Intelligent land-based unmanned platform hydrogen-lithium hybrid power system and management method

Abstract

The application belongs to the technical field of new energy power systems, and particularly relates to an intelligent land-based unmanned platform hydrogen-lithium hybrid power system and a management method, wherein the system comprises a gas supply module, a power supply module, an energy storage module, an energy management controller and a slope sensor, wherein the energy management controller is configured to: when a slope angle detected by the slope sensor is greater than a first set threshold, control the energy storage module to output power as a main power source; and when the slope angle is less than or equal to the first set threshold, control the fuel cell to output power as a main power source.

Description

Technical Field

[0001] This invention belongs to the field of new energy power system technology, and more specifically, it relates to an intelligent land-based unmanned platform hydrogen-lithium hybrid power system and management method. Background Technology

[0002] Currently, unmanned platforms, with their superior advantage of requiring no close human operation, have been widely used in fields such as military, agriculture, logistics, environmental monitoring, and emergency rescue. They have demonstrated enormous potential in improving work efficiency and reducing personnel risk costs and operating costs.

[0003] As the "heart" of an unmanned platform, the power system directly determines its core performance characteristics, including range, load capacity, quietness, and environmental adaptability. Compared to traditional land-based unmanned platforms powered by internal combustion engines and batteries, hydrogen fuel cells are widely recognized as the ideal power source for next-generation unmanned platforms due to their significant advantages such as high energy density, low pollution, and low infrared thermal signature. They produce only water during operation, exhibiting excellent environmental friendliness and making them particularly suitable for applications requiring long endurance and high stealth.

[0004] However, despite the significant advantages of hydrogen fuel cells, their application as a single power source still faces numerous technical challenges in practical applications. Firstly, the chemical reaction process of hydrogen fuel cells is relatively slow, making it impossible to provide a large current instantaneously like lithium batteries. When unmanned platforms need to accelerate suddenly, climb hills, or cope with sudden loads, the power output of fuel cells lags behind, failing to meet instantaneous high power demands and potentially leading to platform performance degradation or even mission failure. Furthermore, fuel cells themselves cannot absorb regenerative energy. When unmanned platforms decelerate or descend hills, the generated kinetic energy cannot be recovered, resulting in waste. This provides ample room for demonstrating the necessity of hydrogen-lithium hybrid power systems.

[0005] Therefore, in view of this, we will study and improve the existing structure and its shortcomings, and provide a hydrogen-lithium hybrid power system for an intelligent land-based unmanned platform, in order to achieve a more practical value. Summary of the Invention

[0006] In view of the problems mentioned in the background art above, the present invention provides an intelligent land-based unmanned platform hydrogen-lithium hybrid power system and management method.

[0007] On one hand, this invention provides a hydrogen-lithium hybrid power system for an intelligent land-based unmanned platform, including a gas supply module, a power supply module, an energy storage module, a slope sensor, and an energy management controller. The gas supply module stores and supplies hydrogen; the power supply module includes a DC / DC converter and a power system, used to convert the electrical energy generated by the hydrogen fuel cell to power the power system to drive the unmanned platform; the energy storage module includes a lithium battery and a supercapacitor; the slope sensor is used to detect the slope angle of the ground where the unmanned platform is located in real time; the energy management controller is electrically connected to the slope sensor, the gas supply module, the power supply module, and the energy storage module, used to receive slope signals and status data of each module, and control the working status of the gas supply module, the power supply module, and the energy storage module accordingly; wherein, the energy management controller is configured to: when the slope angle detected by the slope sensor is greater than a first set threshold, control the energy storage module to output power as the main power source; when the slope angle is less than or equal to the first set threshold, control the fuel cell to output power as the main power source.

[0008] Furthermore, the energy management controller is also configured to: calculate the remaining hydrogen ratio of the fuel cell and the remaining charge ratio of the lithium battery in real time, and calculate the difference between the two; adjust the power distribution strategy of the fuel cell and the lithium battery according to the different ranges in which the difference is located, so that the remaining hydrogen ratio and the remaining charge ratio tend to be balanced.

