Hydrogen fuel hybrid construction machine energy management method and system

Abstract

The application discloses a hydrogen fuel hybrid engineering mechanical energy management method and system, and belongs to the field of hydrogen energy hybrid mechanical engineering. VCU sends a hydrogen fuel cell request power to FCCU according to the current power battery SOC, FCCU judges the interval of the hydrogen fuel cell request power, sets the hydrogen fuel cell output power according to the preset corresponding relationship between the hydrogen fuel cell request power interval and the hydrogen fuel cell output power. The strategy of gradually increasing the hydrogen fuel cell output power can reduce the loss caused by the system load fluctuation and prolong the service life of the equipment. When the key is turned off, the hydrogen stack shutdown time is predicted through a hydrogen stack shutdown time prediction model, and the 'high-voltage electronic fan + hydraulic pump idling + LED light always-on' multi-system collaborative energy consumption is started according to the predicted hydrogen stack shutdown time and the power battery SOC, so that the risk of overcharging of the power battery is reduced and the system safety is improved.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy hybrid machinery, and in particular to an energy management method and system for hydrogen fuel hybrid engineering machinery. Background Technology

[0002] In construction machinery such as excavators, hydrogen fuel cell generators have a long rated power response time, taking about ten minutes to go from idle to rated output, which does not meet the need for the machinery to quickly enter the working state. Therefore, a power battery pack is added as an auxiliary power source to make up for the shortcomings of hydrogen fuel cell generators in responding quickly to the power demand of the vehicle, thus forming a hybrid excavator device with hydrogen energy battery and power battery.

[0003] In the excavator's energy management system, the vehicle controller (VCU) receives the vehicle's power demand and collects the state of charge (SOC) of the power battery. Based on the vehicle's power demand and the power battery's SOC, it sends a power request to the fuel cell control unit (FCCU). Upon receiving the power request from the VCU, the FCCU controls the hydrogen fuel cell to output the corresponding rated power. Directly outputting the requested rated power causes the unit to frequently and drastically switch between full and low loads, leading to equipment fatigue, increased equipment failure rate, and shortened fuel cell lifespan.

[0004] Secondly, the hydrogen fuel generator used on excavators has a relatively long shutdown time. During the period from receiving the power-off command to the completion of the hydrogen stack shutdown, there is still current output. Because the power battery is only used as an auxiliary power source, the capacity of the power battery used is small, and there is a risk of overcharging of the power battery during the power-off process.

[0005] Furthermore, existing energy management systems mostly rely on passive heat dissipation, resulting in a crude energy distribution between hydrogen fuel cells and power batteries, which can easily lead to overcharging or energy waste in the power batteries. Moreover, the cooling systems only dissipate heat without recovering energy, resulting in low energy utilization efficiency and insufficient safety. Summary of the Invention

[0006] The purpose of this invention is to provide an energy management method and system for hydrogen fuel cell hybrid engineering machinery. With the VCU as the intelligent hub, it optimizes the dynamic energy distribution between the hydrogen fuel cell and the power battery to achieve efficient energy utilization, reduce losses caused by system load fluctuations, reduce the risk of overcharging the power battery, and improve system safety.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, a method for energy management of hydrogen fuel cell hybrid engineering machinery is provided, including: The VCU determines the current SOC range based on the current SOC of the power battery sent by the BMS; based on the SOC range and the power demand of the vehicle, it sends a power request for the hydrogen fuel cell to the FCCU. The FCCU determines the range in which the hydrogen fuel cell requests power is located based on the pre-defined range of hydrogen fuel cell request power. Based on the pre-defined correspondence between the hydrogen fuel cell request power range and the hydrogen fuel cell output power, the FCCU sets the hydrogen fuel cell output power. VUC determines whether the power demand of the vehicle is greater than the output power of the hydrogen fuel cell. If the power demand of the vehicle is greater than the output power of the hydrogen fuel cell, the power battery will make up for the missing output power. If the power demand of the vehicle is less than the output power of the hydrogen fuel cell, the excess power generated by the hydrogen fuel cell will be used to charge the power battery.

