method fully considers the impact of the regenerated power of the braking system on the required power of the fuel cell system, thereby reducing vehicle fuel consumption.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] Firstly, a braking energy management and control method for fuel cell buses is proposed, including:

[0007] Obtain the battery's SOC value, brake pedal opening, and motor speed;

[0008] The vehicle is in a braking state based on the brake pedal opening and motor speed;

[0009] When the vehicle is in braking condition, if the battery's SOC value is greater than or equal to a first set value, the required power of the fuel cell system is determined to be 0; if the battery's SOC value is less than the first set value, the expected regenerative braking power of the vehicle is determined based on the motor speed, and the required power of the fuel cell system is determined by calculating the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

[0010] Secondly, a braking energy management and control system for fuel cell buses is proposed, including:

[0011] The data acquisition module is used to acquire the battery's SOC value, brake pedal opening, and motor speed.

[0012] The vehicle controller is used to determine whether the vehicle is in a braking state based on the brake pedal opening and motor speed.

[0013] The requested power determination module is used to determine the requested power of the fuel cell system as 0 if the battery's SOC value is greater than or equal to a first set value when the vehicle is in a braking state; if the battery's SOC value is less than the first set value, the expected regenerative braking power of the vehicle is determined based on the motor speed, and the requested power of the fuel cell system is determined by calculating the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

[0014] Thirdly, an electronic device is proposed, including a memory and a processor, as well as computer instructions stored in the memory and running on the processor, wherein the computer instructions, when executed by the processor, complete the steps described in the method for brake energy management and control of a fuel cell bus.

[0015] Fourthly, a computer-readable storage medium is proposed for storing computer instructions, which, when executed by a processor, complete the steps described in a fuel cell bus braking energy management and control method.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. When determining the power required by the fuel cell system during battery charging, this invention first determines whether the vehicle is in a braking state. When the vehicle is in a braking state, the expected regenerative braking power is determined based on the motor speed. Combined with the battery's SOC value, the power required by the fuel cell system is determined based on the expected regenerative braking power. This incorporates the energy recovered by the braking system into the process of determining the power required by the fuel cell system, achieving balanced management of energy recovery in both the fuel cell system and the braking system, and reducing fuel consumption.

[0018] 2. When determining the required power of the fuel cell system, this invention fully considers the impact of vehicle braking and different SOC values ​​of the battery on the required power of the fuel cell system. Therefore, based on different SOC values ​​of the battery and whether the vehicle is in a braking state, the required power of the fuel cell system is determined in stages, ensuring that the required power of the fuel cell system determined in each stage can not only meet the charging needs of the power battery, but also reduce fuel consumption.

[0019] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0021] Figure 1 The flowchart is for an embodiment of the disclosed method. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0024] Example 1

[0025] In this embodiment, a braking energy management and control method for a fuel cell bus is disclosed, such as... Figure 1 As shown, it includes:

[0026] Obtain the battery's SOC value, brake pedal opening, and motor speed;

[0027] The vehicle is in a braking state based on the brake pedal opening and motor speed;

[0028] When the vehicle is in braking condition, if the battery's SOC value is greater than or equal to a first set value, the required power of the fuel cell system is determined to be 0; if the battery's SOC value is less than the first set value, the expected regenerative braking power of the vehicle is determined based on the motor speed, and the required power of the fuel cell system is determined by calculating the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

[0029] In this embodiment, after the vehicle controller is activated, the motor speed n and the battery state of charge (SOC) value are received via CAN message.

[0030] The vehicle controller determines whether the vehicle is in a braking state. Specifically:

[0031] When the brake pedal opening A is less than the preset opening value, or the motor speed n is less than or equal to the braking torque complete exit speed n2, the vehicle is determined to be in a non-braking state.

[0032] When the brake pedal opening is greater than the preset opening value and the motor speed n is greater than the braking torque complete exit speed n2, the vehicle is determined to be in a braking state.

[0033] Preferably, the preset opening value is 5.

[0034] When the vehicle is determined to be in a non-braking state, the fuel cell system (Fcu) power request does not need to consider the vehicle's expected regenerative braking power; the expected required power P of the fuel cell system is determined based on the battery's SOC value. f The expected power demand P from the fuel cell system f and the battery's maximum continuous rechargeable power P bat The minimum value is selected from the values ​​to represent the required power P of the fuel cell system. s .

