Hydrogen-lithium hybrid control system applied to unmanned aerial vehicle and two-wheeled vehicle

Abstract

The invention relates to the technical field of energy management, and discloses a hydrogen-lithium hybrid control system applied to an unmanned aerial vehicle and a two-wheeled vehicle, which comprises an anti-backflow unit arranged between a direct current-direct current converter and a bus to form one-way confluence from a fuel cell to the bus and block reverse current, the control unit collects the voltage, current and temperature of the fuel cell, the converter, the bus and the stored energy, and executes access and current limiting according to a preset stack voltage working range, a bus target range and a stack voltage threshold, when the stack voltage and the bus are in a target interval, the stored energy is charged in a limited manner, and when the bus voltage drops or the stack voltage is lower than the threshold, current limiting is kept, and the stored energy is discharged to the bus; when any channel is abnormal, the anti-backflow function is closed, and power supply is maintained by other channels or stored energy, so that dynamic power switching and distribution of limited charging and seamless discharging are realized on the premise of not introducing recharge and circulating current and not depending on high-loss devices, and continuity and stability of a bus are ensured.

Description

Technical Field

[0001] This invention relates to the field of energy management technology, and more specifically, to a hydrogen-lithium hybrid control system for use in drones and two-wheeled vehicles. Background Technology

[0002] In existing technologies for lightweight platforms such as drones and two-wheeled vehicles, the power supply side is usually composed of fuel cells and lithium-based energy storage due to limitations in volume, mass, heat dissipation, and response time. Existing technologies mostly achieve continuous power supply through energy shaping and bus stabilization methods, including abstract steps such as source-side regulation, power conversion, unidirectional control, threshold control, and state monitoring. The applicable premise is usually that the load change range is limited, the bus filtering margin is sufficient, and the single source operating point is stable.

[0003] In actual operating conditions, there are two unstable factors. One is that the propulsion or driving load undergoes a step change on the order of milliseconds, causing bus voltage fluctuations. The other is the risk of reverse current and circulating current caused by the inconsistency between the fuel cell and energy storage voltages. The combined impact of these factors on existing energy shaping and bus stabilization methods is to trigger reinjection or coupling disturbances and reduce switching continuity, thereby affecting power supply stability. Therefore, the technical problem that needs to be solved is to achieve dynamic power switching and distribution between fuel cells and lithium-based energy storage for restricted charging and seamless discharging without introducing reinjection and circulating current and without relying on high-loss devices.

[0004] In view of this, the present invention proposes a hydrogen-lithium hybrid control system for use in drones and two-wheeled vehicles to solve the above problems. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a hydrogen-lithium hybrid control system applicable to drones and two-wheeled vehicles.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, a hydrogen-lithium hybrid control system for use in drones and two-wheeled vehicles is provided, comprising: Fuel cell unit; A DC-DC converter, the input of which is connected to the output of the fuel cell unit; DC bus, used to collect electrical energy and supply power to the load interface; The backflow prevention unit is located between the output terminal of the DC-DC converter and the DC bus to block the reverse current from the DC bus to the DC-DC converter and fuel cell unit. Energy storage unit, connected in parallel to the DC bus; Load interface, connected to the DC bus; The control unit, electrically connected to the fuel cell unit, DC-DC converter, DC bus, and energy storage unit, is configured to: acquire voltage, current, and temperature signals from the fuel cell unit, DC-DC converter output, DC bus, and energy storage unit; when the fuel cell unit passes its power-on self-test and the stack pressure is within the preset stack pressure operating range, output enable, current limiting, or voltage limiting control signals to the DC-DC converter, enabling limited charging of the energy storage unit when the DC bus is within the preset target range; when the DC bus voltage is detected to be below the preset target range or the fuel cell unit voltage is below the preset stack pressure threshold, maintain the DC-DC converter in current-limited output mode, allowing the energy storage unit to discharge to the DC bus to maintain power supply; when any power supply channel experiences an abnormal state, shut down the backflow prevention unit of that channel to achieve isolation, while the remaining channels or energy storage units continue to maintain DC bus power supply.

[0007] In some embodiments, the fuel cell unit includes a first fuel cell stack and a second fuel cell stack, which are connected in parallel to a DC bus after passing through corresponding DC-DC converters and corresponding anti-backflow units.

