A fixed time period based energy management method for fuel cell vehicles

Abstract

The application discloses a kind of fixed time period-based fuel cell car energy management method, comprising: after vehicle starts, whether fuel cell system is started according to power battery SOC and current working condition is determined;Fuel cell system starts, and the output power of fuel cell system is determined according to the energy consumption of fixed time period.The fixed time period-based fuel cell car energy management method of the application provides a kind of simple and efficient energy management strategy, by adding fuel cell system start-stop strategy and output power correction coefficient to optimize the energy management strategy based on fixed time period, by optimizing the output power calculation method of fuel cell system, the value of power battery at start is maintained, unnecessary charging is avoided, the economy of system is improved, and the variable load to fuel cell is also reduced, the life of fuel cell is prolonged, on the basis of guaranteeing the life of fuel cell, more efficient energy management is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery energy management, and more particularly, to a fuel cell vehicle energy management method based on fixed time periods. BACKGROUND

[0002] Fuel cell vehicles are a new type of clean energy vehicles, and are attracting more and more attention due to their high efficiency, environmental protection and long endurance. Fuel cell hybrid vehicles combine fuel cells and power battery systems, and through the coordinated work of the two, achieve optimization of power output and maximization of energy utilization efficiency. Therefore, the energy management system plays a crucial role: in various driving conditions, the energy output between the fuel cell and the power battery is reasonably distributed to ensure the efficiency and economy of vehicle operation; the state of the fuel cell and the power battery is monitored in real time and adjusted in time to prolong the service life of the system; the energy utilization strategy is optimized to maximize the vehicle's range.

[0003] Although fuel cell vehicles have made some progress in energy management, the current energy management strategy still has some shortcomings: traditional energy management strategies are difficult to achieve optimal energy distribution between fuel cells and power batteries in various complex driving conditions; the current energy management system has a slow response speed when dealing with rapidly changing driving demands, affecting the driving experience; some energy management strategies rely on complex optimization algorithms, which are computationally intensive and difficult to apply in real-time in actual vehicles.

[0004] Therefore, there is an urgent need for a fuel cell vehicle energy management method based on fixed time periods. SUMMARY

[0005] The purpose of the present application is to provide a fuel cell vehicle energy management method based on fixed time periods to solve the problems in the prior art and maintain the stability of the power battery power without frequent changes in the power load of the power stack.

[0006] The present application provides a fuel cell vehicle energy management method based on fixed time periods, which comprises:

[0007] After the vehicle starts, it is determined whether to start the fuel cell system according to the power battery SOC and the current working condition;

[0008] After the fuel cell system is started, the output power of the fuel cell system is determined according to the energy consumption of the fixed time period.

[0009] The fuel cell vehicle energy management method based on fixed time periods as described above, wherein, preferably, after the vehicle starts, it is determined whether to start the fuel cell system according to the power battery SOC and the current working condition, specifically comprising:

[0010] According to the road condition mode, the opening state of the fuel cell system manual switch, and the current SOC and the threshold value corresponding to the different road condition modes Determine whether to start the fuel cell system.

[0011] The fixed period-based fuel cell vehicle energy management method as described above, wherein preferably, the threshold value corresponding to the different road condition modes Comprise: And Wherein, The upper limit value in the i-th road condition mode is represented, The intermediate threshold value in the i-th road condition mode is represented, The lower limit value in the i-th road condition mode is represented.