[0009] Furthermore, the energy management controller is also equipped with an equivalent minimum consumption strategy, which calculates the globally optimal power allocation ratio based on hydrogen consumption rate, battery health loss, and power conversion loss.

[0010] Furthermore, the energy management controller is also equipped with a hydrogen fuel cell health status prediction model, which predicts the health status of the fuel cell using a hydrogen fuel cell health status prediction formula.

[0011] Furthermore, the gas supply module includes a high-pressure hydrogen storage tank, a pressure reducing valve, a solenoid valve, and a hydrogen fuel cell stack connected in sequence. The pressure reducing valve is used to regulate the hydrogen pressure entering the circuit, and the solenoid valve is used to regulate the hydrogen flow rate entering the hydrogen fuel cell stack.

[0012] Furthermore, it also includes a sensor group for monitoring the status of the gas supply module, the sensor group including one or a combination of a pressure sensor and a hydrogen flow meter, the energy management controller being connected to the sensor group and configured to: send a warning signal to the power system and trigger a return or stop procedure when the total hydrogen consumption is detected to reach a threshold and / or the pressure inside the hydrogen storage container is lower than a safety threshold.

[0013] On the other hand, the present invention provides a method for energy management of hydrogen-lithium hybrid power on an intelligent land-based unmanned platform, comprising the following steps: S1: real-time acquisition of the slope angle detected by the slope sensor; S2: selection of the main power source based on the comparison result of the slope angle and a first set threshold; S3: dynamic allocation of the output power of the fuel cell and the lithium battery / supercapacitor according to the total power demand of the unmanned platform and the real-time status of the fuel cell and the energy storage module.

[0014] Furthermore, it also includes step S4: cyclically executing steps S1-S3 and determining in real time whether the pressure and / or temperature safety thresholds are triggered. If triggered, a warning signal is sent to the power system and the return or stop procedure is triggered.

[0015] The beneficial effects of this invention are:

[0016] 1. By directly sensing changes in the external environment through slope sensors, the power source can be switched in advance and with precision, which perfectly solves the problem of slow dynamic response of fuel cells and significantly improves the terrain passability of unmanned platforms.

[0017] 2. It integrates terrain-based rule control and hydrogen-electricity balance-based optimization algorithms, which not only ensures instantaneous power response but also ensures the most economical energy consumption throughout the entire journey, maximizing the driving range. Attached Figure Description

[0018] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings;

[0019] Figure 1 This is a schematic diagram of the present invention; Detailed Implementation

[0020] like Figure 1 As shown, an intelligent land-based unmanned platform hydrogen-lithium hybrid power system includes a gas supply module, a power supply module, an energy storage module, a slope sensor, and an energy management controller. The gas supply module stores and supplies hydrogen. The power supply module includes a DC / DC converter and a power system, used to convert the electrical energy generated by the hydrogen fuel cell to power the power system to drive the unmanned platform. The energy storage module includes a lithium battery and a supercapacitor. The slope sensor is used to detect the slope angle of the ground where the unmanned platform is located in real time. The energy management controller is electrically connected to the slope sensor, gas supply module, power supply module, and energy storage module, used to receive slope signals and status data of each module, and control the working status of the gas supply module, power supply module, and energy storage module accordingly. The energy management controller is configured to: control the energy storage module as the main power source when the slope angle detected by the slope sensor is greater than a first set threshold; and control the fuel cell as the main power source when the slope angle is less than or equal to the first set threshold.

[0021] The gas supply section includes a high-pressure hydrogen storage tank, a pressure reducing valve, a solenoid valve, and a hydrogen fuel cell stack. Hydrogen is stored in the high-pressure hydrogen storage tank at a pressure of 35 MPa. After the pressure is regulated by the pressure reducing valve, the energy management controller controls the opening of the solenoid valve to regulate the flow of hydrogen entering the anode of the hydrogen fuel cell stack. The exhaust gas of hydrogen is discharged through the outlet.

