Surplus energy discharge control method and system for fuel cell vehicle

Abstract

A surplus energy discharge control method and system for a fuel cell vehicle, wherein the method comprises: calculating a change value of total vehicle demand power of a fuel cell vehicle between a current moment and a following moment; when the change value is greater than a maximum power drop allowed by a fuel cell system, acquiring the output power of the fuel cell system, the charging power of a power battery, and the dissipation power of a surplus energy discharge circuit at the following moment and comparing those to determine a surplus energy dissipation mode of the vehicle, wherein the surplus energy dissipation mode comprises: performing dissipation by means of the surplus energy discharge circuit, and / or simultaneously performing dissipation by means of a cooling module and a heating module of a temperature regulation system, respectively; and adjusting the operation of the surplus energy discharge circuit and / or the temperature regulation system on the basis of the surplus energy dissipation mode. In the present application, by introducing a lightweight surplus energy discharge circuit to dissipate the surplus energy of the fuel cell vehicle in a timely and accurate manner, the surplus energy discharge cost of the vehicle is reduced, improving the cost-performance ratio of vehicle design.

Description

A method and system for controlling residual energy discharge in fuel cell vehicles Technical Field

[0001] This application belongs to the field of fuel cell technology, specifically relating to a method and system for controlling the residual energy discharge of fuel cell vehicles. Background Technology

[0002] Full-power fuel cell vehicles typically use a high-power fuel cell stack and a low-capacity lithium battery as the vehicle's driving power source. Currently, due to the immaturity of fuel cell stack technology, its output power lags behind the vehicle's power demand. This means that the vehicle's power demand often changes abruptly, but the fuel cell stack's output power cannot keep pace. Therefore, when the fuel cell stack is outputting high power, if the vehicle suddenly decelerates or brakes, the vehicle's power demand is lower, but the fuel cell's output power cannot drop suddenly. This can lead to the following malfunctions: 1. The vehicle cannot brake or decelerate quickly; 2. The regenerative power of the battery is too high, leading to overcharging and damage; 3. The fuel cell stack cannot release power in time, causing it to stall.

[0003] To address the aforementioned issues, the most common industry practice is to equip fuel cell vehicles with high-capacity or high-power batteries to promptly absorb excess power from the fuel cell stack. However, equipping them with high-capacity or high-power batteries leads to excessively high overall vehicle costs. Furthermore, high-capacity or high-power batteries are often bulky, increasing the complexity of vehicle design. Summary of the Invention

[0004] This application proposes a method and system for controlling the residual energy discharge of fuel cell vehicles. By introducing a lightweight residual energy discharge circuit, the residual energy of fuel cell vehicles can be consumed in a timely and accurate manner, thereby reducing the cost of residual energy discharge and improving the cost-effectiveness of vehicle design.

[0005] The first aspect of this application provides a method for controlling the residual energy discharge of a fuel cell vehicle, applied to a fuel cell vehicle, wherein the fuel cell vehicle includes a power battery, a fuel cell system, a residual energy discharge circuit, and a temperature regulation system, the temperature regulation system including a cooling module and a heating module, and the residual energy discharge circuit and the temperature regulation system are electrically connected to the output terminal of the fuel cell system; the method includes:

[0006] Calculate the change in the total power demand of the fuel cell vehicle between the current time and the next time.

[0007] When the change value is greater than the maximum allowable power reduction of the fuel cell system, the output power of the fuel cell system, the charging power of the power battery, and the absorption power of the residual energy discharge circuit at the next moment are obtained and compared to determine the residual energy absorption method of the vehicle; wherein, the residual energy absorption method includes absorption through the residual energy discharge circuit, and / or absorption through the refrigeration module and heating module of the temperature regulation system at the same time.

[0008] Adjust the operation of the residual energy discharge circuit and / or temperature regulation system according to the residual energy consumption method.

[0009] When the driver performs rapid deceleration, the above scheme first calculates the change in the total power demand of the fuel cell vehicle between the current moment and the next moment. This clarifies the degree of power reduction that the vehicle can absorb during deceleration, providing data support for a more accurate calculation of the additional energy the vehicle needs to absorb. Then, the change is compared with the maximum output power that the fuel cell system can reduce to determine whether the adjusted fuel cell system can fully adapt to the vehicle's power changes, i.e., without the need for the residual energy discharge circuit to participate in power absorption. When the adjusted fuel cell system operates at minimum output power, there is still additional power that needs to be absorbed in a timely manner; otherwise, it will overheat and cause the fuel cell system to malfunction. In this case, it is necessary to enter the residual energy absorption mode. By adjusting the absorption power of the residual energy discharge circuit, the residual energy generated by the fuel cell system is consumed in a timely manner, preventing the fuel cell system from rapidly overheating due to the inability to absorb residual energy in a timely manner during rapid deceleration, thus affecting the vehicle's driving safety and ensuring stable operation of the vehicle during rapid deceleration or emergency braking.

[0010] In one possible implementation of the first aspect, when the residual energy is absorbed through the residual energy discharge circuit, adjusting the operation of the residual energy discharge circuit or the temperature control system according to the residual energy absorption method specifically includes:

[0011] The fuel cell system is set to operate at the minimum allowable output power at the next moment, and the output voltage of the fuel cell system corresponding to the minimum output power is obtained;

[0012] Based on the power absorbed by the residual energy discharge circuit and the output voltage, the duty cycle of the switching transistor in the residual energy discharge circuit is calculated; wherein, the residual energy discharge circuit includes a switching transistor and a resistor; the residual energy discharge circuit is electrically connected to the output terminal of the fuel cell system.

[0013] The switching transistor is controlled according to the duty cycle to adjust the power absorption of the residual energy discharge circuit.

[0014] The above scheme first calculates the duty cycle of the switching transistor in the residual energy discharge circuit, thereby precisely adjusting the power absorbed by the residual energy discharge circuit.

[0015] In one possible implementation of the first aspect, the duty cycle of the switching transistor in the residual energy discharge circuit is calculated, specifically as follows:

[0016] The formula for calculating the duty cycle is:

[0017] In the formula, D M1 P is the duty cycle. reqCSP U is the power absorbed by the residual energy discharge circuit, R is the resistance value of the residual energy discharge circuit, and U is the power absorbed by the residual energy discharge circuit. FCS The output voltage is denoted as .

[0018] In one possible implementation of the first aspect, when the residual energy is absorbed simultaneously through the residual energy discharge circuit and the refrigeration module and heating module of the temperature control system respectively, the adjustment of the operation of the residual energy discharge circuit or the temperature control system according to the residual energy absorption method specifically includes:

[0019] The fuel cell system is set to operate at the minimum allowable output power of the fuel cell system at the next moment;

[0020] The residual energy discharge circuit is configured to operate at a preset maximum absorption power.

[0021] The cooling module and the heating module are controlled to simultaneously absorb energy at a preset output power; wherein the preset output power is set according to the minimum output power, the second total power demand of the vehicle at the next moment, the maximum charging power allowed by the power battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0022] In one possible implementation of the first aspect, the output power of the fuel cell system, the charging power of the power battery, and the absorption power of the residual energy discharge circuit at the next moment are obtained and compared to determine the vehicle's residual energy absorption method, specifically:

[0023] Based on the current output power of the fuel cell system and the maximum power drop, the minimum allowable output power of the fuel cell system at the next moment is obtained.

[0024] Based on the minimum output power, the maximum allowable charging power of the power battery at the next moment is obtained; wherein, the fuel cell system provides rechargeable electrical energy for the power battery.

[0025] When the minimum output power is less than the sum of the maximum charging power and the vehicle's second total demand power at the next moment, the vehicle is determined to operate in the first residual energy consumption mode, and the residual energy discharge circuit and the temperature regulation system are controlled not to perform residual energy consumption.

[0026] When operating in the first residual energy absorption mode, the output power of the fuel cell system and the absorption power of the residual energy discharge circuit at the next moment are controlled to satisfy: P ReqFCS_next =P FCS_min_next ; P reqCSP =0;

[0027] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP This refers to the power absorbed by the residual energy discharge circuit.

