A power supply control system and method of an eVTOL low-voltage distribution box

Abstract

The application discloses a power supply control system and method of an eVTOL low-voltage power distribution box, and relates to the technical field of power supply control.The system comprises a multi-source double-bus power supply unit, a voltage reduction unit and an output unit.The multi-source double-bus power supply unit comprises a first and a second bus independent power supply channel, which are isolated based on contactors.The first bus independent power supply channel comprises x heterogeneous power sources and x ideal diodes, and the x heterogeneous power sources comprise high-voltage to low-voltage DC-DC power sources, ground power sources and n lithium battery power sources.The second bus independent power supply channel comprises y heterogeneous power sources and y ideal diodes, and the y heterogeneous power sources comprise y lithium battery power sources.The voltage reduction unit comprises m DC-DC voltage reduction converters.The output unit comprises m ideal diodes connected in parallel with the output ends of the DC-DC voltage reduction converters.The application guarantees the stability and quality of power supply, and ensures that onboard equipment works in a stable voltage and current environment.

Description

Technical Field

[0001] This invention relates to the field of power supply control technology, and in particular to a power supply control system and method for an eVTOL low-voltage distribution box. Background Technology

[0002] With the rapid development of electric vertical takeoff and landing (eVTOL) technology, the requirements for the reliability and stability of low-voltage power distribution systems are increasing. Traditional low-voltage power distribution systems struggle to guarantee the normal operation of the entire power system when faced with partial power supply failures or abnormal situations, exhibiting low reliability and poor fault tolerance. Meanwhile, current eVTOL power supply systems primarily employ a centralized single-bus architecture, which carries the risk of single-point failure. Furthermore, backup power switching relies on the software control of the microcontroller unit, posing a risk of program crashes. The single-bus architecture also leads to software scheduling priority conflicts, resulting in delayed interruption response and an inability to handle sudden power anomalies during eVTOL flight. Moreover, this single-bus architecture leaves the load end without independent protection; a short circuit in a single device could trigger a bus-level power outage, affecting the normal operation of onboard equipment. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a power supply control system and method for an eVTOL low-voltage distribution box, which ensures the stability and quality of power supply and ensures that airborne equipment operates in a stable voltage and current environment.

[0004] To solve the above-mentioned technical problems, the present invention provides a power supply control system for an eVTOL low-voltage distribution box, the system comprising: a multi-source dual-bus power supply unit, a step-down unit, and an output unit, wherein the step-down unit is connected to the multi-source dual-bus power supply unit and the output unit respectively;

[0005] The multi-source dual-bus power supply unit includes a first independent bus power supply channel and a second independent bus power supply channel. The first independent bus power supply channel and the second independent bus power supply channel are isolated based on a first contactor and a second contactor. The first independent bus power supply channel includes x heterogeneous power supplies and x ideal diodes, where x is an integer greater than or equal to 3. The x heterogeneous power supplies include a high-voltage to low-voltage DC-DC power supply, a ground power supply, and n lithium battery power supplies, where n is an integer greater than or equal to 1. The second independent bus power supply channel includes y heterogeneous power supplies and y ideal diodes. The y heterogeneous power supplies include y lithium battery power supplies, where y is an integer greater than or equal to 2. The first contactor and the second contactor, together with the ideal diodes of the first independent bus power supply channel and the second independent bus power supply channel, form a cooperative protection state.

[0006] The step-down unit includes a first step-down module and a second step-down module. Each step-down module includes m DC-DC step-down converters connected in parallel, where m is an integer greater than or equal to 2. The first step-down module is connected to the first independent power supply channel of the bus, and the second step-down module is connected to the second independent power supply channel of the bus.

[0007] The output unit includes m ideal diodes, and one of the m ideal diodes is connected to one of the corresponding DC-DC buck converters in the m DC-DC buck converters.

[0008] The ideal diode includes a detection circuit and a metal-oxide-semiconductor (MOSFET). The detection circuit includes a power electronic switch chip with pins including IN, OUT, and GATE. The IN and OUT pins of the power electronic switch chip are connected to the MOSFET. The power electronic switch chip is an LTC4357HMS8 power electronic switch chip, and the MOSFET is an IRLR2905TRPBF MOSFET. The on-resistance of the IRLR2905TRPBF MOSFET is less than or equal to 27mΩ. The reverse turn-off time of the ideal diode is less than or equal to 0.5μs, and the forward voltage drop is less than or equal to 0.1V.

[0009] If the output load is 12V, the rated current of the ideal diode is configured to be less than or equal to 5A. If the output load is 28V, the rated current of the ideal diode is configured to be greater than or equal to 20A, and the ideal diode is connected in parallel with several Zener diodes.

[0010] Optionally, the y-channel lithium battery power supplies in the second independent power supply channel of the busbar are redundant.

