Power control method and system for fuel cell vehicle

Abstract

The invention provides a power control method and system for a fuel cell vehicle. The method comprises the steps that the target output power of a fuel cell is determined according to the real-time demand power of a 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 the upper limit of the power which can be reached by the fuel cell and the maximum charging power and the maximum discharging power of the auxiliary cell, the power range of the operation power of the electric drive system of the target vehicle is determined; adjusting the real-time output power of the fuel cell to the target output power of the fuel cell; in the power adjusting process of the fuel cell, the operation power of the electric drive system is controlled within the power range, and the stability and safety of operation of the fuel cell vehicle are improved.

Description

Technical Field

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

[0002] Fuel cell vehicles are a relatively popular new energy vehicle technology in recent years. They have the characteristics of zero emission, no pollution, high energy efficiency, etc. In extended-range full-power fuel cell vehicles, fuel cells are the main auxiliary source of the vehicle, and are often paired with a small lithium battery or nickel-metal hydride battery as an auxiliary power source.

[0003] Since the power of the auxiliary battery of the extended-range full-power fuel cell vehicle is often only a few degrees of electricity (most of them do not exceed 5 degrees of electricity), its charging and discharging power is relatively limited. At present, there is a more obvious defect in the fuel cell system, that is, the rate of change of its output power is slow, that is, the power increase or decrease cannot change suddenly, which makes the power control of the full-power fuel cell vehicle under severe conditions such as rapid acceleration / rapid deceleration extremely difficult. Take the rapid deceleration condition as an example. At this time, the power request of the whole vehicle suddenly changes from a large value to a small value. The fuel cell needs to quickly reduce its output power to respond to the power request of the whole vehicle in time. However, since the output power of the fuel cell cannot change suddenly, the extra power can only be absorbed by the auxiliary battery. 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 power required by the whole vehicle, it will cause auxiliary battery overcurrent, vehicle rapid deceleration failure or fuel cell blockage and other faults. Summary of the invention

[0004] In response to 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 to suddenly change the output power of the fuel cell, 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 a target output power of the fuel cell according to a real-time power requirement of the target vehicle;

[0007] 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;

[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 power range.

[0010] The present application provides a power control method for a fuel cell vehicle, which determines the target output power of the fuel cell at the next moment by analyzing the real-time power demand of the fuel cell vehicle and the real-time status of the fuel cell and the auxiliary battery. At the same time, considering the slow change rate of the output power of the fuel cell, the power range of the operating power of the electric drive system is determined according to the maximum output power change rate of the fuel cell and the maximum charge and 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 power range, so that the change in the operating power of the electric drive system matches the change in the real-time output power of the fuel cell, reducing the charging and discharging pressure of the auxiliary battery, avoiding the auxiliary battery overcurrent, vehicle rapid deceleration failure or fuel cell blockage caused by excessive changes in the operating power of the electric drive system, and improving the stability and safety of the fuel cell vehicle.

[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 according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower and / or upper power limit achievable by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery. The specific formula is:

[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 is the target output power of the fuel cell, P 下限 is the lower limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

[0015] In an 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 a 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 takes a long time to adjust to the target output power. Therefore, in this process, it is necessary to limit the operating power of the electric drive system 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 increase requested by the VCU to the FCU is very steep, the power upper limit of the MCU (motor control unit) is controlled so that the actual total operating power is lower than (the maximum discharge power allowed by the auxiliary battery) + (the maximum value between the lower power limit and the target output power that can be achieved during the fuel cell power sampling period), that is, to ensure the power of the whole vehicle, and to enable the fuel cell and the auxiliary battery to operate within the safe power range, to avoid failure of the fuel cell or the auxiliary battery. Similarly, if the target output power reduction requested by the VCU to the FCU is very steep, the power lower limit of the MCU is controlled so that the actual total operating power is higher than (the maximum value between the power lower limit and the target output power that can be achieved within the fuel cell power sampling period) - (the maximum allowable charging power of the auxiliary battery), which effectively improves the stability and safety of the fuel cell vehicle operation.

[0016] Furthermore, the specific calculation formula for the lower limit of power that the fuel cell can achieve is:

[0017] P 下限 =P fc -△P fc ×△t

[0018] Among them, 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 of the vehicle control system.

