A power control method and system for a fuel cell vehicle

Abstract

The application provides a power control method and system for a fuel cell vehicle, the method comprising: determining a target output power of a fuel cell according to a real-time demand power of a target vehicle; determining a power range of an operation power of an electric drive system of the target vehicle according to the target output power of the fuel cell, a real-time output power of the fuel cell, a lower limit and / or an upper limit of a reachable power of the fuel cell, and a maximum charging power and a maximum discharging power of an auxiliary battery; adjusting the real-time output power of the fuel cell to the target output power of the fuel cell; and controlling the operation power of the electric drive system within the power range during the power adjustment of the fuel cell, thereby improving the stability and safety of the fuel cell vehicle.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy and vehicle control technology, in particular to a power control method and system for a fuel cell vehicle. BACKGROUND

[0002] The fuel cell vehicle is a new energy vehicle technology that has been popular in recent years, which has the characteristics of zero emission, no pollution, high energy efficiency, etc. In the full power type fuel cell vehicle with range extender, the fuel cell is often used as the main auxiliary source of the vehicle, and a small capacity lithium battery or nickel hydrogen battery is often used as an auxiliary power source.

[0003] Since the capacity of the auxiliary battery of the full power type fuel cell vehicle with range extender is usually only a few degrees (most of which do not exceed 5 degrees), the charging and discharging power is limited. At present, there is a relatively obvious defect in the fuel cell system, that is, the change rate of the output power is slow, that is, the power cannot be suddenly increased or decreased, which makes the power control of the full power type fuel cell vehicle in the severe working conditions such as sudden acceleration / sudden deceleration become extremely difficult. Taking the sudden deceleration condition as an example, at this time the power request of the whole vehicle is suddenly changed from a large value to a small value, and the fuel cell needs to quickly reduce its output power to respond to the power request of the whole vehicle. However, since the output power of the fuel cell cannot be suddenly changed, the excess part of the power can only be absorbed by the auxiliary battery, and when the maximum allowable charging power of the auxiliary battery is still lower than the difference between the output power of the fuel cell and the demand power of the whole vehicle, it will cause the auxiliary battery to overcurrent, the whole vehicle to fail to sudden decelerate, or the fuel cell to be blocked, etc. SUMMARY

[0004] In view of the above technical problems, the present application provides a power control method and system for a fuel cell vehicle, which eliminates potential vehicle failures caused by the inability of the fuel cell output power to suddenly change, and improves the stability and safety of the fuel cell vehicle operation.

[0005] In a first aspect, the present application provides a power control method for a fuel cell vehicle, comprising:

[0006] determining the target output power of the fuel cell according to the real-time demand power of the target vehicle;

[0007] determining the power range of the power system operation power of the target vehicle according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower limit and / or upper limit of the power that the fuel cell can reach, and the maximum charging power and the maximum discharging power of the auxiliary battery;

[0008] adjusting the real-time output power of the fuel cell to the target output power of the fuel cell;

[0009] During the power adjustment process of the fuel cell, the operating power of the electric drive system is controlled within the specified power range.

[0010] This application provides a power control method for fuel cell vehicles. By analyzing the real-time power demand of the fuel cell vehicle and the real-time status of the fuel cell and auxiliary battery, the target output power of the fuel cell at the next moment is determined. Simultaneously, considering the relatively slow rate of change of the fuel cell's output power, the power range of the electric drive system's operating power is determined based on the maximum rate of change of the fuel cell's output power and the maximum charge / discharge power of the auxiliary battery. While adjusting the real-time output power of the fuel cell, the operating power of the electric drive system is controlled within the stated power range, ensuring that the changes in the electric drive system's operating power match the changes in the fuel cell's real-time output power. This reduces the charging and discharging pressure on the auxiliary battery, avoids malfunctions such as auxiliary battery overcurrent, sudden vehicle deceleration failure, or fuel cell blockage caused by excessively drastic changes in the electric drive system's operating power, and improves the stability and safety of the fuel cell vehicle's operation.

[0011] In one possible implementation, if the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, then the power range of the electric drive system operating power of the target vehicle is determined based on the target output power of the fuel cell, the real-time output power of the fuel cell, the lower and / or upper power limits achievable by the fuel cell, and the maximum charging and discharging power of the auxiliary battery, using the following formula:

[0012] Max(P target ,P 下限 )-P HVPart -P bat_char_max ≤P VCUReqMCU

[0013] ≤Max(P target ,P 下限 )-P HVPart +P bat_dis_max

[0014] Among them, P target P represents the target output power of the fuel cell. 下限 P represents the lower limit of the achievable power of the fuel cell. HVPart P represents the power requirement of the high-voltage accessories of the target vehicle. bat_char_max P is the maximum charging power of the auxiliary battery. VCUReqMCU P represents the operating power of the electric drive system of the target vehicle. bat_dis_max This represents the maximum discharge power of the auxiliary battery.