[0022] Simultaneously, air, powered by a fan, enters the cathode of the fuel cell stack, supplying oxygen to the fuel cell for reaction. The hydrogen fuel cell stack consumes hydrogen and reacts with oxygen in the air to generate electricity. In addition, water produced by the hydrogen-oxygen reaction in the stack is periodically purged by exhaust to prevent flooding and performance degradation. The power supply and charging section consists of a DC / DC module, an electronic speed controller, a power system, lithium batteries, and a supercapacitor energy storage module. The output of the hydrogen fuel cell stack is regulated by a DC / DC converter and then connected to the electronic speed controller to supply power to the power system. The power system uses conventional drive motors, electronic controls, and other existing means, which do not need further explanation. The power system drives the unmanned platform.

[0023] The generated electricity can also be sent to the energy storage module to charge and store it.

[0024] The energy storage module includes a lithium battery and a supercapacitor, both connected to a DC bus via a bidirectional DC / DC converter. When instantaneous power demands exceed the fuel cell's rated power, such as during hill climbing or acceleration, the energy management controller controls the bidirectional DC / DC converter to operate in discharge mode, with the energy storage module providing additional power. During downhill driving or braking, it operates in charging mode to recover energy.

[0025] The slope sensor (which can be a tilt sensor or IMU) monitors the vehicle's pitch angle, i.e., the gradient angle, in real time and sends the data to the energy management controller. The energy management controller is the system's control center, with a built-in processor and memory storing the control program. It receives signals from the slope sensor, as well as voltage, current, temperature, pressure, and flow signals from various components. It controls the operation of solenoid valves, DC / DC converters, and bidirectional DC / DC converters via control lines.

[0026] Specifically, regarding the overall allocation and use of the energy management system:

[0027] The energy management controller collects data from slope sensors, fuel cells, lithium batteries, voltage, current, hydrogen flow, and other data.

[0028] The energy management controller compares the real-time slope angle with a first set threshold of 15°: if the slope angle is greater than 15°, the energy storage module is requested to provide power first, with the fuel cell as a supplement; if the slope angle is less than or equal to 15°, the fuel cell is given priority to provide power, and its surplus power is used to charge the energy storage module.

[0029] The reason for setting the first threshold at 15° is that hydrogen fuel cells have the advantage of high energy density but the disadvantage of low power density: although their output power is relatively stable, there are significant problems with sudden and large increases in power output, with a response delay, making it difficult to cope with sudden surges in power demand. In contrast, lithium batteries have the advantage of high power density, but their energy density is relatively low. The intelligent land-based unmanned platform requires a huge amount of power from the system during start-up and shutdown, and the power required is also greatly affected by rapid changes in slope. Furthermore, during operation, as the slope angle increases, the power required to overcome the slope's gravity increases rapidly (especially after exceeding 15°), causing the required traction power to rise non-linearly and sharply. Therefore, 15° was chosen as the turning point for system switching.

[0030] Furthermore, hydrogen fuel cells operate on slopes below 15 degrees, preventing them from being under prolonged overload. Overload significantly reduces stack life and efficiency, and the power demand below 15 degrees is typically within the high-efficiency range of hydrogen fuel cells. This also aligns with the characteristics of lithium batteries: lithium batteries excel at handling short-term, high-power conditions, and their intervention at slopes greater than 15 degrees allows them to leverage their advantages for "sprinting" uphill. Once the slope is flat or the road conditions have eased, they can switch back to hydrogen-electric mode or be recharged, preventing deep discharge of the lithium battery.

[0031] The hybrid strategy of "hydrogen-electric as the main power source and lithium-ion as the auxiliary power source" achieves a powerful combination of energy density and power density. The platform can achieve long-range operation on flat terrain using hydrogen-electric power, while lithium-ion batteries ensure passability on steep slopes, thus achieving the optimal solution for global energy utilization.