[0008] Furthermore, the correspondence between the requested power range of the hydrogen fuel cell and the output power of the hydrogen fuel cell includes: By adopting a strategy of gradually increasing the requested power, the operating range of the hydrogen fuel cell requested power is divided into several continuous intervals, and each interval corresponds to a fixed output power value of the hydrogen fuel cell.

[0009] Furthermore, the correspondence between the requested power range of the hydrogen fuel cell and the output power of the hydrogen fuel cell includes: If P 请 0≤P 请 <P 请 1. Then the output power P of the hydrogen fuel cell 输 For P 输 1; If P 请 1≤P 请 <P 请 2. Then the output power P of the hydrogen fuel cell 输 For P 输 2; If P 请 2≤P 请 <P 请 3. Then the output power P of the hydrogen fuel cell 输 For P 输 3; If P 请 3≤P 请 <P 请 4. The output power P of the hydrogen fuel cell is... 输 For P 输 4, Among them, P 请 For the power requested by the hydrogen fuel cell, P 请 0, P 请 1. P 请 2. P 请 3. P请 4 represents the minimum requested power of the hydrogen fuel cell, the first requested power of the hydrogen fuel cell, the second requested power of the hydrogen fuel cell, the third requested power of the hydrogen fuel cell, and the maximum requested power of the hydrogen fuel cell, respectively. 输 1. P 输 2. P 输 3. P 输 4 represents the first, second, third, and fourth output power of the hydrogen fuel cell.

[0010] Furthermore, a high-voltage electric fan is installed on the engineering machinery, and the energy management method for the hydrogen fuel hybrid engineering machinery also includes: When the key is turned off, the VCU inputs the hydrogen fuel remaining amount, hydrogen stack temperature gradient, and real-time shutdown data uploaded by the FCCU into the hydrogen stack shutdown time prediction model to predict the hydrogen stack shutdown time. If the predicted hydrogen stack shutdown time is ≥3 minutes, the VCU will activate a multi-system coordinated energy consumption mechanism involving "high-pressure electric fan + hydraulic pump idling + LED lights constantly on".

[0011] Furthermore, the energy management method for hydrogen fuel cell hybrid engineering machinery also includes: If the predicted hydrogen stack shutdown time is less than 3 minutes and the power battery SOC is less than B, the VCU controls the BMS to enter the charging mode and store the remaining power of the hydrogen fuel cell into the power battery; where B is the highest remaining power in the power battery SOC range. The VCU will again determine whether the SOC of the power battery is greater than B. If so, it will start the multi-system coordinated energy consumption of "high-voltage electronic fan + hydraulic pump idling + LED lights always on".

[0012] Furthermore, the energy management method for hydrogen fuel cell hybrid engineering machinery also includes: If the predicted hydrogen stack shutdown time is less than 3 minutes and the power battery SOC is greater than or equal to B, the "high-voltage electronic fan + hydraulic pump idling + LED lights on" multi-system coordinated energy consumption will be activated.

[0013] Furthermore, a permanent magnet synchronous generator is installed on the main shaft of the high-voltage electric fan, and a supercapacitor is provided. The energy management method for the hydrogen fuel cell hybrid power engineering machinery also includes: The kinetic energy generated by the rotation of the high-voltage electric fan is converted into electrical energy by a permanent magnet synchronous generator, and then transmitted to low-power loads and / or supercapacitors for energy storage after being regulated by a DC-DC converter.

[0014] Furthermore, the energy management method for hydrogen fuel cell hybrid engineering machinery also includes: If the VCU determines that the supercapacitor's SOC is greater than 80% and the power battery's SOC is less than A, it will start reverse power supply and control the BMS to convert the supercapacitor's power into a high voltage via a DC-DC converter and transmit it to the power battery; where A is the lowest remaining power in the power battery's SOC range.

[0015] The shutdown data includes ambient temperature and altitude correction factor.

[0016] Furthermore, the hydrogen reactor shutdown time prediction model is obtained according to the following method: The LSTM neural network was trained using historical hydrogen fuel remaining amount, historical hydrogen reactor temperature gradient, and historical shutdown data uploaded in real time by the FCCU. The output of the LSTM neural network was then corrected using the Kalman filter algorithm to obtain a hydrogen reactor shutdown time prediction model.