[0015] In the embodiments of the present application, when the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, it is necessary to reduce the real-time output power of the fuel cell. Since the power output of the fuel cell has hysteresis, after the VCU (vehicle control unit) sends a power request to the FCU (fuel cell control unit), if the power change amplitude is large, the fuel cell often needs a long time to adjust to the target output power, and therefore it is necessary to limit the operating power of the electric drive system in this process to avoid the operating power of the electric drive system exceeding the safe power range composed of the fuel cell and the auxiliary battery. If the target output power requested by the VCU to the FCU increases sharply, the power upper limit of the MCU (motor control unit) is controlled, so that the actual total power is lower than (the maximum discharge power allowed by the auxiliary battery) + (the maximum value between the power lower limit that can be reached in the fuel cell power sampling period and the target output power), that is, the power of the whole vehicle is guaranteed, and the fuel cell and the auxiliary battery can operate in the safe power range to avoid failure of the fuel cell or the auxiliary battery. Similarly, if the target output power requested by the VCU to the FCU decreases sharply, the power lower limit of the MCU is controlled, so that the actual total power is higher than (the maximum value between the power lower limit that can be reached in the fuel cell power sampling period and the target output power) - (the maximum charge power allowed by the auxiliary battery), which effectively improves the stability and safety of the fuel cell vehicle operation.

[0016] Further, the specific calculation formula of the power lower limit that can be reached by the fuel cell is:

[0017] P 下限 = P fc -△P fc ×△t

[0018] Wherein, P fc is the real-time output power of the fuel cell,△P fc is the maximum output power change rate of the fuel cell, and△t is the sampling interval time of the vehicle control system.

[0019] In a possible implementation manner, if the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the power range of the operating power of the electric drive system of the target vehicle is determined according to the target output power of the fuel cell, the real-time output power of the fuel cell, the power lower limit and / or upper limit that can be reached by the fuel cell, and the maximum charge power and the maximum discharge power of the auxiliary battery, and the specific formula is:

[0020] Min(P target ,P 上限 )-P HVPart -P bat_char_max ≤P VCUReqMCU

[0021] ≤ Min(P target , P 上限 ) - P HVPart + P bat_dis_max

[0022] P target = P 上限 + P HVPart + P bat_char_max + P VCUReqMCU + P bat_dis_max + P

[0023] Further, the specific calculation formula of the upper limit of the power that the fuel cell can reach is:

[0024] P 上限 = P fc + ΔP fc × Δt

[0025] P fc is the real-time output power of the fuel cell, ΔP fc is the maximum output power change rate of the fuel cell, and Δt is the sampling interval time of the vehicle control system.

[0026] In the embodiments of the present application, when the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the real-time output power of the fuel cell needs to be increased. Similarly, during the power adjustment of the fuel cell, the operation power of the electric drive system needs to be limited to avoid the operation power of the electric drive system exceeding the safe power range composed of the fuel cell and the auxiliary battery, thereby effectively improving the stability and safety of the fuel cell vehicle operation.

[0027] Further, the real-time demand power of the target vehicle is calculated according to the real-time operation data of the target vehicle, including:

[0028] calculating the driving demand power of the target vehicle according to the accelerator pedal opening degree of the target vehicle, the current torque of the motor, and the current rotating speed of the motor;

[0029] calculating the high-voltage accessory demand power of the target vehicle according to the current input voltage, input current value, and vehicle state of the high-voltage accessory of the target vehicle;

[0030] determining the real-time demand power of the target vehicle according to the driving demand power and the high-voltage accessory demand power.

[0031] The embodiment of the present application provides a method for calculating real-time demand power, which realizes the calculation of the real-time demand power of a target vehicle by monitoring and calculating the driving demand power and the high-voltage accessory demand power of the target vehicle at the current time, and provides a data basis for subsequent power control.

[0032] Further, the real-time output power of the fuel cell is obtained according to the real-time running data of the target vehicle, including: obtaining the real-time output power of the fuel cell through a fuel cell controller of the target vehicle, or collecting the real-time output voltage and the real-time output current of the fuel cell, and then calculating the real-time output power of the fuel cell according to the real-time output voltage and the real-time output current.

[0033] In a possible implementation, when the real-time state of charge of the auxiliary battery is lower than the preset expected value, the target output power of the fuel cell is determined according to the real-time demand power of the target vehicle, including:

[0034] When the real-time demand power is less than or equal to the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the output power corresponding to the highest energy efficiency point of the fuel cell.

[0035] In a possible implementation, when the real-time state of charge of the auxiliary battery is lower than the preset expected value, the target output power of the fuel cell is determined according to the real-time demand power of the target vehicle, including:

[0036] When the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the sum of the real-time demand power and the planned charging power of the auxiliary battery, wherein the planned charging power is determined according to the difference between the real-time state of charge of the auxiliary battery and the preset expected value.

[0037] Further, when the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the sum of the real-time demand power and the planned charging power of the auxiliary battery, and the specific formula is:

[0038] P target = P + P bat_char_max × (S0C - SOC exp ) / △S0C

[0039] Wherein, P target is the target output power of the fuel cell, P is the real-time demand power, and P bat_char_maxS0C is the real-time state of charge of the auxiliary battery exp △S0C is the difference between the maximum SOC limit value of the auxiliary battery allowed to be charged and the minimum SOC limit value allowed to be discharged.

[0040] Further, the power control method further comprises: when the real-time output power of the fuel cell is adjusted to the target output power of the fuel cell, charging the auxiliary battery according to the difference between the target output power of the fuel cell and the real-time demand power.