[0019] 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 power range of the electric drive system operating power 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 and / or upper power limit achievable by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery. 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] Among them, P target is the target output power of the fuel cell, P 上限 is the upper limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

[0023] Furthermore, the specific calculation formula for the upper power limit that the fuel cell can achieve is:

[0024] P 上限 =P fc +△P fc ×△t

[0025] Among them, 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 of the vehicle control system.

[0026] In the embodiment 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 process of the fuel cell, the operating power of the electric drive system needs to be limited to prevent the operating power of the electric drive system from 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] Furthermore, the real-time required power of the target vehicle is calculated based on the real-time operating data of the target vehicle, including:

[0028] Calculating the required driving power of the target vehicle according to the accelerator pedal opening, the current torque of the motor and the current speed of the motor;

[0029] Calculate the required power of the high-voltage accessories of the target vehicle according to the current input voltage and input current value of the high-voltage accessories of the target vehicle and the vehicle state;

[0030] The real-time power requirement of the target vehicle is determined according to the driving power requirement and the high-voltage accessory power requirement.

[0031] An embodiment of the present application provides a method for calculating real-time power demand. By real-time monitoring and calculating the driving power demand and high-voltage accessory power demand of the fuel cell vehicle at the current moment, the real-time power demand of the target vehicle is calculated, providing a data basis for subsequent power control.

[0032] Furthermore, the real-time output power of the fuel cell is calculated based on the real-time operating data of the target vehicle, including: acquiring 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 based on the real-time output voltage and the real-time output current.

[0033] In a possible implementation, 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 according to the real-time required power of the target vehicle includes:

[0034] When the real-time required 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.

[0035] In a possible implementation, 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 according to the real-time required power of the target vehicle includes:

[0036] When the real-time required 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 required power and the planned charging power of the auxiliary battery, wherein the planned charging power is determined based on the difference between the real-time charge of the auxiliary battery and the preset expected value.

[0037] Furthermore, when the real-time required 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 to be the sum of the real-time required power and the planned charging power of the auxiliary battery. The specific formula is:

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

[0039] Among them, P target is the target output power of the fuel cell, P is the real-time required power, and P bat_char_maxis the maximum charging power of the auxiliary battery, SOC is the real-time charge of the auxiliary battery, SOC exp is the preset expected value, and ΔSOC is the difference between the maximum SOC limit allowed for charging of the auxiliary battery and the minimum SOC limit allowed for discharging.

[0040] Furthermore, 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.

[0041] The embodiment of the present application further considers the situation of low power of the auxiliary battery. Since the power output of the fuel cell has a 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 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, it is necessary not only to consider the supply and demand balance between the real-time output power of the fuel cell and the operating power of the electric drive system, but also to consider the timely charging of the auxiliary battery through the excess output power of the fuel cell. Therefore, in the embodiment of the present application, the real-time demand power is first 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 output power corresponding to the highest energy efficiency point of the fuel cell can be controlled to output. 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 be used to charge the auxiliary battery at the same time. When the real-time required power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the fuel cell no longer takes the highest efficiency point as the primary consideration, but instead takes the most suitable power of the auxiliary battery (or the health of the battery) as the primary consideration. On the one hand, it supplies power to the vehicle and high-voltage electrical appliances, and on the other hand, it charges the auxiliary battery linearly according to the deviation between the battery power and the expected value. While ensuring the normal operation of the fuel cell vehicle, the power of the auxiliary battery is gradually restored to improve the stability and safety of the vehicle operation.

[0042] In a second aspect, accordingly, an embodiment of the present application provides a power control system for a fuel cell vehicle, including 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] Wherein, the battery target power determination module is used to determine the target output power of the fuel cell according to the real-time required power of the target vehicle;

[0044] The electric drive power range determination module is used 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 maximum discharging power of the auxiliary battery;

[0045] The battery power adjustment module is used 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 used to control the operating power of the electric drive system within the power range during the power adjustment process of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 : A flow chart of a power control method for a fuel cell vehicle provided in an embodiment of the present application.