[0017] Secondly, a hydrogen fuel cell hybrid power engineering machinery energy management system is provided, including: BMS is used to send the power battery SOC to VCU in real time; The VCU is used to determine the current SOC range based on the current SOC of the power battery sent by the BMS; based on the SOC range and the power demand of the vehicle, it sends a power request from the hydrogen fuel cell to the FCCU; it determines whether the power demand of the vehicle is greater than the output power of the hydrogen fuel cell, and based on the determination result, it controls the power battery to make up for the missing output power, or controls the excess power generated by the hydrogen fuel cell to charge the power battery. The FCCU is used to determine the range in which the hydrogen fuel cell requests power is located based on the pre-defined range of requested power. It then sets the output power of the hydrogen fuel cell according to the pre-defined correspondence between the requested power range and the output power of the hydrogen fuel cell.

[0018] Furthermore, the hydrogen fuel cell hybrid power engineering machinery energy management system further includes: a high-voltage electric fan, a hydraulic pump, and LED lights. The high-voltage electric fan, hydraulic pump, and LED lights are all connected to the VCU. The high-voltage electric fan is also connected to the BMS and FCCU. The VCU includes a hydrogen reactor shutdown time prediction model. The FCCU is used to upload the remaining hydrogen fuel, hydrogen stack temperature gradient and shutdown data to the VCU in real time. The hydrogen reactor shutdown time prediction model is used to predict the hydrogen reactor shutdown time based on the hydrogen fuel remaining amount, hydrogen reactor temperature gradient and real-time shutdown data uploaded by the FCCU in real time. The VCU is used to control the BMS to enter the charging mode to store the remaining power of the hydrogen fuel cell into the power battery based on the predicted hydrogen stack shutdown time and power battery SOC, or to start the "high-voltage electronic fan + hydraulic pump idling + LED lights on" multi-system coordinated energy consumption.

[0019] Furthermore, the hydrogen fuel cell hybrid power engineering machinery energy management system also includes a supercapacitor, a permanent magnet synchronous generator mounted on the high-voltage electric fan spindle, the permanent magnet synchronous generator being connected to the supercapacitor, and the supercapacitor being connected to the BMS. The permanent magnet synchronous generator is used to convert the kinetic energy generated by the rotation of the high-voltage electric fan into electrical energy and transmit it to low-power loads and / or supercapacitor energy storage. The VCU is used to initiate reverse power supply, transferring the supercapacitor's energy to the power battery.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses the VCU as the central control unit to dynamically adjust the requested power of the hydrogen fuel cell based on the SOC of the power battery. It adopts a strategy of gradually increasing the requested power and sets the output power of the hydrogen fuel cell to a few fixed power points. Then, based on the power demand of the vehicle and the output power of the hydrogen fuel cell, it controls the power battery to supplement the missing output power or to charge the power battery with the excess power generated by the hydrogen fuel cell. With this scheme, the output power can be flexibly adjusted according to the actual power demand, avoiding energy waste. It can also ensure that the hydrogen fuel cell operates in the high-efficiency range as much as possible, reducing energy loss in the process of converting hydrogen energy into electrical energy, reducing the overall operating cost. At the same time, it can also avoid the hydrogen fuel cell from frequently and drastically switching between full load and low load, reducing the loss caused by system load fluctuations, and extending the equipment maintenance cycle and overall service life. 2. Utilize the hydrogen reactor shutdown time prediction model to predict the hydrogen reactor shutdown time in advance. Based on the predicted hydrogen reactor shutdown time and the power battery SOC, adopt a multi-system coordinated energy consumption approach of "high-voltage electronic fan + hydraulic pump idling + LED lights on" to overcome the limitations of passive heat dissipation, accurately control the power battery SOC within a reasonable range, reduce the risk of power battery overcharging when the key is turned off, improve system safety, and extend the life of the power battery. 3. The use of a high-voltage electronic fan to recover kinetic energy and a supercapacitor for bidirectional power supply improves the energy recovery efficiency of the whole vehicle, reduces energy loss during shutdown, and enhances energy utilization. Attached Figure Description

[0021] Figure 1 This is a system structure block diagram of the present invention; Figure 2 This is a simplified flowchart of the power control strategy for the hydrogen fuel cell excavator in an embodiment of the present invention; Figure 3 This is a simplified flowchart of the electrical energy control strategy for a hydrogen fuel cell excavator in an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments. These embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0023] Example 1

[0024] like Figure 1 As shown in the figure, an energy management system for a hydrogen fuel cell hybrid excavator provided in this embodiment of the invention includes a vehicle control unit (VCU), a battery management system (BMS), and a fuel cell control system (FCCU).