[0041] The embodiment of the present application further considers the case of low power of the auxiliary battery. Since the power output of the fuel cell has hysteresis, the difference between the real-time output power of the fuel cell and the running power of the electric drive system needs to rely on the auxiliary battery for power compensation. When the real-time state of charge of the auxiliary battery is lower than the preset expected value, the power compensation of the auxiliary battery may fail at any time, affecting the stable operation of the vehicle. At this time, when determining the target output power, not only the balance between the real-time output power of the fuel cell and the running power of the electric drive system needs to be considered, but also the charging of the auxiliary battery by the excess output power of the fuel cell in time. Therefore, in the embodiment of the present application, first, the real-time demand power is compared with the output power corresponding to the highest energy efficiency point of the fuel cell. When the real-time demand power is less than or equal to the output power corresponding to the highest energy efficiency point of the fuel cell, the fuel cell can be controlled to output at the output power corresponding to the highest energy efficiency point. On the one hand, the power supply demand of the whole vehicle can be met at the highest energy efficiency, and on the other hand, the excess output power can also charge the auxiliary battery at the same time. When the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the highest efficiency point is no longer the primary consideration factor of the fuel cell, and the most suitable power of the auxiliary battery (or the health degree of the battery) becomes the primary consideration factor. On the one hand, the vehicle is driven and the high-voltage electrical appliances are powered, and on the other hand, the auxiliary battery is charged linearly according to the deviation of the battery power from the expected value. While ensuring the normal operation of the fuel cell vehicle, the power of the auxiliary battery is gradually restored, and the stability and safety of the vehicle operation are improved.

[0042] Secondly, the present application provides a power control system for a fuel cell vehicle, comprising a battery target power determination module, an electric drive power range determination module, a battery power adjustment module, and an electric drive power control module.

[0043] The battery target power determination module is configured to determine the target output power of the fuel cell according to the real-time demand power of the target vehicle.

[0044] The electric drive power range determination module is configured to determine a power range of the electric drive system operating power of the target vehicle according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower limit and / or upper limit of the power reachable by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery.

[0045] The battery power adjustment module is configured to adjust the real-time output power of the fuel cell to the target output power of the fuel cell.

[0046] The electric drive power control module is configured to control the electric drive system operating power within the power range during the power adjustment of the fuel cell. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 FIG. 1 is a flow diagram of a power control method for a fuel cell vehicle according to an embodiment of the present application.

[0048] Figure 2 FIG. 2 is a structural diagram of a power control system for a fuel cell vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0050] It should be noted that the step numbers in the text are only for the convenience of explaining the specific embodiments, and do not serve as the basis for limiting the execution sequence of the steps. In the description of the present application, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features.

[0051] Throughout the specification, the fuel cell vehicle and the target vehicle described in the present specification are any vehicle equipped with a fuel cell and an auxiliary battery, wherein the fuel cell serves as the main power source of the vehicle, the auxiliary battery serves as an auxiliary power source, and the auxiliary battery can be charged by the fuel cell.

[0052] Embodiment One:

[0053] As shown in FIG. 1, embodiment one provides a power control method for a fuel cell vehicle, comprising steps S1-S4: Figure 1 The power control method for a fuel cell vehicle comprises the following steps:

[0054] Step S1, determining a target output power of a fuel cell according to a real-time demand power of a target vehicle;

[0055] Step S2, determining a power range of an electric drive system operating power of the target vehicle according to the target output power of the fuel cell, a real-time output power of the fuel cell, a lower limit and / or an upper limit of a reachable power of the fuel cell, and a maximum charging power and a maximum discharging power of an auxiliary battery;

[0056] Step S3, adjusting the real-time output power of the fuel cell to the target output power of the fuel cell;

[0057] Step S4, controlling the electric drive system operating power in the power range during the power adjustment of the fuel cell.

[0058] The present application provides a power control method for a fuel cell vehicle, by analyzing a real-time demand power of the fuel cell vehicle and real-time states of the fuel cell and the auxiliary battery, a target output power of the fuel cell at a next time is determined. Meanwhile, considering the feature that the output power of the fuel cell changes slowly, a power range of an electric drive system operating power is determined according to a maximum output power change rate of the fuel cell and a maximum charging and discharging power of the auxiliary battery. While adjusting the real-time output power of the fuel cell, the electric drive system operating power is controlled in the power range, so that the change of the electric drive system operating power matches the change of the real-time output power of the fuel cell, the charging and discharging pressure of the auxiliary battery is reduced, and the faults such as overcurrent of the auxiliary battery, invalidation of sudden deceleration of the whole vehicle, and blockage of the fuel cell caused by too drastic change of the electric drive system operating power are avoided, so that the stability and safety of the fuel cell vehicle operation are improved.

[0059] Further, in step S1, the real-time demand power of the target vehicle is calculated according to real-time operation data of the target vehicle, including:

[0060] calculating a driving demand power of the target vehicle according to a throttle opening degree of the target vehicle, a current torque of the motor, and a current rotating speed of the motor;

[0061] calculating a high-voltage accessory demand power of the target vehicle according to a current input voltage, a current input current value of the high-voltage accessory of the target vehicle, and a vehicle state;

[0062] determining the real-time demand power of the target vehicle according to the driving demand power and the high-voltage accessory demand power.