[0028] One possible implementation of the first aspect also includes:

[0029] When the minimum output power is greater than or equal to the sum of the maximum charging power and the second total demand power of the vehicle at the next moment, and less than the sum of the maximum charging power, the second total demand power and the maximum absorption power of the residual energy discharge circuit, the vehicle is determined to operate in the second residual energy absorption mode, and the residual energy discharge circuit is controlled to absorb residual energy.

[0030] When the minimum output power is greater than or equal to the sum of the maximum charging power, the second total demand power, and the maximum absorption power of the residual energy discharge circuit, the vehicle is determined to operate in the third residual energy absorption mode, and the residual energy discharge circuit and the temperature regulation system are both controlled to absorb residual energy.

[0031] The above scheme first obtains power consumption information such as the minimum allowable output power of the fuel cell system and the maximum allowable charging power of the power battery, providing data support for ensuring the safety of vehicle components during subsequent adjustments. Then, it compares the minimum allowable output power of the fuel cell system with the vehicle's power consumption information to determine whether the excess energy can be absorbed by adjusting the vehicle's power consumption when the fuel cell system operates at the minimum output power, and whether the participation of a residual energy discharge circuit is necessary. If the vehicle still cannot completely absorb the excess energy, the absorption power of the residual energy discharge circuit is adjusted to completely absorb the excess energy. Because only one residual energy discharge circuit is needed to absorb the excess energy, the cost of vehicle absorption control is low, and no additional battery is required to consume the excess energy.

[0032] In one possible implementation of the first aspect, the vehicle is determined to operate in a second residual energy absorption mode, and the residual energy discharge circuit is controlled to absorb residual energy, specifically as follows:

[0033] When operating in the second residual energy consumption mode, the output power of the fuel cell system and the consumption power of the residual energy discharge circuit at the next moment are controlled to satisfy: P ReqFCS_next =P FCS_min_next ; P reqCSP =P FCS_min_next -P next -P Bat-max_next ;

[0034] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. next P is the second total power demand of the vehicle at the next moment. Bat-max_next This represents the maximum charging power allowed for the power battery at the next moment.

[0035] In one possible implementation of the first aspect, determining that the vehicle operates in a third residual energy absorption mode, and controlling both the residual energy discharge circuit and the temperature regulation system to absorb residual energy, specifically involves:

[0036] When operating in the third residual energy consumption mode, upon receiving a cooling command at the current moment, the operating power of the cooling module and the operating power of the heating module at the next moment are controlled to satisfy: P reqAC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =P reqAC_next -P T_next ;

[0037] In the formula, P reqAC_next P represents the operating power of the cooling module at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. next P represents the total power demand of the vehicle at the next moment. Bat-max_next P represents the maximum charging power of the power battery at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit; reqPTC_next The operating power of the heating module in the next moment;

[0038] When operating in the third residual energy consumption mode, upon receiving a heating command at the current moment, the output power of the fuel cell system and the consumption power of the residual energy discharge circuit are controlled for the next moment: P reqPTC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqAC_next =P reqPTC_next -P T_next ;

[0039] When operating in the third residual energy consumption mode, if no cooling or heating command is received at the current moment, the operating power of the cooling module and the operating power of the heating module at the next moment are controlled to satisfy: P ReqFCS_next =P FCS_min_next ; P reqCSP =P CSP_max ; P reqAC_next =(P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =(P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2;

[0040] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. CSP_max P is the maximum power absorbed by the residual energy discharge circuit. reqAC_next P represents the operating power of the cooling module AC at the next moment. next P is the second total power demand of the vehicle at the next moment. reqPTC_next The operating power of the heating module PTC at the next moment.

[0041] When there is excessive residual energy and the residual energy discharge circuit is overburdened, the above solution uses a hybrid operating mode by controlling the temperature regulation system to both heat and cool the vehicle. This allows the temperature regulation system to share some of the residual energy dissipation task without affecting the driver's driving experience, thus stabilizing the normal operation of the fuel cell system.

[0042] In one possible implementation of the first aspect, the change in the total power demand of the fuel cell vehicle between the current time and the next time is calculated, specifically as follows:

[0043] Calculate the first total power demand of the vehicle at the current moment, and calculate the second total power demand of the vehicle at the next moment;

[0044] Calculate the difference between the first total power demand and the second total power demand to obtain the change value;

[0045] The specific formula for calculating the first total power demand is: P now =P M_now +P T_nowt +P Acc_nowt ;

[0046] In the formula, P now P is the first total power demand. M_now P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the current moment. T_nowt P represents the power consumption of the vehicle's temperature regulation system at the current moment. Acc_nowt This represents the power consumed by other high-voltage loads on the vehicle at the current moment.

[0047] The specific formula for calculating the second total power demand is: P next =P M_next +P T_next +P Acc_next ;

[0048] In the formula, P next P is the second total power demand. M_next P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. Acc_next This is the power consumed by the vehicle's other high-voltage loads in the next moment.

[0049] The second aspect of this application provides a residual energy discharge control system for a fuel cell vehicle, the system comprising: a vehicle power change value calculation module, a residual energy consumption method selection module, and a residual energy discharge module;

[0050] Among them, the vehicle power change value calculation module is used to calculate the change in the total power demand of the fuel cell vehicle between the current moment and the next moment;

[0051] The waste energy consumption mode selection module is used to obtain and compare the output power of the fuel cell system, the charging power of the power battery, and the consumption power of the waste energy discharge circuit at the next moment when the change value is greater than the maximum allowable power reduction of the fuel cell system, and determine the waste energy consumption mode of the vehicle; wherein, the waste energy consumption mode includes consumption through the waste energy discharge circuit, and / or consumption through the refrigeration module and heating module of the temperature regulation system simultaneously;

[0052] The residual energy discharge module is used to adjust the operation of the residual energy discharge circuit and / or the temperature regulation system according to the residual energy consumption method. Attached Figure Description

[0053] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0054] Figure 1 is a schematic flowchart of a residual energy discharge control method for a fuel cell vehicle according to a certain embodiment of this application;

[0055] Figure 2 is a schematic diagram of the residual energy discharge circuit of a residual energy discharge control method for a fuel cell vehicle provided in a certain embodiment of this application;

[0056] Figure 3 is a structural diagram of a residual energy discharge control system for a fuel cell vehicle provided in a certain embodiment of this application. Detailed Implementation

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0058] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0059] First Embodiment

[0060] Due to the immaturity of fuel cell stack technology, when a car decelerates rapidly, causing a sharp drop in total power demand, the fuel cell stack's output power cannot cope with the sudden change and cannot quickly reduce its output power. This leads to the vehicle's inability to brake or decelerate quickly and overcharging of the power battery. Furthermore, the excess output power of the fuel cell stack cannot be dissipated in time, causing it to overheat rapidly and potentially leading to battery failure. Typically, a high-power battery is added to the vehicle to dissipate the excess energy generated by the fuel cell stack. However, adding an extra high-power battery increases the overall cost of the vehicle, resulting in low cost-effectiveness. Therefore, the challenge lies in minimizing hardware modifications to keep the overall cost low while ensuring vehicle safety, performance, and high cost-effectiveness.

[0061] As shown in Figure 1, Figure 1 is a schematic flowchart of a residual energy discharge control method for a fuel cell vehicle according to a certain embodiment of this application. The residual energy discharge control method for a fuel cell vehicle in this embodiment includes steps S1 to S3, which are described in detail below:

[0062] Step S1: After the vehicle enters the rapid deceleration or braking mode, calculate the change in the total power demand of the fuel cell vehicle between the current moment and the next moment.

[0063] In practice, a vehicle's fuel cell system uses a traditional boost circuit to raise the low voltage to the high voltage required by the vehicle's high-voltage circuit, supplying power to the lithium battery, motor controller, and high-voltage loads (including the cooling module, heating module, and other high-voltage loads). To promptly dissipate the excess energy generated by the fuel cell system, this embodiment connects an excess energy discharge circuit in parallel between the output of the fuel cell system and the front end of the traditional boost circuit. This circuit consists of a switching transistor and a resistor. The excess energy discharge circuit, along with the high-voltage loads (cooling and heating modules), constitutes the excess energy discharge system of the fuel cell vehicle. The cooling and heating modules are part of the vehicle's temperature regulation system, capable of cooling and heating the vehicle's interior space.