[0048] Figure 2 : A structural schematic diagram of a power control system for a fuel cell vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0050] It should be noted that the step numbers in the text are only for the convenience of explanation of the specific embodiments and do not serve to limit the order in which the steps are executed. In the description of this application, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0051] Throughout the specification, the fuel cell vehicle and target vehicle described in this 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 1:

[0053] like Figure 1 As shown, embodiment 1 provides a power control method for a fuel cell vehicle, comprising steps S1-S4:

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

[0055] Step S2, determining 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;

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

[0058] The present application provides a power control method for a fuel cell vehicle, which determines the target output power of the fuel cell at the next moment by analyzing the real-time power demand of the fuel cell vehicle and the real-time status of the fuel cell and the auxiliary battery. At the same time, considering the slow change rate of the output power of the fuel cell, the power range of the operating power of the electric drive system is determined according to the maximum output power change rate of the fuel cell and the maximum charge and 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 power range, so that the change in the operating power of the electric drive system matches the change in the real-time output power of the fuel cell, reducing the charging and discharging pressure of the auxiliary battery, avoiding the auxiliary battery overcurrent, vehicle rapid deceleration failure or fuel cell blockage caused by excessive changes in the operating power of the electric drive system, and improving the stability and safety of the fuel cell vehicle.

[0059] Furthermore, in step S1, the real-time required power of the target vehicle is calculated based on the real-time operating data of the target vehicle, including:

[0060] Calculating the required driving power of the target vehicle according to the accelerator pedal opening, the current torque of the motor and the current speed of the motor;

[0061] Calculate the required power of the high-voltage accessories of the target vehicle according to the current input voltage and input current value of the high-voltage accessories of the target vehicle and the vehicle state;

[0062] The real-time power requirement of the target vehicle is determined according to the driving power requirement and the high-voltage accessory power requirement.

[0063] Among them, the high-voltage accessories are all high-voltage parts in the target vehicle except the electric drive system. The high-voltage accessory power requirement of the target vehicle is usually calculated by multiplying the current and voltage of each high-voltage accessory to obtain the power requirement of each high-voltage accessory, and then summing them up to obtain the high-voltage accessory power requirement of the target vehicle. As for the driving power requirement of the target vehicle, a power comparison table is usually preset in the vehicle system. The power comparison table records the driving power requirements corresponding to different accelerator pedal openings, current motor torques, and current motor speeds. During vehicle operation, the vehicle system only needs to look up the table according to the current accelerator pedal opening, current motor torque, and current motor speed to obtain the corresponding driving power requirement. Furthermore, the real-time power requirement of the target vehicle is determined based on the driving power requirement and the high-voltage accessory power requirement. The specific formula is:

[0064] P=P m0 +P HVPart

[0065] Wherein, P is the real-time required power, P m0 is the driving power requirement, P HVPart Power is required for the high voltage accessories.

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

[0067] In a 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 according to the real-time required power of the target vehicle includes:

[0068] When the real-time required 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 required 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. The specific formula is:

[0070] P target =P fc-eff

[0071] Among them, P target is the target output power of the fuel cell, Pfc-eff The output power corresponding to the highest energy efficiency point of the fuel cell. When the auxiliary battery is low in power, when the total power required by 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 the power corresponding to the output power corresponding to the highest energy efficiency point of the fuel cell. On the one hand, it can meet the power supply needs of the vehicle with the highest energy efficiency, and on the other hand, it can also charge the auxiliary battery at the same time.

[0072] In a 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 according to the real-time required power of the target vehicle includes:

[0073] When the real-time required 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 required power and the planned charging power of the auxiliary battery, wherein the planned charging power is determined based on the difference between the real-time charge of the auxiliary battery and the preset expected value.

[0074] Furthermore, when the real-time required 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 to be the sum of the real-time required power and the planned charging power of the auxiliary battery. The specific formula is:

[0075] P target =P+P bat_char_max ×(SOC-SOC exp ) / △S0C

[0076] Among them, P target is the target output power of the fuel cell, P is the real-time required power, and P bat_char_max is the maximum charging power of the auxiliary battery, SOC is the real-time charge of the auxiliary battery, SOC exp is the preset expected value, and ΔSOC is the difference between the maximum SOC limit allowed for charging of the auxiliary battery and the minimum SOC limit allowed for discharging.

[0077] In this embodiment, when the total power demand of the whole 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 external output power based on a comprehensive consideration of three indicators: the real-time power demand of the whole vehicle, the maximum chargeable power of the auxiliary battery, and the deviation of the auxiliary battery power.

[0078] Furthermore, in step S2, the real-time output power of the fuel cell is calculated based on the real-time operating data of the target vehicle, including: acquiring 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 based on the real-time output voltage and the real-time output current.