[0063] The high-voltage accessories refer to all high-voltage components in the target vehicle except for the electric drive system. Calculating the power requirement of the high-voltage accessories of the target vehicle typically involves multiplying the current and voltage of each high-voltage accessory to obtain their individual power requirements, and then summing these to obtain the total power requirement of the target vehicle's high-voltage accessories. For the drive power requirement of the target vehicle, a power lookup table is usually preset in the vehicle system. This table records the drive power requirement corresponding to different accelerator pedal openings, current motor torque, and current motor speed. During vehicle operation, the vehicle system only needs to look up the table based on the current accelerator pedal opening, current motor torque, and current motor speed to obtain the corresponding drive power requirement. Furthermore, the real-time power requirement of the target vehicle is determined based on the drive power requirement and the power requirement of the high-voltage accessories using the following formula:

[0064] P = P m0 +P HVPart

[0065] Where P is the real-time power demand, P m0 For the drive power requirement, P HVPart The required power for the high-voltage accessory.

[0066] This application provides a method for calculating real-time power demand. By monitoring and calculating the current driving power demand and high-voltage accessory power demand of a fuel cell vehicle, the real-time power demand of the target vehicle can be calculated, providing a data basis for subsequent power control.

[0067] In one possible implementation, in step S1, when the real-time charge of the auxiliary battery is lower than a preset expected value, determining the target output power of the fuel cell based on the real-time power demand of the target vehicle includes:

[0068] When the real-time demand power is less than or equal to the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined to be the output power corresponding to the highest energy efficiency point of the fuel cell.

[0069] Furthermore, when the real-time power demand is less than or equal to the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined to be the output power corresponding to the highest energy efficiency point of the fuel cell, and the specific formula is as follows:

[0070] P target =P fc-eff

[0071] Among them, P target P represents the target output power of the fuel cell.fc-eff The output power corresponding to the highest energy efficiency point of the fuel cell. When the total power demand of the vehicle is lower than the power corresponding to the output power corresponding to the highest energy efficiency point of the fuel cell, the fuel cell outputs power corresponding to the output power corresponding to the highest energy efficiency point of the fuel cell, which can supply power to the vehicle with the highest energy efficiency and charge the auxiliary battery at the same time.

[0072] In one possible implementation, in step S1, when the real-time state of charge of the auxiliary battery is lower than the preset expected value, the target output power of the fuel cell is determined according to the real-time power demand of the target vehicle, including:

[0073] When the real-time power demand is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the sum of the real-time power demand and the planned charging power of the auxiliary battery, wherein the planned charging power is determined according to the difference between the real-time state of charge of the auxiliary battery and the preset expected value.

[0074] Further, when the real-time power demand is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the sum of the real-time power demand and the planned charging power of the auxiliary battery, and the specific formula is:

[0075] P target = P + P bat_char_max × (SOC - SOC exp ) / △SOC

[0076] wherein P target is the target output power of the fuel cell, P is the real-time power demand, P bat_char_max is the maximum charging power of the auxiliary battery, SOC is the real-time state of charge of the auxiliary battery, SOC exp is the preset expected value, and △SOC is the difference between the maximum SOC limit value allowed to be charged and the minimum SOC limit value allowed to be discharged.

[0077] In this embodiment, when the total power demand of the vehicle is greater than the power corresponding to the output power corresponding to the highest energy efficiency point of the fuel cell, the fuel cell calculates the output power according to the real-time power demand of the vehicle, the maximum chargeable power of the auxiliary battery, and the state of charge deviation of the auxiliary battery.

[0078] Further, in step S2, the real-time output power of the fuel cell is calculated according to the real-time running data of the target vehicle, including: obtaining the real-time output power of the fuel cell through the fuel cell controller of the target vehicle, or collecting the real-time output voltage and the real-time output current of the fuel cell, and then calculating the real-time output power of the fuel cell according to the real-time output voltage and the real-time output current.

[0079] In one possible implementation, in step S2, if the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, the power range of the running power of the electric drive system of the target vehicle is determined according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower limit and / or the upper limit of the reachable power of the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery, and the specific formula is:

[0080] Max(P target ,P 下限 )-P HVPart -P bat_char_max ≤P VCUReqMCU

[0081] ≤Max(P target ,P 下限 )-P HVPart +P bat_dis_max

[0082] wherein P target is the target output power of the fuel cell, P 下限 is the lower limit of the reachable power of the fuel cell, P HVPart is the high-voltage accessory demand power of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the running power of the electric drive system of the target vehicle, and P bat_dis_max is the maximum discharging power of the auxiliary battery.