[0064] Figure 2 is a schematic diagram of the residual energy discharge circuit provided in an embodiment of this application. The leftmost element in the figure is the fuel cell system, and the rightmost elements are the power battery, motor controller, high-voltage load, etc., which require power from the fuel cell system. The residual energy discharge circuit is located between the fuel cell system and the Boost converter circuit. M1 is the switching transistor of the residual energy discharge circuit, R is the resistor of the residual energy discharge circuit, and M2 is the switching transistor of the Boost converter circuit. When the vehicle suddenly decelerates or brakes, the power required by the electric drive system drops sharply. When the total power required by the high-voltage load on the high-voltage bus is lower than the output power of the fuel cell, the residual energy discharge system starts working. The switching transistor connects the residual energy discharge circuit so that the resistor in the residual energy discharge circuit can dissipate the residual energy of the fuel cell, ensuring the normal operation of the vehicle and high-voltage components. The residual energy discharge system consists of a residual energy discharge circuit and a temperature regulation system. When the fuel cell system needs to absorb too much residual energy, the refrigeration module and heating module of the temperature regulation system will also participate in the absorption of residual energy.

[0065] In the embodiments of this application, the residual energy discharge circuit, the cooling module AC, and the heating module PTC together constitute the residual energy discharge system, which has two working modes: 1. Single working mode, that is, at most one of the cooling module AC and the heating module PTC can be in working state at the same time, that is, the whole vehicle can only be in either heating or cooling working state, or neither of them can be in working state, so as to reduce the energy consumption of the whole vehicle; 2. Hybrid working mode, that is, the cooling module AC and the heating module PTC can work simultaneously at the same time to consume the residual energy of the fuel cell as quickly as possible.

[0066] The single operating mode is used for the vehicle's normal operating conditions, while the hybrid operating mode is specifically used for the residual energy discharge system of fuel cell vehicles.

[0067] If the driver suddenly decelerates or brakes while the vehicle is in motion, causing the vehicle to be in a state of rapid deceleration, a vehicle rapid deceleration command will be issued.

[0068] Upon receiving a vehicle emergency deceleration command, the total power demand of the vehicle after emergency deceleration or braking at the next moment is obtained using a lookup table (denoted as the second total power demand). The specific expression is: P next =P M_next +P T_next +P Acc_next ;

[0069] In the formula, P next P is the second total power demand. M_next P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. Acc_next This is the power consumed by the vehicle's other high-voltage loads in the next moment.

[0070] The power consumption of the vehicle's motor controller or the feedback power of the regenerative energy system at the next moment, the power consumption of the vehicle's temperature regulation system at the next moment, and the power consumption of other high-voltage loads of the vehicle at the next moment are obtained by using a lookup table method based on the current data.

[0071] Specifically, the power consumption of the vehicle's temperature regulation system at the next moment is: P T_next =P AC_next or P T_next =P PTC_next ;

[0072] In the formula, P AC_next The power consumption of the cooling module AC when the temperature control system is in single-mode operation at the next moment; P PTC_next The power consumed by the heating module PTC when the temperature control system is in single working mode at the next moment.

[0073] Then, the total power demand of the vehicles at the current moment (denoted as the first total power demand) is collected, specifically: P now =P M_now +P T_nowt +P Acc_nowt ;

[0074] In the formula, P now P is the first total power demand. M_now P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the current moment. T_nowt P represents the power consumption of the vehicle's temperature regulation system at the current moment. Acc_nowt This represents the power consumed by other high-voltage loads on the vehicle at the current moment.

[0075] The power consumption of the vehicle's motor controller or the feedback power of the regenerative energy system at the current moment, the power consumption of the vehicle's temperature regulation system at the current moment, and the power consumption of other high-voltage loads of the vehicle at the current moment are obtained by collecting data from the vehicle.

[0076] Specifically, the power consumption of the vehicle's temperature regulation system at the current moment is: P T_now =P AC_now or P T_now =P PTC_now ;

[0077] In the formula, P AC_now P represents the power consumption of the cooling module AC when the temperature control system is in single-mode operation at the current moment; PTC_now This represents the power consumption of the heating module PTC when the temperature control system is in single operating mode at the current moment.

[0078] Then, the difference between the first total power demand and the second total power demand is calculated to obtain the change in total vehicle power demand ΔP between the current time and the next time, specifically: ΔP = P now -P next ;

[0079] Then, obtain the maximum allowable power drop ΔP of the fuel cell system. FCS And compare the change value ΔP with the maximum power reduction ΔP FCS A comparison is made to determine whether the surplus energy problem can be solved simply by adjusting the output power of the fuel cell system. The maximum power reduction ΔP is mentioned below. FCS Vehicle calibration.

[0080] When △P<=△P FCSThis indicates that the change in the total power demand of the vehicle during rapid deceleration or braking, ΔP, is less than or equal to the maximum allowable power reduction ΔP of the fuel cell system. FCS At this point, the power reduction rate of the fuel cell system is sufficient to meet the power reduction rate of the entire vehicle. There is no issue of the fuel cell system burning out due to an insufficient power reduction rate leading to insufficient energy absorption. Therefore, the residual energy discharge circuit is not required for residual energy absorption. Based on the maximum power reduction ΔP... FCS The output power of the fuel cell system can be directly adjusted, that is, the fuel cell system is set to operate based on the difference between the output power of the fuel cell system and the change value, specifically expressed as: P ReqFCS_next =P FCS_next -△P; P reqCSP =0;

[0081] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_next Let P be the output power of the fuel cell system, and ΔP be the change in the total power demand of the vehicle between the current time and the next time. reqCSP This refers to the power absorbed by the residual energy discharge circuit.

[0082] Otherwise, △P>=△P FCS This indicates the maximum allowable power reduction ΔP of the fuel cell system within a short period of time. FCS Because the fuel cell system's power output cannot keep up with the change in the vehicle's total power demand (ΔP) during rapid deceleration or braking, the rate of power reduction relative to the vehicle's total power demand is very slow. Consequently, the fuel cell system still generates a significant amount of excess energy that cannot be absorbed in a timely manner. Therefore, it is necessary to employ excess energy absorption methods, involving the excess energy discharge circuit and other high-voltage loads to assist in power absorption and alleviate the vehicle's power consumption pressure. These other high-voltage loads include high-voltage distribution boxes, high-voltage wiring harnesses, and DC / DC converters.

[0083] Step S2: When the change value is greater than the maximum allowable power reduction of the fuel cell system, obtain the output power of the fuel cell system, the charging power of the power battery, and the absorption power of the residual energy discharge circuit at the next moment and compare them to determine the residual energy absorption method of the vehicle.

[0084] Collect the current output power P of the fuel cell system FCS_now Calculate the minimum allowable output power of the fuel cell system at the next moment, specifically: P FCS_min_next =max{P FCS_now -△P FCS ,0};

[0085] In the formula, P FCS_min_next For the minimum output power, ΔP FCSThis represents the maximum allowable power drop for the fuel cell system; the minimum output power ranges from 0 to P. FCS_now With △P FCS The difference between them.

[0086] Based on the minimum output power, the maximum allowable charging power of the power battery at the next moment is obtained by looking up a table. In this embodiment, the power battery is a lithium battery.

[0087] First, the minimum output power P FCS_min_next With the maximum charging power P Bat-max_next The second total power demand P of the vehicle at the next moment next Compare the sums. If P FCS_min_next <P next +P Bat-max_next This indicates that the output power of the fuel cell system can be completely absorbed by the high-voltage load of the vehicle and the power battery, without the need for the residual energy discharge circuit to participate in power absorption. It can be determined that the vehicle operates in the first residual energy absorption mode to complete the residual energy absorption. Therefore, the fuel cell system is operated with the minimum output power to protect the power battery and prevent excessive residual energy from causing the power battery to overcharge.

[0088] The power consumed by the high-voltage load of the vehicle is the total power demand of the vehicle.