[0035] Preferably, when the vehicle is in a non-braking state based on the brake pedal opening and motor speed, if the battery's SOC value is greater than or equal to a second set value, the expected power demand of the fuel cell system is 0.

[0036] If the SOC value of the battery is less than the second set value, the expected required power P of the fuel cell system is... f Based on the reference requested power P of the fuel cell system t Sure.

[0037] In practical implementation, when the vehicle is determined to be in a non-braking state, the expected power demand P required by the fuel cell system is determined based on the battery's SOC value. f When Soc ≥ the second set value, there is no need to continuously charge the power battery, the fuel cell system shuts down, and the expected required power P of the fuel cell system is... f =0; if the first set value ≤ Soc < the second set value, then the expected required power P of the fuel cell system is 0. f =P t P t The baseline requested power for the fuel cell system is given by: If the third setpoint ≤ Soc < the first setpoint, the expected required power P of the fuel cell system is given by: f =P t *1.2; If Soc < the third set value, then the expected required power P of the fuel cell system is... f =P t *1.6.

[0038] Preferably, the first setting value is 60, the second setting value is 70, and the third setting value is 45.

[0039] The expected power requirement P of the fuel cell system f The specific calculation formula is as follows:

[0040]

[0041] P f With the battery's maximum continuous rechargeable power P bat By comparison, the minimum value is taken as the required power P of the fuel cell system. s P s =min{P f ,P bat}

[0042] When the vehicle is determined to be in a braking state, the Fcu power request during battery charging needs to be coordinated with the vehicle's expected regenerative braking power. At this time, if the battery's SOC value is greater than or equal to the first set value, the power requested by the fuel cell system is determined to be 0; if the battery's SOC value is less than the first set value, the vehicle's expected regenerative braking power is determined based on the motor speed, and the power requested by the fuel cell system is determined by calculating the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

[0043] Specifically, when the vehicle is determined to be in a braking state, if the battery's SOC value is greater than or equal to the third set value and less than the first set value, the power requested by the fuel cell system is half the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

[0044] If the battery's SOC value is less than the third set value, the power required by the fuel cell system is equal to the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

[0045] Specifically, when the vehicle is determined to be in a braking state, if Soc ≥ 70, the power battery charging relies entirely on regenerative braking energy, the fuel cell system shuts down, and the required power P of the fuel cell system... s =0; If 60≤Soc<70, the fuel cell system needs to rapidly unload during braking in this section, and the required power P of the fuel cell system is 0. s =0; If 45≤Soc<60, most of the battery charging in this range comes from regenerative braking energy, and a small portion comes from Fcu charging. The power required by the fuel cell system is equal to half the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power, i.e., P s =0.5*(P bat -P a If Soc < 45, charging the power battery in this range requires the combined action of the braking system and Fcu, and the requested power of the fuel cell system is equal to the battery's maximum continuous rechargeable power P. bat Subtract the vehicle's expected regenerative braking power P a That is, P s =P bat -Pa At this point, the specific formula for calculating the required power of the fuel cell system is as follows:

[0046]

[0047] Vehicle expected regenerative braking power P a The process of determining is as follows:

[0048] Determine the actual braking torque T required by the vehicle based on the motor speed n. need According to the actual required braking torque T need Determine the vehicle's expected regenerative braking power P a .

[0049] To prevent the EBS from requesting excessive braking torque and failing to disengage quickly when the vehicle comes to a stop, which could cause the motor to reverse, the braking torque is controlled jointly by the vehicle controller and the Electronic Braking System (EBS) during low-speed operation.