[0083] In the embodiment of the present application, when the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, the real-time output power of the fuel cell needs to be reduced. Since the power output of the fuel cell has hysteresis, after the VCU (vehicle control unit) sends a power request to the FCU (fuel cell control unit), if the power change amplitude is large, the fuel cell often needs a long time to adjust to the target output power, and therefore the operating power of the electric drive system needs to be limited in this process to avoid the operating power of the electric drive system exceeding the safe power range composed of the fuel cell and the auxiliary battery. If the target output power requested by the VCU to the FCU increases sharply, the power upper limit of the MCU (motor control unit) is controlled, so that the actual total power is lower than (the maximum discharge power allowed by the auxiliary battery) + (the maximum value between the power lower limit that can be reached in the fuel cell power sampling period and the target output power), that is, the power of the whole vehicle is guaranteed, and the fuel cell and the auxiliary battery can operate in the safe power range to avoid failure of the fuel cell or the auxiliary battery. Similarly, if the target output power requested by the VCU to the FCU decreases sharply, the power lower limit of the MCU is controlled, so that the actual total power is higher than (the maximum value between the power lower limit that can be reached in the fuel cell power sampling period and the target output power) - (the maximum charge power allowed by the auxiliary battery), which effectively improves the stability and safety of the fuel cell vehicle operation.

[0084] Further, the specific calculation formula of the power lower limit that can be reached by the fuel cell is:

[0085] P 下限 = P fc -△P fc ×△t

[0086] Wherein, P fc is the real-time output power of the fuel cell,△P fc is the maximum output power change rate of the fuel cell, and△t is the sampling interval time of the vehicle control system.

[0087] In a possible implementation manner, in step S2, if the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the power range of the operating power of the electric drive system of the target vehicle is determined according to the target output power of the fuel cell, the real-time output power of the fuel cell, the power lower limit and / or upper limit that can be reached by the fuel cell, and the maximum charge power and the maximum discharge power of the auxiliary battery, and the specific formula is:

[0088] Min(P target ,P 上限 )-P HVPart -P bat_char_max ≤P VCUReqMCU

[0089] ≤ Min(P target , P 上限 )-P HVPart +P bat_dis_max

[0090] wherein P target is the target output power of the fuel cell, P 上限 is the upper limit of the power that the fuel cell can reach, P HVPart is the high-voltage accessory demand power of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the electric drive system operating power of the target vehicle, and P bat_dis_max is the maximum discharging power of the auxiliary battery.

[0091] Further, the specific calculation formula of the upper limit of the power that the fuel cell can reach is:

[0092] P 上限 = P fc +△P fc ×△t

[0093] wherein P fc is the real-time output power of the fuel cell,△P fc is the maximum output power variation rate of the fuel cell, and△t is the sampling interval time of the vehicle control system.

[0094] In the embodiments of the present application, when the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the real-time output power of the fuel cell needs to be increased. Similarly, during the power adjustment of the fuel cell, the operating power of the electric drive system needs to be limited to avoid the operating power of the electric drive system exceeding the safe power range composed of the fuel cell and the auxiliary battery, thereby effectively improving the stability and safety of the fuel cell vehicle operation.

[0095] In a preferred embodiment, step S2 is combined with step S1. When the real-time state of charge of the auxiliary battery is lower than the preset expected value, if the real-time demand power is less than or equal to the output power corresponding to the highest energy efficiency point of the fuel cell, and the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, the power range of the electric drive system operating power of the target vehicle is specifically:

[0096] Max(P fc-eff , P fc -△P fc ×△t)-P HVPart -P bat_char_max ≤P VCUReqMCU

[0097] ≤ Max(P fc-eff , P fc -△P fc ×△t)-P HVPart +P bat_dis_max

[0098] When the real-time state of charge of the auxiliary battery is lower than the preset expected value, if the real-time demand power is less than or equal to the output power corresponding to the maximum energy efficiency point of the fuel cell, and the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the power range of the power of the electric drive system of the target vehicle is specifically:

[0099] Min(P fc-eff , P fc +△P fc ×△t)-P HVPart -P bat_char_max ≤P VCUReqMCU

[0100] ≤ Min(P fc-eff , P fc +△P fc ×△t)-P HVPart +P bat_dis_max

[0101] On the other hand, when the real-time state of charge of the auxiliary battery is lower than the preset expected value, if the real-time demand power is greater than the output power corresponding to the maximum energy efficiency point of the fuel cell, and the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, the power range of the power of the electric drive system of the target vehicle is specifically:

[0102] Max(P+P bat_char_max ×(S0C-SOC exp ) / △S0C, P fc -△P fc ×△t)-P HVPart

[0103] -P bat_char_max ≤P VCUReqMCU

[0104] ≤ Max(P+P bat_char_max ×(S0C-SOC exp ) / △S0C, P fc -△P fc ×

[0105] △t)-P HVPart +P bat_dis_max

[0106] When the real-time SOC of the auxiliary battery is lower than the preset expected value, if the real-time required power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, and the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the power range of the power of the electric drive system of the target vehicle is specifically:

[0107] Min(P+P bat_char_max ×(S0C-SOC exp ) / △S0C,P fc +△P fc ×△t)-P HVPart

[0108] -P bat_char_max ≤P VCUReqMCU

[0109] ≤Min(P+P bat_char_max ×(S0C-SOC exp ) / △S0C,P fc +△P fc ×

[0110] △t)-P HVPart +P bat_dis_max

[0111] Further, the power control method further comprises: when the real-time output power of the fuel cell is adjusted to the target output power of the fuel cell, charging the auxiliary battery according to the difference between the target output power of the fuel cell and the real-time required power.