[0011] Optionally, the high-voltage to low-voltage DC-DC power supply, ground power supply, and n-channel lithium battery power supply in the first independent bus power supply channel are combined into one output voltage through corresponding ideal diodes, and the y-channel lithium battery power supply in the second independent bus power supply channel are combined into another output voltage through corresponding ideal diodes.

[0012] Optionally, the multi-source dual-bus power supply unit further includes a manual switch outside the distribution box. The first set of switches of the manual switch outside the distribution box is connected to the first independent power supply channel of the bus, and the second set of switches of the manual switch outside the distribution box is connected to the second independent power supply channel of the bus.

[0013] Optionally, the multi-source dual-bus power supply unit further includes a DC-DC circuit, which is connected to the external manual switch of the distribution box.

[0014] Optionally, the multi-source dual-bus power supply unit further includes an overvoltage protection module, which is connected to an ideal diode.

[0015] Optionally, the overvoltage protection module includes an LTC4367 power controller.

[0016] Optionally, the external manual switch of the distribution box is in a dual-redundant independent state with respect to the first contactor and the second contactor.

[0017] In addition, the present invention also provides a power supply control method for an eVTOL low-voltage distribution box, the power supply control method being implemented based on the aforementioned power supply control system for the eVTOL low-voltage distribution box, the power supply control method comprising:

[0018] When powered on, the IN and OUT pins of the power electronic switch chip detect the load current flowing through the metal-oxide-semiconductor field-effect transistor. The power electronic switch chip drives the GATE pin to reduce the forward high voltage of the metal-oxide-semiconductor field-effect transistor.

[0019] If the load current is positive and the positive voltage drop decreases to the first preset threshold, the first pull-down value is applied to the GATE pin of the power electronic switch chip.

[0020] If the load current is reversed and the voltage difference between the IN and OUT pins of the power electronic switch chip is less than the second preset threshold, the GATE pin of the power electronic switch chip is processed to apply a second pull-down value.

[0021] If the voltage difference between the first independent power supply channel and the second independent power supply channel of the bus is less than or equal to the third preset threshold, the power electronic switch chip controls the metal-oxide-semiconductor field-effect transistor to maintain the conduction state and distribute the current ratio.

[0022] If the voltage difference between the first independent power supply channel and the second independent power supply channel of the busbar is greater than a third preset threshold, the metal-oxide-semiconductor field-effect transistor is controlled to be turned off within a preset time.

[0023] This invention provides a power supply control system and method for an eVTOL low-voltage distribution box. The multi-source dual-bus power supply unit, step-down unit, and output unit work collaboratively through hardware logic, without relying on microcontroller commands. The redundancy of these units ensures stable system operation even in the event of partial or DC-DC power supply failures, providing more effective rapid shutdown capabilities, improving the reliability of the low-voltage distribution box, and reducing the risk of system failure due to power supply issues. Simultaneously, the independent power supply channels and independent operation of the ideal diodes in the multi-source dual-bus power supply unit avoid interference between different devices and power supplies, ensuring power supply stability and quality, and guaranteeing that airborne equipment operates under stable voltage and current conditions. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the power supply control system of the eVTOL low-voltage distribution box in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the multi-source dual-bus power supply unit in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the structural composition of the step-down unit in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of an ideal diode in an embodiment of the present invention;

[0029] Figure 5 This is a flowchart illustrating the power supply control method for the eVTOL low-voltage distribution box in an embodiment of the present invention. Detailed Implementation

[0030] 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 only some embodiments of the present invention, and not all embodiments. Based on the 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.

[0031] Example 1

[0032] Please see Figure 1, Figure 1 This is a schematic diagram of the power supply control system of the eVTOL low-voltage distribution box in an embodiment of the present invention. The system includes: a multi-source dual-bus power supply unit, a step-down unit, and an output unit. The step-down unit is connected to the multi-source dual-bus power supply unit and the output unit, respectively.

[0033] The multi-source dual-bus power supply unit includes a first independent bus power supply channel and a second independent bus power supply channel. The first independent bus power supply channel and the second independent bus power supply channel are isolated based on a first contactor and a second contactor. The first independent bus power supply channel includes x heterogeneous power supplies and x ideal diodes, where x is an integer greater than or equal to 3. The x heterogeneous power supplies include a high-voltage to low-voltage DC-DC power supply, a ground power supply, and n lithium battery power supplies, where n is an integer greater than or equal to 1. The second independent bus power supply channel includes y heterogeneous power supplies and y ideal diodes. The y heterogeneous power supplies include y lithium battery power supplies, where y is an integer greater than or equal to 2.