[0008] In some embodiments, the DC-DC converter is a non-isolated unidirectional buck-boost type and can switch between constant voltage, constant power and current limiting modes. The control unit selects the operating mode according to preset switching conditions.

[0009] In some embodiments, the anti-backflow unit includes a power metal-oxide-semiconductor tube, a drive control circuit, and a potential difference detection circuit. The potential difference detection circuit is used to detect the potential difference between the DC bus and the corresponding channel, and the drive control circuit realizes unidirectional conduction and shutdown accordingly.

[0010] In some embodiments, when the energy storage unit is allowed to perform limited charging, the control unit constrains the DC-DC converter output according to the preset charging current limit and the preset bus voltage limit, and adjusts the preset charging current limit based on the temperature and state of charge estimation results of the energy storage unit.

[0011] In some embodiments, the preset bus target range has a preset hysteresis band, and the preset stacking pressure operating range is composed of a preset upper stacking pressure threshold and a preset lower stacking pressure threshold. The hysteresis band is used to implement a hysteresis-based switching between restricted charging and discharging.

[0012] In some embodiments, the control unit performs channel-level judgment on overvoltage, undervoltage, overcurrent and overtemperature of each power supply channel, and shuts down the backflow prevention unit of any channel to achieve isolation when an abnormal state occurs, while the remaining channels and energy storage unit maintain DC bus power supply.

[0013] In some embodiments, a hydrogen concentration sensor is also included. The hydrogen concentration sensor is electrically connected to the control unit. When the hydrogen concentration is detected to exceed a preset concentration threshold, the control unit prohibits charging the energy storage unit and shuts off the enabling of the relevant power supply channel.

[0014] In some embodiments, the DC bus is provided with a pre-charge branch and a bypass switch. The pre-charge branch is connected in series with a current limiting element to limit the inrush current. The bypass switch is closed by the control unit after the pre-charge is completed and the DC bus voltage reaches a preset parallel access threshold.

[0015] In some embodiments, the precharge branch series resistor or thermistor serves as a current limiting element, and the bypass switch is a power metal-oxide-semiconductor transistor or a relay.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, within a DC bus architecture, an anti-backflow unit is installed between the DC-DC converter output and the DC bus to establish a unidirectional current path from the fuel cell unit to the DC bus, blocking reverse current from the DC bus to the DC-DC converter and fuel cell unit. The control unit collects voltage, current, and temperature signals from the fuel cell unit, DC-DC converter output, DC bus, and energy storage unit, and implements access and current limiting control based on a preset stack pressure operating range, a preset bus target range, and a preset stack pressure threshold. When the fuel cell unit passes its power-on self-test and the stack pressure is within the preset stack pressure operating range and the DC bus voltage is within the preset bus target range, the system achieves the desired voltage. When the target range is reached, the energy storage unit is subjected to restricted charging. When the DC bus voltage is detected to be lower than the preset target range or the fuel cell unit voltage is lower than the preset stack voltage threshold, the DC-DC converter is kept in current-limited output and the energy storage unit discharges to the DC bus to maintain power supply. When any power supply channel has an abnormal state, the anti-backflow unit of that channel is shut down and the other channels or energy storage units continue to maintain the DC bus power supply. In this way, without introducing backflow and circulating current and without relying on high-loss devices, dynamic power switching and distribution between the fuel cell unit and the energy storage unit for restricted charging and seamless discharging are realized, and the continuous and stable power supply of the DC bus is maintained. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the hydrogen-lithium hybrid control system for drones and two-wheeled vehicles in this invention. Figure 2 This is a schematic diagram of the hydrogen-lithium hybrid framework of a two-wheeled vehicle based on the hydrogen-lithium hybrid control system of a drone and a two-wheeled vehicle in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the term covers the element or object listed after the term and its equivalents, without excluding other elements or objects. Terms such as “connection” or “linked” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0020] Example 1 Please see Figure 1 and Figure 2 As shown, this embodiment discloses a hydrogen-lithium hybrid control system for use in drones and two-wheeled vehicles, including: Fuel cell unit; A DC-DC converter, the input of which is connected to the output of the fuel cell unit; DC bus, used to collect electrical energy and supply power to the load interface; An anti-backflow unit is installed between the output terminal of the DC-DC converter and the DC bus to block reverse current from the DC bus to the DC-DC converter and the fuel cell unit. An energy storage unit is connected in parallel to the DC bus; The load interface is connected to the DC bus. The control unit, electrically connected to the fuel cell unit, DC-DC converter, DC bus, and energy storage unit, is configured to: acquire voltage, current, and temperature signals from the fuel cell unit, the DC-DC converter output, the DC bus, and the energy storage unit; when the fuel cell unit passes its power-on self-test and its stack pressure is within a preset stack pressure operating range, output enable, current limiting, or voltage limiting control signals to the DC-DC converter, enabling limited charging of the energy storage unit when the DC bus is within a preset target range; when the DC bus voltage is detected to be below the preset target range or the fuel cell unit voltage is below a preset stack pressure threshold, maintain the DC-DC converter in current-limited output mode, allowing the energy storage unit to discharge to the DC bus to maintain power supply; when any power supply channel experiences an abnormal state, shut down the backflow prevention unit for that channel to achieve isolation, while the remaining channels or the energy storage unit continue to maintain power supply to the DC bus.