[0112] The embodiments of the present application further consider the case of low power of the auxiliary battery. Since the power output of the fuel cell has hysteresis, the difference between the real-time output power of the fuel cell and the operating power of the electric drive system needs to rely on the auxiliary battery for power compensation. When the real-time state of charge of the auxiliary battery is lower than the preset expected value, the power compensation of the auxiliary battery may fail at any time, affecting the stable operation of the vehicle. At this time, when determining the target output power, not only the balance between the real-time output power of the fuel cell and the operating power of the electric drive system needs to be considered, but also the charging of the auxiliary battery by the excess output power of the fuel cell needs to be considered. Therefore, in the embodiments of the present application, first, the real-time demand power is compared with the output power corresponding to the highest energy efficiency point of the fuel cell. When the real-time demand power is less than or equal to the output power corresponding to the highest energy efficiency point of the fuel cell, the fuel cell can be controlled to output at the output power corresponding to the highest energy efficiency point. On the one hand, the power supply demand of the whole vehicle can be met at the highest energy efficiency, and on the other hand, the excess output power can also charge the auxiliary battery at the same time. When the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the highest efficiency point of the fuel cell is no longer the primary consideration factor, and the most suitable state of charge (or the health degree of the battery) of the auxiliary battery becomes the primary consideration factor. On the one hand, the vehicle is driven and the high-voltage electrical appliances are powered, and on the other hand, the auxiliary battery is charged according to the deviation degree of the state of charge of the battery from the expected value. While ensuring the normal operation of the fuel cell vehicle, the state of charge of the auxiliary battery is gradually restored, and the stability and safety of the vehicle operation are improved.

[0113] In summary, the beneficial effects of the embodiments of the present application are:

[0114] (1) A power control method for a fuel cell vehicle is provided. By the limiting method, potential vehicle failures caused by the non-mutability of the output power of the fuel cell system can be eliminated.

[0115] (2) A method for calculating the target output power of the fuel cell in the case of low power of the auxiliary battery is provided. The method is around the output power value P fc-eff of the highest energy efficiency point of the fuel cell system. The method can greatly improve the energy efficiency of the whole vehicle.

[0116] (3) An auxiliary battery charging control method in the case of low power of the auxiliary battery is provided. The auxiliary battery is charged at P bat_char_max ×(S0C-SOC exp ) / △S0C or P fc-eff -P VCUReqMCU -P HVPart , so that the auxiliary battery can be continuously charged under low power.

[0117] (4)On the one hand, the output power of the fuel cell is accurately calculated, on the other hand, the demand power change rate of the drive system is limited, and the charging and discharging behavior of the auxiliary battery under low power is reasonably controlled. Through the cooperation of the three, not only can potential vehicle failures caused by the sudden change of the output power of the fuel cell system be avoided, but also the vehicle can work at a high efficiency working point, and the auxiliary battery can be continuously charged under low power, that is, the advantages of sufficient vehicle power, high safety, low energy consumption, small auxiliary battery damage and smooth vehicle operation are achieved.

[0118] Embodiment two:

[0119] As shown in Figure 2 , embodiment two provides a power control system for a fuel cell vehicle, comprising a battery target power determination module 10, an electric drive power range determination module 20, a battery power adjustment module 30 and an electric drive power control module 40;

[0120] The battery target power determination module 10 is configured to determine the target output power of the fuel cell according to the real-time demand power of the target vehicle;

[0121] The electric drive power range determination module 20 is configured to determine the power range of the electric drive system operating power of the target vehicle according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower limit and / or upper limit of the power that the fuel cell can reach, and the maximum charging power and the maximum discharging power of the auxiliary battery;

[0122] The battery power adjustment module 30 is configured to adjust the real-time output power of the fuel cell to the target output power of the fuel cell;

[0123] The electric drive power control module 40 is configured to control the electric drive system operating power within the power range during the power adjustment of the fuel cell.

[0124] In one possible implementation, if the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, the electric drive power range determination module 20 determines the power range of the electric drive system operating power of the target vehicle according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower limit and / or upper limit of the power that the fuel cell can reach, and the maximum charging power and the maximum discharging power of the auxiliary battery, and the specific formula is:

[0125] Max(P target ,P 下限 )-P HVPart -P bat_char_max ≤P VCUReqMCU

[0126] ≤ Max(P target , P 下限 ) - P HVPart + P bat_dis_max

[0127] wherein P target is the target output power of the fuel cell, P 下限 is the lower limit of the power achievable by the fuel cell, P HVPart is the high-voltage accessory demand power of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the electric drive system operating power of the target vehicle, and P bat_dis_max is the maximum discharging power of the auxiliary battery.

[0128] Further, the specific calculation formula of the lower limit of the power achievable by the fuel cell is:

[0129] P 下限 = P fc - ΔP fc × Δt

[0130] wherein P fc is the real-time output power of the fuel cell, ΔP fc is the maximum output power change rate of the fuel cell, and Δt is the sampling interval time of the vehicle control system.