[0034] Specifically, a multi-source dual-bus three-level redundant power supply architecture is formed through a multi-source dual-bus power supply unit, a step-down unit, and an output unit, ensuring that airborne equipment can obtain a stable and reliable power supply in various complex environments. The structure of the multi-source dual-bus power supply unit is as follows: Figure 2As shown, the multi-source dual-bus power supply unit includes a first independent bus power supply channel and a second independent bus power supply channel. The first and second independent bus power supply channels are asymmetrically grouped, are at the same level, and are independent of each other. The first and second independent bus power supply channels are isolated based on a first contactor and a second contactor to ensure that a single bus failure does not affect the continued independent power supply of the other bus. The first independent bus power supply channel includes x heterogeneous power supplies and x ideal diodes. The x heterogeneous power supplies include a high-voltage to low-voltage DC-DC power supply, a ground power supply, and n lithium battery power supplies. The high-voltage to low-voltage DC-DC power supply, the ground power supply, and the n lithium battery power supplies are connected in parallel. The high-voltage to low-voltage DC-DC power supply is supplied by an electric vertical take-off and landing (EVTOL) aircraft. The external power module of the eVTOL (Landing Power Module) distribution box steps down and regulates the 800V voltage from the eVTOL's built-in power battery to 49V before inputting it to the distribution box. The ground power supply is an external power source provided by the eVTOL's external step-down and regulated digital power supply. This power supply is only used during ground testing and not during flight. The specific number of n lithium battery power supplies is set according to actual conditions, where n is an integer greater than or equal to 1 (e.g., n=1, n=2, etc.). The lithium battery power supplies are low-voltage batteries and can use 48V lithium batteries. The second independent bus power supply channel includes y heterogeneous power supplies and y ideal diodes. The y heterogeneous power supplies include y lithium battery power supplies, the number of which is also set according to actual conditions, where y is an integer greater than or equal to 2 (e.g., y=2, y=3, etc.). The lithium battery power supplies can use 48V lithium batteries. The first and second independent bus power supply channels are independent and do not overlap, with no capacitive coupling between them. The first and second contactors, along with the ideal diodes of the first and second independent bus power supply channels, form a coordinated protection state. When a contactor trips due to a fault, the ideal diode of the first independent bus power supply channel detects the current interruption and immediately triggers the ideal diode of the other independent bus power supply channel to increase its conduction priority within 0.5μs, ensuring that the output voltage fluctuation is ≤±0.5V. Simultaneously, an overvoltage protection module is connected in series in the contactor coil power supply circuit. When the coil voltage >30V, the overvoltage protection module cuts off the power supply to prevent bus short circuits caused by contactor sticking. Figure 2 The multi-source dual-bus power supply unit shown is not a limitation on all devices and may include more components than shown.

[0035] In the specific implementation of this invention, the y-channel lithium battery power supplies in the second independent power supply channel of the busbar are redundant.

[0036] Specifically, the lithium battery power supplies are redundant with each other, so if any one battery fails, another battery can continue to supply power to the second independent power supply channel of the bus.

[0037] In the specific implementation of this invention, the high-voltage to low-voltage DC-DC power supply, ground power supply and n-channel lithium battery power supply in the first independent power supply channel of the bus are combined into one output voltage through corresponding ideal diodes, and the y-channel lithium battery power supply in the second independent power supply channel of the bus are combined into another output voltage through corresponding ideal diodes.

[0038] Specifically, in the first independent bus power supply channel, the high-voltage to low-voltage DC-DC power supply, the ground power supply, and the n lithium battery power supplies are combined into one output voltage through corresponding ideal diodes. The high-voltage to low-voltage DC-DC power supply interval overvoltage protection module is connected to its corresponding ideal diode, and the ground power supply interval overvoltage protection module is also connected to its corresponding ideal diode. The first independent bus power supply channel summarizes the output voltages of each power supply through the ideal diodes to obtain one output voltage. Each power supply is independent of the others. In the second independent bus power supply channel, the y lithium battery power supplies are combined into another output voltage through corresponding ideal diodes. Each lithium battery power supply is connected to its corresponding ideal diode. The Y-channel lithium battery power supplies in the second bus independent power supply channel are independent of each other. The ideal diodes combine the output voltages of all lithium battery power supplies into a single output voltage. When the aircraft is undergoing ground testing or static operation and mains power is readily available, ground power can be used as the power input, saving valuable energy for the power battery and low-voltage battery. During flight, power is supplied by a high-voltage to low-voltage DC-DC power supply and lithium battery power. In case of a single bus failure, the other bus can provide independent power. Compared with existing technologies, dual-bus independent power supply significantly improves the reliability and flexibility of power supply. At the same time, the ideal diodes combine the power supplies, providing the system with diverse power input options and ensuring the independence and reliability of the power supply under equipment operating conditions.

[0039] Meanwhile, the ideal diode requires no microcontroller unit and achieves 0.5μs fast turn-off through pure hardware, ensuring a smooth transfer of current from one path to another and avoiding oscillations. In the event of a power supply failure or short circuit, it minimizes reverse current transients, ensuring stable and reliable power merging and reverse current protection functions, and effectively preventing mutual interference between power supplies.