[0050] When the motor speed is less than or equal to the speed n2 at which the braking torque is fully disengaged, it indicates that the vehicle's braking torque has been fully disengaged, and the actual braking torque T required by the vehicle is... need =0;

[0051] When the motor speed is greater than the braking torque exit speed n2 and less than or equal to the braking torque exit speed n1, it indicates that the motor is in a low-speed phase. The vehicle controller then participates in the braking torque calculation, determining the required braking torque T3 and the current braking exit torque T4 based on the motor speed. The minimum value between the required braking torque T3 and the current braking exit torque T4 is selected as the actual braking torque required by the vehicle. The current braking exit torque T4 is then calculated through interpolation based on the current motor speed. In the formula, T s The reference torque is;

[0052] When the motor speed exceeds the braking torque and begins to exit at speed n1, it indicates that the motor is in a high-speed phase. The vehicle controller does not participate in the braking torque calculation; instead, it determines the required braking torque T3 based on the motor speed and uses this T3 as the actual required braking torque for the vehicle. Therefore, the actual required braking torque T... need The specific calculation formula is as follows:

[0053]

[0054] The vehicle controller will calculate the actual braking torque T required by the vehicle. need The signal is sent to the motor controller. Considering motor efficiency, an efficiency coefficient k is set. Therefore, the expected braking torque of the vehicle is T = k * T. need The actual expected power recovery of the vehicle

[0055] The process for determining the required braking torque T3 for the current vehicle is as follows:

[0056] Determine the current maximum regenerative power P of the motor based on the motor speed. mot ;

[0057] The minimum value between the maximum regenerative braking power of the motor and the maximum continuously rechargeable power of the battery is selected as the maximum allowable regenerative braking power P for the current vehicle. max ;

[0058] Determine the maximum allowable regenerative torque T2 for the current vehicle based on the motor speed and brake pedal opening.

[0059] The minimum value between the current vehicle's required braking torque T1 and the vehicle's maximum allowable recovery torque T2 is selected as the current vehicle's required braking torque T3.

[0060] In this embodiment, the maximum braking torque T of the current motor is determined based on the motor speed. max ;

[0061] Based on the motor speed n and the current maximum braking torque T of the motor max Determine the current maximum regenerative power P of the motor. mot ,

[0062] Preferably, after the vehicle controller is activated, it receives the motor speed n via CAN message, and then obtains the current maximum braking torque T of the motor by looking up a table based on the motor power supply characteristic curve. max .

[0063] The vehicle controller receives the battery's maximum continuous rechargeable power P via CAN messages. bat Compare the two values ​​and take the minimum value as the maximum allowable regenerative power P for the current vehicle. max P max =min{P mot ,P bat The vehicle controller will calculate P. max Send to the EBS system.

[0064] The EBS system calculates the required braking torque T1 for the current vehicle based on the current motor speed and brake pedal opening, and then combines this with the maximum allowable regenerative braking power P sent by the vehicle controller. max Calculate the maximum allowable regenerative torque T2 for the current vehicle. Compare the two values ​​and take the minimum value as the braking torque required by the current vehicle for the vehicle controller, T3 = min{T1,T2}.

[0065] The method disclosed in this embodiment determines the power required by the fuel cell system when charging the power battery. First, it judges whether the vehicle is in a braking state by the brake pedal opening and the motor speed. When it is determined that the vehicle is in a braking state, the expected regenerative braking power of the vehicle is determined based on the motor speed. Combined with the battery's SOC value, the power required by the fuel cell system is determined by the expected regenerative braking power of the vehicle. In this way, the energy recovered by the braking system is included in the process of determining the power required by the fuel cell system, thereby achieving balanced management of energy recovery of the fuel cell system and the braking system and reducing fuel consumption.

[0066] Example 2

[0067] In this embodiment, a braking energy management and control system for a fuel cell bus is disclosed, comprising:

[0068] The data acquisition module is used to acquire the battery's SOC value, brake pedal opening, and motor speed.

[0069] The vehicle controller is used to determine whether the vehicle is in a braking state based on the brake pedal opening and motor speed.

[0070] The requested power determination module is used to determine the requested power of the fuel cell system as 0 if the battery's SOC value is greater than or equal to a first set value when the vehicle is in a braking state; if the battery's SOC value is less than the first set value, the expected regenerative braking power of the vehicle is determined based on the motor speed, and the requested power of the fuel cell system is determined by calculating the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

[0071] Example 3

[0072] In this embodiment, an electronic device is disclosed, including a memory and a processor, as well as computer instructions stored in the memory and running on the processor. When the processor executes the computer instructions, it completes the steps described in the fuel cell bus braking energy management control method disclosed in Embodiment 1.