[0012] The fixed period-based fuel cell vehicle energy management method as described above, wherein preferably, after the vehicle is started, whether to start the fuel cell system is determined according to the power battery SOC and the current working condition, and specifically comprises:

[0013] Step S11, start: first determine whether the high voltage of the vehicle is opened, if yes, enter step S12; otherwise, loop detection;

[0014] Step S12, select road condition mode: select different road condition modes according to different road conditions;

[0015] Step S13, determine the state of the fuel cell system manual switch: if the manual switch is opened, enter step S14, otherwise enter step S15;

[0016] Step S14, compare the power battery Value with the Upper limit value Of the current road condition mode: if the power battery Value is less than the Upper limit value Of the current road condition mode, start the fuel cell system, and then return to step S11; otherwise, do not start the fuel cell system, and return to step S11;

[0017] Step S15, compare the power battery Value with the Lower limit value of the SOC corresponding to the current road condition mode: if the power battery Value is less than the Lower limit value of the SOC corresponding to the current road condition mode, start the fuel cell system, and then enter step S16; otherwise, do not start the fuel cell system, and then return to step S11;

[0018] Step S16, compare the power battery The middle threshold between the value and the current traffic mode For comparison: If the power battery The value is greater than the middle threshold corresponding to the current traffic mode , then shut down the fuel cell system and return to step S11; otherwise, directly return to step S11.

[0019] The above-mentioned fuel cell vehicle energy management method based on fixed time periods, wherein preferably, after the fuel cell system is started, the output power of the fuel cell system is determined based on the energy consumption in the fixed time period, specifically including:

[0020] Calculate the average power consumption of the vehicle in the previous time period, and calculate the initial power demand based on the comparison between the average power consumption of the vehicle in the previous time period and the idle power; optimize the initial power demand based on the fuel cell output power correction coefficient and the power difference correction coefficient to obtain the optimized power demand; determine the output power of the fuel cell system in the current time period based on the comparison between the optimized power demand and the output power of the fuel cell system in the previous time period.

[0021] The above-mentioned fuel cell vehicle energy management method based on fixed time periods, wherein preferably, after the fuel cell system is started, the output power of the fuel cell system is determined based on the energy consumption in the fixed time period, specifically including:

[0022] Step S21: Start: Record the power battery initial value at the time of starting the fuel cell system. value , then proceed to step S22;

[0023] Step S22: Power calculation: Calculate the average power consumption of the vehicle in the previous time period. , then proceed to step S23;

[0024] Step S23: Based on the average power consumption of the vehicle in the previous time period and idle power Compare the results and calculate the initial required power :The average power consumption of the vehicle in the previous period and idle power The initial power requirement is compared with the size of is the larger value of the two, and then proceeds to step S24;

[0025] Step S24, calculate the power difference: use the initial power Subtract the current power Get the current With initial The difference ,like , then the optimized demand power is calculated by the following formula : , wherein, represents a correction coefficient, is negatively correlated with the initial demand power , is positively correlated with the difference between the current and the initial , then step S25 is entered; otherwise, the fuel cell system current time period output power is the initial demand power , and step S22 is returned to;

[0026] Step S25, power comparison: according to the comparison result of the optimized demand power and the output power of the fuel cell system in the last time period , the output power of the fuel cell system in the current time period is determined: if , then the output power of the fuel cell system in the current time period is , and step S22 is returned to; otherwise, the output power of the fuel cell system in the current time period is , and step S22 is returned to.

[0027] The present application provides a fixed time period-based energy management method for a fuel cell vehicle, and provides a simple and efficient energy management strategy. The fixed time period-based energy management strategy is optimized by adding a fuel cell system start-stop strategy and an output power correction coefficient. The output power calculation method of the fuel cell system is optimized, the power battery is maintained at the value at startup, unnecessary charging is avoided, the economy of the system is improved, the variable load on the fuel cell is reduced, and the service life of the fuel cell is prolonged. On the basis of ensuring the service life of the fuel cell, more efficient energy management is achieved. On the basis of the fixed time period-based energy management strategy, a road condition selection strategy is added to adapt to complex road conditions, solving the shortcoming that the traditional strategy cannot adapt to complex and variable road conditions. The output power calculation method is also optimized, and the power battery power is maintained stable without frequent changes in the power load of the power battery. By setting an upper limit value for the power battery under the current road condition mode, overcharging of the power battery is avoided, energy waste is avoided, and the service life of the power battery is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0028] To make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described below with reference to the accompanying drawings, in which:

[0029] Figure 1A flowchart of an embodiment of a fuel cell vehicle energy management method based on a fixed period provided by the present invention;

[0030] Figure 2 Logic diagram for starting the fuel cell system;

[0031] Figure 3 Logic diagram for determining the output power of a fuel cell system. DETAILED DESCRIPTION

[0032] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure, its application, or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions, and numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0033] The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are simply used to distinguish different parts. Terms such as "include" or "comprising" mean that the elements preceding the term include the elements listed after the term, and do not exclude the possibility of also including other elements. Terms such as "upper," "lower," and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be an intervening component between the specific component and the first component or the second component. When a specific component is described as being connected to another component, the specific component may be directly connected to the other component without an intervening component, or may not be directly connected to the other component but have an intervening component.

[0035] All terms (including technical or scientific terms) used in this disclosure have the same meaning as those understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0036] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0037] In the current energy management strategy, the output power of the fuel cell each time is based on the average output power of the previous time period, which has obvious hysteresis, which can cause the power battery to be overcharged or overdischarged, and the SOC of the power battery cannot be maintained at a stable level, which can affect the stability, efficiency and life of the system. And in the face of complex road conditions (such as mountain roads, urban traffic, etc.), the driving demand changes frequently, and the fixed time period strategy is difficult to adapt to these changes, resulting in poor energy management effect.

[0038] As shown in Figure 1 , the fixed time period based fuel cell vehicle energy management method provided by the embodiment in the actual execution process specifically includes the following steps:

[0039] Step S1, after the vehicle starts, it is determined whether to start the fuel cell system according to the SOC of the power battery and the current working condition.

[0040] In an embodiment of the present application, whether to start the fuel cell system is determined according to the road condition mode, the opening state of the fuel cell system manual switch and the current SOC and the threshold value corresponding to different road condition modes .

[0041] Among them, the threshold value corresponding to different road condition modes includes: and , wherein, represents the upper limit value under the i-th road condition mode, represents the intermediate threshold value under the i-th road condition mode, represents the lower limit value under the i-th road condition mode.

[0042] In different working conditions, different lower limit SOCs are set for the power battery, which can meet the power demand of the whole vehicle, and by setting the upper limit value for the SOC of the power battery, overcharging can be avoided.

[0043] As shown in Figure 2 , in an embodiment of the fixed time period based fuel cell vehicle energy management method of the present application, the step S1 specifically can include:

[0044] Step S11, start: first judge whether the high voltage of the vehicle is opened, if it is opened, enter step S12; otherwise, loop detection.

[0045] Step S12, select road condition mode: select different road condition modes according to different road conditions.

[0046] Step S13, judge the state of the fuel cell system manual switch: if the manual switch is opened, enter step S14, otherwise enter step S15.

[0047] Step S14, comparing the power battery SOC value with the lower limit value of the current road condition mode. upper limit value If the power battery SOC value is less than the lower limit value of the current road condition mode, the fuel cell system is started, and then the process returns to step S11; otherwise, the fuel cell system is not started, and the process returns to step S11. upper limit value

[0048] Step S15, comparing the power battery SOC value with the lower limit value of the current road condition mode. If the power battery SOC value is less than the lower limit value of the current road condition mode, the fuel cell system is started, and then the process returns to step S11; otherwise, the fuel cell system is not started, and the process returns to step S11. lower limit value

[0049] Step S16, comparing the power battery SOC value with the intermediate threshold value of the current road condition mode. If the power battery SOC value is greater than the intermediate threshold value of the current road condition mode, the fuel cell system is turned off, and then the process returns to step S11; otherwise, the process directly returns to step S11.

[0050] Step S2, after the fuel cell system is started, the output power of the fuel cell system is determined according to the energy consumption of a fixed time period.