[0025] BMS is used to send the power battery SOC to VCU in real time; The VCU is used to determine the current SOC range based on the current SOC of the power battery sent by the BMS, and send a power request for the hydrogen fuel cell to the FCCU based on the SOC range and the power demand of the vehicle. The FCCU is used to determine the range in which the hydrogen fuel cell requests power is located based on the pre-divided hydrogen fuel cell request power range, and to set the hydrogen fuel cell output power according to the pre-defined correspondence between the hydrogen fuel cell request power range and the hydrogen fuel cell output power. The VCU is also used to determine whether the power demand of the vehicle is greater than the output power of the hydrogen fuel cell, and based on the determination result, to control the power battery to make up for the missing output power, or to control the excess power generated by the hydrogen fuel cell to charge the power battery.

[0026] like Figure 1 As shown, the energy management system for the hydrogen fuel cell hybrid excavator also includes a high-voltage electric fan, a hydraulic pump, and LED lights. The high-voltage electric fan, hydraulic pump, and LED lights are all connected to the VCU, and the high-voltage electric fan is also connected to the BMS and FCCU.

[0027] High-voltage electric fans are used to cool the entire vehicle.

[0028] VCU includes a hydrogen reactor shutdown time prediction model.

[0029] The FCCU is also used to upload hydrogen fuel remaining amount, hydrogen stack temperature gradient and shutdown data to VCU in real time; The hydrogen reactor shutdown time prediction model is used to predict the hydrogen reactor shutdown time based on the hydrogen fuel remaining amount, hydrogen reactor temperature gradient and real-time shutdown data uploaded by the FCCU in real time.

[0030] The shutdown data includes ambient temperature and altitude correction factor.

[0031] The hydrogen reactor shutdown time prediction model was obtained using the following method: The LSTM neural network was trained using historical hydrogen fuel remaining amount, historical hydrogen reactor temperature gradient, and historical shutdown data uploaded in real time by the FCCU. The output of the LSTM neural network was then corrected using the Kalman filter algorithm to obtain a hydrogen reactor shutdown time prediction model.

[0032] In a specific implementation, the model is trained with more than 1,000 sets of data to achieve a prediction error of ≤20 seconds.

[0033] The VCU is also used to control the BMS to enter the charging mode to store the remaining power of the hydrogen fuel cell into the power battery based on the predicted hydrogen stack shutdown time and power battery SOC, or to start a multi-system coordinated energy consumption of "high-voltage electronic fan + hydraulic pump idling + LED lights always on".

[0034] like Figure 1 As shown, the system also includes a 300V / 10F supercapacitor. Supercapacitors have the advantages of fast charging and discharging, long cycle life, high power, and high safety.

[0035] A 3kW permanent magnet synchronous generator is installed on the main shaft of the high-voltage electric fan. The permanent magnet synchronous generator is connected to a supercapacitor, which is connected to a BMS for energy recovery.

[0036] Permanent magnet synchronous generators are used to convert the kinetic energy generated by the rotation of a high-voltage electric fan into electrical energy and transmit it to low-power loads and / or supercapacitor energy storage.

[0037] The VCU is used to start reverse power supply, which transmits the supercapacitor's energy to the power battery after being regulated by a DC-DC converter.

[0038] Example 2

[0039] like Figure 2 As shown in the figure, an energy management method for a hydrogen fuel cell hybrid excavator provided by an embodiment of the present invention includes: Step 201: After the key is powered on, the VCU determines the range of the SOC based on the current SOC of the power battery and the optimal use and storage range of the power battery sent by the BMS. Based on the range of the SOC and the power demand of the whole vehicle, the VCU sends a power request for the hydrogen fuel cell to the FCCU. The optimal usage and storage range for power batteries is A≤SOC≤B, where A is the lowest remaining charge within the SOC range of the power battery, and B is the highest remaining charge within the SOC range of the power battery.