[0089] Regarding the above description, the specific expression for the first surplus energy absorption method is: P ReqFCS_next =P FCS_min_next ; P reqCSP =0;

[0090] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP This refers to the power absorbed by the residual energy discharge circuit.

[0091] The above formula indicates that the output power of the fuel cell system at the next moment is set to the minimum output power, and the absorption power of the residual energy discharge circuit is set to 0.

[0092] If P exists FCS_min_next >=P next +P Bat-max_next In this case, the minimum output power P will be... FCS_min_next With the maximum charging power P Bat-max_next The second total power demand P of the vehicle at the next moment next The maximum absorbance power P of the residual energy discharge circuit CSP_max Compare the sums. When P exists. FCS_min_next <P next+P Bat-max_next +P CSP_max This indicates that the output power of the fuel cell system can be absorbed by the vehicle's high-voltage load, the power battery, and the residual energy discharge circuit. In this case, the fuel cell system operates at the minimum output power, and the absorption power of the residual energy discharge circuit is set according to the residual energy consumed by the vehicle's high-voltage load and the power battery. That is, the vehicle is determined to operate in a second residual energy absorption mode to complete the residual energy absorption, allowing the residual energy discharge circuit to participate in the residual energy absorption. The specific expression is: P ReqFCS_next =P FCS_min_next ; P reqCSP =P FCS_min_next -P next -P Bat-max_next ;

[0093] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. next P is the second total power demand of the vehicle at the next moment. Bat-max_next This represents the maximum charging power allowed for the power battery at the next moment. Among these, the maximum absorption power P of the residual energy discharge circuit is... CSP_max It is obtained from the calibration of the whole vehicle.

[0094] The above formula means that the output power of the fuel cell system at the next moment is set to the minimum output power; the power absorbed by the residual energy discharge circuit is set to the difference between the minimum output power and the second total demand power and the maximum charging power. That is, the residual energy that the vehicle high voltage load and the power battery can absorb are considered first, and then the residual energy discharge circuit is used to absorb the remaining residual energy.

[0095] Furthermore, since the residual energy discharge circuit is actually composed of a high-power switching transistor and a resistor, the duty cycle of the switching transistor needs to be considered when adjusting its absorption power. Therefore, the duty cycle needs to be calculated based on the resistor and the output voltage of the fuel cell system. The switching transistor is controlled according to the duty cycle to adjust the absorption power of the residual energy discharge circuit, thereby achieving more precise adjustment of the residual energy discharge circuit.

[0096] Specifically, the output voltage of the fuel cell system corresponding to the minimum allowable output power is first obtained by looking up a table, and then the calculation is performed according to the preset duty cycle formula:

[0097] In the formula, D M1 P is the duty cycle. reqCSP U is the power absorbed by the residual energy discharge circuit, R is the resistance value of the residual energy discharge circuit, and U is the power absorbed by the residual energy discharge circuit. FCSThe output voltage is denoted as .

[0098] As an improvement to the above solution, when the power reduction rate of the fuel cell system is too slow relative to the vehicle speed reduction rate, the excess energy generated by the fuel cell system will be too much, so much so that the high-voltage load of the vehicle, the power battery, and the excess energy discharge circuit alone cannot absorb the excess output power in time. At this time, it is necessary to introduce the cooling module and heating module of the excess energy discharge system to participate in additional excess energy absorption and accelerate the excess energy absorption process. That is, the vehicle is determined to operate in a third excess energy absorption mode, so that the excess energy discharge circuit and the temperature regulation system both participate in the excess energy absorption.

[0099] Specifically, when P FCS_min_next >=P next +P Bat-max_next +P CSP_max If, at the next moment, the output power of the fuel cell system is greater than or equal to the sum of the vehicle's total power demand, the maximum charging power of the battery, and the maximum absorption power of the residual energy discharge circuit, it indicates that the fuel cell system has generated excessive residual energy in a short period of time. Failure to absorb this residual energy in time will cause the battery system to overheat rapidly, thus affecting the vehicle's deceleration effect. In this situation, it is necessary to schedule the cooling and heating modules of the residual energy discharge system to operate simultaneously, i.e., to put the system into a hybrid operating mode. This involves simultaneously operating the cooling and heating modules to discharge the energy from the fuel cell system. Specifically, the fuel cell system is set to operate at its minimum allowable output power at the next moment; the residual energy discharge circuit is set to operate at a preset maximum absorption power; and the cooling and heating modules simultaneously absorb the residual energy at the set output power. The set output power is determined based on the minimum output power, the vehicle's second total power demand at the next moment, the maximum allowable charging power of the battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0100] The third method of residual energy consumption takes into account whether the driver intends to heat up or cool down the vehicle when performing braking operations such as sudden braking or sudden deceleration, in order to determine the output power of the cooling module and the heating module.

[0101] When the driver has no intention of adjusting the temperature, the output power of the fuel cell system and the absorption power of the residual energy discharge circuit at the next moment are controlled by the following formula: P ReqFCS_next =P FCS_min_next ; P reqCSP =P CSP_max ; P reqAC_next =(P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =(PFCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2;

[0102] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. CSP_max P is the maximum power absorbed by the residual energy discharge circuit. reqAC_next P represents the operating power of the cooling module at the next moment. next P is the second total power demand of the vehicle at the next moment. reqPTC_next This is the operating power of the heating module for the next moment.

[0103] At this time, because the cooling module and the heating module operate simultaneously and have the same operating power, the cooling effect of the cooling module can be offset by the heating effect of the heating module. Therefore, when the system enters the hybrid working mode, the cooling module and the heating module can assist in consuming the excess energy generated by the fuel cell system without affecting the driving environment, thus accelerating the consumption of excess energy. This ensures that even with a relatively low total power demand of the vehicle and a low charging power of the power battery, the vehicle can still perform stable acceleration or braking, guaranteeing the vehicle's power, safety, and the driver's driving experience.

[0104] Additionally, regarding the temperature control system, when the driver controls the temperature control system to cool down (i.e., upon receiving a cooling command at the current moment), the operating power of the cooling module AC and the heating module PTC is set to: P reqAC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =P reqAC_next -P T_next ;

[0105] In the formula, P reqAC_next P represents the operating power of the cooling module at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. next P represents the total power demand of the vehicle at the next moment. Bat-max_next P represents the maximum charging power of the power battery at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit; reqPTC_next This is the operating power of the heating module for the next moment.

[0106] When the driver's intention is to cool down, the operating power of the cooling module is set first. The operating power of the cooling module is related to the operating power of the temperature regulation system, the minimum allowable output power of the fuel cell system, the total power demand of the vehicle at the next moment, the maximum charging power of the power battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0107] When the driver controls the temperature control system to heat, i.e., when a heating command is received at the current moment, the operating power of the cooling module and the heating module is set to: P reqPTC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqAC_next =P reqPTC_next -P T_next ;

[0108] When the driver's intention is to heat the vehicle, the operating power of the heating module is prioritized. The operating power of the heating module is related to the operating power of the temperature regulation system, the minimum allowable output power of the fuel cell system, the total power demand of the vehicle at the next moment, the maximum charging power of the power battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0109] At this time, because the cooling module and the heating module operate simultaneously and have the same operating power, the cooling effect of the cooling module can be offset by the heating effect of the heating module. Therefore, when the system enters the hybrid working mode, the cooling module and the heating module can assist in consuming the excess energy generated by the fuel cell system without affecting the driving environment, thus accelerating the consumption of excess energy. This ensures that even with a relatively low total power demand of the vehicle and a low charging power of the power battery, the vehicle can still perform stable acceleration or braking, guaranteeing the vehicle's power, safety, and the driver's driving experience.

[0110] Moreover, compared to adding a high-power battery to a car, introducing a residual energy discharge circuit requires less hardware modification to the vehicle, and more changes to the control methods and software. The overall cost increase is lower, it is more practical, and it improves the cost-effectiveness of vehicle design.

[0111] Step S3: Adjust the operation of the residual energy discharge circuit and / or temperature regulation system according to the residual energy consumption method.