[0021] In this embodiment, as Figure 1 and Figure 2 As shown, the DC-DC converter is located between the fuel cell unit and the DC bus. Its input terminal receives the stack voltage DC from the fuel cell unit, and its output terminal is connected to the DC bus after passing through the anti-backflow unit. The DC-DC converter is used to perform voltage matching and controlled power supply under the action of the enable current limiting or voltage limiting control of the control unit, so as to achieve deterministic power switching and distribution between limited charging and discharging maintenance.

[0022] The backflow prevention unit is located between the DC-DC converter output and the DC bus. It is used to achieve unidirectional conduction and block the reverse current from the DC bus to the DC-DC converter and fuel cell unit. The backflow prevention unit, together with the DC-DC converter, can avoid the risk of backflow and circulating current when multiple channels are connected in parallel, and the control unit can perform channel isolation when abnormal channel conditions occur.

[0023] It is understandable that, such as Figure 1 and Figure 2 As shown, the DC bus serves as the system's common power supply path, electrically connected to the load interface and in parallel with the energy storage unit. The control unit is electrically connected to the DC-DC converter of the fuel cell unit and the energy storage unit to complete the acquisition, judgment, and control output of voltage, current, and temperature signals. The load interface is located at... Figure 1 Connect the flight controller and the electronic speed controller, in Figure 2 The motor controller's DC input terminal is connected, and the communication interface includes existing communication and control signal links such as CAN, 485, or PWM. The control unit interacts with the DC-DC converter through the above links to enable and adjust the duty cycle or current and voltage limits, and interacts with the load-side controller to exchange status and commands. The above interfaces are all commonly used components by those skilled in the art and are consistent with the connection relationships shown in the figure.

[0024] In this embodiment, as Figure 1 As shown, the UAV hydrogen hybrid framework includes a servo motor as an example of a load-side actuator. The servo motor interacts with the flight controller or control unit via PWM or bus protocol. Its power supply is provided by the load interface. The servo motor is an existing component used to illustrate the diversity of load types and does not participate in the power supply determination and channel isolation process composed of DC-DC converter and anti-backflow unit. The hydrogen concentration sensor is electrically connected to the control unit to provide environmental safety signals. When the concentration exceeds the preset concentration threshold, the control unit can prohibit charging of the energy storage unit and shut down the relevant power supply channel. The hydrogen concentration sensor is an existing gas sensor that works with the CAN or 485 link shown in the figure to realize alarm uploading and policy triggering.

[0025] The I / O device is reserved as an expansion interface for the control unit to connect peripherals such as local display buttons, indicators, or relays. This interface does not affect the power path of the DC-DC converter and the backflow prevention unit, and is only used for human-machine interaction and status prompts. Those skilled in the art can choose to connect or not connect according to product requirements.

[0026] In this embodiment, as Figure 2 As shown, the power supply module of the two-wheeled vehicle hydrogen hybrid frame is located between the energy storage unit and the control unit. It is used to convert the DC bus side or energy storage side voltage into the low-voltage DC required by the control unit and sensors. The power supply module is an existing step-down or isolated board-level power supply. Its operation does not change the main power path determination logic composed of DC-DC converter and anti-backflow unit.