[0040] The charging and discharging strategy for the power battery is set as follows: If SOC < A, then P请 =P 需 +T; If SOC is in the interval [A, B], then P 请 =P 需 ; If SOC > B, then P 请 =P 需 -T.

[0041] Among them, P 请 For the power requested by the hydrogen fuel cell, P 需 The value is the power required for the entire vehicle, T is the power required for charging or discharging the power battery, and is the specific power value, such as 20kW.

[0042] This charging and discharging strategy is designed to ensure that the SOC of the power battery quickly meets the condition A≤SOC≤B under critical conditions. For example, before the vehicle starts, because the hydrogen fuel cell generator starts slowly, the power battery becomes the primary energy source, and its SOC will rapidly drop below A, i.e., SOC<A. At this point, P... 请 =P 需 +T, when the hydrogen fuel cell output power P 输 After stabilization, the output power P of the hydrogen fuel cell 输 > The required power P of the whole vehicle 需 At this time, the power battery will replenish the charge. When SOC=B, if the hydrogen fuel cell output power P 输 > The required power P of the whole vehicle 需 The remaining power will continue to be supplied to the power battery. When SOC > B, P 请 =P 需 -T, at this time the hydrogen fuel cell output power P 输 <Power requirement P of the whole vehicle 需 This will consume the stored power of the power battery.

[0043] Step 202: The FCCU determines the range in which the hydrogen fuel cell requests power is located based on the pre-divided hydrogen fuel cell request power range, and sets the hydrogen fuel cell output power according to the pre-defined correspondence between the hydrogen fuel cell request power range and the hydrogen fuel cell output power. This invention does not directly request rated power, but instead adopts a strategy of gradually increasing the requested power, setting the output power of the hydrogen fuel cell to a fixed number of power points:

[0044] Among them, P 请 0, P 请 1. P 请 2. P 请 3. P 请4 represents the minimum requested power of the hydrogen fuel cell, the first requested power of the hydrogen fuel cell, the second requested power of the hydrogen fuel cell, the third requested power of the hydrogen fuel cell, and the maximum requested power of the hydrogen fuel cell, respectively. 输 1. P 输 2. P 输 3. P 输 4 represents the first, minimum, second, third, and fourth output power (maximum) of the hydrogen fuel cell. These power values ​​are set according to the actual operating conditions of the vehicle, and typically vary depending on the vehicle's condition.

[0045] After the vehicle starts the fuel cell system, the FCCU determines the power request P of the hydrogen fuel cell. 请 The interval in which it is located, according to P 请 The hydrogen fuel cell output power P is set in the specified range. 输 For example, when determining the requested power P of a hydrogen fuel cell. 请 In [P] 请0 P 请1 [Range, controlling the output power P of the hydrogen fuel cell] 输 For P 输1 .

[0046] During normal operation, VUC determines the vehicle's required power P. 需 Is it greater than the output power P of the hydrogen fuel cell? 输 If the total vehicle power requirement P 需 Greater than the output power P of the hydrogen fuel cell 输 The missing output power is then supplemented by the power battery. If the total vehicle power requirement P 需 Less than the output power P of the hydrogen fuel cell 输 The excess power generated by the hydrogen fuel cell is then used to charge the power battery.

[0047] By adopting a strategy of gradually increasing the requested power, operational flexibility and energy efficiency can be improved, while reducing losses caused by system load fluctuations. Specifically: 1. Adapt to dynamic load demand: It can flexibly adjust the output power according to the actual power demand, avoid energy waste, and cope with sudden load growth to ensure power supply stability; 2. Optimize energy conversion efficiency: Hydrogen fuel cells are most efficient in a specific power range (usually 70%-90% of rated power). By using step-by-step adjustment, hydrogen fuel cells can be kept in the high-efficiency range as much as possible, reducing energy loss in the process of converting hydrogen energy into electricity and reducing overall operating costs. 3. Extend equipment lifespan: Avoid frequent and drastic switching between full load and low load in hydrogen fuel cells, reduce the impact and fatigue of mechanical parts, lower the probability of failure, and extend the equipment maintenance cycle and overall lifespan.