[0112] In this embodiment of the application, the power of the residual energy discharge circuit and the operating power of the refrigeration module and heating module in the temperature regulation system, as well as the output power of the fuel cell system, are set according to the residual energy consumption method in step S2.

[0113] The residual energy discharge control method for fuel cell vehicles provided in this application can be applied to a terminal, a server, or software running on either a terminal or a server. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, etc.; the server can be configured as an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application implementing a charging temperature control method, etc., but is not limited to the above forms.

[0114] This application can also be used in numerous general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics devices, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices. This application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0115] Implementing the embodiments of this application has the following beneficial effects:

[0116] In this embodiment, when the driver performs rapid deceleration control on the vehicle, the change in the vehicle's total power demand between the current moment and the next moment is first calculated. This clarifies the degree of power reduction that the vehicle can absorb during deceleration, providing data support for a more accurate calculation of the additional energy the vehicle needs to absorb. Then, the change is compared with the maximum output power that the fuel cell system can reduce to determine whether the adjusted fuel cell system can fully adapt to the vehicle's power changes, i.e., without the need for the residual energy discharge circuit to participate in power absorption. When the adjusted fuel cell system operates at minimum output power, there is still additional power that needs to be absorbed in a timely manner; otherwise, it will overheat and cause the fuel cell system to malfunction. At this time, it is necessary to enter the residual energy absorption mode. By adjusting the absorption power of the residual energy discharge circuit, the residual energy generated by the fuel cell system is consumed in a timely manner, preventing the fuel cell system from rapidly overheating due to the inability to absorb residual energy in a timely manner during rapid deceleration, thus affecting the vehicle's driving safety and ensuring stable operation of the vehicle during rapid deceleration or emergency braking.

[0117] Second Embodiment

[0118] Furthermore, in order to implement the residual energy discharge control system of the fuel cell vehicle corresponding to the above method embodiments and achieve the corresponding functions and technical effects, Figure 3 provides a structural diagram of the residual energy discharge control system of a fuel cell vehicle. For ease of explanation, only the parts related to this embodiment are shown. The residual energy discharge control system of the fuel cell vehicle provided in this application embodiment includes:

[0119] The vehicle power change calculation module 201 is used to calculate the change in the total power demand of the fuel cell vehicle between the current moment and the next moment.

[0120] In practice, a vehicle's fuel cell system uses a traditional boost circuit to raise the low voltage to the high voltage required by the vehicle's high-voltage circuit, supplying power to the lithium battery, motor controller, and high-voltage loads (including the cooling module, heating module, and other high-voltage loads). To promptly dissipate the excess energy generated by the fuel cell system, this embodiment connects an excess energy discharge circuit in parallel between the output of the fuel cell system and the front end of the traditional boost circuit. This circuit consists of a switching transistor and a resistor. The excess energy discharge circuit, along with the high-voltage loads (cooling and heating modules), constitutes the excess energy discharge system of the fuel cell vehicle. The cooling and heating modules are part of the vehicle's temperature regulation system, capable of cooling and heating the vehicle's interior space.

[0121] When the vehicle suddenly decelerates or brakes, the power required by the electric drive system drops sharply. When the total power demanded by the high-voltage load on the high-voltage bus is lower than the output power of the fuel cell, the residual energy discharge system starts to operate. This involves connecting the residual energy discharge circuit via a switching transistor, allowing the circuit's resistance to dissipate the residual energy from the fuel cell, ensuring the normal operation of the vehicle and high-voltage components. The residual energy discharge system consists of a residual energy discharge circuit and a temperature regulation system. When the fuel cell system needs to absorb excessive residual energy, the cooling and heating modules of the temperature regulation system will also participate in the residual energy absorption process.

[0122] In the embodiments of this application, the residual energy discharge circuit, the cooling module AC, and the heating module PTC together constitute the residual energy discharge system, which has two working modes: 1. Single working mode, that is, at most one of the cooling module AC and the heating module PTC can be in working state at the same time, that is, the whole vehicle can only be in either heating or cooling working state, or neither of them can be in working state, so as to reduce the energy consumption of the whole vehicle; 2. Hybrid working mode, that is, the cooling module AC and the heating module PTC can work simultaneously at the same time to consume the residual energy of the fuel cell as quickly as possible.

[0123] The single operating mode is used for the vehicle's normal operating conditions, while the hybrid operating mode is specifically used for the residual energy discharge system of fuel cell vehicles.

[0124] If the driver suddenly decelerates or brakes while the vehicle is in motion, causing the vehicle to be in a state of rapid deceleration, a vehicle rapid deceleration command will be issued.

[0125] Upon receiving a vehicle emergency deceleration command, the total power demand of the vehicle after emergency deceleration or braking at the next moment is obtained using a lookup table (denoted as the second total power demand). The specific expression is: P next =P M_next +P T_next +P Acc_next ;

[0126] In the formula, P next P is the second total power demand. M_next P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. Acc_next This is the power consumed by the vehicle's other high-voltage loads in the next moment.

[0127] The power consumption of the vehicle's motor controller or the feedback power of the regenerative energy system at the next moment, the power consumption of the vehicle's temperature regulation system at the next moment, and the power consumption of other high-voltage loads of the vehicle at the next moment are obtained by using a lookup table method based on the current data.

[0128] Specifically, the power consumption of the vehicle's temperature regulation system at the next moment is: P T_next =P AC_next or P T_next =P PTC_next ;

[0129] In the formula, P AC_next The power consumption of the cooling module AC when the temperature control system is in single-mode operation at the next moment; P PTC_next The power consumed by the heating module PTC when the temperature control system is in single working mode at the next moment.

[0130] Then, the total power demand of the vehicles at the current moment (denoted as the first total power demand) is collected, specifically: P now =P M_now +P T_nowt +P Acc_nowt ;

[0131] In the formula, P now P is the first total power demand. M_now P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the current moment. T_nowt P represents the power consumption of the vehicle's temperature regulation system at the current moment. Acc_nowt This represents the power consumed by other high-voltage loads on the vehicle at the current moment.

[0132] The power consumption of the vehicle's motor controller or the feedback power of the regenerative energy system at the current moment, the power consumption of the vehicle's temperature regulation system at the current moment, and the power consumption of other high-voltage loads of the vehicle at the current moment are obtained by collecting data from the vehicle.

[0133] Specifically, the power consumption of the vehicle's temperature regulation system at the current moment is: P T_now =P AC_now or P T_now =P PTC_now ;

[0134] In the formula, P AC_now P represents the power consumption of the cooling module AC when the temperature control system is in single-mode operation at the current moment; PTC_now This represents the power consumption of the heating module PTC when the temperature control system is in single operating mode at the current moment.

[0135] Then, the difference between the first total power demand and the second total power demand is calculated to obtain the change in total vehicle power demand ΔP between the current time and the next time, specifically: ΔP = P now -P next ;

[0136] Then, obtain the maximum allowable power drop ΔP of the fuel cell system. FCS And compare the change value ΔP with the maximum power reduction ΔP FCS A comparison is made to determine whether the surplus energy problem can be solved simply by adjusting the output power of the fuel cell system. The maximum power reduction ΔP is mentioned below. FCS Vehicle calibration.

[0137] When △P<=△P FCS This indicates that the change in the total power demand of the vehicle during rapid deceleration or braking, ΔP, is less than or equal to the maximum allowable power reduction ΔP of the fuel cell system. FCS At this point, the power reduction rate of the fuel cell system is sufficient to meet the power reduction rate of the entire vehicle. There is no issue of the fuel cell system burning out due to an insufficient power reduction rate leading to insufficient energy absorption. Therefore, the residual energy discharge circuit is not required for residual energy absorption. Based on the maximum power reduction ΔP... FCS The output power of the fuel cell system can be directly adjusted, that is, the fuel cell system is set to operate based on the difference between the output power of the fuel cell system and the change value, specifically expressed as: P ReqFCS_next =P FCS_next -△P; P reqCSP =0;

[0138] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_next Let P be the output power of the fuel cell system, and ΔP be the change in the total power demand of the vehicle between the current time and the next time. reqCSP This refers to the power absorbed by the residual energy discharge circuit.