[0079] In a 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, then the power range of the electric drive system operating power 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 and / or upper power limit achievable by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery. 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] Among them, P target is the target output power of the fuel cell, P 下限 is the lower limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

[0083] In an 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 a 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 takes a long time to adjust to the target output power. Therefore, in this process, it is necessary to limit the operating power of the electric drive system 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 increase requested by the VCU to the FCU is very steep, the power upper limit of the MCU (motor control unit) is controlled so that the actual total operating power is lower than (the maximum discharge power allowed by the auxiliary battery) + (the maximum value between the lower power limit and the target output power that can be achieved during the fuel cell power sampling period), that is, to ensure the power of the whole vehicle, and to enable the fuel cell and the auxiliary battery to operate within the safe power range, to avoid failure of the fuel cell or the auxiliary battery. Similarly, if the target output power reduction requested by the VCU to the FCU is very steep, the power lower limit of the MCU is controlled so that the actual total operating power is higher than (the maximum value between the power lower limit and the target output power that can be achieved within the fuel cell power sampling period) - (the maximum allowable charging power of the auxiliary battery), which effectively improves the stability and safety of the fuel cell vehicle operation.

[0084] Furthermore, the specific calculation formula for the lower limit of power that the fuel cell can achieve is:

[0085] P 下限 =P fc -△P fc ×△t

[0086] Among them, 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 of the vehicle control system.

[0087] In a possible implementation, in step S2, if the target output power of the fuel cell is greater than 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 according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower and / or upper power limit achievable by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery. 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] Among them, P target is the target output power of the fuel cell, P 上限 is the upper limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

[0091] Furthermore, the specific calculation formula for the upper power limit that the fuel cell can achieve is:

[0092] P 上限 =P fc +△P fc ×△t

[0093] Among them, 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 of the vehicle control system.

[0094] In the embodiment 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 process of the fuel cell, the operating power of the electric drive system needs to be limited to prevent the operating power of the electric drive system from 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 charge of the auxiliary battery is lower than the preset expected value, if the real-time required 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, then 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 charge of the auxiliary battery is lower than the preset expected value, if the real-time required 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 greater than 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 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 charge 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 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 specifically:

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

[0103] -P bat_char_max ≤P VCUReqMCU

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

[0105] △t)-P HVPart +P bat_dis_max

[0106] When the real-time charge 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, then the power range of the electric drive system operating power of the target vehicle is specifically:

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

[0108] -P bat_char_max ≤P VCUReqMCU

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

[0110] △t)-P HVPart +P bat_dis_max

[0111] Furthermore, 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 embodiment of the present application further considers the situation of low power of the auxiliary battery. Since the power output of the fuel cell has a 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 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, it is necessary not only to consider the supply and demand balance between the real-time output power of the fuel cell and the operating power of the electric drive system, but also to consider the timely charging of the auxiliary battery through the excess output power of the fuel cell. Therefore, in the embodiment of the present application, the real-time demand power is first 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 output power corresponding to the highest energy efficiency point of the fuel cell can be controlled to output. 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 be used to charge the auxiliary battery at the same time. When the real-time required power is greater than the output power corresponding to the highest energy efficiency point of the fuel cell, the fuel cell no longer takes the highest efficiency point as the primary consideration, but instead takes the most suitable power of the auxiliary battery (or the health of the battery) as the primary consideration. On the one hand, it supplies power to the vehicle and high-voltage electrical appliances, and on the other hand, it charges the auxiliary battery linearly according to the deviation between the battery power and the expected value. While ensuring the normal operation of the fuel cell vehicle, the power of the auxiliary battery is gradually restored to improve the stability and safety of the vehicle operation.

[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 which potential vehicle failures caused by the non-mutational output power of the fuel cell system can be eliminated.

[0115] (2) A method for calculating the target output power of a fuel cell when the auxiliary battery is low in power is provided. The method is based on the output power value P corresponding to the highest energy efficiency point of the fuel cell system. fc-eff Working can greatly improve the energy efficiency of the entire vehicle.

[0116] (3) A method for controlling the charging of an auxiliary battery when the auxiliary battery is low in power is provided, that is, bat_char_max ×(SOC-SOC exp ) / △S0C or P fc-eff -P VCUReqMCU -P HVPart Charge the power battery to ensure that the auxiliary battery can continue to be charged when the battery is low;

[0117] (4) The embodiment of the present application, on the one hand, accurately calculates the output power of the fuel cell, and on the other hand, limits the rate of change of the required power of the drive system, and reasonably controls the charging and discharging behavior of the auxiliary battery under low power. Through the coordination of the three, not only can potential vehicle failures caused by the non-mutational output power of the fuel cell system be avoided, but the whole vehicle can also operate at a high-efficiency working point, and can ensure that the auxiliary battery can be continuously charged under low power, that is, the advantages of sufficient vehicle power, high safety, low energy consumption, less damage to the auxiliary battery, and smooth operation of the whole vehicle are achieved.