[0048] It is worth noting that because there will still be current output during the hydrogen stack shutdown process, if the remaining power of the power battery is greater than B when the excavator key is turned off, there will be no power output at this time, and the power battery will be at risk of overcharging.

[0049] Therefore, such as Figure 3 As shown in the embodiment of the present invention, the energy management method for a hydrogen fuel cell hybrid excavator further includes: Step 301: Power off the key. The VCU inputs the hydrogen fuel remaining amount, hydrogen stack temperature gradient, and real-time shutdown data uploaded by the FCCU into the hydrogen stack shutdown time prediction model to predict the hydrogen stack shutdown time. Determine whether the predicted hydrogen stack shutdown time is greater than or equal to 3 minutes. If yes, proceed to step 302; otherwise, proceed to step 303. Step 302: The VCU starts a multi-system coordinated energy consumption process involving "high-voltage electronic fan + hydraulic pump idling + LED lights constantly on" to reduce the risk of overcharging of the vehicle's power battery; Step 303: Determine whether the SOC of the power battery is greater than or equal to B. If yes, proceed to step 302; otherwise, proceed to step 304. Step 304: The VCU controls the BMS to enter the charging mode, stores the remaining power of the hydrogen fuel cell into the power battery, and checks again whether the SOC of the power battery is greater than B. If so, proceed to step 302.

[0050] Using a high-voltage electric fan to consume the remaining power of the hydrogen fuel cell not only improves the overall vehicle's heat dissipation efficiency but also avoids overcharging of the power battery, thus enhancing system safety.

[0051] Using a hydraulic pump to run idle can help dissipate heat, quickly reduce oil temperature, release residual high pressure in the pipeline, prevent pressure from continuing to act on the seals after shutdown, and reduce the risk of leakage.

[0052] Using LED lights that are constantly on can both accelerate energy consumption and prevent overcharging, while also illuminating the construction site.

[0053] In one embodiment, the energy management method for the hydrogen fuel cell hybrid excavator further includes: The kinetic energy generated by the rotation of the high-voltage electric fan is converted into electrical energy by a permanent magnet synchronous generator, and then transmitted to low-power loads and / or supercapacitors for energy storage after being regulated by a DC-DC converter.

[0054] The specific energy flow is as follows: fan rotation kinetic energy → electromagnetic induction power generation → DC-DC converter voltage regulation (300V→24V / 48V) → low-power load (instrument panel / sensor) or supercapacitor energy storage (for the next startup).

[0055] In one embodiment, the energy management method for the hydrogen fuel cell hybrid excavator further includes: If the VCU determines that the supercapacitor's SOC is greater than 80% and the power battery's SOC is less than A, it will start reverse power supply and control the BMS to convert the supercapacitor's power into a high voltage via a DC-DC converter and transmit it to the power battery.

[0056] The specific energy flow is as follows: supercapacitor → DC-DC converter (24V / 48V → 300V) → power battery.

[0057] By employing a high-voltage electronic fan to recover kinetic energy and a supercapacitor for bidirectional power supply, the energy recovery efficiency of the entire vehicle can be improved and energy loss during shutdown can be reduced.

[0058] This invention uses the VCU (Vehicle Control Unit) as the central hub to dynamically adjust the requested power of the hydrogen fuel cell based on the SOC (State of Charge) of the power battery. It employs a strategy of gradually increasing the requested power, setting the output power of the hydrogen fuel cell to a few fixed power points. Then, based on the vehicle's power demand and the hydrogen fuel cell's output power, it controls the power battery to supplement the insufficient output power or uses the excess power generated by the hydrogen fuel cell to charge the power battery. This not only allows for flexible adjustment of output power according to actual power demand, avoiding energy waste, but also ensures that the hydrogen fuel cell operates within its high-efficiency range as much as possible, reducing energy loss during the hydrogen-to-electricity conversion process and lowering overall operating costs. Furthermore, it avoids frequent and drastic switching between full and low loads, reducing losses caused by system load fluctuations and extending equipment maintenance cycles and overall lifespan. Utilizing a hydrogen stack shutdown time prediction model to predict the hydrogen stack shutdown time in advance, and based on the predicted shutdown time and power battery SOC, it employs a multi-system coordinated energy consumption approach involving a high-voltage electric fan, a hydraulic pump idling, and constantly lit LED lights. This precisely controls the power battery SOC within a reasonable range, reducing the risk of overcharging when the ignition is turned off, improving system safety, and extending power battery life. In addition, using a high-voltage electric fan to recover kinetic energy and store it in a supercapacitor or supply it to a low-power load can improve the energy recovery efficiency of the whole vehicle and reduce energy loss during shutdown.