[0051] In an embodiment of the present application, the average consumption power of the whole vehicle in the previous time period is calculated, and the initial demand power is calculated according to the comparison result of the average consumption power of the whole vehicle in the previous time period and the idle power; the initial demand power is optimized based on the fuel cell output power correction coefficient and the electric quantity difference correction coefficient to obtain the optimized demand power; the output power of the fuel cell system in the current time period is determined according to the comparison result of the optimized demand power and the output power of the fuel cell system in the previous time period.

[0052] As shown in FIG. 2, in an embodiment of the fuel cell vehicle energy management method based on a fixed time period of the present application, step S2 can specifically include: Figure 3

[0053] Step S21, starting: recording the initial power battery SOC value at the starting moment of the fuel cell system, and then entering step S22.

[0054] ​​​​​​​​​​​Step S22: Power calculation: Calculate the average power consumption of the vehicle in the previous time period. , then go to step S23.

[0055] Step S23: Based on the average power consumption of the vehicle in the previous time period and idle power Compare the results and calculate the initial required power :The average power consumption of the vehicle in the previous period and idle power The initial power requirement is compared with the size of is the larger value between the two, and then enters step S24.

[0056] Step S24, calculate the power difference: use the initial power Subtract the current power Get the current With initial The difference ,like , the optimized required power is calculated by the following formula : ,in, represents the correction factor, and initial power demand Negative correlation, With the current With initial The difference Positive correlation, then enter step S25; otherwise the fuel cell system output power in the current time period Initial power requirement , return to step S22.

[0057] in, , by using the correction factor Optimizing the initial required power can maintain the stability of the power battery SOC and introduce a correction factor .in, is the fuel cell output power correction coefficient, which is negatively correlated with the required output power of the fuel cell; is the power difference correction coefficient, which is positively correlated with the power difference of the fuel cell system.

[0058] When the power battery SOC is less than the starting value, that is, When the fuel cell maintains the power output of the previous time period , which can avoid frequent changes in the fuel cell load power.

[0059] Step S25: Power comparison: based on the optimized required power Compared with the output power of the fuel cell system in the previous period The comparison result of the fuel cell system is used to determine the output power of the fuel cell system in the current time period: , then the output power of the fuel cell system in the current time period is , then returns to step S22; otherwise, the output power of the fuel cell system in the current time period is , then return to step S22.

[0060] The fuel cell vehicle energy management method based on fixed time periods provided by the embodiment of the present invention provides a simple and efficient energy management strategy. The energy management strategy based on fixed time periods is optimized by adding a fuel cell system start-stop strategy and an output power correction coefficient. The output power calculation method of the fuel cell system is optimized to reduce the power battery Maintaining the value at startup avoids unnecessary charging, improves the economy of the system, and at the same time reduces the variable load on the fuel cell, prolongs the life of the fuel cell, and achieves more efficient energy management on the basis of ensuring the life of the fuel cell; on the basis of the energy management strategy based on a fixed time period, a road condition selection strategy is added to adapt to complex road conditions, which solves the shortcomings of traditional strategies that cannot adapt to complex and changeable road conditions, and optimizes the output power calculation method to maintain the stability of the power battery power without frequently changing the stack load power; by setting the upper limit value for the power battery in the current road condition mode, overcharging of the power battery is avoided, which not only avoids energy waste but also prolongs the life of the power battery.