[0139] Otherwise, △P>=△P FCS This indicates the maximum allowable power reduction ΔP of the fuel cell system within a short period of time. FCS Because the fuel cell system's power output cannot keep up with the change in the vehicle's total power demand (ΔP) during rapid deceleration or braking, the rate of power reduction relative to the vehicle's total power demand is very slow. Consequently, the fuel cell system still generates a significant amount of excess energy that cannot be absorbed in a timely manner. Therefore, it is necessary to employ excess energy absorption methods, involving the excess energy discharge circuit and other high-voltage loads to assist in power absorption and alleviate the vehicle's power consumption pressure. These other high-voltage loads include high-voltage distribution boxes, high-voltage wiring harnesses, and DC / DC converters.

[0140] The waste energy consumption mode selection module 202 is used to obtain and compare the output power of the fuel cell system, the charging power of the power battery, and the consumption power of the waste energy discharge circuit at the next moment when the change value is greater than the maximum allowable power reduction of the fuel cell system, and determine the waste energy consumption mode of the vehicle; wherein, the waste energy consumption mode includes consumption through the waste energy discharge circuit, and / or consumption through the refrigeration module and heating module of the temperature regulation system simultaneously.

[0141] In this embodiment of the application, the minimum allowable output power of the fuel cell system at the next moment is obtained based on the current output power of the fuel cell system and the maximum power drop.

[0142] Based on the minimum output power, the maximum allowable charging power of the power battery at the next moment is obtained; wherein, the fuel cell system provides rechargeable electrical energy for the power battery.

[0143] When the minimum output power is greater than or equal to the sum of the maximum charging power and the second total demand power of the vehicle at the next moment, and less than the sum of the maximum charging power, the second total demand power and the maximum absorption power of the residual energy discharge circuit, the vehicle is determined to operate in the second residual energy absorption mode, the residual energy discharge circuit is controlled to participate in residual energy absorption, and the temperature regulation system does not participate in residual energy absorption.

[0144] When the minimum output power is greater than or equal to the sum of the maximum charging power, the second total demand power, and the maximum absorption power of the residual energy discharge circuit, the vehicle is determined to operate in the third residual energy absorption mode, and the residual energy discharge circuit and the temperature regulation system are both controlled to participate in the residual energy absorption.

[0145] Wherein, when the residual energy is absorbed through the residual energy discharge circuit, the specific steps of adjusting the operation of the residual energy discharge circuit or the temperature regulation system according to the residual energy absorption method are as follows: setting the fuel cell system to operate at the minimum allowable output power of the fuel cell system at the next moment, and obtaining the output voltage of the fuel cell system corresponding to the minimum output power; calculating the duty cycle of the switching transistor of the residual energy discharge circuit based on the absorption power of the residual energy discharge circuit and the output voltage; wherein, the residual energy discharge circuit includes a switching transistor and a resistor; the residual energy discharge circuit is electrically connected to the output terminal of the fuel cell system; and controlling the switching transistor according to the duty cycle to adjust the absorption power of the residual energy discharge circuit.

[0146] Wherein, when the waste energy is absorbed simultaneously through the waste energy discharge circuit and the refrigeration module and heating module of the temperature regulation system respectively, the adjustment of the operation of the waste energy discharge circuit or the temperature regulation system according to the waste energy absorption method is specifically as follows:

[0147] The fuel cell system is set to operate at the minimum allowable output power of the fuel cell system at the next moment;

[0148] The residual energy discharge circuit is set to operate at a preset maximum absorption power; the cooling module and the heating module are controlled to absorb residual energy simultaneously at a preset output power; wherein, the preset output power is set according to the minimum output power, the second total demand power of the vehicle at the next moment, the maximum allowable charging power of the power battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0149] The residual energy discharge module 203 is used to adjust the operation of the residual energy discharge circuit and / or the temperature regulation system according to the residual energy consumption method.

[0150] In this embodiment of the application, the power of the waste energy discharge circuit and the operating power of the refrigeration module and heating module in the temperature regulation system, as well as the output power of the fuel cell system, are set according to the determined waste energy consumption method.

[0151] In some embodiments, the surplus energy consumption method selection module 202 specifically comprises:

[0152] Collect the current output power P of the fuel cell system FCS_now Calculate the minimum allowable output power of the fuel cell system at the next moment, specifically: P FCS_min_next =max{P FCS_now -△P FCS ,0};

[0153] In the formula, P FCS_min_next For the minimum output power, ΔP FCS This represents the maximum allowable power drop for the fuel cell system; the minimum output power ranges from 0 to P. FCS_now With △P FCS The difference between them.

[0154] Based on the minimum output power, the maximum allowable charging power of the power battery at the next moment is obtained by looking up a table. In this embodiment, the power battery is a lithium battery.

[0155] First, the minimum output power P FCS_min_next With the maximum charging power P Bat-max_next The second total power demand P of the vehicle at the next moment next Compare the sums. If P FCS_min_next <P next +P Bat-max_nextThis indicates that the output power of the fuel cell system can be completely absorbed by the high-voltage load of the vehicle and the power battery, without the need for the residual energy discharge circuit to participate in power absorption. It can be determined that the vehicle operates in the first residual energy absorption mode to complete the residual energy absorption. Therefore, the fuel cell system is operated with the minimum output power to protect the power battery and prevent excessive residual energy from causing the power battery to overcharge.

[0156] The power consumed by the high-voltage load of the vehicle is the total power demand of the vehicle.

[0157] Regarding the above description, the specific expression for the first surplus energy absorption method is: P ReqFCS_next =P FCS_min_next ; P reqCSP =0;

[0158] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP This refers to the power absorbed by the residual energy discharge circuit.

[0159] The above formula indicates that the output power of the fuel cell system at the next moment is set to the minimum output power, and the absorption power of the residual energy discharge circuit is set to 0.

[0160] If P exists FCS_min_next >=P next +P Bat-max_next In this case, the minimum output power P will be... FCS_min_next With the maximum charging power P Bat-max_next The second total power demand P of the vehicle at the next moment next The maximum absorbance power P of the residual energy discharge circuit CSP_max Compare the sums. When P exists. FCS_min_next <P next +P Bat-max_next +P CSP_max This indicates that the output power of the fuel cell system can be absorbed by the vehicle's high-voltage load, the power battery, and the residual energy discharge circuit. In this case, the fuel cell system operates at the minimum output power, and the absorption power of the residual energy discharge circuit is set according to the residual energy consumed by the vehicle's high-voltage load and the power battery. That is, the vehicle is determined to operate in a second residual energy absorption mode to complete the residual energy absorption, allowing the residual energy discharge circuit to participate in the residual energy absorption. The specific expression is: P ReqFCS_next =P FCS_min_next ; P reqCSP =P FCS_min_next -P next -P Bat-max_next ;

[0161] In the formula, PReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. next P is the second total power demand of the vehicle at the next moment. Bat-max_next This represents the maximum charging power allowed for the power battery at the next moment. Among these, the maximum absorption power P of the residual energy discharge circuit is... CSP_max It is obtained from the calibration of the whole vehicle.

[0162] The above formula means that the output power of the fuel cell system at the next moment is set to the minimum output power; the power absorbed by the residual energy discharge circuit is set to the difference between the minimum output power and the second total demand power and the maximum charging power. That is, the residual energy that the vehicle high voltage load and the power battery can absorb are considered first, and then the residual energy discharge circuit is used to absorb the remaining residual energy.

[0163] Furthermore, since the residual energy discharge circuit is actually composed of a high-power switching transistor and a resistor, the duty cycle of the switching transistor needs to be considered when adjusting its absorption power. Therefore, the duty cycle needs to be calculated based on the resistor and the output voltage of the fuel cell system. The switching transistor is controlled according to the duty cycle to adjust the absorption power of the residual energy discharge circuit, thereby achieving more precise adjustment of the residual energy discharge circuit.