[0059] The present invention has been disclosed above with reference to preferred embodiments, but it is not intended to limit the present invention. All technical solutions obtained by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the present invention.

Claims

1. A method for energy management of hydrogen fuel cell hybrid engineering machinery, characterized in that, include: The VCU determines the current SOC range based on the current SOC of the power battery sent by the BMS. Based on the SOC range and the vehicle's power requirements, send a power request for the hydrogen fuel cell to the FCCU. The FCCU determines the range in which the hydrogen fuel cell requests power is located based on the pre-defined range of hydrogen fuel cell request power. Based on the pre-defined correspondence between the hydrogen fuel cell request power range and the hydrogen fuel cell output power, the FCCU sets the hydrogen fuel cell output power. The VCU determines whether the vehicle's power demand is greater than the hydrogen fuel cell's output power. If the vehicle's power demand is greater than the hydrogen fuel cell's output power, the power battery will make up for the missing output power. If the vehicle's power demand is less than the hydrogen fuel cell's output power, the excess power generated by the hydrogen fuel cell will be used to charge the power battery. The method further includes installing a high-voltage electric fan on the engineering machinery. When the key is turned off, the VCU inputs the hydrogen fuel remaining amount, hydrogen stack temperature gradient, and real-time shutdown data uploaded by the FCCU into the hydrogen stack shutdown time prediction model to predict the hydrogen stack shutdown time. If the predicted hydrogen stack shutdown time is greater than or equal to the preset threshold, the VCU will start a multi-system coordinated energy consumption process involving "high-pressure electric fan + hydraulic pump idling + LED lights constantly on". If the predicted hydrogen stack shutdown time is less than the preset threshold and the power battery SOC is less than B, the VCU controls the BMS to enter the charging mode and store the remaining power of the hydrogen fuel cell into the power battery. Where B represents the highest remaining charge within the SOC range of the power battery; VCU again determines whether the SOC of the power battery is greater than B. If so, it starts the "high voltage electronic fan + hydraulic pump idling + LED light on" multi-system coordinated energy consumption. If the predicted hydrogen stack shutdown time is less than the preset threshold and the power battery SOC is greater than or equal to B, the "high-voltage electronic fan + hydraulic pump idling + LED lights on" multi-system coordinated energy consumption will be activated.

2. The energy management method for hydrogen fuel cell hybrid engineering machinery according to claim 1, characterized in that, The correspondence between the requested power range of the hydrogen fuel cell and the output power of the hydrogen fuel cell includes: By adopting a strategy of gradually increasing the requested power, the operating range of the hydrogen fuel cell requested power is divided into several continuous intervals, and each interval corresponds to a fixed output power value of the hydrogen fuel cell.

3. The energy management method for hydrogen fuel cell hybrid engineering machinery according to claim 2, characterized in that, The correspondence between the requested power range of the hydrogen fuel cell and the output power of the hydrogen fuel cell includes: If P 请 0≤P 请 <P 请 1. Then the output power P of the hydrogen fuel cell 输 For P 输 1; If P 请 1≤P 请 <P 请 2. Then the output power P of the hydrogen fuel cell 输 For P 输 2; If P 请 2≤P 请 <P 请 3. Then the output power P of the hydrogen fuel cell 输 For P 输 3; If P 请 3≤P 请 <P 请 4. The output power P of the hydrogen fuel cell is... 输 For P 输 4, Among them, P 请 For the power requested by the hydrogen fuel cell, P 请 0, P 请 1. P 请 2. P 请 3. P 请 4 represents the minimum requested power of the hydrogen fuel cell, the first requested power of the hydrogen fuel cell, the second requested power of the hydrogen fuel cell, the third requested power of the hydrogen fuel cell, and the maximum requested power of the hydrogen fuel cell, respectively. 输 1. P 输 2. P 输 3. P 输 4 represents the first, second, third, and fourth output power of the hydrogen fuel cell.