[0040] The multiple power supplies in the independent power supply channel of the busbar are combined into a single busbar voltage using ideal diodes. Due to the unidirectional conductivity of ideal diodes, there is no current path between the power supplies, preventing backflow. Also due to the unidirectional conductivity of ideal diodes, the power supply with the higher voltage takes over, while the power supply with the lower voltage stops supplying power and acts as a backup. When the three voltages are equal, such as within 25mV, they simultaneously supply power to the circuits downstream of the busbar, automatically allocating power according to their respective voltage levels. Combining multiple power supplies into a single power supply using ideal diodes effectively improves the reliability of the power supply system.

[0041] In a specific implementation of the present invention, the multi-source dual bus power supply unit further includes a manual switch outside the distribution box. The first set of switches of the manual switch outside the distribution box is connected to the first independent power supply channel of the bus, and the second set of switches of the manual switch outside the distribution box is connected to the second independent power supply channel of the bus.

[0042] The multi-source dual-bus power supply unit also includes a DC-DC circuit, which is connected to the external manual switch of the distribution box.

[0043] The multi-source dual-bus power supply unit also includes an overvoltage protection module, which is connected to an ideal diode.

[0044] The overvoltage protection module includes an LTC4367 power controller.

[0045] The external manual switch of the distribution box is in a dual-redundant independent state with respect to the first and second contactors.

[0046] Specifically, the structure of contactor-controlled independent power supply channels for each bus is as follows: Figure 2As shown, the external manual toggle switch of the distribution box is a mechanical hardware switch with four circuits, each group consisting of two circuits. Each group controls one contactor. The first group of switches controls the first contactor, and the second group controls the second contactor. Both the first and second contactors can be 100A contactors. Different contactors are connected in series on different busbars. The first busbar has an independent power supply channel connected to the first contactor, and the second busbar has an independent power supply channel connected to the second contactor. A high-voltage to low-voltage DC-DC power supply is connected in series with an overvoltage protection module, as is the ground power supply. The overvoltage protection module includes an LTC4367 power controller. The LTC4367 power controller provides protection and monitoring of the power lines. It can quickly react to overvoltage and undervoltage events and cut off the power supply when the power line is abnormal. The LTC4367 power controller also provides current limiting protection to prevent instantaneous excessive current, thus protecting the load. Simultaneously, this power controller has a fast response speed, reacting in milliseconds to protect the circuit and load. The multi-source dual-bus power supply unit includes an overvoltage protection module, which adds an overvoltage protection barrier to the power supply channel to prevent external high voltage from burning out the contactor coil.

[0047] The multi-source dual-bus power supply unit also includes a DC-DC circuit, which is connected to an external manual switch in the distribution box. The DC-DC circuit includes a DC-DC step-down converter, an overvoltage protection module, and an ideal diode. When the external manual switch is closed, it triggers the corresponding DC-DC circuit inside the distribution box. The first set of switches on the external manual switch connects to the first independent power supply channel of the busbar, and the second set of switches connects to the second independent power supply channel of the busbar. Each independent power supply channel of the busbar transmits power through the external manual switch. Yes, the DC-DC circuit steps down the electrical energy and provides the converted energy to the contactor's internal coil. The magnetic attraction of the contactor's physical contacts closes the contacts. After closure, each busbar's independent power supply channel outputs voltage. When the external manual switch of the distribution box is opened, the first and second contactors disconnect their physical contacts. The external manual switch, along with the first and second contactors, are both in a dual-redundant independent state, ensuring that the failure of any single point within the contactor control system of the low-voltage distribution box does not affect the normal power supply to all low-voltage equipment on the aircraft. The contactor parameters include: maximum switching voltage of 750V, minimum segment current of 1500A, and rated contact load of 200A.

[0048] When a relay in an independent power supply channel of a certain busbar disconnects due to a coil fault, the ideal diode on the corresponding independent power supply channel detects the current interruption and immediately triggers the ideal diode of another busbar to increase its conduction priority. Within 0.5μs, the load current is replenished to ensure uninterrupted output voltage. The relay coil power supply circuit is connected in series with an overvoltage protection module. When the coil voltage is >30V, the overvoltage module cuts off the power supply, and the ideal diode simultaneously turns off the current of the corresponding busbar to prevent short circuits on the busbar caused by contactor sticking, forming a closed-loop protection of "overvoltage-cut-off-isolation".

[0049] In a specific implementation of the present invention, the step-down unit includes a first step-down module and a second step-down module. Each step-down module includes m DC-DC step-down converters, which are connected in parallel. m is an integer greater than or equal to 2. The first step-down module is connected to the first independent power supply channel of the bus, and the second step-down module is connected to the second independent power supply channel of the bus.

[0050] Specifically, such as Figure 3 As shown, the step-down unit includes a first step-down module and a second step-down module. Each step-down module includes m DC-DC step-down converters connected in parallel, where m is an integer greater than or equal to 2. The first step-down module is connected to the first independent power supply channel of the bus and is powered by the first independent power supply channel of the bus. The second step-down module is connected to the second independent power supply channel of the bus and is powered by the second independent power supply channel of the bus. The input of each DC-DC step-down converter comes from a different independent power supply channel of the bus, realizing cross-bus redundancy of power supply.