[0027] The vehicle start button is connected to the control unit via I / O to provide start / stop commands to the control unit. The control unit then executes the pre-charge branch conduction and bypass opening / closing and restricted charging access sequence after the DC bus voltage reaches the preset parallel access threshold. The above button is an existing human-machine interface that does not change the control judgment conditions for maintaining restricted charging and discharging.

[0028] For example, such as Figure 1 and Figure 2 The common structure shown first determines access based on the preset stack pressure working range and the preset bus target range during operation, and sends current limiting or voltage limiting control quantities to the DC-DC converter. Then, it is connected to the DC bus in one direction through the anti-backflow unit. When the DC bus voltage is lower than the preset bus target range or the fuel cell unit voltage is lower than the preset stack pressure threshold, the energy storage unit undertakes the discharge maintenance and shuts down the corresponding anti-backflow unit in the abnormal channel state to maintain continuous and stable power supply.

[0029] In this embodiment, the reason why the control unit synchronously collects the voltage, current and temperature of the fuel cell unit, DC-DC converter output, DC bus and energy storage unit and uses them to determine access and limit values ​​is that parallel power supplies are prone to unconstrained coupling and uncertain circulating currents under load step and source-side state fluctuations. The purpose of this process is to issue enable and current limiting or voltage limiting control quantities only when the fuel cell unit is within the preset stack pressure operating range and the DC bus is within the preset bus target range. Measurable limited charging access conditions are established from the source side, and when the bus drops or the stack pressure decreases, the current limiting is maintained and the energy storage unit discharges to maintain the load to ensure uninterrupted power supply.

[0030] It should be noted that the backflow prevention unit is set between the DC-DC converter output and the DC bus to form a unidirectional current-carrying path. Its location selection can directly block the reverse current from the DC bus to the DC-DC converter and fuel cell unit. Combined with channel-level anomaly detection, it can immediately isolate the channel when overvoltage, undervoltage, overcurrent, overtemperature or communication failure occurs in any channel. At the same time, the inrush current is limited by the sequential control of the precharge branch and bypass switch, and it is connected to the main path only after reaching the preset parallel access threshold. Thus, in the case of multi-channel parallel connection, the power path is clear and the switching sequence is controllable.

[0031] Compared to existing technologies that directly connect high-loss devices in parallel or rely on continuous series connection, the above processing logic replaces the long-term voltage drop path with threshold access and current limiting, replaces the passive suppression of backflow with the unidirectional conduction of the backflow prevention unit, and replaces the coarse-grained treatment of whole-machine shutdown with channel-level isolation. In this way, without introducing backflow and circulating current and without relying on high-loss devices, it can achieve deterministic dynamic power switching and distribution between limited charging and seamless discharging, and keep the DC bus continuous and stable under load step and source fluctuation conditions.

[0032] The direct technical effects obtained by the above-mentioned technical means include reducing conduction losses and heat load, reducing inter-channel coupling disturbances, shortening the state stabilization time during the power-on phase, improving scalability and maintainability in multi-channel parallel systems, and meeting the continuous power supply requirements under the constraints of volume, mass, heat dissipation, and response time of lightweight platforms such as drones and two-wheeled vehicles. The above-mentioned technical effects correspond one-to-one with the technical problems proposed in the background technology, and are reflected in the coordinated control of restricted charging access, discharge maintenance during bus drop, and channel abnormal isolation under the same hardware resource conditions, thereby achieving stable power supply to the target system.

[0033] The fuel cell unit includes a first fuel cell stack and a second fuel cell stack. The first fuel cell stack and the second fuel cell stack are connected in parallel to the DC bus after passing through corresponding DC-DC converters and corresponding anti-backflow units. The DC-DC converter is a non-isolated unidirectional buck-boost type and can switch between constant voltage, constant power and current limiting modes. The control unit selects the operating mode according to preset switching conditions.