4. The energy management method for hydrogen fuel cell hybrid engineering machinery according to claim 1, characterized in that, A permanent magnet synchronous generator is mounted on the main shaft of the high-voltage electronic fan, and a supercapacitor is also provided. The method further includes: The kinetic energy generated by the rotation of the high-voltage electric fan is converted into electrical energy by a permanent magnet synchronous generator, and then transmitted to low-power loads and / or supercapacitors for energy storage after being regulated by a DC-DC converter.

5. The energy management method for hydrogen fuel cell hybrid engineering machinery according to claim 4, characterized in that, Also includes: If the VCU determines that the supercapacitor's SOC is greater than 80% and the power battery's SOC is less than A, it will start reverse power supply and control the BMS to convert the supercapacitor's power into a high voltage via a DC-DC converter and transmit it to the power battery; where A is the lowest remaining power in the power battery's SOC range.

6. The energy management method for hydrogen fuel cell hybrid engineering machinery according to claim 1, characterized in that, The shutdown data includes ambient temperature and altitude correction factor.

7. The energy management method for hydrogen fuel cell hybrid engineering machinery according to claim 1, characterized in that, The hydrogen reactor shutdown time prediction model was obtained using the following method: The LSTM neural network was trained using historical hydrogen fuel remaining amount, historical hydrogen reactor temperature gradient, and historical shutdown data uploaded in real time by the FCCU. The output of the LSTM neural network was then corrected using the Kalman filter algorithm to obtain a hydrogen reactor shutdown time prediction model.

8. A hydrogen fuel cell hybrid power engineering machinery energy management system, characterized in that, include: BMS is used to send the power battery SOC to VCU in real time; VCU is used to determine the current SOC range of the power battery based on the current SOC sent by the BMS. Based on the SOC range and the vehicle's power requirements, the system sends a power request from the hydrogen fuel cell to the FCCU; it determines whether the vehicle's power requirements exceed the hydrogen fuel cell's output power, and based on the determination result, controls the power battery to supplement the missing output power, or controls the excess power generated by the hydrogen fuel cell to charge the power battery. The FCCU is used to determine the range in which the hydrogen fuel cell requests power is located based on the pre-divided hydrogen fuel cell request power range, and to set the hydrogen fuel cell output power according to the pre-defined correspondence between the hydrogen fuel cell request power range and the hydrogen fuel cell output power. It also includes: a high-voltage electric fan, a hydraulic pump, and LED lights, all of which are connected to the VCU. The high-voltage electric fan is also connected to the BMS and FCCU. The VCU includes a hydrogen reactor shutdown time prediction model. The FCCU is used to upload the remaining hydrogen fuel, hydrogen stack temperature gradient and shutdown data to the VCU in real time. The hydrogen reactor shutdown time prediction model is used to predict the hydrogen reactor shutdown time based on the hydrogen fuel remaining amount, hydrogen reactor temperature gradient and real-time shutdown data uploaded by the FCCU in real time. The VCU is used to control the BMS to enter the charging mode to store the remaining power of the hydrogen fuel cell into the power battery based on the predicted hydrogen stack shutdown time and power battery SOC, or to start the "high-voltage electronic fan + hydraulic pump idling + LED lights always on" multi-system coordinated energy consumption. The energy management system is used to implement the energy management method for hydrogen fuel hybrid engineering machinery as described in claim 1.

9. The hydrogen fuel cell hybrid power engineering machinery energy management system according to claim 8, characterized in that, It also includes a supercapacitor. A permanent magnet synchronous generator is mounted on the main shaft of the high-voltage electronic fan. The permanent magnet synchronous generator is connected to the supercapacitor, and the supercapacitor is connected to the BMS. The permanent magnet synchronous generator is used to convert the kinetic energy generated by the rotation of the high-voltage electric fan into electrical energy and transmit it to low-power loads and / or supercapacitor energy storage. The VCU is used to initiate reverse power supply, transferring the supercapacitor's energy to the power battery.

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