[0051] It should be noted that if one of the DC-DC buck converters in the buck unit fails, it will not recover automatically. Instead, it will achieve automatic fault isolation through an ideal diode, which will not affect the normal power supply of other DC-DC buck converters in the same buck unit. For example, if a fuse blows due to overcurrent caused by a load fault, it will only disconnect the power supply to the faulty device itself, without affecting the output power supply. When the aircraft lands on the ground, the damaged component needs to be replaced for repair.

[0052] In a specific implementation of the present invention, the output unit includes m ideal diodes, and one of the m ideal diodes is connected to one of the corresponding DC-DC buck converters in the m DC-DC buck converters.

[0053] The ideal diode includes a detection circuit and a metal-oxide-semiconductor (MOSFET). The detection circuit includes a power electronic switch chip with pins including IN, OUT, and GATE. The IN and OUT pins of the power electronic switch chip are connected to the MOSFET. The power electronic switch chip is an LTC4357HMS8 power electronic switch chip, and the MOSFET is an IRLR2905TRPBF MOSFET. The on-resistance of the IRLR2905TRPBF MOSFET is less than or equal to 27mΩ. The reverse turn-off time of the ideal diode is less than or equal to 0.5μs, and the forward voltage drop is less than or equal to 0.1V.

[0054] If the output load is 12V, the rated current of the ideal diode is configured to be less than or equal to 5A. If the output load is 28V, the rated current of the ideal diode is configured to be greater than or equal to 20A, and the ideal diode is connected in parallel with several Zener diodes.

[0055] Specifically, an ideal diode refers to a hardware module based on a metal-oxide-semiconductor field-effect transistor (MOSFET) and a detection circuit. By monitoring the current direction in real time, it achieves reverse current blocking at the 0.5μs level, offering lower on-state voltage drop and faster response speed compared to traditional Schottky diodes. The output of the DC-DC buck converter is connected in parallel with ideal diodes, utilizing hardware logic to achieve seamless switching at the 0.5μs level, avoiding power supply mutual charging and oscillation. Each DC-DC buck converter independently steps down the voltage and then combines the outputs through ideal diodes. For example, two DC-DC buck converters in a 28V output unit are connected in parallel; if one fails, the other automatically assumes 100% load, further improving the reliability of the low-voltage power supply system.

[0056] As demonstrated by the experiment, when the DC-DC power supply (49V) is suddenly cut off, the ideal diode of the low-voltage battery (48V) turns on within 0.48μs, and the output voltage drops from 49V to 48.2V, with a fluctuation of 0.8V, which meets the power supply requirements of the eVTOL servo (fluctuation ≤ ±1V).

[0057] The detection circuit in the ideal diode includes a power electronic switch chip, specifically the LTC4357HMS8. The LTC4357HMS8 was chosen because its operating temperature range of -40℃ to +125℃ covers the eVTOL flight environment. As the ideal diode controller, the LTC4357HMS8 is a positive high-voltage ideal diode controller used to drive an external N-channel MOSFET to replace a Schottky diode, forming an ideal diode. When used in diode or high-current diode applications, this chip reduces power consumption, heat dissipation, voltage drop, and printed circuit board area. The chip can easily perform an OR operation on the power supply to improve overall system reliability. In diode OR applications, the LTC4357HMS8 power electronic switch chip is used to control the forward voltage drop across the MOSFET to ensure a smooth current transfer from one path to another without oscillations. In the event of a power failure or short circuit, the fast shutdown operation minimizes reverse current transients.

[0058] The LTC4357HMS8 power electronic switch chip acts as the "brain" of an ideal diode, responsible for voltage detection, logic judgment, and gate drive. Its IN and OUT pins sample the input (power supply) and output (load) voltages in real time, detecting the voltage difference to determine the current direction. The sampling frequency is ≥1MHz. Its GATE pin outputs the drive voltage to control the conduction and turn-off of the external MOSFET. When turned off, it achieves rapid cut-off through a strong pull-down. At the same time, the IN / OUT pins can be equipped with an RC filter network to suppress electromagnetic radiation from 100MHz to 1GHz, avoiding interference with airborne communications (such as RS-422).

[0059] The metal-oxide-semiconductor field-effect transistor (MOSFET) used is the IRLR2905TRPBF. The IRLR2905TRPBF was selected because its 200A rated current meets the transient load requirements of the servo motor. The IRLR2905TRPBF operates based on N-channel MOSFET technology. During basic operation, when the voltage applied to the gate changes, the resulting electric field modulates the charge distribution in the channel, thereby controlling the flow of drain-source current. The unique operating principle of this MOSFET is reflected in its advanced material and structural design, enabling it to operate stably and reliably under high voltage and high current conditions.