[0073] Example 4

[0074] In this embodiment, a computer-readable storage medium is disclosed for storing computer instructions, which, when executed by a processor, complete the steps described in the fuel cell bus braking energy management and control method disclosed in Embodiment 1.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for managing and controlling braking energy in a fuel cell bus, characterized in that, include: Obtain the battery's SOC value, brake pedal opening, and motor speed; The vehicle is in a braking state based on the brake pedal opening and motor speed; When the vehicle is in braking condition, if the battery's SOC value is greater than or equal to a first set value, the required power of the fuel cell system is determined to be 0; if the battery's SOC value is less than the first set value, the expected regenerative braking power of the vehicle is determined based on the motor speed, and the required power of the fuel cell system is determined by calculating the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power. When the vehicle is determined to be in a braking state, if the battery's SOC value is greater than or equal to the third set value and less than the first set value, the power requested by the fuel cell system is half the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power. If the SOC value of the battery is less than the third set value, the power required by the fuel cell system is equal to the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power. Determine the actual braking torque required by the vehicle based on the motor speed; determine the expected regenerative braking power of the vehicle based on the actual braking torque required. When the motor speed is less than or equal to the braking torque and the speed is completely disengaged, the actual braking torque required by the vehicle is 0. When the motor speed is greater than the braking torque and the speed is completely withdrawn, and when the speed is less than or equal to the braking torque and the speed is withdrawn, the required braking torque and the current braking withdrawal torque of the vehicle are determined based on the motor speed. The minimum value between the required braking torque and the current braking withdrawal torque of the vehicle is selected as the actual required braking torque of the vehicle. When the motor speed exceeds the braking torque and the braking torque is reduced, the braking torque required by the vehicle at the current time is determined based on the motor speed, and this braking torque is taken as the actual braking torque required by the vehicle.

2. The method for brake energy management and control of a fuel cell bus as described in claim 1, characterized in that, When the vehicle is determined to be in a non-braking state, the expected power demand of the fuel cell system is determined based on the battery's SOC value. The minimum value between the expected required power of the fuel cell system and the maximum continuous rechargeable power of the battery is selected as the required power of the fuel cell system.

3. The method for brake energy management and control of a fuel cell bus as described in claim 1, characterized in that, When the vehicle is determined to be in a non-braking state, if the SOC value of the battery is greater than or equal to the second set value, the expected power demand of the fuel cell system is 0. If the SOC value of the battery is less than the second set value, the expected required power of the fuel cell system is determined based on the baseline required power of the fuel cell system.

4. The method for brake energy management and control of a fuel cell bus as described in claim 1, characterized in that, Determine the current maximum recovery power of the motor based on the motor speed; The minimum value between the maximum regenerative braking power of the motor and the maximum continuous rechargeable power of the battery is selected as the maximum regenerative braking power allowed for the current vehicle. The maximum allowable regenerative torque for the current vehicle is determined based on the motor speed and brake pedal opening. The minimum value between the current braking torque required by the vehicle and the maximum allowable regenerative braking torque of the vehicle is selected as the current braking torque required by the vehicle.

5. A fuel cell bus braking energy management and control system employing the method described in claim 1, characterized in that, include: The data acquisition module is used to acquire the battery's SOC value, brake pedal opening, and motor speed. The vehicle controller is used to determine whether the vehicle is in a braking state based on the brake pedal opening and motor speed. The requested power determination module is used to determine the requested power of the fuel cell system as 0 if the battery's SOC value is greater than or equal to a first set value when the vehicle is in a braking state; if the battery's SOC value is less than the first set value, the expected regenerative braking power of the vehicle is determined based on the motor speed, and the requested power of the fuel cell system is determined by calculating the difference between the battery's maximum continuous rechargeable power and the vehicle's expected regenerative braking power.

6. An electronic device, characterized in that, It includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, which, when executed by the processor, complete the steps of the braking energy management control method for a fuel cell bus as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, Used to store computer instructions, which, when executed by a processor, complete the steps of the braking energy management and control method for a fuel cell bus as described in any one of claims 1-4.

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