[0034] In this embodiment, the fuel cell unit uses a first fuel cell stack and a second fuel cell stack, which are respectively connected to the DC bus via corresponding DC-DC converters and corresponding anti-backflow units. This is to ensure that the voltage transformation and current limiting of each power supply channel can be independently controlled when connected in parallel. The anti-backflow unit provides unidirectional conduction to block the reverse current from the DC bus to the DC-DC converter and the fuel cell unit, avoiding backflow or circulating current between channels due to stack voltage differences, so that the parallel system remains controllable at the channel level under load step and stack voltage fluctuations.

[0035] It should be noted that the first and second fuel cell stacks are equipped with separate DC-DC converters instead of sharing the same converter. The purpose is to ensure that different stacks can still output according to their respective capabilities even when their aging levels and instantaneous stack pressures are inconsistent. The control unit can issue enable and current-limiting or voltage-limiting control quantities to each channel separately. Furthermore, the control unit is configured to monitor and balance the output current of the first and second fuel cell stacks in real time. By comparing the output current of each stack with a preset current reference value or the rated capacity ratio of each stack, the control unit dynamically adjusts the current-limiting value or operating mode (such as constant current mode) of the corresponding DC-DC converter, so that the output current of each stack is distributed proportionally to achieve power balance, avoid single-channel overload or light load, and cooperate with their respective anti-backflow units to realize channel-level access and exit, reducing power mismatch and bus disturbance caused by single-point constraints.

[0036] The DC-DC converter is set as a non-isolated unidirectional buck-boost type. This structural choice is based on the constraints of size, mass and efficiency of the lightweight platform. The non-isolated structure reduces the energy loss and heat dissipation pressure caused by magnetic and isolation devices while meeting the requirements of voltage boost and sag. The unidirectional property and the anti-backflow unit form a consistent power flow constraint, which is conducive to establishing a stable unidirectional current-carrying relationship on the DC bus side.

[0037] Understandably, the DC-DC converter supports constant voltage mode, constant power mode, and current limiting mode, and the control unit selects the operating mode according to preset switching conditions. The constant voltage mode is used to maintain the DC bus voltage close to the preset bus target range. The constant power mode is used to output the preset power to stabilize the operating point of the fuel cell unit under the condition that the stack voltage is allowed. The current limiting mode is used to limit the channel current to avoid exceeding the limit during restricted charging and bus drop maintenance. The mode switching is based on voltage threshold and current threshold and is executed in conjunction with the channel state determination.

[0038] Compared to direct parallel connection or suppression of backflow using high-voltage-drop devices, the combined effect of the above structure and control is that when the channel is connected, the voltage matching and current constraint are completed by the respective DC-DC converters, and the anti-backflow unit ensures unidirectional current convergence. Thus, stable power supply of the parallel system is achieved without introducing backflow and circulating current and without relying on high-loss devices. In combination with the technical problems in the background art, deterministic dynamic power switching and distribution can be achieved between limited charging and discharging maintenance, and the continuity and stability of DC bus power supply can be maintained under load step and voltage fluctuation conditions.

[0039] The backflow prevention unit includes a power metal-oxide-semiconductor transistor, a drive control circuit, and a potential difference detection circuit. The drive control circuit also receives isolation commands from the control unit. When the control unit detects an abnormal channel state and issues a shutdown command, the drive control circuit prioritizes the signal from the potential difference detection circuit and forcibly shuts down the power metal-oxide-semiconductor transistor to ensure reliable isolation when the channel is abnormal, avoiding the risk of reverse current or circulating current. Under normal conditions, the drive control circuit controls the conduction or shutdown according to the signal from the potential difference detection circuit. The potential difference detection circuit is used to detect the potential difference between the DC bus and the corresponding channel. The drive control circuit realizes unidirectional conduction and shutdown accordingly. When the control unit allows limited charging of the energy storage unit, it constrains the DC-DC converter output according to the preset charging current limit and the preset bus voltage limit, and adjusts the preset charging current limit based on the temperature and state of charge estimation results of the energy storage unit. In this embodiment, the temperature is collected by the temperature sensor on the energy storage unit. After noise reduction and validity verification, the operating temperature is formed. The control unit performs outlier removal and consistency checks on the multi-point temperature measurement results. If necessary, it performs interpolation estimation based on the existing thermal model to obtain a representative temperature for charging safety determination. The state of charge is estimated using the existing method of coulomb measurement combined with open-circuit voltage lookup table. The control unit integrates the charging and discharging current according to the sampling period to obtain the charge increment and adds it to the previous state of charge. During the rest or quasi-rest period, the terminal voltage is read to approximate the open-circuit voltage and the deviation is corrected according to the correspondence between open-circuit voltage and state of charge to obtain the state of charge for current limiting constraints.