[0032] Furthermore, if the threshold is set too low (e.g., 10°), it will frequently trigger lithium battery power, potentially wasting its cycle life. Also, due to the low energy density of lithium batteries, it may increase the need for mid-cycle charging or battery swapping. If the threshold is set too high (e.g., 20°), the hydrogen fuel cell may be forced to operate under overload for extended periods within the 15°-20° range, damaging its lifespan and reliability. Therefore, 15° is a point that strikes a balance between lifespan and economic efficiency.

[0033] Hydrogen-electricity balance calculation: The energy management controller calculates the remaining hydrogen ratio S in the fuel cell in real time. H2 Given the remaining charge percentage of the lithium battery, Ssoc(t), calculate the difference between them, S(t). The formula is as follows:

[0034]

[0035] In the formula:

[0036] S SOC (t) represents the remaining percentage of the lithium battery charge at the current moment relative to the initial charge.

[0037] S H2 (t) represents the remaining percentage of hydrogen mass at the current moment relative to the initial hydrogen mass (%).

[0038] Q total The rated capacity (Ah) of the lithium battery;

[0039] SOC init This represents the initial state of charge of the lithium battery.

[0040] SOC(t) represents the state of charge of the lithium battery at the current moment.

[0041] m H2,initm The initial hydrogen mass (g) of the fuel cell system;

[0042] m H2 (t) represents the remaining hydrogen mass (g) of the fuel cell system at the current moment.

[0043] Subsequently, the controller dynamically adjusts the power allocation strategy based on the magnitude of the difference S(t):

[0044] When S(t) < −a%, it is defined as a “negative state”: indicating that the lithium battery’s power consumption rate is faster than the hydrogen consumption rate. In this state, the controller prioritizes reducing the lithium battery’s discharge power or increasing its charging power to protect the lithium battery and prevent it from over-discharging.

[0045] When −a%≤S(t)≤a%, it is defined as an “equilibrium state”, indicating that the hydrogen-electricity consumption rate is basically balanced. In this state, the controller allocates power with the primary goal of improving the efficiency of the fuel cell system, typically keeping the fuel cell operating within its optimal efficiency range.

[0046] When S(t) > a%, it is defined as a "positive state": indicating that the hydrogen consumption rate is faster than the lithium battery power consumption rate. In this state, the controller appropriately increases the discharge power ratio of the lithium battery to save precious hydrogen fuel and extend the overall driving range.

[0047] Because the discharge characteristics of lithium batteries are non-linear, their discharge voltage curve typically drops sharply at low SOC levels. Over-discharge can severely damage battery life and even cause safety issues. If the value of 'a' is set too small, the system may frequently adjust even with slight imbalances in the hydrogen-to-electricity ratio, leading to power fluctuations. Therefore, the setting of 'a' must reserve a sufficient safety buffer for the lithium battery's SOC. Ideally, the value of 'a' should be between 1 and 5, with a minimum value of 3. In this invention, the threshold 'a' for the hydrogen-to-electricity balance state is defined through systematic simulation optimization and real-vehicle calibration. First, based on the fuel cell efficiency MAP, the lithium battery's internal resistance and SOC characteristic curves, and the vehicle dynamics model, a forward model of the system is built in a simulation environment. Then, a dual-objective optimization function is defined, focusing on extending lithium battery life and reducing total hydrogen consumption. Through sweep simulations of parameter 'a%' from 1% to 5% under typical operating conditions, such as continuous hill climbing and flat cruising, the impact of different 'a' values ​​on the minimum SOC of the lithium battery, hydrogen consumption, and mode switching frequency is analyzed. Simulation results show that when a=3, the system can achieve a better balance between hydrogen consumption and lithium battery consumption while ensuring that the lithium battery SOC is not lower than 25% of the safety boundary. The total hydrogen consumption is low and the control mode switching is smooth. Finally, this value was further verified in the real vehicle calibration and was determined to be the optimal parameter of the control strategy.

[0048] For example, even on flat ground, if the system is in a "positive state" (rapid hydrogen consumption), the discharge ratio of the lithium battery will still be appropriately increased to protect the precious hydrogen fuel.