[0118] Embodiment 2:

[0119] like Figure 2 As shown, the second embodiment provides a power control system for a fuel cell vehicle, including 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] Wherein, the battery target power determination module 10 is used to determine the target output power of the fuel cell according to the real-time required power of the target vehicle;

[0121] The electric drive power range determination module 20 is used 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 maximum discharging power of the auxiliary battery;

[0122] The battery power adjustment module 30 is used 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 used to control the operating power of the electric drive system within the power range during the power adjustment process of the fuel cell.

[0124] In a 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 and / or upper power limit that the fuel cell can reach, and the maximum charging power and the maximum discharging power of the auxiliary battery. 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] Among them, P target is the target output power of the fuel cell, P 下限 is the lower limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

[0128] Furthermore, the specific calculation formula for the lower limit of power that the fuel cell can achieve is:

[0129] P 下限 =P fc -△P fc ×△t

[0130] Among them, 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 of the vehicle control system.

[0131] In a 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 and / or upper power limit that the fuel cell can reach, and the maximum charging power and the maximum discharging power of the auxiliary battery. 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 +△P fc ×△t)-P HVPart +P bat_dis_max

[0134] Among them, P target is the target output power of the fuel cell, P 上限is the upper limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

[0135] Furthermore, the specific calculation formula for the upper power limit that the fuel cell can achieve is:

[0136] P 上限 =P fc +△P fc ×△t

[0137] Among them, 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 of the vehicle control system.

[0138] Furthermore, the real-time required power of the target vehicle is calculated based on the real-time operating data of the target vehicle, including:

[0139] Calculating the required driving power of the target vehicle according to the accelerator pedal opening, the current torque of the motor and the current speed of the motor;

[0140] Calculate the required power of the high-voltage accessories of the target vehicle according to the current input voltage and input current value of the high-voltage accessories of the target vehicle and the vehicle state;

[0141] The real-time power requirement of the target vehicle is determined according to the driving power requirement and the high-voltage accessory power requirement.

[0142] Furthermore, the real-time output power of the fuel cell is calculated based on the real-time operating data of the target vehicle, including: acquiring 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 based on the real-time output voltage and the real-time output current.

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

[0144] When the real-time required 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.

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

[0146] When the real-time required 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 required power and the planned charging power of the auxiliary battery, wherein the planned charging power is determined based on the difference between the real-time charge of the auxiliary battery and the preset expected value.

[0147] Furthermore, when the real-time required 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 to be the sum of the real-time required power and the planned charging power of the auxiliary battery. The specific formula is:

[0148] P target =P+P bat_char_max ×(SOC-SOC exp ) / △S0C

[0149] Among them, P target is the target output power of the fuel cell, P is the real-time required power, and P bat_char_max is the maximum charging power of the auxiliary battery, SOC is the real-time charge of the auxiliary battery, SOC exp is the preset expected value, and ΔSOC is the difference between the maximum SOC limit allowed for charging of the auxiliary battery and the minimum SOC limit allowed for discharging.

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

[0151] The present application provides a power control system for fuel cell vehicles, which determines the target output power of the fuel cell at the next moment by analyzing the real-time power demand of the fuel cell vehicle and the real-time status of the fuel cell and the auxiliary battery. At the same time, considering the slow change rate of the output power of the fuel cell, the power range of the operating power of the electric drive system is determined according to the maximum output power change rate of the fuel cell and the maximum charge and 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 power range, so that the change of the operating power of the electric drive system matches the change of the real-time output power of the fuel cell, reducing the charging and discharging pressure of the auxiliary battery, avoiding the auxiliary battery overcurrent, vehicle rapid deceleration failure or fuel cell blockage caused by the excessive change of the operating power of the electric drive system, and improving the stability and safety of the operation of the fuel cell vehicle.

[0152] The more detailed working principle and step flow of this embodiment can refer to, but are not limited to, the relevant records of Embodiment 1.

[0153] The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A power control method for a fuel cell vehicle, characterized in that: include: Determining a target output power of the fuel cell according to a real-time power requirement of the target vehicle; 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; adjusting the real-time output power of the fuel cell to the target output power of the fuel cell; During the power adjustment process of the fuel cell, the operating power of the electric drive system is controlled within the power range.