[0040] Furthermore, to improve stability under dynamic operating conditions, the control unit can jointly estimate the state of charge based on the existing results of the equivalent circuit model parameter identification, and perform state fusion on the results of coulomb measurement and voltage correction to suppress estimation deviations caused by sensor zero drift and short-term load fluctuations. The control unit reads the upper limit of charging current from a preset mapping table based on temperature and state of charge, and applies hysteresis and slope limits to this limit to avoid boundary jitter. If abnormal temperature or voltage / current sampling is detected, a conservative derating or charging prohibition strategy is executed. The above limits and the preset bus voltage upper limit together constrain the DC-DC converter output, so that restricted charging remains safe and consistent under different thermal states and charge levels.

[0041] In addition, the control unit sets a reliability judgment and time consistency check for the estimated link. When the reliability is lower than the threshold or the estimation result changes abruptly, the mapping table update is paused and the current limit is maintained until normal sampling is resumed, thereby ensuring the continuity and predictability of the restricted charging criterion when information is insufficient.

[0042] The preset bus target range has a preset hysteresis band, and the preset stack pressure working range consists of the preset stack pressure upper threshold and the preset stack pressure lower threshold. The hysteresis band is used to implement a hysteresis-based switching between restricted charging and discharging. The control unit performs channel-level judgment on overvoltage, undervoltage, overcurrent and overtemperature of each power supply channel, and shuts down the anti-backflow unit of any channel to achieve isolation when an abnormal state occurs. The remaining channels and energy storage units maintain DC bus power supply. The hydrogen concentration sensor is electrically connected to the control unit. When the hydrogen concentration exceeds the preset concentration threshold, the control unit prohibits charging the energy storage unit and shuts off the relevant power supply channels.

[0043] In this embodiment, the backflow prevention unit includes a power metal-oxide-semiconductor transistor, a drive control circuit, and a potential difference detection circuit. The potential difference detection circuit is used to detect the potential difference between the DC bus and the corresponding channel and provide the drive control circuit with a turn-on or turn-off criterion. Based on this, the drive control circuit controls the power metal-oxide-semiconductor transistor to achieve unidirectional turn-on and turn-off, thereby blocking the reverse current from the DC bus to the DC-DC converter and fuel cell unit when the channel is connected or disconnected and when the bus status changes, so as to avoid backflow and circulating current.

[0044] It should be noted that when the control unit allows limited charging of the energy storage unit, it jointly constrains the DC-DC converter output according to the preset upper limit of charging current and the preset upper limit of bus voltage. The purpose of the joint constraint is to simultaneously limit the overshoot of channel current and bus voltage and reduce the dependence on bus filtering. The control unit also adjusts the preset upper limit of charging current based on the estimated results of the temperature and state of charge of the energy storage unit in order to maintain charging safety and consistency under different thermal and state of charge conditions.

[0045] The preset bus target range has a preset hysteresis band, and the preset stack voltage operating range consists of a preset upper stack voltage threshold and a preset lower stack voltage threshold. The hysteresis band is used to implement a hysteresis-based switching between restricted charging and discharging. Its purpose is to avoid back-and-forth oscillations and maintain the stability of the control criteria when the bus voltage or stack voltage is close to the boundary, so that the channel access and exit and the triggering of energy storage discharge have clear intervals and sequences.

[0046] In this embodiment, the control unit performs channel-level judgment on overvoltage, undervoltage, overcurrent, and overtemperature of each power supply channel, and shuts down the anti-backflow unit of any channel when an abnormal state occurs to achieve isolation. The remaining channels and energy storage units maintain DC bus power supply. This channel-level isolation limits the abnormality to a local path and prevents it from spreading to the bus. Combined with unidirectional conduction, it can reduce coupling disturbances and maintain continuous power supply to the load side.