[0060] The IRLR2905TRPBF metal-oxide-semiconductor field-effect transistor is an ideal diode actuator responsible for carrying the main circuit current. Key parameters of the IRLR2905TRPBF include: drain-source voltage of 55V (covering eVTOL 28V / 48V bus voltage), continuous drain current of 42A (meeting the peak current requirements of servos, flight controllers, and other equipment), and on-resistance ≤71mΩ (low conduction loss). Driven by the GATE pin of a power electronic switch chip, the MOSFET functions as a low-resistance path when forward-biased and quickly cuts off when reverse-biased, replacing the unidirectional conduction function of a traditional Schottky diode while reducing forward voltage drop (≤0.1V) and power loss (more than 75% lower than Schottky diodes).

[0061] When the MOSFET is turned on, the forward voltage drop is ≤0.1V (calculated from RDS(on)×Iload, such as 42A current, the voltage drop is ≈71mΩ×42A≈0.03V), which is much lower than that of traditional Schottky diodes (0.5V~0.8V). A single ideal diode can reduce power consumption by more than 80%. Its reverse leakage current in the off state is ≤1μA, avoiding energy loss when the power supply is idle, and is especially suitable for the low power consumption requirements of eVTOL standby and other states.

[0062] If the output load is 12V, the rated current of the ideal diode is configured to be less than or equal to 5A and the on-resistance to be less than or equal to 27mΩ. If the output load is 28V, the rated current of the ideal diode is configured to be greater than or equal to 20A, and the ideal diode is connected in parallel with several Zener diodes. If the output load is 32~50V, the threshold of the detection circuit of the ideal diode is dynamically adjusted to 36V~50.5V to ensure stable conduction under wide voltage input, realizing differentiated configuration of the ideal diode according to the load type.

[0063] The mean time between failures (MTBF) of this ideal diode is ≥10. 6 It has a lifespan of 100 hours, equivalent to 114 years of continuous operation, far exceeding the design life of eVTOL. It can withstand a reverse transient current of 100A / 10μs and will not be damaged by short-circuit transients. It complies with the IEC61000-4-2 standard, with contact discharge ±8kV and air discharge ±15kV, and is compatible with the electrostatic environment in eVTOL assembly and maintenance.

[0064] like Figure 4As shown, upon power-up, the load current initially flows through the body diode of the MOSFET. The IN and OUT pins of the power electronic switch chip detect the load current flowing through the metal-oxide-semiconductor field-effect transistor (MOSFET). The power electronic switch chip drives the GATE pin to reduce the forward high voltage of the MOSFET, which can be driven to reduce the forward high voltage of the MOSFET to 25mV. Simultaneously, if the load is overcurrent, it is isolated by the respective fuses blowing.

[0065] If the load current is positive and the forward voltage drop decreases to the first preset threshold, the first preset threshold can be set to 25mV. The first pull-down value is applied to the GATE pin of the power electronic switch chip, and a slight pull-down is applied to the GATE pin to keep the MOSFET forward voltage drop at 25mV.

[0066] If the load current is reversed and the voltage difference between the IN and OUT pins of the power electronic switch chip is less than the second preset threshold, the second preset threshold can be set to -25mV. The second pull-down value is applied to the GATE pin of the power electronic switch chip, that is, a stronger pull-down is applied to the GATE pin to turn off the MOSFET to prevent current reverse flow.

[0067] In the event of a power supply failure, such as a sudden short circuit in a fully loaded power supply, a reverse current temporarily flows through the MOSFET. This current originates from any load capacitor or other power source. In this situation, the power electronic switching chip will respond quickly and turn off the MOSFET within approximately 500ns, thereby minimizing the interference of the faulty power supply on the output bus.

[0068] In summary, this invention provides a power supply control system for an eVTOL low-voltage distribution box. The multi-source dual-bus power supply unit, step-down unit, and output unit work collaboratively through hardware logic, without relying on microcontroller commands. The redundancy of the multi-source dual-bus power supply unit, step-down unit, and output unit ensures stable system operation even in the event of partial power supply or DC-DC power supply failures, providing more effective rapid shutdown capabilities, improving the reliability of the low-voltage distribution box, and reducing the risk of system failure due to power supply issues. Simultaneously, the independent power supply channels and independent operation of the ideal diodes in the multi-source dual-bus power supply unit avoid interference between different devices and power supplies, ensuring power supply stability and quality, and guaranteeing that airborne equipment operates under stable voltage and current conditions.

[0069] Example 2

[0070] Please see Figure 5 , Figure 5 This is a flowchart illustrating a power supply control method for an eVTOL low-voltage distribution box according to another embodiment of the present invention, the method comprising:

[0071] S51: When powered on, the IN and OUT pins of the power electronic switch chip detect the load current flowing through the metal-oxide-semiconductor field-effect transistor. The power electronic switch chip drives the GATE pin to reduce the forward high voltage of the metal-oxide-semiconductor field-effect transistor.