[0131] In one possible implementation, if the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the electric drive power range determination module 20 determines the power range of the electric drive system operating power of the target vehicle according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower limit and / or upper limit of the power achievable by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery, and the specific formula is:

[0132] Min(P target , P 上限 ) - P HVPart - P bat_char_max ≤ P VCUReqMCU

[0133] ≤ Min(P target , P fc + ΔP fc × Δt) - P HVPart + P bat_dis_max

[0134] wherein P target is the target output power of the fuel cell, P 上限P HVPart P bat_char_max P VCUReqMCU P bat_dis_max P

[0135] Further, the specific formula of the upper limit of the power that the fuel cell can reach is:

[0136] P 上限 = P fc +△P fc ×△t

[0137] Wherein, P fc is the real-time output power of the fuel cell,△P fc is the maximum output power change rate of the fuel cell,△t is the sampling interval time of the vehicle control system.

[0138] Further, the real-time demand power of the target vehicle is calculated according to the real-time running data of the target vehicle, including:

[0139] According to the accelerator pedal opening degree of the target vehicle, the current torque of the motor and the current speed of the motor, the driving demand power of the target vehicle is calculated;

[0140] According to the current input voltage, input current value and vehicle state of the high-voltage accessory of the target vehicle, the high-voltage accessory demand power of the target vehicle is calculated;

[0141] According to the driving demand power and the high-voltage accessory demand power, the real-time demand power of the target vehicle is determined.

[0142] Further, the real-time output power of the fuel cell is calculated according to the real-time running data of the target vehicle, including: obtaining the real-time output power of the fuel cell through the fuel cell controller of the target vehicle, or collecting the real-time output voltage and real-time output current of the fuel cell, and then calculating the real-time output power of the fuel cell according to the real-time output voltage and the real-time output current.

[0143] In a possible implementation manner, when the real-time state of charge of the auxiliary battery is lower than the preset expected value, the battery target power determination module 10 determines the target output power of the fuel cell according to the real-time demand power of the target vehicle, including:

[0144] When the real-time demand power is less than or equal to the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the output power corresponding to the highest energy efficiency point of the fuel cell.

[0145] In a possible implementation, when the real-time state of charge of the auxiliary battery is lower than the preset expected value, the battery target power determination module 10 determines the target output power of the fuel cell according to the real-time demand power of the target vehicle, including:

[0146] When the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the sum of the real-time demand power and the planned charging power of the auxiliary battery, wherein the planned charging power is determined according to the difference between the real-time state of charge of the auxiliary battery and the preset expected value.

[0147] Further, when the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the sum of the real-time demand power and the planned charging power of the auxiliary battery, and the specific formula is:

[0148] P target = P + P bat_char_max × (SOC0 - SOC exp ) / △SOC

[0149] wherein P target is the target output power of the fuel cell, P is the real-time demand power, P bat_char_max is the maximum charging power of the auxiliary battery, SOC0 is the real-time state of charge of the auxiliary battery, SOC exp is the preset expected value, and △SOC is the difference between the maximum SOC limit value allowed to be charged and the minimum SOC limit value allowed to be discharged of the auxiliary battery.

[0150] In a possible implementation, the power control system further includes a charging module, configured to charge the auxiliary battery according to the difference between the target output power of the fuel cell and the real-time demand power when the real-time output power of the fuel cell is adjusted to the target output power of the fuel cell.

[0151] The application provides a power control system for a fuel cell vehicle, which determines a target output power of a fuel cell at a next moment by analyzing real-time demand power of the fuel cell vehicle and real-time states of the fuel cell and an auxiliary battery. Meanwhile, considering that the output power of the fuel cell changes slowly, a power range of the power of an electric drive system is determined according to a maximum output power change rate of the fuel cell and a maximum charge-discharge power of the auxiliary battery. The real-time output power of the fuel cell is adjusted, and the power of the electric drive system is controlled within the power range, so that the change of the power of the electric drive system matches the change of the real-time output power of the fuel cell, the charge-discharge pressure of the auxiliary battery is reduced, and the faults such as overcurrent of the auxiliary battery, failure of sudden deceleration of the vehicle or blockage of the fuel cell caused by too sharp change of the power of the electric drive system are avoided, so that the stability and safety of the fuel cell vehicle are improved.

[0152] The working principle and step flow of the embodiment are described in detail, but are not limited to the description in the embodiment one.

[0153] The above specific embodiments further illustrate the purpose, technical solutions and advantages of the application. It should be understood that the above description is only for specific embodiments of the application and is not used to limit the protection scope of the application. It is particularly pointed out that any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A power control method for a fuel cell vehicle, characterized by, The method comprises the following steps: determining a target output power of a fuel cell according to a real-time demand power of a target vehicle; determining a power range of an operation power of an electric drive system of the target vehicle according to the target output power of the fuel cell, a real-time output power of the fuel cell, a lower limit and / or an upper limit of a reachable power of the fuel cell, and a maximum charging power and a maximum discharging power of an auxiliary battery; if the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, the power range of the operation power of the electric drive system of the target vehicle is determined according to the following formula: wherein, is a target output power of the fuel cell, is a lower limit of power achievable by the fuel cell, is a high-voltage accessory demand power of the target vehicle, is a maximum charging power of the auxiliary battery, is an electric drive system operating power of the target vehicle, is a maximum discharging power of the auxiliary battery; if the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the power range of the operation power of the electric drive system of the target vehicle is determined according to the following formula: wherein, is a target output power of the fuel cell, is an upper limit of power achievable by the fuel cell, is a high-voltage accessory demand power of the target vehicle, is a maximum charging power of the auxiliary battery, is an electric drive system operating power of the target vehicle, is a maximum discharging power of the auxiliary battery; adjusting the real-time output power of the fuel cell to the target output power of the fuel cell; controlling the operation power of the electric drive system within the power range during the power adjustment of the fuel cell.