[0164] Specifically, the output voltage of the fuel cell system corresponding to the minimum allowable output power is first obtained by looking up a table, and then the calculation is performed according to the preset duty cycle formula:

[0165] In the formula, D M1 P is the duty cycle. reqCSP U is the power absorbed by the residual energy discharge circuit, R is the resistance value of the residual energy discharge circuit, and U is the power absorbed by the residual energy discharge circuit. FCS The output voltage is denoted as .

[0166] As an improvement to the above solution, when the power reduction rate of the fuel cell system is too slow relative to the vehicle speed reduction rate, the excess energy generated by the fuel cell system will be too much, so much so that the high-voltage load of the vehicle, the power battery, and the excess energy discharge circuit alone cannot absorb the excess output power in time. At this time, it is necessary to introduce the cooling module and heating module of the excess energy discharge system to participate in additional excess energy absorption and accelerate the excess energy absorption process. That is, the vehicle is determined to operate in a third excess energy absorption mode, so that the excess energy discharge circuit and the temperature regulation system both participate in the excess energy absorption.

[0167] Specifically, when P FCS_min_next >=P next +P Bat-max_next +P CSP_maxIf, at the next moment, the output power of the fuel cell system is greater than or equal to the sum of the vehicle's total power demand, the maximum charging power of the battery, and the maximum absorption power of the residual energy discharge circuit, it indicates that the fuel cell system has generated excessive residual energy in a short period of time. Failure to absorb this residual energy in time will cause the battery system to overheat rapidly, thus affecting the vehicle's deceleration effect. In this situation, it is necessary to schedule the cooling and heating modules of the residual energy discharge system to operate simultaneously, i.e., to put the system into a hybrid operating mode. This involves simultaneously operating the cooling and heating modules to discharge the energy from the fuel cell system. Specifically, the fuel cell system is set to operate at its minimum allowable output power at the next moment; the residual energy discharge circuit is set to operate at a preset maximum absorption power; and the cooling and heating modules simultaneously absorb the residual energy at the set output power. The set output power is determined based on the minimum output power, the vehicle's second total power demand at the next moment, the maximum allowable charging power of the battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0168] The third method of residual energy consumption takes into account whether the driver intends to heat up or cool down the vehicle when performing braking operations such as sudden braking or sudden deceleration, in order to determine the output power of the cooling module and the heating module.

[0169] When the driver has no intention of adjusting the temperature, the output power of the fuel cell system and the absorption power of the residual energy discharge circuit at the next moment are controlled by the following formula: P ReqFCS_next =P FCS_min_next ; P reqCSP =P CSP_max ; P reqAC_next =(P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =(P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2;

[0170] In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. CSP_max P is the maximum power absorbed by the residual energy discharge circuit. reqAC_next P represents the operating power of the cooling module at the next moment. next P is the second total power demand of the vehicle at the next moment. reqPTC_next This is the operating power of the heating module for the next moment.

[0171] At this time, because the cooling module and the heating module operate simultaneously and have the same operating power, the cooling effect of the cooling module can be offset by the heating effect of the heating module. Therefore, when the system enters the hybrid working mode, the cooling module and the heating module can assist in consuming the excess energy generated by the fuel cell system without affecting the driving environment, thus accelerating the consumption of excess energy. This ensures that even with a relatively low total power demand of the vehicle and a low charging power of the power battery, the vehicle can still perform stable acceleration or braking, guaranteeing the vehicle's power, safety, and the driver's driving experience.

[0172] Additionally, regarding the temperature control system, when the driver controls the temperature control system to cool down (i.e., upon receiving a cooling command at the current moment), the operating power of the cooling module AC and the heating module PTC is set to: P reqAC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =P reqAC_next -P T_next ;

[0173] In the formula, P reqAC_next P represents the operating power of the cooling module at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. next P represents the total power demand of the vehicle at the next moment. Bat-max_next P represents the maximum charging power of the power battery at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit; reqPTC_next This is the operating power of the heating module for the next moment.

[0174] When the driver's intention is to cool down, the operating power of the cooling module is set first. The operating power of the cooling module is related to the operating power of the temperature regulation system, the minimum allowable output power of the fuel cell system, the total power demand of the vehicle at the next moment, the maximum charging power of the power battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0175] When the driver controls the temperature control system to heat, i.e., when a heating command is received at the current moment, the operating power of the cooling module and the heating module is set to: P reqPTC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqAC_next =PreqPTC_next -P T_next ;

[0176] When the driver's intention is to heat the vehicle, the operating power of the heating module is prioritized. The operating power of the heating module is related to the operating power of the temperature regulation system, the minimum allowable output power of the fuel cell system, the total power demand of the vehicle at the next moment, the maximum charging power of the power battery at the next moment, and the absorption power of the residual energy discharge circuit.

[0177] At this time, because the cooling module and the heating module operate simultaneously and have the same operating power, the cooling effect of the cooling module can be offset by the heating effect of the heating module. Therefore, when the system enters the hybrid working mode, the cooling module and the heating module can assist in consuming the excess energy generated by the fuel cell system without affecting the driving environment, thus accelerating the consumption of excess energy. This ensures that even with a relatively low total power demand of the vehicle and a low charging power of the power battery, the vehicle can still perform stable acceleration or braking, guaranteeing the vehicle's power, safety, and the driver's driving experience.

[0178] Moreover, compared to adding a high-power battery to a car, introducing a residual energy discharge circuit requires less hardware modification to the vehicle, and more changes to the control methods and software. The overall cost increase is lower, it is more practical, and it improves the cost-effectiveness of vehicle design.

[0179] In another implementation example, the above-mentioned residual energy discharge control system for fuel cell vehicles includes a processor, wherein the processor is used to execute the above-mentioned program modules stored in memory, including: a vehicle power change value calculation module 201, a residual energy consumption mode selection module 202, and a residual energy discharge module 203.

[0180] Implementing the embodiments of this application has the following beneficial effects:

[0181] In this embodiment, when the driver performs rapid deceleration control on the vehicle, the change in the vehicle's total power demand between the current moment and the next moment is first calculated. This clarifies the degree of power reduction that the vehicle can absorb during deceleration, providing data support for a more accurate calculation of the additional energy the vehicle needs to absorb. Then, the change is compared with the maximum output power that the fuel cell system can reduce to determine whether the adjusted fuel cell system can fully adapt to the vehicle's power changes, i.e., without the need for the residual energy discharge circuit to participate in power absorption. When the adjusted fuel cell system operates at minimum output power, there is still additional power that needs to be absorbed in a timely manner; otherwise, it will overheat and cause the fuel cell system to malfunction. At this time, it is necessary to enter the residual energy absorption mode. By adjusting the absorption power of the residual energy discharge circuit, the residual energy generated by the fuel cell system is consumed in a timely manner, preventing the fuel cell system from rapidly overheating due to the inability to absorb residual energy in a timely manner during rapid deceleration, thus affecting the vehicle's driving safety and ensuring stable operation of the vehicle during rapid deceleration or emergency braking.

[0182] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, or improvements made by those skilled in the art within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for controlling residual energy discharge in a fuel cell vehicle, characterized in that, The method is applied to a fuel cell vehicle, which includes a power battery, a fuel cell system, a waste energy discharge circuit, and a temperature control system. The temperature control system includes a cooling module and a heating module. The waste energy discharge circuit and the temperature control system are electrically connected to the output terminal of the fuel cell system. The method includes: Calculate the change in the total power demand of the fuel cell vehicle between the current time and the next time. When the change value is greater than the maximum allowable power reduction of the fuel cell system, the output power of the fuel cell system, the charging power of the power battery, and the absorption power of the residual energy discharge circuit at the next moment are obtained and compared to determine the residual energy absorption method of the vehicle; wherein, the residual energy absorption method includes absorption through the residual energy discharge circuit, and / or absorption through the refrigeration module and heating module of the temperature regulation system at the same time. Adjust the operation of the residual energy discharge circuit and / or temperature regulation system according to the residual energy consumption method.