[0049] After the judgment is completed, the energy management controller sends a power command to the corresponding DC / DC converter for execution. This process is repeated cyclically, with real-time checks to determine if safety thresholds such as hydrogen storage capacity, pressure, and temperature are triggered.

[0050] Once triggered, S112 is executed immediately, issuing a warning and controlling the unmanned platform to enter a safe mode (such as returning to base).

[0051] The core value of fuel cell health status prediction lies in achieving proactive safety protection and life cycle optimization of the power system. When the prediction model detects that the SOH value exceeds the preset threshold, the energy management module will immediately intervene: First, it triggers gradient load reduction protection—by dynamically adjusting the opening of the hydrogen flow solenoid valve and the air compressor speed, it limits the fuel cell output power within a safe range, preventing irreversible damage to the stack due to membrane electrode dehydration or flooding; the lithium battery and supercapacitor take over the excess load, maintaining the continuous operation of the unmanned platform, which can effectively avoid system paralysis caused by sudden failures and extend the service life of core components.

[0052] The prediction of the fuel cell's health status can be obtained using the following formula:

[0053]

[0054] In the formula:

[0055] Initial attenuation coefficient: Characterizes the degree of attenuation of the initial performance of the new fuel cell stack relative to the ideal state. It is obtained through the operation test of the new fuel cell stack and is measured as the ratio of the actual output voltage to the nominal voltage in the first hour.

[0056]

[0057] Time decay factor: Characterizes the natural aging rate of a fuel cell over time. It is obtained by voltage decay curve through constant load operation test and the logarithmic decay slope is calculated.

[0058]

[0059] The load impact weight characterizes the impact of dynamic load changes on fuel cell lifespan. The relationship between voltage drop and current change is measured through a stepped load change experiment.

[0060]

[0061] Because lithium batteries have a high discharge rate, they can provide timely power replenishment as auxiliary power, primarily through instantaneous high-power replenishment. Typically, when the power output is below 1300 W, the hydrogen fuel cell can meet the current power requirements, and excess energy is used to charge the lithium battery through the energy management module's lithium battery charging interface, maintaining the lithium battery in a good charge state. To maintain the entire system at the lowest energy consumption and highest performance, the energy management controller is also equipped with an equivalent minimum consumption strategy. By evaluating hydrogen consumption, battery health energy consumption, and stack protection energy consumption to achieve equivalent minimum consumption, the energy consumption of the intelligent land-based unmanned platform's hydrogen-lithium hybrid power control system is further reduced, enhancing the system's range to more than twice that of traditional fuel and lithium batteries.

[0062]

[0063] SOC is the remaining percentage of the lithium battery charge at the current moment relative to the initial charge.

[0064] m H2 The hydrogen mass consumption rate per unit time (g / s);

[0065] dP FC / dt represents the rate of change of the fuel cell output power;

[0066] w1: The weight of the hydrogen consumption term in the objective function, which is dynamically adjusted based on temperature compensation;

[0067] Dynamic adjustment:

[0068] w2: The weight of the battery health item in the objective function;

[0069] Dynamic adjustment:

[0070] w3: The weight of the power change term in the objective function.

[0071] Dynamic adjustment: )

[0072] The hydrogen-lithium hybrid power control system, through ingenious design, achieves a perfect fusion of the high energy density of hydrogen and the high power density of lithium batteries. The installation of high-precision slope sensors is crucial for the stable and safe operation of the land-based unmanned platform. The application of intelligent algorithms is the core of ensuring minimal energy consumption and optimal performance of the unmanned platform. It represents the ideal solution under current technological conditions, balancing long endurance, high power, high reliability, high economy, and environmental adaptability. It is not only an inevitable path to solving existing technological problems but also a key technological measure to push the performance boundaries of intelligent land-based unmanned platforms to higher dimensions. Developing this solution has significant strategic and practical implications for enhancing my country's core competitiveness in the field of high-end unmanned equipment.