[0061] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0062] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A fuel cell vehicle energy management method based on a fixed period, characterized in that: include: After the vehicle is started, it determines whether to start the fuel cell system based on the power battery SOC and current operating conditions; After the fuel cell system is started, the output power of the fuel cell system is determined based on the energy consumption in a fixed time period. After the fuel cell system is started, the output power of the fuel cell system is determined based on the energy consumption in a fixed time period, specifically including: Calculate the average power consumption of the vehicle in the previous time period, and calculate the initial power demand based on the comparison between the average power consumption of the vehicle in the previous time period and the idle power; optimize the initial power demand based on the fuel cell output power correction coefficient and the power difference correction coefficient to obtain the optimized power demand; determine the output power of the fuel cell system in the current time period based on the comparison between the optimized power demand and the output power of the fuel cell system in the previous time period. After the fuel cell system is started, the output power of the fuel cell system is determined based on the energy consumption in a fixed time period, specifically including: Step S21, start: record the initial SOC value of the power battery at the time of starting the fuel cell system SOC Start , then proceed to step S22; Step S22: Power calculation: Calculate the average vehicle power consumption P in the previous time period. V (t-1), then proceed to step S23; Step S23: Based on the average vehicle power consumption P in the previous time period V Compare the result of (t-1) with the idle power P0 to calculate the initial required power P Req1 :The average vehicle power consumption P in the previous period V (t-1) is compared with the idle power P0, the initial required power P Req1 is the larger value of the two, and then proceeds to step S24; Step S24, calculate the power difference: use the initial power SOC Start Subtract the current power SOC to get the difference SOC between the current SOC and the initial SOC Diff , if SOC Diff >0, the optimized required power P is calculated by the following formula Req2 :P Req2 =P Req1 ·α·β, where α and β represent correction coefficients, and α is related to the initial required power P Req1 Negative correlation, β is the difference between the current SOC and the initial SOC Diff Positive correlation, then enter step S25; otherwise the fuel cell system output power P in the current time period N (t) is the initial required power P Req1 , return to step S22; Step S25, power comparison: according to the optimized required power P Req2 Compared with the output power P of the fuel cell system in the previous period N The comparison result of (t-1) determines the output power of the fuel cell system in the current time period: If P Req2 <P N (t-1), the output power of the fuel cell system in the current time period is P N (t-1), then return to step S22; otherwise, the output power of the fuel cell system in the current time period is P Req2 , then return to step S22.

2. The method for fuel cell vehicle energy management based on fixed time periods according to claim 1, characterized in that: After the vehicle is started, determining whether to start the fuel cell system is based on the power battery SOC and the current operating conditions, specifically including: Whether to start the fuel cell system is determined according to the road condition mode, the on state of the fuel cell system manual switch, the current SOC and the threshold SOC corresponding to different road condition modes.

3. The method for fuel cell vehicle energy management based on fixed time periods according to claim 2, characterized in that: The threshold SOC corresponding to the different road condition modes includes: SOC max (i) SOC mid (i) and SOC min (i), where SOC max (i) represents the upper limit value under the i-th road condition mode, SOC mid (i) represents the intermediate threshold value and SOC under the i-th road condition mode min (i) represents the lower limit value under the i-th road condition mode.

4. The method for fuel cell vehicle energy management based on fixed time periods according to claim 3, characterized in that: After the vehicle is started, determining whether to start the fuel cell system is based on the power battery SOC and the current operating conditions, specifically including: Step S11, start: first determine whether the high voltage of the vehicle is turned on, if it is turned on, go to step S12; otherwise, loop detection; Step S12, selecting a road condition mode: selecting a different road condition mode according to different road conditions; Step S13, determining the state of the manual switch of the fuel cell system: if the manual switch is on, proceed to step S14; otherwise, proceed to step S15; Step S14: compare the power battery SOC value with the SOC upper limit SOC of the current road condition mode. max (i) Compare: If the power battery SOC value is less than the SOC upper limit value SOC of the current road condition mode max (i) If the fuel cell system is started, the process returns to step S11; otherwise, the fuel cell system is not started, and the process returns to step S11; Step S15: Compare the power battery SOC value with the SOC lower limit SOC corresponding to the current road condition mode. min (i) Compare: If the power battery SOC value is less than the SOC lower limit value SOC corresponding to the current road condition mode min (i) If the fuel cell system is started, the process proceeds to step S16; otherwise, the fuel cell system is not started, and the process returns to step S11; Step S16: compare the power battery SOC value with the intermediate threshold SOC of the current road condition mode. mid (i) Comparison: If the power battery SOC value is greater than the intermediate threshold SOC corresponding to the current road condition mode mid (i) If yes, the fuel cell system is shut down and the process returns to step S11; otherwise, the process returns to step S11 directly.

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