[0047] The hydrogen concentration sensor is electrically connected to the control unit. When the hydrogen concentration exceeds the preset concentration threshold, the control unit prohibits charging the energy storage unit and shuts down the relevant power supply channels. The above safety linkage is used to reduce energy injection and eliminate possible ignition sources when the ambient hydrogen is abnormal, thereby increasing the safety shutdown capability without changing the main power path judgment and keeping the bus under control in conjunction with channel isolation.

[0048] Compared to existing technologies that directly connect in parallel or rely on high-loss devices to suppress backflow, the unidirectional conduction formed by potential difference detection and drive control can determine the on and off states when the potential relationship between the bus and the channel is clear. The combined constraint of limited charging and hysteresis switching can be stably executed under load step and voltage fluctuation conditions. Channel-level anomaly isolation and environmental safety linkage can reduce coupling disturbances and maintain continuous power supply to the bus. Accordingly, the technical problems in the background technology can be addressed by achieving dynamic power switching and distribution of limited charging and seamless discharging without introducing backflow and circulating current and without relying on high-loss devices, while maintaining the stability and maintainability of the system.

[0049] The DC bus is equipped with a pre-charge branch and a bypass switch. The pre-charge branch is connected in series with a current limiting element to limit the inrush current. The bypass switch is closed by the control unit after the pre-charge is completed and the DC bus voltage reaches the preset parallel access threshold. The pre-charge branch also includes a series switching element (such as a relay or a power metal oxide semiconductor tube). This switching element is controlled to close by the control unit during the pre-charge stage. When the bypass switch is closed, the control unit immediately opens the switching element to cut off the pre-charge branch, avoid the continuous loss of the current limiting element, and switch to the low-loss main path. The pre-charge branch is connected in series with a resistor or thermistor as a current limiting element, and the bypass switch is a power metal oxide semiconductor tube or a relay. In this embodiment, the purpose of setting a pre-charge branch and a bypass switch on the DC bus is to first use the restricted path during the power-on phase to suppress inrush current and establish a stable measurement reference. The pre-charge branch is connected in series with a current-limiting element to limit the instantaneous current surge caused by the energy storage unit and the large capacitor load. The control unit closes the bypass switch to switch to the low-loss main path after detecting that the DC bus voltage has reached the preset parallel access threshold, thereby avoiding the impact and misjudgment caused by direct parallel connection before the bus voltage is established.

[0050] The current-limiting element of the precharge branch is a series resistor or a thermistor. Both are commonly used devices in this field and are easy to implement and maintain. The series resistor provides a definite current-limiting characteristic, which is convenient for calculating the precharge time and thermal load. The thermistor has high resistance in the cold state to limit the initial current and its resistance decreases after heating to reduce losses. The control unit can select one of them according to the platform's thermal and volume constraints and configure the corresponding precharge timing and threshold judgment logic. The bypass switch is a power metal oxide semiconductor tube or a relay. The power metal oxide semiconductor tube has a low on-state voltage drop after closing and is easy to achieve fast and controllable switching on and off by gate drive. The relay has good insulation gap and turn-off isolation capability and simple control method. Both are driven by the control unit and close after the precharge is completed and the DC bus voltage reaches the preset parallel access threshold, so as to switch to the low-loss power supply path when the access conditions are met and maintain the same timing as the limited charging judgment.

[0051] Compared to existing technologies that directly connect in parallel or use continuously connected high-loss devices in series to limit inrush current, the sequential control of the pre-charge branch and bypass switch mentioned above reduces the power-on inrush current and device thermal load under the same hardware conditions, reduces the dependence on bus filtering and avoids false grid connection due to voltage failure. At the same time, after the bypass is closed, the continuous loss is reduced through the low-voltage drop main path. Corresponding to the technical problems in the background technology, it provides a stable voltage base and determinable switching conditions for subsequent restricted charging and seamless discharging without relying on high-loss devices, and maintains the continuity and stability of DC bus power supply.

[0052] The accompanying drawings of the embodiments of this invention only involve the structures involved in the embodiments of this invention. Other structures can refer to the general design. In the absence of conflict, the features of the same embodiment and different embodiments of this invention can be combined with each other. The above are only specific implementations of this invention, but the protection scope of this invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this invention should be included within the protection scope of this invention. Therefore, the protection scope of this invention should be determined by the protection scope of the claims.