[0072] In a specific implementation of this invention, upon power-up, the load current initially flows through the main diode of the MOSFET. The IN and OUT pins of the power electronic switch chip detect the load current flowing through the metal-oxide-semiconductor field-effect transistor (MOSFET). The power electronic switch chip drives the GATE pin to reduce the forward high voltage of the MOSFET, which can be driven to reduce the forward high voltage of the MOSFET to 25mV. Simultaneously, if there is an overcurrent in the load, it is isolated by the respective fuses blowing.

[0073] S52: If the load current is positive and the positive voltage drop decreases to the first preset threshold, apply the first pull-down value to the GATE pin of the power electronic switch chip.

[0074] In the specific implementation of this invention, if the load current is positive and the forward voltage drop decreases to the first preset threshold, the first preset threshold can be set to 25mV. The first pull-down value is applied to the GATE pin of the power electronic switch chip, and a weak pull-down is applied to the GATE pin to keep the MOSFET forward voltage drop at 25mV.

[0075] S53: If the load current is reversed and the voltage difference between the IN and OUT pins of the power electronic switch chip is less than the second preset threshold, apply the second pull-down value to the GATE pin of the power electronic switch chip.

[0076] In the specific implementation of this invention, if the load current is reversed and the voltage difference between the IN and OUT pins of the power electronic switch chip is less than the second preset threshold, the second preset threshold can be set to -25mV. The internal comparator of the power electronic switch chip triggers the shutdown logic, and applies a second pull-down value to the GATE pin of the power electronic switch chip, that is, applies a stronger pull-down to the GATE pin to turn off the MOSFET to prevent current backflow. The GATE pin pulls the drive voltage down to -12V within 0.5μs, so that the MOSFET is quickly turned off.

[0077] S54: If the voltage difference between the first independent power supply channel and the second independent power supply channel of the bus is less than or equal to the third preset threshold, the power electronic switch chip controls the metal-oxide-semiconductor field-effect transistor to maintain the on state and distribute the current ratio.

[0078] In the specific implementation of this invention, if the voltage difference between the first independent power supply channel and the second independent power supply channel of the bus is less than or equal to the third preset threshold, the third preset threshold can be set to 25mV. The power electronic switch chip controls the metal-oxide-semiconductor field-effect transistors to remain on, and the current is distributed according to the voltage ratio (e.g., the 49V and 48V buses bear 52% and 48% of the load current respectively) to avoid single power supply overload.

[0079] S55: If the voltage difference between the first independent power supply channel and the second independent power supply channel of the bus is greater than the third preset threshold, the metal-oxide-semiconductor field-effect transistor is controlled to be turned off within a preset time.

[0080] In the specific implementation of this invention, if the voltage difference between the first independent power supply channel and the second independent power supply channel of the bus is greater than the third preset threshold, the power electronic switch chip controls the metal-oxide-semiconductor field-effect transistor to turn off within 0.5μs, while the high potential side remains on, and the output voltage fluctuation is ≤±0.5V, which meets the power supply stability requirements of avionics equipment such as eVTOL servos (allowable fluctuation ≤±1V) and flight controllers (allowable fluctuation ≤±0.3V).

[0081] This invention provides a power supply control method for an eVTOL low-voltage distribution box. The IN and OUT pins of the power electronic switch chip detect the load current flowing through the metal-oxide-semiconductor field-effect transistor. If the load current is positive and the forward voltage drop decreases to a first preset threshold, a first pull-down value is applied to the GATE pin of the power electronic switch chip. If the load current is negative and the voltage difference between the IN and OUT pins of the power electronic switch chip is less than a second preset threshold, a second pull-down value is applied to the GATE pin of the power electronic switch chip. This prevents the current from the independent power supply channel of another normal bus from flowing back to the faulty module, avoiding damage to core equipment such as flight controllers and servos due to reverse current surges. The response speed is faster than that of traditional software control. If the voltage difference between the first independent power supply channel and the second independent power supply channel is less than or equal to a third preset threshold, the power electronic switch chip controls the metal-oxide-semiconductor field-effect transistor to maintain its on-state and distribute current proportionally; if the voltage difference between the first independent power supply channel and the second independent power supply channel is greater than the third preset threshold, the metal-oxide-semiconductor field-effect transistor is controlled to turn off within a preset time to avoid single power supply overload and meet the power supply stability requirements of avionics equipment such as eVTOL.

[0082] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc.