2. A power control method for a fuel cell vehicle according to claim 1, characterized by, The specific calculation formula of the lower limit of the reachable power of the fuel cell is as follows: wherein, is a real-time output power of the fuel cell, is a maximum output power change rate of the fuel cell, is a sampling interval time of the vehicle control system.

3. The power control method for a fuel cell vehicle according to claim 1, characterized by, The specific calculation formula of the upper limit of the reachable power of the fuel cell is as follows: wherein, is a real-time output power of the fuel cell, is a maximum output power change rate of the fuel cell, is a sampling interval time of the vehicle control system.

4. The power control method for a fuel cell vehicle according to claim 1, characterized by, The real-time demand power of the target vehicle is calculated according to real-time operation data of the target vehicle, which comprises the following steps: calculating a driving demand power of the target vehicle according to an accelerator pedal opening degree of the target vehicle, a current torque of an electric motor, and a current rotating speed of the electric motor; calculating a high-voltage accessory demand power of the target vehicle according to a current input voltage, a current input current value of a high-voltage accessory of the target vehicle, and a vehicle state; determining the real-time demand power of the target vehicle according to the driving demand power and the high-voltage accessory demand power.

5. The power control method for a fuel cell vehicle according to claim 1, characterized by, The real-time output power of the fuel cell is calculated according to real-time operation data of the target vehicle, which comprises the following steps: acquiring the real-time output power of the fuel cell through a fuel cell controller of the target vehicle, or collecting a real-time output voltage and a real-time output current of the fuel cell, and then calculating the real-time output power of the fuel cell according to the real-time output voltage and the real-time output current.

6. A power control method for a fuel cell vehicle according to any one of claims 1 to 5, characterized by, When the real-time state of charge of the auxiliary battery is lower than a preset expected value, the determination of the target output power of the fuel cell according to the real-time demand power of the target vehicle comprises the following steps: when the real-time demand power is less than or equal to an output power corresponding to a highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as the output power corresponding to the highest energy efficiency point of the fuel cell.

7. A power control method for a fuel cell vehicle according to any one of claims 1 to 5, characterized by, When the real-time state of charge of the auxiliary battery is lower than a preset expected value, the determination of the target output power of the fuel cell according to the real-time demand power of the target vehicle comprises the following steps: when the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the target output power of the fuel cell is determined as a sum of the real-time demand power and a planned charging power of the auxiliary battery, wherein the planned charging power is determined according to a difference between the real-time state of charge of the auxiliary battery and the preset expected value.

8. A power control method for a fuel cell vehicle as defined in claim 7, characterized by, The target output power of the fuel cell is determined as the sum of the real-time demand power and the planned charging power of the auxiliary battery when the real-time demand power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, and the specific formula is: wherein, is a target output power of the fuel cell, is the real-time demand power, is a maximum charging power of the auxiliary battery, is a real-time state of charge of the auxiliary battery, is the preset desired value, is a difference between a maximum SOC limit value for allowing charging and a minimum SOC limit value for allowing discharging of the auxiliary battery.

9. A power control method for a fuel cell vehicle according to any one of claims 1 to 5, characterized by, The power control method further comprises: when the real-time output power of the fuel cell is adjusted to the target output power of the fuel cell, charging the auxiliary battery according to the difference between the target output power of the fuel cell and the real-time demand power.

10. A power control system for a fuel cell vehicle, characterized by comprising: The power control method comprises a battery target power determination module, an electric drive power range determination module, a battery power adjustment module, and an electric drive power control module. The battery target power determination module is configured to determine the target output power of the fuel cell according to the real-time demand power of the target vehicle. The electric drive power range determination module is configured to determine the power range of the electric drive system operating power of the target vehicle according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower limit and / or upper limit of the power that can be reached by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery. If the target output power of the fuel cell is less than or equal to the real-time output power of the fuel cell, the power range of the electric drive system operating power of the target vehicle is determined according to the following formula: wherein, is a target output power of the fuel cell, is a lower limit of power achievable by the fuel cell, is a high-voltage accessory demand power of the target vehicle, is a maximum charging power of the auxiliary battery, is an electric drive system operating power of the target vehicle, is a maximum discharging power of the auxiliary battery; If the target output power of the fuel cell is greater than the real-time output power of the fuel cell, the power range of the electric drive system operating power of the target vehicle is determined according to the following formula: wherein, is a target output power of the fuel cell, is an upper limit of power achievable by the fuel cell, is a high-voltage accessory demand power of the target vehicle, is a maximum charging power of the auxiliary battery, is an electric drive system operating power of the target vehicle, is a maximum discharging power of the auxiliary battery; The battery power adjustment module is configured to adjust the real-time output power of the fuel cell to the target output power of the fuel cell. The electric drive power control module is configured to control the electric drive system operating power within the power range during the power adjustment of the fuel cell.

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