[0073] The present invention has been described in detail above. The specific embodiments are provided only to help understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A hydrogen-lithium hybrid power system for an intelligent land-based unmanned platform, characterized in that, include: A gas supply module is used to store and supply hydrogen. The gas supply module includes a high-pressure hydrogen storage tank, a pressure reducing valve, a solenoid valve and a hydrogen fuel cell stack connected in sequence. The pressure reducing valve is used to regulate the hydrogen pressure entering the circuit and the solenoid valve is used to regulate the hydrogen flow rate entering the hydrogen fuel cell stack. The power supply module includes a DC / DC converter and a power system, which is used to convert the electrical energy generated by the hydrogen fuel cell to power the power system to drive the unmanned platform. An energy storage module, comprising a lithium battery and a supercapacitor, wherein the lithium battery and the supercapacitor are connected to a DC bus via a bidirectional DC / DC converter; A slope sensor is used to detect the slope angle of the ground where the unmanned platform is located in real time. An energy management controller is electrically connected to a slope sensor, a gas supply module, a power supply module, and an energy storage module. It is used to receive slope signals and status data of each module, and control the working status of the gas supply module, the power supply module, and the energy storage module accordingly. The energy management controller is configured as follows: Collect data from slope sensors, fuel cells, lithium batteries, voltage, current, temperature, pressure, and hydrogen flow rates; The real-time slope angle is compared with a first set threshold of 15°. If the slope angle is greater than 15°, the system enters the energy storage priority mode, which prioritizes requesting power from the energy storage module, with the fuel cell serving as a supplement. If the slope angle is less than or equal to 15°, the system enters the fuel cell priority mode, which prioritizes power from the fuel cell and uses the excess power of the fuel cell to charge the energy storage module. After determining the energy storage priority mode or fuel cell priority mode, the remaining hydrogen ratio of the fuel cell and the remaining charge ratio of the lithium battery are calculated in real time, and the difference S(t) between them is calculated. According to the different ranges of the difference S(t), the power allocation strategy in the corresponding mode is modified: when S(t) < -a%, the discharge power of the lithium battery is reduced or the charging power of the lithium battery is increased; when -a% ≤ S(t) ≤ a%, the fuel cell is maintained in the optimal efficiency range; when S(t) > a%, the discharge power ratio of the lithium battery is increased; where a = 3, and the energy management controller is configured to ensure that the SOC of the lithium battery is not lower than a preset safety boundary. The energy management controller is also configured with an equivalent minimum consumption strategy. Under the energy storage priority mode or fuel cell priority mode and the power allocation strategy after the difference S(t) is corrected, the power allocation ratio between the fuel cell and the lithium battery is calculated by hydrogen consumption rate, battery health loss and power conversion loss. The energy management controller is also equipped with a hydrogen fuel cell health status prediction model. When the hydrogen fuel cell health status prediction model detects that the fuel cell health status meets the preset protection conditions, it triggers gradient load reduction protection. By dynamically adjusting the opening degree of the solenoid valve and the speed of the air compressor, the output power of the fuel cell is limited to a safe range, and the lithium battery and supercapacitor take over the excess load to maintain the continuous operation of the unmanned platform.

2. An energy management method applied to the hydrogen-lithium hybrid power system of the intelligent land-based unmanned platform as described in claim 1, characterized in that: Includes the following steps: S1: Real-time acquisition of the slope angle detected by the slope sensor; S2: Based on the comparison result between the slope angle and the first set threshold, select the main power source; S3: Based on the total power requirements of the unmanned platform and the real-time status of the fuel cell and energy storage module, dynamically allocate the output power of the fuel cell and lithium battery / supercapacitor.

3. The energy management method for a hydrogen-lithium hybrid power system of an intelligent land-based unmanned platform according to claim 2, characterized in that: It also includes step S4: cyclically execute steps S1-S3, and determine in real time whether the pressure and / or temperature safety thresholds are triggered. If triggered, send a warning signal to the power system and trigger the return or stop procedure.

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