[0083] Furthermore, the above provides a detailed description of the power supply control system and method for an eVTOL low-voltage distribution box provided by the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A power supply control system for an eVTOL low-voltage distribution box, characterized in that, The system includes: a multi-source dual-bus power supply unit, a step-down unit, and an output unit, wherein the step-down unit is connected to the multi-source dual-bus power supply unit and the output unit respectively; The multi-source dual-bus power supply unit includes a first independent bus power supply channel and a second independent bus power supply channel. The first independent bus power supply channel and the second independent bus power supply channel are isolated based on a first contactor and a second contactor. The first independent bus power supply channel includes x heterogeneous power supplies and x ideal diodes, where x is an integer greater than or equal to 3. The x heterogeneous power supplies include a high-voltage to low-voltage DC-DC power supply, a ground power supply, and n lithium battery power supplies, where n is an integer greater than or equal to 1. The second independent bus power supply channel includes y heterogeneous power supplies and y ideal diodes. The y heterogeneous power supplies include y lithium battery power supplies, where y is an integer greater than or equal to 2. The first contactor and the second contactor, together with the ideal diodes of the first independent bus power supply channel and the second independent bus power supply channel, form a cooperative protection state. The step-down unit includes a first step-down module and a second step-down module. Each step-down module includes m DC-DC step-down converters connected in parallel, where m is an integer greater than or equal to 2. The first step-down module is connected to the first independent power supply channel of the bus, and the second step-down module is connected to the second independent power supply channel of the bus. The output unit includes m ideal diodes, and one of the m ideal diodes is connected to one of the corresponding DC-DC buck converters in the m DC-DC buck converters. The ideal diode includes a detection circuit and a metal-oxide-semiconductor (MOSFET). The detection circuit includes a power electronic switch chip with pins including IN, OUT, and GATE. The IN and OUT pins of the power electronic switch chip are connected to the MOSFET. The power electronic switch chip is an LTC4357HMS8 power electronic switch chip, and the MOSFET is an IRLR2905TRPBF MOSFET. The on-resistance of the IRLR2905TRPBF MOSFET is less than or equal to 27mΩ. The reverse turn-off time of the ideal diode is less than or equal to 0.5μs, and the forward voltage drop is less than or equal to 0.1V. If the output load is 12V, the rated current of the ideal diode is configured to be less than or equal to 5A. If the output load is 28V, the rated current of the ideal diode is configured to be greater than or equal to 20A, and the ideal diode is connected in parallel with several Zener diodes.

2. The power supply control system for the eVTOL low-voltage distribution box according to claim 1, characterized in that, The y-channel lithium battery power supplies in the second independent power supply channel of the busbar are redundant.

3. The power supply control system for the eVTOL low-voltage distribution box according to claim 1, characterized in that, In the first independent power supply channel for the bus, the high-voltage to low-voltage DC-DC power supply, the ground power supply, and the n-channel lithium battery power supply are combined into one output voltage through corresponding ideal diodes. In the second independent power supply channel for the bus, the y-channel lithium battery power supply is combined into another output voltage through corresponding ideal diodes.

4. The power supply control system for the eVTOL low-voltage distribution box according to claim 1, characterized in that, The multi-source dual bus power supply unit also includes a manual switch outside the distribution box. The first set of switches of the manual switch outside the distribution box is connected to the first independent power supply channel of the bus, and the second set of switches of the manual switch outside the distribution box is connected to the second independent power supply channel of the bus.

5. The power supply control system for the eVTOL low-voltage distribution box according to claim 1, characterized in that, The multi-source dual-bus power supply unit also includes a DC-DC circuit, which is connected to the external manual switch of the distribution box.

6. The power supply control system for the eVTOL low-voltage distribution box according to claim 1, characterized in that, The multi-source dual-bus power supply unit also includes an overvoltage protection module, which is connected to an ideal diode.

7. The power supply control system for the eVTOL low-voltage distribution box according to claim 6, characterized in that, The overvoltage protection module includes an LTC4367 power controller.

8. The power supply control system for the eVTOL low-voltage distribution box according to claim 4, characterized in that, The external manual switch of the distribution box is in a dual-redundant independent state with the first contactor and the second contactor. The first set of switches of the external manual switch controls the first contactor, and the second set of switches of the external manual switch controls the second contactor. The first independent power supply channel of the first bus is connected in series with the first contactor, and the second independent power supply channel of the second bus is connected in series with the second contactor.

9. A power supply control method for an eVTOL low-voltage distribution box, characterized in that, The power supply control method is implemented based on the power supply control system of the eVTOL low-voltage distribution box according to any one of claims 1 to 8, and the power supply control method includes: When powered on, the IN and OUT pins of the power electronic switch chip detect the load current flowing through the metal-oxide-semiconductor field-effect transistor. The power electronic switch chip drives the GATE pin to reduce the forward high voltage of the metal-oxide-semiconductor field-effect transistor. If the load current is positive and the positive voltage drop decreases to the first preset threshold, the first pull-down value is applied to the GATE pin of the power electronic switch chip. If the load current is reversed and the voltage difference between the IN and OUT pins of the power electronic switch chip is less than the second preset threshold, the GATE pin of the power electronic switch chip is processed to apply a second pull-down value. If the voltage difference between the first independent power supply channel and the second independent power supply channel of the bus is less than or equal to the third preset threshold, the power electronic switch chip controls the metal-oxide-semiconductor field-effect transistor to maintain the conduction state and perform current proportional distribution, wherein the current proportional distribution is the current proportional to the voltage. If the voltage difference between the first independent power supply channel and the second independent power supply channel of the busbar is greater than a third preset threshold, the metal-oxide-semiconductor field-effect transistor is controlled to be turned off within a preset time.

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