2. A power control method for a fuel cell vehicle as claimed in claim 1, characterized in that: 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 according to the target output power of the fuel cell, the real-time output power of the fuel cell, the lower and / or upper power limit achievable by the fuel cell, and the maximum charging power and maximum discharging power of the auxiliary battery. The specific formula is: Max(P target ,P 下限 )-P HVPart -P bat_char_max ≤P VCUReqMCU ≤Max(P target ,P 下限 )-P HVPart +P bat_dis_max Among them, P target is the target output power of the fuel cell, P 下限 is the lower limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

3. A power control method for a fuel cell vehicle as claimed in claim 2, characterized in that: The specific calculation formula for the lower limit of power that the fuel cell can achieve is: P 下限 =P fc -△P fc ×△t Among them, 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 of the vehicle control system.

4. A power control method for a fuel cell vehicle as claimed in claim 1, characterized in that: 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 target output power of the fuel cell, the real-time output power of the fuel cell, the lower and / or upper power limit achievable by the fuel cell, and the maximum charging power and the maximum discharging power of the auxiliary battery. The specific formula is: Min(P target ,P 上限 )-P HVPart -P bat_char_max ≤P VCUReqMCU ≤Min(P target ,P 上限 )-P HVPart +P bat_dis_max Among them, P target is the target output power of the fuel cell, P 上限 is the upper limit of power that the fuel cell can achieve, P HVPart is the power demand of the high-voltage accessories of the target vehicle, P bat_char_max is the maximum charging power of the auxiliary battery, P VCUReqMCU is the operating power of the electric drive system of the target vehicle, P bat_dis_max is the maximum discharge power of the auxiliary battery.

5. A power control method for a fuel cell vehicle as claimed in claim 4, characterized in that: The specific calculation formula for the upper power limit that the fuel cell can achieve is: P 上限 =P fc +△P fc ×△t Among them, 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 of the vehicle control system.

6. A power control method for a fuel cell vehicle as claimed in claim 1, characterized in that: The real-time required power of the target vehicle is calculated based on the real-time operating data of the target vehicle, including: Calculating the required driving power of the target vehicle according to the accelerator pedal opening, the current torque of the motor and the current speed of the motor; Calculate the required power of the high-voltage accessories of the target vehicle according to the current input voltage and input current value of the high-voltage accessories of the target vehicle and the vehicle state; The real-time power requirement of the target vehicle is determined according to the driving power requirement and the high-voltage accessory power requirement.

7. A power control method for a fuel cell vehicle as claimed in claim 1, characterized in that: The real-time output power of the fuel cell is calculated based on the real-time operating data of the target vehicle, including: acquiring 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 based on the real-time output voltage and the real-time output current.

8. A power control method for a fuel cell vehicle according to any one of claims 1 to 7, characterized in that: 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 according to the real-time required power of the target vehicle includes: When the real-time required 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.

9. A power control method for a fuel cell vehicle according to any one of claims 1 to 7, characterized in that: 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 according to the real-time required power of the target vehicle includes: When the real-time required 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 required power and the planned charging power of the auxiliary battery, wherein the planned charging power is determined based on the difference between the real-time charge of the auxiliary battery and the preset expected value.

10. A power control method for a fuel cell vehicle as claimed in claim 9, characterized in that: When the real-time required 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 to be the sum of the real-time required power and the planned charging power of the auxiliary battery. The specific formula is: P target =P+P bat_char_max ×(S0C-SOC exp ) / △S0C Among them, P target is the target output power of the fuel cell, P is the real-time required power, and P bat_char_max is the maximum charging power of the auxiliary battery, SOC is the real-time charge of the auxiliary battery, SOC exp is the preset expected value, and ΔSOC is the difference between the maximum SOC limit allowed for charging of the auxiliary battery and the minimum SOC limit allowed for discharging.

11. A power control method for a fuel cell vehicle according to any one of claims 1 to 7, characterized in that: The power control method further includes: 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.

12. A power control system for a fuel cell vehicle, characterized in that: It includes 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; Wherein, the battery target power determination module is used to determine the target output power of the fuel cell according to the real-time required power of the target vehicle; The electric drive power range determination module is used 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 maximum discharging power of the auxiliary battery; The battery power adjustment module is used 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 used to control the operating power of the electric drive system within the power range during the power adjustment process of the fuel cell.

Images