Claims

1. A hydrogen-lithium hybrid control system for use in drones and two-wheeled vehicles, characterized in that, include: Fuel cell unit; A DC-DC converter, the input of which is connected to the output of the fuel cell unit; DC bus, used to collect electrical energy and supply power to the load interface; An anti-backflow unit is installed between the output terminal of the DC-DC converter and the DC bus to block reverse current from the DC bus to the DC-DC converter and the fuel cell unit. An energy storage unit is connected in parallel to the DC bus; The load interface is connected to the DC bus. The control unit is electrically connected to the fuel cell unit, the DC-DC converter, the DC bus, and the energy storage unit, and is configured to: collect voltage, current, and temperature signals from the fuel cell unit, the DC-DC converter output, the DC bus, and the energy storage unit; When the fuel cell unit passes the power-on self-test and the stack pressure is within the preset stack pressure operating range, it outputs an enable, current limiting, or voltage limiting control quantity to the DC-DC converter, and performs limited charging on the energy storage unit when the DC bus is within the preset bus target range. When the DC bus voltage is detected to be lower than the preset bus target range or the fuel cell unit voltage is lower than the preset stacking voltage threshold, the DC-DC converter is kept in current-limited output, and the energy storage unit discharges to the DC bus to maintain power supply. When any power supply channel experiences an abnormal state, the anti-backflow unit of that channel is shut down to achieve isolation, while the remaining channels or the energy storage unit continue to maintain power supply to the DC bus.

2. The hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 1, characterized in that, The fuel cell unit includes a first fuel cell stack and a second fuel cell stack. The first fuel cell stack and the second fuel cell stack are connected in parallel to the DC bus after passing through corresponding DC-DC converters and corresponding anti-backflow units.

3. The hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 1, characterized in that, The DC-DC converter is a non-isolated unidirectional buck-boost type and can switch between constant voltage, constant power and current limiting modes. The control unit selects the operating mode according to preset switching conditions.

4. A hydrogen-lithium hybrid control system for drones and two-wheeled vehicles according to claim 3, characterized in that, The backflow prevention unit includes a power metal-oxide-semiconductor tube, a drive control circuit, and a potential difference detection circuit. The potential difference detection circuit is used to detect the potential difference between the DC bus and the corresponding channel, and the drive control circuit realizes unidirectional conduction and shutdown accordingly.

5. A hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 4, characterized in that, When the energy storage unit is allowed to be charged under limited conditions, the control unit constrains the output of the DC-DC converter according to the preset upper limit of charging current and the preset upper limit of bus voltage, and adjusts the preset upper limit of charging current based on the temperature and state of charge estimation results of the energy storage unit.

6. A hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 5, characterized in that, The preset bus target range has a preset hysteresis band, and the preset stacking pressure working range is composed of a preset upper stacking pressure threshold and a preset lower stacking pressure threshold. The hysteresis band is used to implement a hysteresis-based switching between restricted charging and discharging.

7. A hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 6, characterized in that, The control unit performs channel-level judgment on overvoltage, undervoltage, overcurrent and overtemperature of each power supply channel, and shuts down the anti-backflow unit of any channel to achieve isolation when an abnormal state occurs. The remaining channels and the energy storage unit maintain the DC bus power supply.

8. A hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 7, characterized in that, It also includes a hydrogen concentration sensor, which is electrically connected to the control unit. When the hydrogen concentration is detected to exceed a preset concentration threshold, the control unit prohibits charging the energy storage unit and shuts off the enabling of the relevant power supply channels.

9. A hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 1, characterized in that, The DC bus is equipped with a pre-charge branch and a bypass switch. The pre-charge branch is connected in series with a current limiting element to limit the inrush current. The bypass switch is closed by the control unit after the pre-charge is completed and the DC bus voltage reaches a preset parallel access threshold.

10. A hydrogen-lithium hybrid control system for unmanned aerial vehicles and two-wheeled vehicles according to claim 9, characterized in that, The pre-charge branch series resistor or thermistor serves as a current limiting element, and the bypass switch is a power metal-oxide-semiconductor transistor or a relay.

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