2. The residual energy discharge control method for fuel cell vehicles according to claim 1, characterized in that, When the residual energy is absorbed through the residual energy discharge circuit, the operation of the residual energy discharge circuit or the temperature control system is adjusted according to the residual energy absorption method, specifically as follows: The fuel cell system is set to operate at the minimum allowable output power at the next moment, and the output voltage of the fuel cell system corresponding to the minimum output power is obtained; Based on the power absorbed by the residual energy discharge circuit and the output voltage, the duty cycle of the switching transistor in the residual energy discharge circuit is calculated; wherein, the residual energy discharge circuit includes a switching transistor and a resistor; the residual energy discharge circuit is electrically connected to the output terminal of the fuel cell system. The switching transistor is controlled according to the duty cycle to adjust the power absorption of the residual energy discharge circuit.

3. The residual energy discharge control method for fuel cell vehicles according to claim 2, characterized in that, The duty cycle of the switching transistor in the residual energy discharge circuit is calculated as follows: The formula for calculating the duty cycle is: In the formula, D M1 P is the duty cycle. reqCSP U is the power absorbed by the residual energy discharge circuit, R is the resistance value of the residual energy discharge circuit, and U is the power absorbed by the residual energy discharge circuit. FCS The output voltage is denoted as .

4. The residual energy discharge control method for fuel cell vehicles according to claim 1, characterized in that, The waste energy dissipation method involves simultaneous dissipation through the waste energy discharge circuit and the refrigeration and heating modules of the temperature control system, respectively. Specifically, adjusting the operation of the waste energy discharge circuit or the temperature control system according to the waste energy dissipation method involves: The fuel cell system is set to operate at the minimum allowable output power of the fuel cell system at the next moment; The residual energy discharge circuit is configured to operate at a preset maximum absorption power. The cooling module and the heating module are controlled to simultaneously absorb energy at a preset output power; wherein the preset output power is set according to the minimum output power, the second total power demand of the vehicle at the next moment, the maximum charging power allowed by the power battery at the next moment, and the absorption power of the residual energy discharge circuit.

5. The residual energy discharge control method for a fuel cell vehicle according to any one of claims 1 to 4, characterized in that, The process involves acquiring and comparing the output power of the fuel cell system, the charging power of the power battery, and the absorption power of the residual energy discharge circuit at the next moment to determine the vehicle's residual energy absorption method. Specifically: Based on the current output power of the fuel cell system and the maximum power drop, the minimum allowable output power of the fuel cell system at the next moment is obtained. Based on the minimum output power, the maximum allowable charging power of the power battery at the next moment is obtained; wherein, the fuel cell system provides rechargeable electrical energy for the power battery. When the minimum output power is less than the sum of the maximum charging power and the vehicle's second total demand power at the next moment, the vehicle is determined to operate in the first residual energy consumption mode, and the residual energy discharge circuit and the temperature regulation system are controlled not to perform residual energy consumption. When operating in the first residual energy absorption mode, the output power of the fuel cell system and the absorption power of the residual energy discharge circuit at the next moment are controlled to satisfy: P ReqFCS_next =P FCS_min_next ; P reqCSP ＝0； In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP This refers to the power absorbed by the residual energy discharge circuit.

6. The residual energy discharge control method for fuel cell vehicles according to claim 5, characterized in that, Also includes: When the minimum output power is greater than or equal to the sum of the maximum charging power and the second total demand power of the vehicle at the next moment, and less than the sum of the maximum charging power, the second total demand power and the maximum absorption power of the residual energy discharge circuit, the vehicle is determined to operate in the second residual energy absorption mode, and the residual energy discharge circuit is controlled to absorb residual energy. When the minimum output power is greater than or equal to the sum of the maximum charging power, the second total demand power, and the maximum absorption power of the residual energy discharge circuit, the vehicle is determined to operate in the third residual energy absorption mode, and the residual energy discharge circuit and the temperature regulation system are both controlled to absorb residual energy.

7. The residual energy discharge control method for fuel cell vehicles according to claim 6, characterized in that, The determination that the vehicle is operating in the second residual energy dissipation mode, and the control of the residual energy discharge circuit to dissipate residual energy, specifically involves: When operating in the second residual energy consumption mode, the output power of the fuel cell system and the consumption power of the residual energy discharge circuit at the next moment are controlled to satisfy: P ReqFCS_next =P FCS_min_next ; P reqCSP =P FCS_min_next -P next -P Bat-max_next ; In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. next P is the second total power demand of the vehicle at the next moment. Bat-max_next This represents the maximum charging power allowed for the power battery at the next moment.

8. The residual energy discharge control method for fuel cell vehicles according to claim 6, characterized in that, The determination that the vehicle operates in the third residual energy consumption mode involves controlling both the residual energy discharge circuit and the temperature regulation system to consume residual energy. Specifically: When operating in the third residual energy consumption mode, upon receiving a cooling command at the current moment, the operating power of the cooling module and the operating power of the heating module at the next moment are controlled to satisfy the following: P reqAC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =P reqAC_next -P T_next ; In the formula, P reqAC_next P represents the operating power of the cooling module at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. next P represents the total power demand of the vehicle at the next moment. Bat-max_next P represents the maximum charging power of the power battery at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit; reqPTC_next The operating power of the heating module in the next moment; When operating in the third residual energy consumption mode, upon receiving a heating command at the current moment, the operating power of the cooling module and the operating power of the heating module at the next moment are controlled to satisfy the following: P reqPTC_next =(P T_next +P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqAC_next =P reqPTC_next -P T_next ; When operating in the third residual energy consumption mode, if no cooling or heating command is received at the current moment, the output power of the fuel cell system and the consumption power of the residual energy discharge circuit at the next moment are controlled to satisfy: P ReqFCS_next =P FCS_min_next ; P reqCSP =P CSP_max ; P reqAC_next =(P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; P reqPTC_next =(P FCS_min_next -P next -P Bat-max_next -P reqCSP ) / 2; In the formula, P ReqFCS_next P represents the output power of the fuel cell system at the next moment. FCS_min_next P represents the minimum allowable output power of the fuel cell system at the next moment. reqCSP P is the power absorbed by the residual energy discharge circuit. CSP_max P is the maximum power absorbed by the residual energy discharge circuit. reqAC_next P represents the operating power of the cooling module at the next moment. next P is the second total power demand of the vehicle at the next moment. reqPTC_next This is the operating power of the heating module for the next moment.

9. The residual energy discharge control method for fuel cell vehicles according to claim 1, characterized in that, The calculation of the change in the total power demand of the fuel cell vehicle between the current time and the next time is specifically as follows: Calculate the first total power demand of the vehicle at the current moment, and calculate the second total power demand of the vehicle at the next moment; Calculate the difference between the first total power demand and the second total power demand to obtain the change value; The specific formula for calculating the first total power demand is as follows: P now =P M_now +P T_nowt +P Acc_nowt ; In the formula, P now P is the first total power demand. M_now P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the current moment. T_nowt P represents the power consumption of the vehicle's temperature regulation system at the current moment. Acc_nowt This represents the power consumed by other high-voltage loads on the vehicle at the current moment. The specific formula for calculating the second total power demand is as follows: P next =P M_next +P T_next +P Acc_next ; In the formula, P next P is the second total power demand. M_next P represents the power consumed by the vehicle's motor controller or the feedback power of the regenerative energy system at the next moment. T_next P represents the power consumption of the vehicle's temperature regulation system at the next moment. Acc_next This is the power consumed by the vehicle's other high-voltage loads in the next moment.

10. A waste energy discharge control system for a fuel cell vehicle, characterized in that, include: The module includes a vehicle power change calculation module, a residual energy consumption method selection module, and a residual energy discharge module. Among them, the vehicle power change value calculation module is used to calculate the change in the total power demand of the fuel cell vehicle between the current moment and the next moment; The waste energy consumption mode selection module is used to obtain and compare the output power of the fuel cell system, the charging power of the power battery, and the consumption power of the waste energy discharge circuit at the next moment when the change value is greater than the maximum allowable power reduction of the fuel cell system, and determine the waste energy consumption mode of the vehicle; wherein, the waste energy consumption mode includes consumption through the waste energy discharge circuit, and / or consumption through the refrigeration module and heating module of the temperature regulation system simultaneously; The residual energy discharge module is used to adjust the operation of the residual energy discharge circuit and / or the temperature regulation system according to the residual energy consumption method.

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